Trades Maintenance

Common Industry Jobs (CIJs) Trades/Maintenance Tool Kit

IMIRP program coordinated by:

Industrial Council of Advanced Wood & Allied Forest Ergonomics Workers of Industries Inc. Canada

In cooperation with the Workers’ Compensation Board of British Columbia

1 TRADES/MAINTENANCE TOOL KIT Table of Contents

IMPLEMENTATION NOTES 13

OVERVIEW 15

! Carpenter 15

! Chemical Computer Attendant 15

! Electrician 15

! Fire Watch 16

! Heavy Duty Mechanic 16

! Machinist 16

! Millwright 17

! Oiler 17

! Painter 17

! Pipefitter 18

! Plumber 18

! Welder 18

PHYSICAL DEMANDS ANALYSIS 19

PDA Table of Contents 20

Job Profile 21

Work Organisation 22

! Task Description 22

Workstation Characteristics 23

! Dimensions & Layout 23

Equipment & Machinery Controls 25

Physical Demands 26

! Whole Body Physical Demands 26

! Body Postures and Movements 27

Manual Material Handling 29

! Hand Tools 30

Environmental Conditions 31

! Work Environment 31

! Location of Workstation 31

! Temperature 32

Personal Protective Equipment 32

Appendix A – Job Specific Task Lists with Pictures 33

! Appendix A1 – Carpenter 34

! Appendix A2 – Chemical/Computer Attendant 37

! Appendix A3 – Electrician 39

! Appendix A4 – Fire Watch 42

! Appendix A5 – Heavy Duty Mechanic 46

! Appendix A6 – Machinist 49

! Appendix A7 – Millwright 53

! Appendix A8 – Oiler 58

! Appendix A9 – Painter 61

! Appendix A10 – Pipefitter 64

! Appendix A12 – Welder 68

Appendix B – Examples of Objects Handled 76

Appendix C – Weights of Hand Tools 77

Appendix D – Regional Map 78

RISK FACTOR IDENTIFICATION CHECKLIST 79

Job History 80

Neck 81

Shoulder 82

Elbow 84

Wrist/Hand 86

Low Back or Hip/Thigh 89

Knee 91

Ankle/Foot 92

Characteristics of Objects Being Handled 93

Environmental Conditions 93

Work Organisation 94

WORK MANUAL 95

Work Manual Table of Contents 97

Injury Education 102

Neck 103

! Introduction 104

! Body Mechanics 106

! How Neck Injuries Occur 109

! Examples of Loading on the Neck 112

Fire Watch Tasks 112

Heavy Duty Mechanic Tasks 113

Machinist Tasks 114

Millwright Tasks 115

Painter Tasks 116

Welding Tasks 117

! How to Prevent Neck Injuries 118

! Risk Control Key 119

! Decreasing Demands 120

! Increasing Capabilities 121

Shoulder 122

! Introduction 123

! Functional Anatomy 124

! Body Mechanics 127

! How Shoulder Injuries Occur 128

! Examples of Loading on the Shoulder 132

Carpenter Tasks 132

Chemical/Computer Attendant Tasks 133

Electrician Tasks 134

Heavy Duty Mechanic Tasks 136

Machinist Tasks 137

Millwright Tasks 138

Oiler Tasks 139

Painter Tasks 140

Pipefitting Tasks 141

Plumbing Tasks 142

Welding Tasks 143

! How to Prevent Shoulder Injuries 144

! Risk Control Key 145

! Decreasing Demands 146

! Increasing Capabilities 148

Elbow 150

! Introduction 151

! Functional Anatomy 152

! Body Mechanics 153

! How Elbow Injuries Occur 157

! Examples of Loading on the Elbow 160

Carpenter Tasks 160

Electrician Tasks 161

Heavy Duty Mechanic Tasks 162

Millwright Tasks 163

Painter Tasks 165

Pipefitter Tasks 166

Plumber Tasks 167

Welder Tasks 168

! How to Prevent Elbow Injuries 169

! Risk Control Key 170

! Decreasing Demands 171

! Increasing Capabilities 172

Wrist and Hand 173

! Introduction 174

! Functional Anatomy 175

! Body Mechanics 177

! How Wrist and Hand Injuries Occur 181

! Examples of Loading on the Wrist and Hand 184

Carpenter Tasks 184

Electrician Tasks 185

Heavy Duty Mechanic Tasks 186

Machinist Tasks 187

Millwright Tasks 188

Oiler Tasks 189

Painter Tasks 190

Pipefitter Tasks 191

Welder Tasks 193

! How to Prevent Wrist Injuries 194

! Risk Control Key 195

! Decreasing Demands 196

! Increasing Capabilities 199

Low Back 200

! Introduction 201

! Functional Anatomy 202

! Body Mechanics 203

! How Back Injuries Occur 206

! Examples of Loading on the Back 209

Carpenter Tasks 209

Chemical/Computer Attendant Tasks 210

Electrician Tasks 211

Fire Watch Tasks 212

Heavy Duty Mechanic Tasks 213

Machinist Tasks 214

Millwright Tasks 215

Oiler Tasks 216

Painter Tasks 217

Pipefitter Tasks 218

Plumber Tasks 219

! How to Prevent Back Injuries 222

! Risk Control Key 223

! Decreasing Demands 224

! Increasing Capabilities 227

Knee 229

! Introduction 230

! Functional Anatomy 231

! Body Mechanics 232

! How Knee Injuries Occur 234

! Examples of Loading on the Knee 237

Carpenter Tasks 237

Chemical/Computer Attendant Tasks 238

Fire Watch Tasks 239

Heavy Duty Mechanic Tasks 240

Millwright Tasks 241

Oiler Tasks 242

Painter Tasks 243

Pipefitter Tasks 244

Plumbing Tasks 245

Welding Tasks 246

! How to Prevent Knee Injuries 247

! Risk Control Key 248

! Increasing Capabilities 250

Foot 251

! Introduction 252

! Functional Anatomy 253

! Body Mechanics 254

! How Foot Injuries Occur 258

! How to Prevent Foot Injuries 261

! Risk Control Key 262

! Decreasing Demands 263

! Increasing Capabilities 266

Injury Prevention 268

! Risk Control Key 269

Workstation Design 270

! Introduction 270

! Introduction to Design 271

! General Workstation Layout 272

! Job-Specific Workstation Design Solutions 292

Carpenter 292

Chemical/Computer Attendant 293

Electrician 294

Heavy Duty Mechanic 295

Machinist 296

Oiler 298

Pipefitter 299

Welder 300

Tools and Equipment 302

! Introduction 302

! Tools 303

! Equipment 314

! Miscellaneous Equipment 320

! Job-Specific Tools and Equipment Suggestions 321

Carpenter 321

Chemical/Computer Attendant 321

Electrician 322

Heavy Duty Mechanic 322

Millwright 323

Oiler 324

Painter 325

Pipefitter 326

Plumber 328

Welder 329

Work Strategies 330

! Introduction 330

! General Work Practices 331

Electrician 346

Heavy Duty Mechanic 347

Machinist 347

Millwright 347

Oiler 348

Pipefitter 348

Welder 349

Index of Solutions 351

MSI SAFETY GUIDE

Carpenter 357

Chemical Computer Attendant 363

Electrician 366

Fire Watch 370

Heavy Duty Mechanic 375

Machinist 383

Millwright 387

Oiler 393

Painter 397

Pipefitter 403

Plumber 405

Welder 410

IMPLEMENTATION NOTES

© 2000 IMIRP Society Trades/Maintenance IG (revised) 13 After consultation with the IMIRP Society, the Common Industry Job (CIJ) documents for eight of the Trades/Maintenance jobs (Carpenter, Chemical/Computer Attendant, Electrician, Fire Watch, Machinist, Mechanic (Heavy Duty), Millwright, Oiler, Painter, Pipefitter, Plumber, Welder) were modified from the previous format.

It is very important to note that the function of each of the CIJ documents in the IMIRP Implementation Process remains the same as described in the IMIRP Implementation Guide.

The IMIRP Implementation Process described in the IMIRP Implementation Guide should be used for all jobs covered by IMIRP. If you are familiar with the IMIRP Implementation Process and the use of supporting documentation, the format change for the twelve trades/maintenance jobs should not produce any difficulties. If you are unfamiliar with the process please read the IMIRP Implementation Guide before continuing.

Notable Changes

Overview The Overview only contains a Job Summary from each of the twelve trades/maintenance jobs.

PDA The format of the PDA has changed so that a rehabilitation specialist, worker, and employer enter most of the relevant information. Some examples are provided to assist the users. The Task List contains all of the tasks seen or reported for the twelve trades/maintenance jobs. It is important to look through all of the tasks to indicate which a worker performs.

Risk Factor Identification Checklist The format of the Risk Factor Identification Checklist has changed. The checklist contains relevant examples from the twelve trades/maintenance jobs and asks questions related to specific body parts.

Work Manual The format of the Trades/Maintenance Work Manual combines some of the information in the Body Manual with the information normally found in the Work Manual.

The Trades/Maintenance Work Manual is broken down into the seven identified body part areas. In terms of Injury Education, information is provided on the body part (Functional Anatomy, Body Mechanics), how injuries occur, and specific trades/maintenance job examples are given to illustrate how injuries occur based on different types of loading (Force, Repetition, Duration). In terms of Injury Prevention, general information is provided on how to prevent body part problems (Decrease Demands and/or Increase Capabilities), and examples are given as to how this may be achieved.

The objective of the Work Manual is the same as in the past. In the trades/maintenance job format there are more concepts illustrated that may be applied to a job of interest. There are also job-specific solutions provided. Regardless of the source of solutions (i.e., solutions generated from an understanding of the illustrated concepts or from the job-specific examples), it is important to fill out the appropriate documentation.

MSI Safety Guide The format of the MSI Safety Guide has not changed. Each of the twelve trades/maintenance jobs has its own MSI Safety Guide.

JOB SUMMARIES

Carpenter A Carpenter is responsible for constructing items required by the mill. This work can include both small projects, such as stairs, shelves, and storage cabinets, and large projects, such as sheds and roofs. Materials most commonly used are lumber and plywood. Other materials used include plastic, glass, and metal. A Carpenter may use various tools and equipment, such as a pneumatic nail gun, a skill saw, a hammer, a table saw, a radial arm saw, and a drill. Carpenters may also perform locksmith tasks, painting tasks, and maintenance of fire systems.

Chemical Computer Attendant A Chemical Computer Attendant is responsible for maintaining the chemical systems of the mill. Tasks of a Chemical Computer Attendant include testing the chemical content of lumber process solutions and waste water, monitoring and cleaning filter systems, maintaining chemicals, inspecting for leaks, and performing some maintenance tasks. A Chemical Computer Attendant must be able to recall important chemical information and make decisions based on this information. These decisions may be made very rapidly and in extreme situations. Equipment used by the Chemical Computer Attendant includes ultrasonic sensors, wrenches, shovels, screwdrivers, chemical kits, testing materials, and fluid retrieval systems.

Electrician An Electrician may be responsible for assembling, installing, maintaining, and repairing equipment, machinery, and parts that are powered by electricity. This work may include building control panels for machinery, rewiring equipment in the mill, and installing electric cables in any area of the mill. Work is generally self-paced, except when repairing equipment that has broken down during production. An Electrician may also program computers that control various machines (e.g., optimisers, auto-trimmers). Environmental conditions may vary, as Electricians may work indoors or outdoors as required.

See Disclaimer in PDA & Work Manual © 2000 IMIRP Society Trades/Maintenance Overview (revised) 15 Fire Watch A person assigned to Fire Watch is responsible for monitoring and preventing fires in and around the sawmill. Tasks performed by the Fire Watchperson include monitoring for fires, preparing the work sites for welding, aiding the Welder, and cleaning up the area after welding. A Fire Watchperson must sustain alertness while monitoring for fires due to the nature of the area surrounding the Welder. Equipment used by the Fire Watchperson includes various hoses, nossles, brooms, shovels, and machines to cut metal.

HeavyDutyMechanic A Heavy Duty Mechanic is responsible for maintaining and rebuilding all heavy duty equipment. A Heavy Duty Mechanic will perform preventative maintenance tasks on heavy duty equipment, repair and service heavy duty equipment, work on special projects requiring the building or modification of equipment parts, and complete general clean-up duties. The Heavy Duty Mechanic may be required to work in a shop environment, or outdoors in many weather extremes. A large variety of tools and equipment may be used to complete Heavy Duty Mechanic tasks.

Machinist A Machinist is responsible for fabricating precision metal parts necessary for repairs and maintenance to the mechanical and moving equipment of the mill. Most Machinist work is done in the shop. Equipment used by the Machinist can include lathes, drill presses, milling machines, grinders, and bandsaws, as well as hand tools, such as hammers, wrenches, and hand grinders. Tasks performed by the Machinist while operating stationary equipment can include changing chucks or attachments, setting and adjusting controls, measuring machining, removing machining from attachments, moving materials, and cleaning up.

See Disclaimer in PDA & Work Manual © 2000 IMIRP Society Trades/Maintenance Overview (revised) 16 Millwright A Millwright is responsible for keeping the mill running, fixing any breakdowns, and maintaining machinery to prevent breakdown. Millwrights often ‘whistle chase’ breakdowns in the mill, making the time pressures on these repair tasks significant. Work on larger projects is done between mill calls. Equipment used by the Millwright can include hand tools, such as hammers, wrenches, hand grinders, come-a-longs, and hoists, or other machinery, such as welders, grinders, and drill presses. Tasks performed by the Millwright while maintaining the mill can include repairing and maintaining cylinders, belts, conveyors, chains, motors, and valves, and the fabrication of new equipment.

Oiler An Oiler is responsible for lubricating machinery in the mill. Tasks of the Oiler include walking around the mill to check for machinery that needs to be lubricated, oiling chains, greasing equipment, filling lubricant containers, and moving oil barrels around the mill. An Oiler may fill lubricant containers using automatic whiplines that pump lubricant to machine areas in the mill, or manually using jugs/buckets to carry lubricant around the mill. An Oiler may grease machinery using a manual grease gun, a hand-crank grease pump, or a hydraulic grease pump. An Oiler may move barrels by rolling them manually, or using a dolly, a hoist, or small mobile equipment, such as a loader.

Painter A Painter is responsible for preparing and treating surfaces of equipment, machinery, and buildings. Painting may be done in a shop, in the mill, or outside for larger jobs. Equipment used by a Painter includes grinders, paint guns, sandblasting guns, needle guns, impact wrenches, and power sprayers. Non- powered handtools, such as paint brushes and rollers, are also used. Tasks performed by the Painter include surface preparation work, masking of protected areas, priming surfaces, and painting surfaces. Painters also perform some handling of pieces and materials, and shop clean-up.

See Disclaimer in PDA & Work Manual © 2000 IMIRP Society Trades/Maintenance Overview (revised) 17 Pipefitter A Pipefitter is responsible for ensuring pipes and valves are maintained in good working condition. Equipment used by the Pipefitter includes various welding units and pipe cutters, as well as hand tools such as pipe wrenches, hand grinders, hammers, and circular saws. Tasks performed by the Pipefitter include morning inspection, installation of new lines, and repair of existing lines.

Plumber A Plumber is responsible for installation and maintenance of pipe systems in the mill, usually concentrating on fresh water and waste water systems for employee use. Equipment used by the Plumber includes stationary or portable pipe cutters, pipe wrenches, grinders, torches, and other hand tools. Tasks performed by the Plumber include repair of existing lines, installation of new lines, and monitoring of water quality and filter systems. Substantial task overlap exists between a Plumber and Pipefitter, with Pipefitter being the more common industry job title.

Welder A Welder is responsible for fabricating and maintaining metal components of mill machinery, vehicles, and structures. This work can take place indoors or outdoors as required. Repair tasks to machines or vehicles can be subject to time pressures. Equipment used by the Welder includes various welding units, grinders, hammers, wrenches, pliers, clamps, and brushes. Tasks performed by the Welder include collecting materials, reading plans, measuring, cutting, shaping, and welding metal pieces, grinding and painting finished pieces, shop clean-up, and maintenance.

The purpose of this PDA is to familiarise the healthcare professional with common tasks performed by a worker in a Trades/Maintenance position. The format of the PDA allows for the large variation in the tasks of a Trades/Maintenance person, and can be used to gather information to assist in developing a rehabilitation and return-to-work plan.

Refer to Appendix A for pictures that illustrate common tasks performed by Trades/Maintenance workers.

The Trades/Maintenance jobs assessed include:

A1 - Carpenter A2 - Chemical/Computer Attendant A3 - Electrician A4 - Fire Watch A5 - Heavy Duty Mechanic A6 - Machinist A7 - Millwright A8 - Oiler A9 - Painter A10 - Pipefitter A11 - Plumber A12 - Welder

If the Trades/Maintenance job you are looking for is not included, it may have its own specific PDA (e.g., Planerman).

The PDA should be completed by a healthcare professional, with input from the injured worker. The worker’s supervisor may be contacted for further information or verification of tasks. The completed PDA should include critical tasks that aggravate the injury or prevent the worker from returning to work. Allow the worker to highlight tasks and physical demands of concern. A PDA should be filled out for individual Trades/Maintenance workers following an injury.

Disclaimer The IMIRP Society accepts no responsibility for the use or misuse of the PDA, or the accuracy of the PDA as it applies to any specific workplace.

© 2000 IMIRP Society Trades/Maintenance PDA (revised) 19 PDA Table of Contents Job Profile ...... 21 Work Organisation...... 22 Task Description...... 22 Workstation Characteristics...... 23 Dimensions & Layout...... 23 Flooring, Displays, and Seating...... 24 Equipment & Machinery Controls...... 25 Physical Demands...... 26 Whole Body Physical Demands ...... 26 Body Postures and Movements ...... 27 Manual Material Handling...... 29 Hand Tools ...... 30 Environmental Conditions ...... 31 Work Environment ...... 31 Location of Workstation...... 31 Regional Temperatures...... 32 Personal Protective Equipment...... 32 Appendix A – Job Specific Task Lists with Pictures ...... 33

A1 - Carpenter (page 34) A7 - Millwright (page 50) A2 - Chemical/Computer Attendant (page 37) A8 - Oiler (page 58) A3 - Electrician (page 39) A9 - Painter (page 61) A4 - Fire Watch (page 42) A10 - Pipefitter (page 64) A5 - Heavy Duty Mechanic (page 46) A11 - Plumber (page 67) A6 - Machinist (page 49) A12 - Welder (page 68) Appendix B – Weights of Objects Handled...... 76 Appendix C – Weights of Hand Tools...... 77 Appendix D – Regional Map ...... 78

Date: ______

Company Name: ______Division: ______

Phone: ______Fax: ______

Employee Name: ______Supervisor: ______

Is a Return-to-Work (RTW) strategy in place? ! Yes ! No

If yes, check all that apply: ! Modified Job ! Modified Worksite ! Graduated RTW

Describe:

______

Length of shift ______hours

Formal breaks ! Two 10 minute breaks ! One 30 minute lunch break ! Other: ______

Informal breaks ! Yes, length of break varies ! Yes, approximately ______minutes/shift on average

Work pace control ! Self-paced ! Time pressure (e.g., completing a task during the 30 minute lunch break) ! Other: ______

Job rotation ! Yes ! No Describe: ______

Task Description

Describe common or critical tasks performed by the worker (see example below). Estimate the Percent of Shift each task is performed and place a checkmark in the appropriate column. The Comments section may be used to include information related to duration, frequency, and cycle times. Appendix A may be used to help identify tasks to include in this list.

Percent of Shift

Task Comments Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100% Change knives in machinery ✔ • 90 knives changed on average • Knives are changed once a day, duration of 1 hour

Dimensions & Layout

Sketch workstation(s) and indicate relevant measurements, such as working heights and reaches.

The table below lists several components of a workstation. For Flooring and Displays there are several options provided. Please indicate all of the options that apply to the workstation at your mill. For the Seating section, describe and identify the features of the seat, if applicable. The Comments section may be used to include additional information, especially any workstation characteristics of concern.

Workstation Characteristics Comments Flooring (Check all that apply) ! Cement ! Wood ! Rubber matting ! Metal ! Other: ______Displays (Check all that apply) ! Lights on console ! Mirrors ! Video monitors ! Computer monitors ! Scrolling display ! Signal lights ! Other: ______Seating (Check all that apply) Height of seat: ______cm ! Armrests ! Backrest Depth of seat: ______cm ! Swivel seat Width of seat: ______cm ! Slide track Covering type: ______! Lumbar support ! Footrest ! Casters #______

Indicate if adjustable: ! Height ! Armrests ! Backrest ! Forward tilt

List controls from the legend below that are commonly used by the worker, and specify the control functions if known (see example below). Highlight controls that may aggravate the injury, or which the worker finds difficult to use. The Comments section may be used to include any additional information.

Type of Control Function Comments

Lever Open/close valve • 10 to 12 times/shift • Force required = 5 kg • 5 levers are located above shoulder height

Control Legend

Foot push button Foot pedal Legend switch Hand wheel Finger push button Joystick Toggle switch Rocker switch Crank Lever Round knob Rotary selector switch Thumb wheel

Whole Body Physical Demands

List the tasks/activities associated with each physical demand and check off (✔) the estimated Percent of Shift. The Comments section may be used to include information related to duration, frequency, and cycle times.

Percent of Shift

Physical Demands Tasks or Activity Comments Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100% Walking

Sitting

Standing

Climbing (e.g., stairs, ladders, machinery)

Balancing

Kneeling/ Crouching

Other:

The table below is intended to outline the body postures and movements of concern for a specific individual, related to their job tasks. The Comments section may be used to include information describing posture duration, frequency, cycle times, and hand used.

Percent of Shift

Body Posture Task(s) Comments Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100% Neck Flexion

Extension

Twisting

Shoulder Flexion

Abduction/adduction

Extension

Forearm Rotation

Wrist Wrist Movements

Body Posture Task(s) Comments Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100% Hand/Fingers (see legend below) Handling

Fingering

Gripping

Back Flexion

Lateral Flexion

Twisting

Extension

Legend for Hand/Fingers

Handling grasping, turning, holding, etc. Fingering picking, pinching, etc. Gripping Power Pinch Hook Precision

The table below contains a list of general manual material handling activities. Indicate tasks that require one or more of these activities, and fill in the weight of the objects, or the force required, for each action. The item weights provided in Appendix B can be used as a guideline if specific weights are not available. The Comments section may be used to include information related to duration, frequency, cycle times, and characteristics of objects handled.

Percent of Shift

Activity Task Description Weight Comments (kg) Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100% Pushing

Pulling

Lifting

Lowering

Carrying

List commonly used hand tools in the table below. The weights provided in Appendix C may be used as a guideline if specific weights are not available. The Comments section may be used to include information related to duration, frequency, cycle times, and characteristics of objects handled.

Percent of Shift

Type of Tool Task(s) Weight Comments (kg) Rarely 0to5% Occasionally 6to33% Frequently 34 to 66% Constantly 67 to 100%

Work Environment

The table below contains a list of environmental conditions that may be of concern. If any of these factors aggravate the injury, describe issues in the Comments section.

Factor Comments Vibration (Indicate source) ! Seat ! Floor ! Tool ! Other: ______Noise level

Lighting level

Other:

Location of Workstation

The table below contains a list of potential work environments. Indicate with a checkmark (✔) in the left column which of the work environments apply to the specific workstation. For example, the workstation may be inside a building with both a local fan and heater, exposed to the outside by a doorway that is always open. In this situation, ‘Inside exposed’, ‘Heater present’, and ‘Fan present’ would all be checked.

Work Environment

Outside uncovered Outside covered Inside enclosed Inside exposed Heater present Fan present

The table below contains a list of the geographical regions of British Columbia. For your mill, indicate the appropriate region with a checkmark (✔) in the left column. Refer to the regional map in Appendix D of the PDA.

Region Avg. Max Avg. Min Extreme Max. Extreme Min. July/Aug Dec/Jan Vancouver Island 22.5 oC-0.6oC 36.1 oC -18.8 oC Southwestern BC 22.9 oC0.4oC 35.6 oC -18.3 oC Cariboo Chilcotin Coast 22.2 oC -11.6 oC 36.4 oC -42.5 oC High Country 26.3 oC-9.9oC 39.6 oC -39.7 oC Okanagan Similkameen 26.5 oC-8.4oC 36.0 oC -36.3 oC Kootenay Country 26.2 oC-6.7oC 38.5 oC -32.0 oC British Columbia Rockies 24.7 oC -12.3 oC 37.5 oC -42.2 oC North by Northwest 19.5 oC -11.7 oC 32.9 oC -38.1 oC Peace River Alaska Highway 20.0 oC -20.2 oC 34.6 oC -47.7 oC

Personal Protective Equipment

The table below contains a list of personal protective equipment (PPE). Indicate which of the PPE items are required with a checkmark (✔).

Gloves Hard Hat Leather Apron Type:

Glove Liners Steel-toed Boots Dust Mask

Eye Protection Hearing Protection Seat Belt

Face Shield/Helmet Life Jacket Harness

Knee Pads Other: Other:

This appendix contains common tasks performed by Trades/Maintenance workers. Please note that due to the large variation in tasks performed, a selection of representative tasks have been illustrated. At some mills, there may also be an overlap of tasks between workers (e.g., Millwright performing welding tasks). For these reasons, rehabilitation professionals may have to look at several sub-appendices to identify the tasks performed by any one worker. The worker should be involved in clarifying his/her job tasks.

The Trades/Maintenance Job Task Lists are organised into the following sub-appendices:

The following descriptions illustrate various common tasks performed by a Carpenter.

Clean-up

A Carpenter may have to perform general cleaning duties in the shop, including sweeping and shovelling.

Retrieve materials

A Carpenter may be required to retrieve construction materials, such as plywood and lumber, from storage areas within the shop, or from separate storage areas.

A Carpenter may have to prepare materials by measuring out the desired cut dimensions with various tools, such as measuring tapes, squares, and rulers.

Cut/shape materials

A Carpenter may use hand-held tools, such as circular saws, jig saws, or hand saws, to cut materials down to required sizes. A Carpenter may also use stationary equipment, such as a table saw, a radial arm saw, or a router, to cut and shape materials.

A Carpenter may use various tools, such as pneumatic nailers, pneumatic staplers, palm sanders, hammers, and drills to assemble materials and finish constructed items. Various fastening devices, such as nails, glue, bolts, screws, and staples, are also used.

The following descriptions illustrate various common tasks performed by a Chemical/Computer Attendant.

Test for chemical content

A Chemical Computer Attendant may perform tests, such as pH and QAC tests, to determine the ratio of chemicals in the lumber process system.

Does this task occur at your mill?

! Yes ! No

Monitor and clean filter systems

A Chemical Computer Attendant may monitor and clean the filter systems of debris so that they function optimally.

Does this task occur at your mill?

! Yes ! No

A Chemical Computer Attendant may mix and change chemicals to specified portions for the mill process.

Does this task occur at your mill?

! Yes ! No

Inspect for leaks

A Chemical Computer Attendant may check for air, gas and liquid leaks in boilers, kilns, compressors, etc.

Does this task occur at your mill?

! Yes ! No

Maintenance

A Chemical Computer Attendant may perform some maintenance tasks to keep the chemical processes in operation.

Does this task occur at your mill?

! Yes ! No

The following descriptions illustrate various common tasks performed by an Electrician.

Install/maintain electrical cables and wires

An Electrician installs and maintains cables and wires which provide electricity to various parts of the mill. This task may lead to a variety of physical demands, from crawling under conveyors to climbing ladders to the ceiling.

When breakdowns occur in the mill, an Electrician may be called to solve any electrical problems. This may involve using meters (e.g., voltmeters) or other tools to ensure proper function of various machines and controls.

An Electrician installs various parts and components requiring electricity. Some parts, such as control panels and consoles, may require assembly.

Computer programming

Electricians may be required to program computers that run various equipment and machinery in the mill (e.g., optimisers, chipper systems).

The following descriptions illustrate various common tasks performed by a Fire Watchperson.

Monitor for fires

A Fire Watchperson will monitor for fires around a workstation as the Welder is welding.

Does this task occur at your mill?

! Yes ! No

A Fire Watchperson will monitor areas around the mill for fires.

Does this task occur at your mill?

! Yes ! No

A Fire Watchperson will prepare the area for the welder before welding begins. This includes watering down the area, cleaning debris away from the area, and setting up welding equipment.

Does this task occur at your mill?

! Yes ! No

Clean–up

A Fire Watchperson will clean up the area, remove waste metal, wet down the area, and put away the hoses, when the welding is complete.

Does this task occur at your mill?

! Yes ! No

A Fire Watchperson will aid the Welder by:

Holding objects in place for the Welder

Does this task occur at your mill?

! Yes ! No

Handing the Welder tools while they are welding

Does this task occur at your mill?

! Yes ! No

Retrieving materials needed by the Welder.

Does this task occur at your mill?

! Yes ! No

Cutting materials needed by the Welder.

Does this task occur at your mill?

! Yes ! No

The following descriptions illustrate various common tasks performed by a Heavy Duty Mechanic.

Preventative maintenance

A Heavy Duty Mechanic performs preventative maintenance tasks on heavy duty equipment. This work may involve regular servicing tasks, such as fluid changes and filter changes, or it may involve larger tasks, such as scheduled rebuilds.

Preventative maintenance tasks are usually performed in the Mechanic’s shop, where lifting aids and various powered tools are available. The performance of maintenance tasks may require the Mechanic to climb on, around, or under machinery. It may also involve the use of a variety of hand tools.

A Heavy Duty Mechanic is responsible for repairing heavy duty equipment that breaks down in the field. This may involve a large variety of tasks, depending on what breaks down.

Repairing heavy duty equipment may involve a large variety of working postures. Often, the Mechanic will need to lift heavy objects without lifting aids when completing repairs away from the shop.

Special projects

A Heavy Duty Mechanic may work on projects that require fabricating new equipment or parts, or modifying existing equipment or parts, for heavy duty machinery.

A Heavy Duty Mechanic may be required to perform general clean-up tasks.

The following descriptions illustrate various common tasks performed by a Machinist.

Operate lathe

A Machinist uses a lathe to fabricate metal pieces. This fabrication can include sizing, shaping, boring, and threading.

Subtasks in operating a lathe include:

Change chuck

Machinists use different types of chucks (e.g., three jaw (centre-seeking), four jaw (variable adjustment)) depending on the shape and dimension of the material. Changing chucks can be performed with lifting aids (e.g., electric hoist) or manually.

Set/Adjust lathe

Machinists use controls to manually operate the lathe, or to set the lathe to operate automatically.

Pieces are measured periodically. Frequent lubrication of machining and cutting surfaces is also required.

Remove machining

Pieces are removed when finished, or for transfer to another workstation or machine. Tools used to remove pieces include chuck keys, Allen keys, wrenches, and hammers.

Operate drill press/mill

The physical demands of operating the drill press and mill are similar to the lathe.

Subtasks include :

- Change bits - Set/Adjust press - Measure machining - Remove machining

Hoist

Many Machinists use an electric hoist to move heavy objects, especially chucks and materials.

Cart

Machinists often use carts to move pieces and tools within the shop, and to other parts of the mill.

Operate grinder

Machinists grind pieces using a hand grinder or a stationary grinding machine.

Machinists are responsible for the clean-up of their shop and machines. In addition, Machinists can be responsible for cleaning their work areas in the mill.

The following descriptions illustrate various common tasks performed by a Millwright.

Design and build equipment

A Millwright may fabricate equipment and/or parts that are needed to keep the mill running.

Fix and maintain machinery

A Millwright must fix and maintain machinery in order to keep the mill running.

Millwrights may work on the following:

A Millwright maintains the motors that run machinery and equipment in the mill.

Maintain chains

A Millwright maintains the various chains that move the logs and lumber through the mill.

A Millwright repairs and maintains the various cylinders that operate kickers, pin stops, etc. throughout the mill.

Maintain belts and conveyors

A Millwright replaces and maintains the various belts and conveyors throughout the mill.

Maintain hydraulic hoses

A Millwright replaces and maintains various hydraulic hoses throughout the mill.

A Millwright will maintain the various valves located throughout the mill.

Maintain chainsaws and pike poles

A Millwright will maintain the chainsaws and the pike poles for other mill workers to use.

Change knives

A Millwright may change knives in the mill during downtime.

A Millwright may aid other workers by clearing cross-ups.

The following descriptions illustrate various common tasks performed by an Oiler.

Walk around the mill

An Oiler may do a walking check of the mill at the beginning of each shift.

Oil chains

An Oiler may carry oil containers around the mill to oil chains.

An Oiler may manually grease machinery using a grease gun.

Apply lubricant

An Oiler may apply lubricant to machinery directly from oil cans, or using whiplines from a central reservoir. Oilers also fill lubrication vessels in pneumatic pressure systems.

An Oiler may move oil barrels manually, or by using a dolly or hoist.

The following descriptions illustrate various common tasks performed by a Painter.

Prepare surfaces for painting

A Painter is responsible for preparing surfaces for painting. This work may involve a large variety of tasks, depending on what is being painted and how it can be treated.

Tools used to prepare surfaces include pneumatic grinders, electric grinders, needle guns, electric sanders, sandblasting guns, torches, and pressure washers.

Other tools, such as impact wrenches and wrecking bars, are used to dissemble pieces for painting.

A Painter uses air-powered spray guns and manual painting tools to apply primer and paint to surfaces.

Painters often handle various materials for their work including paint, sand, and tools.

Painters are also responsible for handling items to be painted. This work requires mobile equipment, lifting aids, and manual handling.

Clean-up

A Painter is responsible for clean-up of the paint shop and other work areas. Special care is required for the clean-up of paints and solvents.

The following descriptions illustrate various common tasks performed by a Pipefitter.

Inspect pipes

Pipefitters may inspect all the pipe networks in the mill to determine if repairs are required. These inspections can take place daily or weekly.

Replace damaged pipes or fittings

Pipefitters replace damaged pipes or fittings.

Pipefitters plan the layout of new pipe networks. In most mills, pipes are located in the ceiling.

Pipefitters take measurements for new pipe layouts.

Pipefitters may cut thin pipe with circular saws.

Pipefitters may grind the ends of the pipe to prepare it for welding or threading.

Pipefitters use welding torches to shrink rubber fitting covers onto the pipe to assemble the line. Pipe joints can also be threaded, bolted, or brazed together.

The following descriptions illustrate various common tasks performed by a Plumber.

Repair existing lines

Plumbers replace damaged pipes, fittings, and fixtures, as well as unplugging blocked lines.

Install new lines

A Plumber may be responsible for installing new water lines in the working area of the mill and in mill common rooms, such as washrooms, offices, and lunchrooms. Sub- tasks and tools are similar to those of the Pipefitter.

Monitor water quality systems

Some mills are responsible for treating and monitoring their own wastewater. The responsibility for sampling the water and maintaining filter systems usually falls to the Plumber or Pipefitter.

The following descriptions illustrate various common tasks performed by a Welder.

Collect materials

Welding projects involve work on existing metal structures (maintenance) or creating new items (production). A Welder begins a project by reading blueprints or drawings, and determining the materials required.

When large pieces of metal are needed, hoists, come-a-longs, or forklifts may be used. Tools, such as welding equipment, are often brought to the work site on carts.

A Welder measures the dimensions to be cut out on the metal.

Cut metal

Welders cut metal by using oxy-fuel gas or air carbon arc gouging.

Welders shape or bend metal pieces as required.

Welders fuse metal to metal by welding or brazing. The type of weld depends on the metallurgy of the components. Some examples include fusion welding, braze welding, shielded metal arc, gas metal arc, and flux- cored arc.

Check weld quality

A Welder checks the quality of the welds.

A Welder smoothes the edges of the metal with a hammer, or by using a hand-held or stationary grinder.

Welders are required to maintain the welding equipment. Examples of maintenance activities include replacing and storing tanks, cleaning torches, and re-feeding wire.

Welders attach parts (e.g., rollers, wheels) to welded pieces. A hand drill or drill press may be used in this task.

Depending on the nature of the project, a Welder may paint the welded pieces.

This list may be used as a guide to fill out the Manual Materials Handling section of the PDA if actual weights can not be measured. These items are examples of common objects handled by Trades/Maintenance workers, and were measured during the IMIRP data collection process.

Object Weight (kg) Personal Equipment Weight (kg) 5 hp motor 46.4 Face shield 1.2 50 ton hydraulic jack 36.6 Flash helmet 0.4 Bag of oil absorbent granules 11.8 Flash mask 0.6 Box of bolts 10.5 Helmet 0.1 to 0.5 Box of welding sticks 5.1 to 10.3 Radio 0.8 Brake callipers for Wagner 107.0 Tool belt 2.0 to 12.5 Bucket of oil 17.3 to 18.7 Chain – 100 (1 metre) 8.1 Chain – drag (1 metre) 17.8 to 25.4 Chain – extra heavy duty 9.2 to 21.2 welded steel (1 metre) Chain – offset sidebar 6.3 to 21.1 welded steel (1 metre) Chipper knife 2.7 Chuck for metal lathe 47.4 Console 11.4 Dome top knife 1.2 Flat knife 0.3 Hydraulic cylinders 17.9 to 56.7 Hydraulic pump for Wagner 49.3 Key knife 0.1 Ladder 9.0 Oil can 2.2 to 8.8 Optimiser knife 0.5 Oxygen bottle - empty 58.1 Oxygen bottle - full 74.4 Pin for Wagner 75.4 Portable light 7.5 Portable light 1.1 Power unit 31.0 Small transformer 19.4 Socket 4.5 Spool of wire 3.3 to 22.3 Sprocket 12.4 to 40.3 Tool box 7.5 to 7.7 Vehicle battery 21.0 to 49.0

This list may be used as a guide to fill out the Hand Tool section of the PDA if actual weights can not be measured.

Tool Weight (kg) Tool Weight (kg) Acetylene torch 1.4 Mallet 4.3 Air hose 0.3 Measuring tape 0.2 Allen key 0.2 to 0.8 Paint gun 1.3 Belt sander 3.6 Palm sander 1.0 Chainsaw 7.8 to 8.4 Pipe cutting saw 0.4 Come-a-long 5.8 to 14.5 Pipe wrench 0.4 to 4.6 Crimper 2.9 Pliers 0.1 to 0.4 Crow bar 1.7 Pneumatic nail gun - finishing 1.4 Electric drill 1.5 to 3.1 Pneumatic nail gun -rough 4.0 File 0.1 Pneumatic staple gun 1.2 to 3.2 Gear & bearing remover 7.0 Pry bar 1.9 to 7.3 Grease gun 2.0 to 2.4 Ratchet 0.2 to 5.4 Grease gun cartridge 0.4 Sabre saw 3.7 Grinder 2.5 to 2.9 Screwdriver 0.1 to 0.4 Hammer 0.4 to 1.6 Sledge hammer 6.0 to 9.2 Hand saw 0.6 Square 0.2 Hand-held band saw 7.8 Tool belt 2.0 to 12.5 Impact gun - large 30.0 Utility knife 0.1 Impact gun - small 2.5 to 5.6 Valve wrench 0.1 In-line air gun 0.4 to 2.0 Vise – hand held 2.0 Jig saw drill 2.8 Wire brush 2.9 Level 1.1 Wire cutter 0.3 Level extender 4.2 Wrench 0.3 to 3.6

H I

D B

G C A E F

A - Vancouver Island F - Kootenay Country B - High Country G - British Columbia Rockies C - Southwestern BC H - North by Northwest D - Cariboo Chilcotin Coast I - Peace River Alaska Highway E - Okanagan Similkameen

The Risk Factor Identification Checklist for Trades/Maintenance Jobs is used to identify potential ergonomic risk factors for the following jobs: Carpenter, Chemical/Computer Attendant, Electrician, Fire Watch, Machinist, Mechanic, Millwright, Oiler, Painter, Pipefitter, Plumber, and Welder. If a checklist is required for other Trades/Maintenance jobs, retrieve the job specific Risk Factor Identification Checklist from the appropriate Tool Kit. A separate checklist should be completed for each trade or maintenance job. Keep in mind that the purpose of this checklist is only to identify potential ergonomic risk factors, not to assess them.

The checklist can be used as part of your ergonomic intervention process, when workers express concerns about their work environment, during regular workplace inspections and observations, or when conducting an accident or injury investigation. Ideally, management and worker representatives who have completed the IMIRP Occupational Health & Safety Committee and Supervisor Ergonomics Training Session should complete this checklist. Try to view different workers in the same Trade/Maintenance job when completing the checklist. Some Trades/Maintenance specific examples are given to help answer the questions.

Except for the first two questions, all remaining questions will require an answer with an implied frequency. For all questions indicate with a checkmark whether the answer to the question is ‘No’ or ‘Yes’. This way you will have a record indicating that all risk factors have been considered in the identification process.

If you indicate ‘No’, please continue to the next question. If the question refers to a situation which does not exist for the job (e.g., there is no seating available), please indicate ‘No’ in the appropriate box and continue to the next question.

If your answer is ‘Yes’, please check the appropriate box and then circle the frequency (‘S’ for ‘Sometimes’ or ‘O’ for ‘Often’). If you answer ‘Yes – Sometimes’, then this risk factor may be a potential area of concern. If you answer ‘Yes – Often’ then there is an increased likelihood that this risk factor is an issue for the job. Each mill will be responsible for defining what ‘Sometimes’ and ‘Often’ will mean to them. It is important that people who complete the checklist are consistent in how they determine if a risk factor occurs sometimes or often. Use the ‘Comments’ section to indicate specific tasks, or to make other notes about the direct risk factors.

At the end of each body part section, summarise your findings in the table provided. If any of the direct risk factor sections contain a ‘Yes’, indicate ‘Yes’ in the appropriate section of the summary table. Answer the questions referring to injury statistics and discomfort survey findings. If there are only ‘No’ answers in a direct risk factor section, indicate ‘No’ in the summary table for that section. Use the summary information to determine how you will use the Work Manual.

Since ergonomic risk factors frequently occur in combinations, you may find similar questions in different sections. Answering all questions will ensure situations that involve more than one ergonomic risk factor are identified. It is important to recognise all risk factors that occur in the work area.

Please note that for some of the questions it will be beneficial to ask the worker for their input. Please take the opportunity to include the operator in the risk factor identification process as much as possible. Videotaping the job of interest and reviewing the checklist in a quiet area with the worker may allow for more discussion.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 79 Risk Factor Identification Checklist – Trades/Maintenance Jobs

Trade/Maintenance Job Title: ______

Risk Identification completed by: Checklist filled in:

Management Representative ______! Before Implementation of Solutions ! After Implementation of Solutions Worker Representative ______

Date ______

Job History No Yes Comments 1 Are there records of musculoskeletal injuries or accidents to indicate a risk of musculoskeletal injury? (refer to Worksheet 1 in IMIRP Implementation Guide) 2 Are there worker comments to indicate a risk of musculoskeletal injuries? (refer to Worksheet 2 in IMIRP Implementation Guide)

Definitions:

Force: Force is the amount of physical effort required by the person to do a task and/or maintain control of tools and equipment. The effort depends on the type of grip, object weight and dimensions, body posture, type of activity, surface of the object, temperature, vibration, duration of the task, and number of repetitions.

Repetition: Repetition is defined as similar or the same motions performed repeatedly. The severity of risk depends on the frequency of repetition, speed of the movement or action, the number of muscle groups involved, and the required force. Repetition is influenced by machine or line pacing, incentive programs, piecework, and deadlines.

Static Work Postures: Static loading (sustained exertions) are physical efforts or body postures that are held and require muscle contraction for more than a short time.

Contact Stress: Contact stress is the contact of the body with a hard surface or edge. Contact stress also occurs when a part of the body is used as a hammer or striking instrument.

Awkward Work Postures: Awkward postures occur when there is a deviation from an ideal working posture. Some examples of awkward postures typically include reaching behind, twisting, working overhead, and forward or backward bending.

Vibration: Vibration is oscillation of a tool or surface. Vibration can be transmitted through the arm or through the whole body.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 80 NECK Repetition N Y Comments: Are identical or similar motions S performed over and over again? (e.g., looking up or down frequently) O Ask the worker: Do you spend a large S percentage of the day performing one action or task? O (e.g., looking down while welding pieces) Static Postures Ask the worker: Do tasks require your neck or shoulders to be maintained in S a fixed or static posture? (e.g., looking down at a computer screen O for a long period of time, looking up while working on a task) Awkward Postures Flexion S

O Extension S

O Lateral Bending S

O Rotation S

Please indicate whether the following direct risk factors were identified at the NECK. Repetition "Yes "No Static Postures "Yes "No

Risk Awkward Postures "Yes "No Direct Factors In the Injury Statistics investigation, were "Yes "No there injury reports for the Neck or Head/Eye or Upper Back? In the Discomfort Survey investigation, "Yes "No were there reports of discomfort for the Neck or Head/Eye or Upper Back? Body parts within the circled area will be classified as NECK issues.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 81 SHOULDER Force N Y Comments: Is forceful physical handling performed? such as: S Lifting O Lowering S

O Pushing S

O Pulling S

O Carrying S

O Repetition Are identical or similar motions performed over and over again? S (e.g., hammering, unscrewing pneumatic lubricating vessels) O

Ask the worker: Do you spend a large percentage of the day performing one S action or task? (e.g., fabricating and welding) O

Static Postures Ask the worker: Do tasks require your shoulders to be maintained in a fixed S or static posture? (e.g., holding welding torch, working O under large equipment) Ask the worker: Do you hold parts, tools, or objects for long periods? S (e.g., Welders holding a torch away from the body) O

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 82 Awkward Postures N Y Comments: Flexion S

Extension S

Abduction S

Adduction S

Please indicate whether the following direct risk factors were identified at the SHOULDER. Force "Yes "No Repetition "Yes "No Static Postures Yes No

Factors " " Direct Risk Awkward Postures "Yes "No In the Injury Statistics investigation, were "Yes "No there injury reports for the Shoulder or Upper Back? In the Discomfort Survey investigation, "Yes "No were there reports of discomfort for the Body parts within the circled area will Shoulder or Upper Back? be classified as SHOULDER issues.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 83 ELBOW Force N Y Comments: Is forceful physical handling S performed? such as: Lifting O Lowering S

O Pushing S

O Pulling S

O Carrying S

O Turning materials S

O Are objects handled in a S power grip? (e.g., hammer, pneumatic drill) O

Are objects handled in a S pinch grip? (e.g., nuts, bolts, sheets of O metal, sheets of plywood) Are objects handled in a S hook grip? (e.g., oil cans, tire rims) O Ask the worker: Do you wear gloves *S while performing your job? If the answer is No, check the No box O andgotonextsection. *If the answer to the above question is S Yes, ask the worker: Are the gloves too large/small? O Does the thickness of the gloves cause S problems with gripping? O Repetition Are identical or similar motions S performed over and over again? (e.g., hammering, unscrewing pneumatic O lubrication vessels) Ask the worker: Do you spend a large S percentage of the day performing one action or task? (e.g., using a nail gun) O

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 84 Static Postures N Y Comments: Ask the worker: Do tasks require your hand and arm to be maintained in a S fixed or static posture? (e.g., holding a welding torch, holding the O trigger for an automatic grease gun) Ask the worker: Do you apply constant pressure on controls/objects S with your hand? (e.g., Oilers using automatic grease gun) O Ask the worker: Do you hold parts, S tools, or objects for long periods? (e.g., Welders holding a torch) O

Contact Stress Ask the worker: Do any objects, tools or parts of the workstation put pressure on any parts of your hand or S arm, such as the backs or sides of fingers, palm or base of the hand, O forearm, elbow? (e.g., metal edges of consoles/workstation digging into elbow) Vibration Ask the worker: Is vibration S transmitted to your hand through a tool or piece of equipment? O (e.g., pneumatic drill)

Please indicate whether the following direct risk factors were identified at the ELBOW. Force "Yes "No Repetition "Yes "No Static Postures "Yes "No

Factors Contact Stress Yes No

Direct Risk " " Vibration "Yes "No In the Injury Statistics investigation, were "Yes "No there injury reports for the Elbow or Forearm? In the Discomfort Survey investigation, were "Yes "No there reports of discomfort for the Elbow or Body parts within the circled area will Forearm? be classified as ELBOW issues.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 85 WRIST/HAND Force N Y Comments: Is forceful physical handling S performed? such as: Lifting O Lowering S

O Pushing S

O Pulling S

O Carrying S

O Turning materials S

O Are objects handled in a S power grip? (e.g., hammer, pneumatic drill) O Are objects handled in a S pinch grip? (e.g., nuts, bolts, sheets of O metal, sheets of plywood) Are objects handled in a S hook grip? (e.g., oil cans, tire rims) O Ask the worker: Do you wear gloves *S while performing your job? If the answer is No, check the No box O andgotonextsection. *If the answer to the above question is S Yes, ask the worker: Are the gloves too large/small? O Does the thickness of the gloves cause S problems with gripping? O Repetition Are identical or similar motions S performed over and over again? (e.g., hammering, unscrewing pneumatic O lubrication vessels) Ask the worker: Do you spend a large S percentage of the day performing one action or task? O (e.g., welding metal pieces )

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 86 Static Postures N Y Comments: Ask the worker: Do tasks require any part of your arm or hand to be S maintained in a fixed or static posture? O (e.g., holding a welding torch, holding the trigger for an automatic grease gun) Ask the worker: Do you apply constant pressure on controls/objects S with your hand, foot, or knee? (e.g., Oilers using automatic grease gun) O Ask the worker: Do you hold parts, S tools, or objects for long periods? (e.g., Welders holding a torch) O Contact Stress Ask the worker: Do any objects, tools or parts of the workstation put S pressure on any parts of your hand or arm, such as the backs or sides of O fingers, palm or base of the hand, forearm? (e.g., hand tools that dig into the palm of the hand) Ask the worker: Do you use your S hand like a hammer for striking? (e.g., Pipefitter loosening valve) O Awkward Postures Flexion S

O Extension S

O Ulnar Deviation S

O Radial S Deviation O Vibration Ask the worker: Is vibration S transmitted to your hand through a tool or piece of equipment? O (e.g., pneumatic drill)

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 87 Please indicate whether the following direct risk factors were identified at the WRIST/HAND. Force "Yes "No Repetition "Yes "No Static Postures "Yes "No Contact Stress "Yes "No Awkward Postures "Yes "No

Direct Risk Factors Vibration "Yes "No In the Injury Statistics investigation, were "Yes "No Body parts within the circled area will be there injury reports for the Wrist or classified as WRIST/HAND issues. Hand/Finger or Forearm? In the Discomfort Survey investigation, "Yes "No were there reports of discomfort for the Wrist or Hand/Finger or Forearm?

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 88 LOW BACK OR HIP/THIGH Force N Y Comments: Is forceful physical handling S performed? such as: Lifting O Lowering S

O Pushing S

O Pulling S

O Carrying S

O Repetition Are identical or similar motions S performed over and over again? (e.g., Machinists bending over to adjust the O lathe) Ask the worker: Do you spend a large S percentage of the day performing one action or task? O (e.g., Carpenter nailing on a roof) Static Postures Ask the worker: Do tasks require your S trunk and upper body to be maintained in a fixed or static posture? O (e.g., Pipefitters cutting pipe, Mechanics working under heavy equipment) Are workers required to sit or stand in S a stationary position for long periods of time during the shift? O (e.g., Electricians sitting at a computer, Machinists standing at a lathe) Contact Stress Ask the worker: Do any objects, tools S or parts of the workstation put pressure on any parts of your hip/thigh? O (e.g., machinery that digs into the thigh or hip)

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 89 Awkward Postures N Y Comments: Flexion S

Extension S

Lateral S Bending O

Twisting S

O Vibration Ask the worker: Is your whole body S exposed to vibration for significant portions of the work shift? O (e.g., standing on catwalks and machinery)

Please indicate whether the following direct risk factors were identified at the LOW BACK or HIP/THIGH. Force "Yes "No Repetition "Yes "No Static Postures "Yes "No Contact Stress Yes No

Factors " " Direct Risk Awkward Postures "Yes "No Vibration "Yes "No In the Injury Statistics investigation, were "Yes "No there injury reports for the Low Back or Hip/Thigh? Body parts within the circled area will In the Discomfort Survey investigation, be classified as LOW BACK/ or "Yes "No HIP/THIGH issues. were there reports of discomfort for the Low Back or Hip/Thigh?

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 90 KNEE Repetition N Y Comments: Are identical or similar motions S performed over and over again? (e.g., climbing stairs, crouching) O Static Postures Ask the worker: Do tasks require you S to maintain your knee(s) in a fixed or static posture? O (e.g., kneeling to work under heavy equipment) Are workers required to sit or stand in S a stationary position for long periods of time during the shift? O (e.g., Electricians sitting at a computer, Machinist standing at a lathe) Do workers kneel (with one or both S knees)? (e.g., Millwrights and Welders kneelingtoworkonprojects) O Contact Stress Ask the worker: Do any objects or S parts of the workstation put pressure on your knee(s)? O (e.g., kneeling on a catwalk) Awkward Postures Extreme Flexion S

Please indicate whether the following direct risk factors were identified at the KNEE. Repetition "Yes "No Static Postures "Yes "No Contact Stress

Factors "Yes "No Direct Risk Awkward Postures "Yes "No In the Injury Statistics investigation, were "Yes "No there injury reports for the Knee or Hip/Thigh? In the Discomfort Survey investigation, "Yes "No Body parts within the circled area were there reports of discomfort for the Knee will be classified as KNEE issues. or Hip/Thigh?

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 91 ANKLE/FOOT Repetition N Y Comments: Are identical or similar motions S performed over and over again? (e.g., walking on uneven surfaces) O Static Postures Are workers required to stand in a S stationary position for long periods of time during the shift? O (e.g., Machinist standing at a lathe) Awkward Postures Flexion S

O Extension S

O Vibration Ask the worker: Is your whole body S exposed to vibration for significant portions of the work shift? O (e.g., standing on catwalks and machinery)

Please indicate whether the following direct risk factors were identified at the ANKLE/FOOT. Repetition "Yes "No Static Postures "Yes "No Awkward Postures

Factors "Yes "No Direct Risk Vibration "Yes "No In the Injury Statistics investigation, were "Yes "No there injury reports for the Ankle or Foot? In the Discomfort Survey investigation, "Yes "No were there reports of discomfort for the Ankle or Foot? Body parts within the circled area will be classified as ANKLE/FOOT issues.

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 92 CHARACTERISTICS OF OBJECTS BEING HANDLED N Y Comments: Are there problems handling a load S due to its size or shape? (e.g., motors, long pipes) O Are there problems handling a load S due to its fragile, unbalanced, or non- rigid conditions? (e.g., oil, chains) O Ask the worker: Do you experience S situations where mechanical aids or equipment are not readily available to O assist with manipulating an object? (e.g., hoists) Are handles for tools and equipment S inappropriate in terms of size or shape? (e.g., pneumatic tools, hand tools) O Ask the worker: Do any objects that S you work with (other than tools or equipment) have handles? If the O answer is No, check the No box and go to question 1 in the next section. If the answer to the above question is S Yes, ask the worker: Are the handles an inappropriate size or shape for the O characteristics of the object?

ENVIRONMENTAL CONDITIONS Temperature Ask the worker: Are your hands or S arms exposed to cold from exhaust air, cold liquids or solids? O (e.g., Oilers, Pipefitters) Ask the worker: Are you exposed S directly to temperature extremes that may cause you to use more force or O cause you to fatigue quicker than normal? (e.g., hot or cold, either by equipment or natural environment) Lighting Ask the worker: Do you assume S awkward postures to overcome problems associated with glare, O inadequate lighting, or poor visibility? (e.g., working under equipment)

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 93 ENVIRONMENTAL CONDITIONS CONTINUTED Noise N Y Comments: Have there been complaints on the S level of noise in the work area? O Ask the worker: Are there any S distracting or annoying noises at the workstation? O (e.g., air hoses, whistles)

WORK ORGANISATION N Y Comments: Is the work externally paced or S controlled by a machine or the process? (e.g., programmed lathe) O Do peak workloads or sudden S increases in pace occur with the tasks? (e.g., whistle chasing, working during mill O downtime) Ask the worker: Are there indications S of excessive fatigue or pain, or symptoms of adverse health effects O due to extended work days or overtime? (e.g., extended weekend maintenance) Ask the worker: Are there indications S of excessive fatigue or adverse health effects due to shiftwork? O (e.g., Oilers on graveyards) Ask the worker: Are rest periods or S task variety insufficient to prevent the build-up of fatigue or the risk of O adverse health effects? (e.g., Pipefitter always working overhead) Ask the worker: Are tasks in a job S rotation program similar to one another, and therefore not providing a O variation in movements?

 2000 IMIRP Society Trades/Maintenance Checklist (revised) 94 Injury Education Injury Prevention Industrial Work Musculoskeletal Injury Manual Reduction Program

Trades/Maintenance

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 95 This Work Manual contains information about body parts found to be at risk of musculoskeletal injury (MSI) for Trades/Maintenance Jobs (Injury Education), and how to reduce the risk of MSIs using various control measures (Injury Prevention). Each Work Manual is intended to help Occupational Health and Safety Committee members establish effective solutions to reduce MSIs, and as a resource for workers to understand the MSI risks that they may encounter on the job.

This Work Manual also contains information on how to prevent common MSIs through exercise. Please note exercises described should only be used after consulting a healthcare practitioner.

The General Risk Factor Solutions Manual is a separate document that contains general, preventative information on Environmental Conditions and Work Organisation issues.

Work Manual Trades/Maintenance

Disclaimer The BC sawmill IMIRP documents were developed by Advanced Ergonomics Inc. (AEI) based on analyses conducted in a number of voluntary, participating sawmills in British Columbia and should be considered applicable only to the BC sawmill industry. Modification to these documents may reduce their usefulness and/or lead to hazardous situations. Individuals or committees wishing to make Physical Demands Analyses (PDAs) site-specific, or wishing to implement options from the Work Manuals, are advised to first complete the two-day OHSC and Supervisors Ergonomics Training Session. Modifications to a PDA must be within the scope of competence of those individuals making the changes and must be reported to any rehabilitation professional using the PDA. Neither AEI nor the IMIRP Society accepts any responsibility for the use or misuse of these documents.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 96 WM Table of Contents

INJURY EDUCATION 102

NECK 103 Introduction 104 Functional Anatomy 105 Body Mechanics 106 How Neck Injuries Occur 109 Examples of Loading on the Neck 110 Fire Watch Tasks 112 Heavy Duty Mechanic Tasks 113 Machinist Tasks 114 Millwright Tasks 115 Painter Tasks 116 Welding Tasks 117 How to Prevent Neck Injuries 118 Risk Control Key 119 Decreasing Demands 120 Increasing Capabilities 121

SHOULDER 122 Introduction 123 Functional Anatomy 124 Body Mechanics 127 How Shoulder Injuries Occur 130 Examples of Loading on the Shoulder 132 Carpenter Tasks 132 Chemical/Computer Attendant Tasks 133 Electrician Tasks 134 Fire Watch Tasks 135 Heavy Duty Mechanic Tasks 136 Machinist Tasks 137 Millwright Tasks 138 Oiler Tasks 139 Painter Tasks 140 Pipefitting Tasks 141  2000 IMIRP Society Trades/Maintenance Work Manual (revised) 97 Plumber Tasks 142 Welding Tasks 143 How to Prevent Shoulder Injuries 144 Risk Control Key 145 Decreasing Demands 146 Increasing Capabilities 148

ELBOW 150 Introduction 151 Functional Anatomy 152 Body Mechanics 153 How Elbow Injuries Occur 157 Examples of Loading on the Elbow 160 Carpenter Tasks 160 Electrician Tasks 161 Heavy Duty Mechanic Tasks 162 Millwright Tasks 163 Oiler Tasks 164 Painter Tasks 165 Pipefitter Tasks 166 Plumber Tasks 167 Welder Tasks 168 How to Prevent Elbow Injuries 169 Risk Control Key 170 Decreasing Demands 171 Increasing Capabilities 172

WRIST AND HAND 173 Introduction 174 Functional Anatomy 175 Body Mechanics 177 How Wrist and Hand Injuries Occur 181 Examples of Loading on the Wrist and Hand 184 Carpenter Tasks 184 Electrician Tasks 185 Heavy Duty Mechanic Tasks 186 Machinist Tasks 187  2000 IMIRP Society Trades/Maintenance Work Manual (revised) 98 Millwright Tasks 188 Oiler Tasks 189 Painter Tasks 190 Pipefitter Tasks 191 Plumber Tasks 192 Welder Tasks 193 How to Prevent Wrist Injuries 194 Risk Control Key 195 Decreasing Demands 196 Increasing Capabilities 199

LOW BACK 200 Introduction 201 Functional Anatomy 202 Body Mechanics 203 How Back Injuries Occur 206 Examples of Loading on the Back 209 Carpenter Tasks 209 Chemical/Computer Attendant Tasks 210 Electrician Tasks 211 Fire Watch Tasks 212 Heavy Duty Mechanic Tasks 213 Machinist Tasks 214 Millwright Tasks 215 Oiler Tasks 216 Painter Tasks 217 Pipefitter Tasks 218 Plumber Task 219 Welder Tasks 220 How to Prevent Back Injuries 222 Risk Control Key 223 Decreasing Demands 224 Increasing Capabilities 227

KNEE 229 Introduction 230 Functional Anatomy 231  2000 IMIRP Society Trades/Maintenance Work Manual (revised) 99 Body Mechanics 232 How Knee Injuries Occur 234 Examples of Loading on the Knee 237 Carpenter Tasks 237 Chemical/Computer Attendant Tasks 238 Fire Watch Tasks 239 Heavy Duty Mechanic Tasks 240 Millwright Tasks 241 Oiler Tasks 242 Painter Tasks 243 Pipefitter Tasks 244 Plumber Tasks 245 Welding Tasks 246 How to Prevent Knee Injuries 247 Risk Control Key 248 Decreasing Demands 249 Increasing Capabilities 250

FOOT 251 Introduction 252 Functional Anatomy 253 Body Mechanics 254 How Foot Injuries Occur 258 How to Prevent Foot Injuries 261 Risk Control Key 262 Decreasing Demands 263 Increasing Capabilities 266

INJURY PREVENTION 268 Risk Control Key 269 Workstation Design 270 Job-Specific Workstation Design Solutions 292 Carpenter 292 Chemical/Computer Attendant 293 Electrician 294 Heavy Duty Mechanic 295 Machinist 296  2000 IMIRP Society Trades/Maintenance Work Manual (revised) 100 Millwright 297 Oiler 298 Pipefitter 299 Welder 300

TOOLS AND EQUIPMENT 302 Introduction 302 Tools 303 Equipment 314 Miscellaneous Equipment 320 Job-Specific Tools and Equipment Suggestions 321 Carpenter 321 Chemical/Computer Attendant 321 Electrician 322 Heavy Duty Mechanic 322 Millwright 323 Oiler 324 Painter 325 Pipefitter 326 Plumber 328 Welder 329

WORK STRATEGIES 330 Introduction 330 General Work Practices 331 Job-Specific Work Practices 346 Electrician 346 Heavy Duty Mechanic 347 Machinist 347 Millwright 347 Oiler 348 Pipefitter 348 Welder 349

INDEX OF SOLUTIONS 351

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 101 Injury Education

Musculoskeletal injuries (MSIs) occur when physical demands exceed the capabilities of the body. Most MSIs do not occur from a single event but from an accumulation of stress that weakens the body to the point of failure.

There are benefits and disadvantages to the slow development of musculoskeletal injuries. One negative aspect is that injuries are not recognised early, unlike, for example, when skiers ‘blow out’ their knees, and seek immediate treatment. With slowly progressing injuries, problems may go unchecked for longer periods. The signs and symptoms of MSIs may gradually progress over months or years until a worker is partially disabled. Injuries that go untreated for long periods may become chronic and more difficult to treat. If MSIs progress for too long, the body may not be able to fully recuperate.

A positive aspect to the slow progress of MSIs is that damage can be reversed quickly if caught early. This reversal is referred to as “resetting the injury clock”. If you reset the injury clock soon enough and often enough, serious MSIs can be avoided.

Maintenance exercises are used to reset the injury clock. Like a machine, the body requires regular maintenance to ensure that it works properly. Professional athletes use exercises to keep strong and facilitate the healing of minor injuries. This practice helps aging athletes maintain a high calibre of play and enjoy longer careers and healthier lives.

The Trades/Maintenance Jobs Work Manual describes how slowly progressing injuries occur for each major body part, illustrates examples of loading in Trades/Maintenance jobs, outlines, with examples, information on how to avoid harmful stress, and shows preventive exercises to reset the injury clock.

With simple maintenance, the body can remain healthy and continue to perform at an optimum level - enhancing life both on and off the job.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 102 NECK

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 103 Introduction

Many workers have experienced neck discomfort while performing their work. Often they feel that the pain is a part of the job, something that has to be endured. However, if recognised early, neck discomfort is easy to correct, or even easier to prevent. With simple exercises and work changes, the injury clock can be reset and workers can carry on with their daily activities pain-free.

This manual covers the causes of neck problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 104 Functional Anatomy

The head is supported by the spinal column, which consists of bones (vertebra) that are separated by soft tissue (discs). In the neck, these bones are small and highly mobile, allowing for more rotation and flexion than similar bones in the low back. However, these small bones and tissues can not withstand as much force as the larger bones of the low back.

Through the centre of this spinal column run bundles of nerves which carry messages to and from the body and brain.

There are many muscles in the neck and upper back region, responsible for moving and stabilising the head. Muscles in the neck also attach to the upper aspect of the shoulders, helping to elevate and stabilise the shoulder blades.

Ligaments connect bone to bone in the neck, and prevent movement beyond the end range of motion.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 105 Body Mechanics Teeter Totter Principle (Torque) Neck and upper back muscles must support the weight of the head when it is bent forward. An average head weighs 5 kg (12 lb.), which can be a large load for the small postural muscles of the neck. As the head is bent farther forward, the load on the neck muscles increases.

Every joint in the body may be compared to mechanical systems of levers and pulleys. The principles of torque can be used to determine how hard muscles need to work to counter-balance loads, and how much joint compression is produced as a result of these balanced loads.

Weight of head Muscle tension to counter-balance weight of head

20 kg Muscle Tension

5 kg Muscle Tension

10 kg Joint 25 kg Joint Compression Compression

The more the head bends forward, the greater the supporting load required in the neck muscles, and the greater the joint compression resulting from the two loads combined. The increased muscle force and joint compression result in a greater risk of neck injury.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 106 Optimal Positions Each joint has positions that are optimal for force generation and strength. The body also has extreme positions where it is weak and more prone to injury. These extreme positions are far away from neutral postures. When muscles are stretched beyond optimal positions, the amount of force generated decreases significantly. If the body constantly works in weak positions, it is more likely to become injured.

Grip Strength Test

Try this. Grip two fingers with the wrist straight, and squeeze as hard as you can. Now repeat with a bent wrist. Do you feel a difference in strength between the two positions?

Muscles and joints are designed to work most effectively in their neutral positions. The more the wrist is bent, the weaker the grip. Similarly, the farther the head is bent forward, the weaker the muscles become and the greater the risk of injury.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 107 Postural Changes The body has the ability to adapt to its environment. It can cool itself in a hot climate, and it can adapt to physically demanding work by becoming stronger. However, some adaptive changes are not positive. Workers who continually work with their head down may start to develop problems as a result of postural changes. As the body becomes increasingly misaligned, loading on the affected muscles and joints increases significantly. In addition, postural muscles of the back under constant tension gradually become stretched-weakened, losing their ability to generate force. As a result, spinal alignment gets progressively worse. If caught early, these changes are reversible.

Posture Check

Good Bad

Place low back flat against wall, with feet 20 cm away from the wall. Someone with good alignment should be able to press his or her forearms and hands flat against the wall. For people who have postural problems, this test can be used as a corrective exercise.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 108 How Neck Injuries Occur

It is important to understand the concept of load limits, or tissue tolerances, for the body. If the load on tissues exceeds these tolerances, injuries will occur. Loading of extreme force, repetition, or duration, or a combination of these three, can lead to damage.

Excessive Force To illustrate excessive force, consider the massive amount of force that may be transmitted through the neck during a motor vehicle accident. Due to these large forces, soft tissues of the neck (muscles, tendons, ligaments) are damaged. This injury is referred to as whiplash.

Injury Tissue Tolerance

Load No Injury

Time

Neck injuries due to excessive force are very rare in work situations. Most neck injuries result from repetitive and/or static loading.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 109 Excessive Repetition Repeated bending or twisting of the neck can gradually fatigue tissues.

The neck is designed for motion and thus is less susceptible to injuries than the lower back. However, neck muscles can still become fatigued if movements are frequent, or when the postures assumed are extreme. Repetitive high-speed neck movements also increase the risk of injury. For Welders, loading is increased by repeatedly snapping the welding mask into place. As a result, fatigue of the neck tissues and excess wear on the bones of the neck can occur.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 110 Excessive Duration Workers who continuously look down may eventually develop neck problems. The neck and upper back muscles support the head when bent forward or backward. With the head bent for long periods, the muscles gradually fatigue, and tissue tolerances decrease. Tension neck syndrome can develop if the fatigue is significant. Symptoms of tension neck syndrome include an increase in pain and tenderness in the shoulder and neck areas.

For a muscle to work properly it requires blood to be circulated through it. Dynamic contractions, where the muscle regularly turns on and off, encourage blood circulation, allowing the muscle to “breathe” and stay healthy. By simply changing the type of muscle contraction, tension neck syndrome can be relieved.

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 111 Examples of Loading on the Neck Fire Watch Tasks Load

Time

Awkward Postures Static Postures

Tasks that require forward neck flexion or neck extension place increased load on neck tissues. The duration of tasks performed in this position also leads to increased tissue fatigue in the neck.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 112 Heavy Duty Mechanic Tasks Load

Time

Static Posture Static Posture Static Posture Awkward Posture Awkward Posture

Heavy Duty Mechanics Heavy Duty Mechanics Heavy Duty Mechanics often work with the frequently work with may hold their head up arms held above their necks in a forward unsupported for long shoulder height, flexed position. The periods of time while especially with vehicles duration of tasks working under on hoists or in pits. performed in this machinery. Holding the arms and position also leads to shoulders in this increased tissue fatigue elevated position in the neck. quickly fatigues the muscles of the neck and upper back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 113 Machinist Tasks Load

Time

Repetition Static Posture

Machinists repeatedly twist the neck Machinists are at an increased risk to observe controls and the pieces of for neck tissue fatigue due to the metal, and to measure metal pieces. long duration of non-neutral neck This repetitive motion can lead to postures assumed while working at neck tissue fatigue. various machines.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 114 Millwright Tasks Load

Time

Static Posture Static Posture Static Posture Awkward Posture Awkward Posture Awkward Posture

Millwrights often work Millwrights spend long Holding the neck in this with the arms held above periods with their necks extreme posture fatigues shoulder height, bent forward or to the the neck muscles quickly. especially under machines side while fixing and transfer chains. chains, valves, hoses, Holding the arms in this changing belts, and elevated posture fatigues maintaining equipment. the muscles of the upper back and neck quickly.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 115 Painter Tasks Load

Time

Awkward Posture Awkward Posture Static Posture Static Posture

Painters regularly work with their Painters are at an increased risk for arms raised above shoulder height. neck tissue fatigue due to the long Holding the arms in this position duration of non-neutral neck postures leads to fatigue in the tissues of the assumed while working at various neck and upper back. heights.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 116 Welding Tasks Load

Time Force Static Posture Static Posture Repetition Awkward Posture Awkward Posture

Welders repeatedly Welders frequently Tasks which require snap their masks into work with their necks holding the neck in place, which increases held in a forward flexed extreme forward neck the risk of injury. position. The duration flexion, or neck of tasks performed in extension (head tipped this position also leads back beyond neutral to increased tissue posture), place an even fatigue in the neck. greater load on neck tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 117 How to Prevent Neck Injuries

Use the information below as your guide to prevent neck injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time

Decrease Demands Increase Capabilities • Reduce neck bending by adjusting • Exercise to improve endurance of the working height neck muscles • Design workstation to encourage • Exercise to improve posture and to changes in posture reduce loading on the neck

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 118 Risk Control Key Risk control measures (solutions) are commonly grouped into four categories:

E Engineering Controls These include physical changes to workstations, equipment, materials, production facilities, or any other relevant aspect of the work environment, that reduce or prevent exposure to risk factors.

A Administrative Controls These include any change in procedure that significantly limits daily exposure to risk factors, by control or manipulation of the work schedule or manner in which work is performed. Examples include job rotation, rest breaks, alternative tasks, job enlargement, redesign of work methods, and adjustment of work pace. Some models of risk control include work practice controls within this category.

WP Work Practice Controls These include techniques used to perform the tasks of a job, such as use of tools and equipment, manual material handling techniques, etc. Education and training are an integral part of ensuring effective work practice controls.

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 119 Decreasing Demands

The following examples illustrate various methods of decreasing the physical demands for the neck. Examples for the Neck

WP Work Practice E Engineering Controls Controls

Load

Loading on the Neck Time

Theneckisheldin Moving the head closer To help keep the neck extreme forward flexion to the vertical height of in more neutral work while the Pipefitter is the work reduces neck postures, an object working at this low flexion. Less muscle should be put into an level. The additional force is required to appropriate working weight of the hard hat control the neck height. The benefit of and ear muffs increases posture. an increased height is theforcetheneck lost when the work is muscles need to Note: Kneeling for above the head, generate to counteract long periods can lead to requiring neck the forward flexion of contact stress problems extension for viewing. the head. This also in the knee. places increased load on the bones in the neck.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 120 Increasing Capabilities Exercises for the Neck Follow the instructions on this worksheet to reduce neck discomfort. Exercises should be done daily. Start out slowly and gradually increase exercise intensity. Call your local rehabilitation centre for a tubing supplier. Purchase light resistance tubing and cut into 2 metre lengths.

External Shoulder Rotations With your elbows bent at 90 degrees and thumbs together, pull your hands apart and let the thumbs rotate outwards. As your posture muscles get stronger, finish higher. Do3setsof10.

Chin Tucks With your head upright, tuck chin in. You should feel a gentle stretch in the back of the neck. This exercise can be done lying down initially. Hold for 30 seconds and then relax. Repeat 5times.

Isometric Neck Extensions Apply light resistance to the back of the head with the hands. As neck muscles get stronger more resistance can be applied. Hold for 10 seconds and then relax. Repeat 5 times.

Upper Trapezius Stretch Turn head to the side slightly and reach for the ground. The opposite arm can be used to increase the stretch. Concentrate on relaxing neck muscles during stretching. Hold for 30 seconds and then relax. Repeat 5 times on each side.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 121 SHOULDER

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 122 Introduction

Sports like baseball are known for being extremely stressful on the shoulder joint, and on the small rotator cuff muscles and tendons. When you hear ‘rotator cuff injury’, you typically think of a career-ending sports injury. In the past, that may have been the case. Today, however, with increased understanding of the cause of these injuries and better medical management, athletes are capable of recapturing pre-injury performance levels. These same injury prevention principles that have worked so effectively in the sporting environment are also effective in preventing shoulder injuries in the workplace.

This manual covers the causes of shoulder problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 123 Functional Anatomy

The shoulder is known as a ball and socket joint. However, it might be more accurate to say that the socket is really a depression. Unlike the hip, which is a true ball and socket joint, the shoulder must rely on muscles and ligaments to keep the bones in place.

Built for mobility Built for stability

Hip Joint

Shoulder Joint

Less contact surface between the ball and socket in the shoulder allows for greater range of movement, but sacrifices some stability. In comparison, the hip is designed to provide more stability, which reduces the range of movement.

Small fluid-filled sacs called bursae provide protection for muscle tendons. These sacs act like pulleys in areas where the tendons run across bone, protecting the tendon from fraying.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 124 Posture and Impingement When one thinks of shoulder muscles, usually the large deltoid and trapezius muscles come to mind. However, there is another group of muscles that are responsible for providing stability to the shoulder joint. These are the rotator cuff muscles and their tendons, which lie underneath the deltoids. The large forces that can be generated at the shoulder make it easy to damage these smaller muscles and tendons.

Rotator cuff tendons

Roof of the shoulder complex

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 125 The body has the ability to adapt to its environment. For instance, the body can become stronger to meet the demands placed on it. However, there can also be negative consequences to adaptive change in the workplace. For example, the spine has a deformation memory, and will structurally change over the years to accommodate stress. Workers that are required to look down will start to develop these changes in posture.

One side effect to these postural changes is the increased risk of a worker developing shoulder impingement problems. Impingement of nerves and blood vessels in the shoulder area usually occurs when the arms are lifted above shoulder height, pinching and obstructing these tissues. With progressive postural changes, such as slumped shoulders and forward neck tilt, this impingement can occur when working with the arms at lower levels. Consequently, work that is below shoulder height can lead to shoulder impingement problems for some workers.

Shoulder impingement while working at Shoulder impingement due to poor posture, shoulder height. while working at mid-chest height.

Improving posture can help reduce impingement, and reduce the risk of injury.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 126 Body Mechanics Teeter Totter Principle (Torque) The amount of force that the rotator cuff muscles must generate to stabilise the shoulder depends directly on how close loads are to the shoulder joint. When loads are farther away from the shoulder, there is more loading on the muscles and their tendons. If this loading exceeds the capabilities (tissue tolerances) of the muscles and tendons, an injury will occur.

Weight in hand

Muscle tension to counter-balance weight in hand

Muscles must work harder to counter-balance loads that are held farther away from the body. As a result, the risk of injury also increases.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 127 How Shoulder Injuries Occur

Your body is similar to a lifting machine in the sense that it has load limits. If you exceed these load limits, you risk damaging the equipment. These load limits are referred to as tissue tolerances for the body. An injury can occur when a load exceeds tissue tolerances. Loading of excessive force, repetition, or duration, or a combination of these three, can lead to damage.

Excessive Force Trades/Maintenance workers have to use extreme arm reaches (e.g., into confined spaces) while using heavy hand tools, such as impact wrenches. The large forces required to hold tools and materials in these positions can place workers at risk for shoulder injuries.

Similarly, holding onto a vibrating tool requires the small rotator cuff muscles to work extremely hard to stabilise the shoulder. The combination of reaching away from the body and applying force can produce loads on the shoulder joint that exceed tissue tolerances. The resulting injury is typically a rotator cuff strain.

Injury Tissue Tolerance

No injury Load

Time

Millwrights tighten bolts while in confined spaces. The shoulder joint allows for mobility or stability, but not both at the same time. If you try to apply a lot of force in an awkward position an injury may occur.

Torque or kickback from tools such as impact wrenches increases loading on the shoulder joint.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 128 Excessive Repetition Workers who continuously reach above shoulder height can develop rotator cuff problems due to frequent rubbing of the tendons against bones and ligaments. This causes the rotator cuff tendons to fray.

The bursa sac is another structure in the shoulder that can be affected by repetitive reaching. The bursa is a fluid-filled sac, like a water balloon, that reduces the amount of friction between the tendons and bone. However, the bursa can also swell and become damaged.

Repetitive loading injuries develop over a period of time. When the accumulation of damage significantly weakens tissue, even a small load can result in an injury.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

An Oiler frequently reaches at or above shoulder height to oil and grease equipment. The location of bearing, etc. that require oiling and greasing determine the amount of reaching involved. Repetitive reaching at or above shoulder height can cause tissue fatigue and impingement problems.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 129 Excessive Duration Trades/Maintenance workers who work with their arms away from their body for long periods of time can develop shoulder problems as the rotator cuff muscles gradually fatigue and tissue tolerances decrease. If the fatigue is significant, small loads can result in an injury.

If a muscle is constantly working without producing motion (referred to as a static contraction), blood is squeezed out of the muscle. Muscles are like small motors. Motors require oxygen to allow for combustion. Without oxygen, motors die out. Without blood, which carries oxygen, muscles soon die out as well. In muscles, this “dying out” is called fatigue.

For a muscle to work properly it requires blood to be circulated. During dynamic contractions, in which the muscle turns on then off, blood circulation increases, allowing the muscle to “breathe” and stay healthy. By simply changing the type of muscle contraction, the effects of static contractions can be relieved.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 130 How loading due to shoulder posture affects tissue tolerance:

Posture

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

Welders often have to maintain shoulder postures for prolonged periods of time. Constantly having shoulder muscles activated can cause a rotator cuff strain. Varying which muscles are used while working can help to prevent injuries.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 131 Examples of Loading on the Shoulder Carpenter Tasks Load

Time Repetition Static Posture Awkward Posture Awkward Posture

Carpenters frequently work with their arms away from Carpenters may hold their the body when using tools such as pneumatic nailers shoulders in a raised and hammers. A workbench that is too high may position when using a increase the amount of reaching. hand drill.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 132 Chemical/Computer Attendant Tasks Load

Time Force Awkward Postures

Chemical Computer Attendants often Chemical Computer Attendants often work with hand tools, or lift heavy bags have to reach forward and to the side in of chemicals. This lifting places order to test chemicals, clean filters, and increased loading on tissues of the inspect for leaks. Loading on shoulder shoulder. The heavier the object held in tissues is increased when reaching away the hand, the greater the load on the from the body, and when holding an shoulder. object in the hand while reaching.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 133 Electrician Tasks Load

Time Repetition Static Posture Awkward Posture

Electricians may be required to reach Electricians may hold their arms raised overhead frequently when checking or and shoulders elevated while building or repairing electrical wiring. repairing consoles and control panels at a workbench.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 134 Fire Watch Tasks Load

Time

Force Awkward Postures Awkward Postures Static Postures

A Fire Watch person may be required to A Fire Watch person may be required to apply force when holding materials in reach forward with the arms for place for the Welder. In some work significant periods of time in order to layouts, awkward shoulder postures may prepare a work site or monitor an area also be required. for fire. Depending on the location and nature of the weld, the awkward and static nature of these postures can be increased.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 135 Heavy Duty Mechanic Tasks Load

Time

Static Posture Force Awkward Posture Awkward Posture

A Heavy Duty Mechanic frequently A Heavy Duty Mechanic may be works with the arms held overhead. required to lift, lower, carry, and manipulate heavy objects with the arms away from the body.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 136 Machinist Tasks Load

Time

Force Static Posture Awkward Posture Awkward Posture

A Machinist may be required to use A Machinist may be required to hold force when fastening materials in their arms forward at a bench or in a machines. Sometimes, awkward machine for significant periods of time. shoulder postures are also required.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 137 Millwright Tasks

Light Heavy tool tool Load

Time Force Repetition Static Posture Awkward Postures

Millwrights frequently Millwrights may change Millwrights frequently repair and maintain knives in machinery, such work in confined areas in equipment and as the chipper, which equipment and machinery. This work requires frequent forward machinery. This work may require reaching reaching. may require working forward, overhead, etc. overhead or with the arms for varying lengths of Loading on the shoulder extended in a reaching time. musclesisincreasedwhen position for long periods holding a tool or knife in of time. Millwrights often work the hand while reaching with hand tools, or away from the body. support the weight of machinery parts, which increases the loading on the shoulder. The heavier the object held in the hand, the greater the load on the shoulder.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 138 Oiler Tasks Load

Time Repetition Static Posture Static Posture Awkward Posture Awkward Posture

Oilers may have to Oilers may hold their Oilers may pour manually crank lubricants shoulders in extreme lubricants holding the arm from one location to postures when oiling, away from the body. another. greasing, and filling lubricant vessels.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 139 Painter Tasks Load

Time Repetition Awkward Posture Static Posture

Painters may be required to reach Painters may hold their arms raised and overhead frequently when painting or shoulders elevated while preparing and preparing surfaces above shoulder level. painting surfaces. These risk factors oftenoccurwhenworkingonsurfaces outside the paint shop.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 140 Pipefitting Tasks Load

Time Static Posture Static Posture Force Awkward Posture Awkward Posture Repetition

Pipefitters may be Pipefitters may be Pipefitters may be required to work overhead required to work with the required to forcefully for extended periods arms overhead for periods push and pull wrenches to when installing piping. of time when using hand remove fittings on pipes. tools. This handling can be repeated throughout the shift.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 141 Plumber Tasks Load

Time Force Awkward Posture Repetition Static Posture

Plumbers may be required to forcefully Plumbers may be required to work push and pull wrenches to remove or overhead for extended periods when fasten fittings on pipes. installing piping or maintaining lines.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 142 Welding Tasks

Light Heavy tool tool Load

Time Repetition Static Posture Force Awkward Posture Static Posture Awkward Posture

Welders repeatedly reach Welders frequently weld Welders may hold their and extend the arms to with their shoulder(s) in a arms raised to grind. measure pieces for raised position. This Loading on the shoulder welding. work often requires is increased due to the maintaining one posture weight of the grinder. for several minutes at a time.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 143 How to Prevent Shoulder Injuries

Use the information below as your guide to prevent shoulder injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time

Decrease Demands Increase Capabilities • Reduce torque on the shoulder by • Exercise to improve strength of keeping hands close to the rotator cuff muscles and tendons shoulder when working • Exercise to improve posture in • Avoid repetitive overhead lifting order to reduce impingement if possible • Stretchtohelprelaxrotatorcuff muscles

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 144 Risk Control Key Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 145 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the shoulder. Examples for the Shoulder

Forceful shoulder Teflon tape on pipes and Insulate pipes properly, movements while fittings prevents rusting. preventing them from repairing water line. freezing.

E Engineering E Engineering Controls Controls

Less frequent repairs

Load

Loading on the Shoulder Time

Repairing and replacing To reduce pushing and Properly insulating the pipes can require forceful pulling forces, pipes and pipes can prevent them shoulder movements. fittings should be covered from freezing, which can with Teflon tape. The in turn reduce undue tape allows less rust to strain on the shoulder by develop on metal parts to making repairs less be separated. frequent.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 146 Grinding with prolonged awkward Grinding at a proper height to maintain shoulder postures. neutral shoulder postures for the majority of the time.

E Engineering Controls WP Work Practice Controls

Load

Loading on the Shoulder Time

Welding and grinding is often done with There are different ways to reduce the shoulders held in awkward postures loading on the shoulder: (e.g., arms raised, shoulders elevated) • An adjustable workbench would for prolonged periods of time. allow workers to raise and lower parts so that welding/grinding can be done at an ideal height (E). • Using lifting devices to turn and position large parts for welding and grinding can help workers to maintain neutral shoulder postures for the majority of the time (E, WP).

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 147 Increasing Capabilities Exercises for the Shoulder Follow the instructions on this worksheet to improve rotator cuff tissue tolerances. Exercises should be done daily. Start out slowly and gradually increase exercise intensity. Let pain be your guide. Call your local rehabilitation center for a tubing supplier. Purchase light resistance tubing and cut into 2-meter lengths.

External Shoulder Rotations With your elbow bent at 90 degrees and pressed in to your side, pull tubing away from your body. Stay within pain-free ranges of motion. As your shoulder strengthens, increase the range. Do3setsof10witheacharm.

Internal Shoulder Rotations With your elbows bent at 90 degrees and pressed in to your side, pull tubing towards your body. Stay within pain-free ranges of motion. As your shoulder strengthens, increase the range. Do3setsof10witheacharm.

! " Shoulder Depression Squeeze shoulders together and then down. Make small circles with your hand. Avoid slouching when pressing down. Do 10 circles one way then switch directions. Repeat with opposite arm.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 148 Shoulder Stretch 1 Gently pull elbow towards opposite shoulder. Stretch to the point of mild tingling and not beyond. When the tingling subsides deepen the stretch. Repeat until full range of motion is achieved.

Shoulder Stretch 2 Clasp hands together behind the back. Squeeze the shoulder blades together until a stretch is felt across the chest and front of both shoulders. Hold for 10 to 15 seconds. Repeat.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 149 ELBOW

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 150 Introduction Many workers have experienced elbow discomfort while performing their work. Often they feel that the pain is a part of the job, something that has to be endured. However, if recognised early, elbow discomfort is easy to correct, or even easier to prevent. With simple exercises and work changes, the injury clock can be reset and workers can carry on with their daily activities pain-free.

This manual covers the causes of elbow problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 151 Functional Anatomy

The elbow consists of three bones: two in the forearm, the ulna and radius; and one in the upper arm, the humerus. These bones are held together by several small ligaments. Ligaments connect bone to bone, preventing movement beyond the end range of motion.

Muscles and tendons in the forearm and upper arm are responsible for moving the elbow. Some muscles, such as the brachioradialis, cross over the joint of the elbow. The brachioradialis muscle allows you to bend the elbow to raise a cup to your mouth. Other muscles are found only in the forearm, and are responsible for moving the fingers and hand. Most of these muscles are attached to the elbow joint by a tendon.

Tendons are less flexible than muscles and have a smaller blood supply. For these reasons, recovery time for a tendon injury is generally longer than for a muscular injury.

Running parallel with these muscles are nerves that provide information from the brain to the muscles. The nerve that runs along the back of the arm and along the elbow is the ulnar nerve. If this nerve is hit, a tingling sensation occurs, often referred to as “hitting your funny bone”.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 152 Body Mechanics How Gripping Affects Tissue Tolerances Muscles used for gripping are found in the forearm. Tendons connect both ends of the muscle to the bone. The weak link in the muscle-tendon-bone structure is the tendon-bone junction. Usually the tendon-bone junction at the elbow is the area damaged. This area is damaged by tension generated through the forearm muscles that attach to the bone above the elbow joint.

Weight The heavier the object being gripped, the greater the tension generated by the muscles and the greater the tension at the tendon-bone junction. Increased tension developed during gripping accelerates tissue fatigue and lowers tissue tolerances. With sufficient rest, the body can quickly repair itself and reset its tissue tolerances. However, without sufficient rest, the tissues gradually break down to the point where even light gripping becomes a problem.

10kg Muscle Tension 16kg Muscle Tension

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 153 Gripping Width The width of the grip required also determines the amount of tension generated by muscles and transmitted to the tendon-bone junction. The width of an object affects how much muscle tension needs to be generated. There is an optimal grip width at which the forearm muscles work most efficiently. Outside this grip width, the muscles have to work harder to generate the same tension. Consequently, objects that are too large or too small can increase the tension generated by muscles and transmitted to the tendon-bone junction. If the tension is high enough and the rest period is too short, tissue fatigue will occur and the tissue tolerance will decline.

10kg Muscle Tension 10kg Muscle Tension 10kg Muscle Tension

Narrow grip Optimal grip Wide grip

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 154 Wrist Posture Another factor that affects the amount of tension generated by muscles and transmitted to the tendon-bone junction is the posture of the wrist while gripping. There is an optimal wrist position where the forearm muscles are most efficient at generating tension. This position occurs when the wrist is in its natural relaxed position (referred to as neutral). Deviating from neutral by bending the wrist forward or backward causes the forearm muscles to work harder just to generate equivalent tension. The greater the tension, the quicker the tissue fatigues, and the greater the risk of injury.

Muscle Tension 10kg Muscle Tension 10kg Muscle Tension 10kg

Workers who have to continuously grip controls can develop problems even with light gripping if their wrist posture is not kept neutral.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 155 Common Elbow Injuries Epicondylitis is a common problem in the sawmill industry. Epicondylitis is inflammation of the tendons that insert into the elbow. This condition produces pain at the elbow. Typically, the elbow pain increases with activity and subsides with rest.

Two common names for epicondylitis are tennis elbow and golfer’s elbow. Sports are not the only cause of these conditions. In fact, occupational stress, rather than sports, causes most cases.

Older individuals are more likely to have epicondylitis as a result of a work-related injury from overuse. Regardless of whether the problem is sports-related or work- related, the condition can be prevented.

Area of Area of pain/discomfort pain/discomfort for Tennis for Golfer’s Elbow Elbow

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 156 How Elbow Injuries Occur

To help understand how people develop epicondylitis, imagine the muscles and tendons in the forearm as being similar to a cable used to lift objects. Cables have load limits that should not be exceeded. If these load limits are exceeded, the cable will be damaged.

The muscles and tendons in the forearm are similar to a cable in the sense that they also have load limits. These limits are referred to as tissue tolerances, and an injury will result if the limits are exceeded. Most elbow and forearm problems are not the result of a single injury event (e.g., gripping something that is too heavy). Generally these problems develop from either repetitive loading or from constant loading (e.g., gripping tools and equipment too long). Injuries result when repetitive and/or constant loading reduces tissue tolerance to the point of failure. Excessive Force Injury to the elbow due to a single event of excessive force is rare, except in the case of a fall where the elbow impacts the ground first.

Injury Tissue Tolerance

Load No injury Landing on Elbow

Most injuries to the elbow are not from a single overload event. Elbow injuries typically develop from repetitive and/or constant loading of the tissues in the elbow joint.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 157 Excessive Repetition Repetitive gripping or repetitive rotation of the forearm can weaken the tissues in the elbow. This repetitive loading on the elbow can decrease tissue tolerances to the point of injury, leading to conditions such as epicondylitis.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 158 Excessive Duration Constant loading on the elbow can also weaken tissue. Gripping or keeping the elbow bent with force for long periods loads the tissues in the elbow. Tendons in the elbow are elastic, but with constant loading, these tendons can be damaged.

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 159 Examples of Loading on the Elbow Carpenter Tasks

Heavier tool Lighter tool Load

Time

Force Force Force Static Posture Repetition

Carpenters grip power Carpenters use pneumatic Carpenters frequently handtools, such as palm staplers and nail guns. carry lumber and plywood sanders, for long periods. Repeated kickback from with pinch or hook grips. Loadingontheelbow these tools increases These grips generate increases with high loading on the elbow. The higher levels of tension in gripping forces. Palm heavier the tool, the the elbow than power sanders also vibrate, greater the amount of (cylindrical) grips. The which increases the gripping and muscle heavier the object, the amount of gripping contraction required for higher the load on the required to stabilise and control. This muscle elbow. control the tool. tension greatly increases the load on the elbow.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 160 Electrician Tasks Load

Time

Force Static Posture Repetition Awkward Posture

Electricians pull Electricians often have to Electricians often have to forcefully on large spools work in confined spaces use screwdrivers, which of cable. Forceful that require awkward and require repetitive wrist gripping and pulling static postures of the and forearm rotations. increases the load on the wrist. Keeping the wrist elbow. in an awkward posture while gripping a tool increases the load on the elbow.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 161 Heavy Duty Mechanic Tasks Load

Time

Force Force Force Awkward Postures Repetition Static Posture Awkward Posture Vibration

Mechanics often grip Mechanics forcefully grip Mechanics forcefully grip tools forcefully to remove hammers when thehandleofgrinders old or rusted parts from hammering metal pieces. when grinding metal. The vehicles. Awkward Awkward postures of the harder an operator grips, postures are often used, wrist and forearm the higher the load on the which increases the increase loading on the elbow. Tools that vibrate loading on the elbow. elbow. Many handtools also increase the amount require repetitive motion, of gripping required for and muscle activation. operation.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 162 Millwright Tasks

Loosen Tighten Load

Time

Force Force Force Repetition Repetition

Millwrights often repair Millwrights frequently Millwrights often move hoses, using various pull on tools when heavy machinery parts. handtools to attach or repairing equipment. Forceful gripping remove pieces. Repeated forceful increases loading on the Millwrights will gripping of tools can lead tissues in the elbow. repeatedly pull forcefully to fatigue and injury of Greater loading occurs on a wrench to tighten or the elbow tissues. with heavier objects. loosen hose attachments.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 163 Oiler Tasks

Warm Cool Load

Time

Force Repetition Force

Oilers often have to push Oilers frequently use Oilers often have to carry heavy oil drums. Forceful manual pumps to pump heavy buckets of oil or pushing increases the load oil into equipment lines. grease throughout the on the elbow. Greater loads are placed mill. Forceful gripping of on the elbow when oil is the handle during lifting more difficult to pump. and carrying increases the Low temperatures can load on the elbow. increase this difficulty.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 164 Painter Tasks Load

Time

Force Force Static Posture Static Posture Vibration

Painters grip various handtools to Painters are at an increased risk for prepare and paint surfaces. Forceful elbow tissue fatigue when forcefully gripping is also required to handle gripping vibrating power tools. pieces and materials.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 165 Pipefitter Tasks

Open Load

Time

Force Force Force Repetition Repetition

Pipefitters shape pipe and Pipefitters repeatedly Pipefitters frequently use metal by hammering. open and close valves. wrenches and other tools Heavier tools require Loads on the elbow are to tighten valves, fittings, more force to grip, which increased for valves that or clamps. Forceful can increase the load on aremoredifficulttoturn. gripping of tools can the elbow. Typically this significantly load the occurs for short periods of elbow. time.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 166 Plumber Tasks Load

Time

Force Force Repetition

Plumbers grip hand tools to remove or Plumbers may be required to use fasten fittings on pipes. extreme grip force for heavy hand tool tasks.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 167 Welder Tasks Load

Time

Static Posture Static Posture Repetition Awkward Posture Vibration

Welders often hold the Welders grip the handles Welders often use handles of welding of grinders for long hammers. The harder the torches for long periods. periods. Vibration from Welder has to hammer, Awkward postures of the grinders also increases the the greater the load on the wrist and elbow increase loading on the elbow. elbow. Repetitive use of loading on the elbow. hammers increases loading on the tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 168 How to Prevent Elbow Injuries

Use the information below as your guide to prevent elbow injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time

Decrease Demands Increase Capabilities • If possible, reduce loading by • Exercise to improve the strength of adopting optimal grip width with the forearm muscles and tendons wristinaneutralposition • Stretch to help relax forearm muscles • Use two hands instead of one to handle heavy materials or tools • Minimise vibration and cold temperatures • Purchase appropriately sized gloves

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 169 Risk Control Key Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 170 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the elbow.

Examples for the Elbow

Breakuptasks. Allow tissues to recover. Reset the Injury Clock.

E Engineering WP Work Practice Controls Controls

Load

Loading the elbow Time

Kickback from a pneumatic To reduce loading on the To minimise the duration of nail gun increases the load on elbow the weight of the tools loading on the elbow when the elbow tissues. With can be reduced by purchasing using a pneumatic nail gun, a heavier tools the applied grip or designing lighter tools. worker can break up the force is also greater, which nailing task by alternating to further increases the load on Using a tool balancer can also other job duties. This rotation the elbow. reduce the load on the elbow allows the elbow tissues to due to the weight of the tool. rest and recover. The other tasks performed should involve the use of other muscles groups.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 171 Increasing Capabilities Exercises for the Elbow Follow the instructions on this worksheet to improve strength and flexibility. Exercises should be done daily. Start out slowly and gradually increase exercise intensity.

Wrist Curls Slowly curl wrist with palm up until wrist is straight. Don’t grip the weight too tightly, as you will reduce blood flow to the forearm. Just hold the weight tightly enough so that it doesn’t drop and gradually increase your grip, as the weight becomes heavier. As your strength improves use a heavier weight. Soup cans can be used as weights. Do3setsof10oneachside.

Wrist Extensions Slowly curl wrist with palm down until wrist is straight. Remember not to grip the weight too tightly. Progressively increase using a heavier weight as your condition improves. Do3setsof10oneachside.

Wrist Flexor and Extensor Stretch With your arm extended and fingers pointing up, gently pull hand towards your body. Stretch to the point of mild tingling and not beyond. When the tingling subsides deepen the stretch and repeat until full range of motion is achieved. Over-stretching and tissue tearing are common with this problem so be careful. Repeat with fingers pointing down.

Wrist Rotations Grab a bottle or a stick and slowly rotate the wrist back and forth. Increase the weight and speed of movement as your condition improves. Do3setsof10oneachside.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 172 WRIST AND HAND

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 173 Introduction

Discomfort in the hand, wrist, and/or forearm is common in many industrial work environments. Many of the trades and maintenance positions require frequent manipulation of objects with the hands, and the use of vibrating power tools. Due to these exposures, trades and maintenance workers are at an increased risk for hand and wrist injuries. However, hand and wrist problems can be corrected, or even prevented, with simple exercises and work changes.

This manual covers the causes of hand and wrist problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 174 Functional Anatomy

Muscles used for gripping are found in the forearm.

These muscles attach to the elbow, run down the forearm, and turn into tendons.

These tendons pass under a thick band found at the wrist, and attach to bones in the hand and fingers.

The type of work found in trades and maintenance tasks places workers at risk of developing wrist problems like tendonitis.

Tendonitis can be caused by friction between the tendons, the sheaths, and a thick band of supportive tissue found at the wrist. Over a period of time, the tendons become irritated and painful. Two main factors affect the level of tendon friction: wrist angle and gripping force.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 175 Hand The tendons of the muscles used to bend the fingers attach to bones in the hand and fingers. Protective sheaths surround these tendons, allowing the tendons to pass through the wrist and pull on the fingers. The protective sheaths act to reduce friction between the tendons and surrounding tissues and bones.

Tenosynovitis can develop when the tendon sheaths become irritated, losing their friction-reducing capabilities. The main factor leading to this condition is repeated bending of the fingers.

The hand and fingers can also be damaged through exposure to hand-transmitted vibration. Exposure to vibrating tools or equipment can lead to a condition called Vibration White Finger. Over a period of time, nerves and blood vessels in the hand can break down, resulting in a loss of sensation, and decreased circulation in the hand.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 176 Body Mechanics Wrist Angles Friction between the tendons and the thick wrist band or bones is the main cause of wrist problems. When the wrist is straight, there is little or no friction between these structures. However, activities that require extreme wrist postures increase friction significantly. Tendons are forced against these structures when the wrists are bent, leading to swelling and progressive irritation. Over time, damage from friction can weaken the tendon or the tendon sheaths to the point of injury.

Wrist bent Wrist straight Wrist bent

Tendon friction increases significantly when the wrist is bent.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 177 Gripping Force The other main cause of tendon friction at the wrist is tension produced from gripping. The heavier the object being gripped, the greater the tension generated by the muscles. Tension in the muscle is passed through to tendons and can increase friction at the wrist.

In combination with extreme wrist postures, repeated or continuous gripping can gradually weaken tendon tissue to the point of injury.

10kg Muscle Tension 16kg Muscle Tension

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 178 Feedback The brain sends messages to the muscles to regulate the degree of contraction. Feedback from the muscles is sent back to instruct the brain that the message was carried out. If this feedback is distorted or interfered with, the brain loses its ability to determine the appropriate level of muscle contraction for the task. There are a few factors that may interfere with this feedback.

1) Cold Temperatures Exposure to cold temperatures can interfere with the feedback paths carrying messages back to the brain. This interference can lead to over-gripping of tools or equipment. Exposure to cold may also contribute to a decrease in tissue tolerance.

2) Gloves Wearing gloves while manipulating objects may also result in over-gripping, especially if the gloves do not fit well. The bulkier the gloves, the more distortion there will be in the feedback messages to the brain. This distortion will lead to an over-compensation in the grip force used to handle objects.

3) Vibration Exposure to hand-transmitted vibration can also distort the feedback messages returning to the brain, resulting in over-gripping of tools or equipment.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 179 Repeated Bending of the Fingers The main cause of irritation in the tendon sheaths of the fingers is repeated bending of the fingers. As the fingers are bent, the tendons slide back and forth through the tendon sheaths. The more the fingers are bent, the greater the likelihood for the tendons and their sheaths to become irritated. When the tendon sheaths become irritated, they will lose some of their friction-reducing abilities. Long periods of exposure and high forces can accelerate the irritation and injury of the finger tendons and sheaths.

Vibration Tools and equipment that vibrate at certain frequencies can cause the small nerves and blood vessels in the hand to deteriorate over time, which may lead to decreased sensitivity and circulation in the hands. Some examples of vibrating hand tools are impact wrenches, chain saws, and hand grinders.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 180 How Wrist and Hand Injuries Occur

To help understand how people develop wrist and hand problems, imagine the muscles and tendons in the forearm, wrist, and hand as being similar to a cable used to lift objects. Cables have load limits that should not be exceeded. If these load limits are exceeded, the cable will be damaged. In the body, these limits are referredtoastissuetolerances,andwillresultinaninjuryifexceeded.

Excessive Force Normally, the wrist and hand do not become injured from a single load application, unless the injury is traumatic. For example, falling on the hand and breaking the wrist would be considered a traumatic injury.

Injury Tissue Tolerance

Load No injury Landing on the Hand

Most injuries to the wrist and hand are not from a single overload event. Most injuries to the wrist and hand occur due to repetitive and/or constant loading, in combination with forceful gripping.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 181 Excessive Repetition The wrist and hand can become injured from repeated loading. Repeated loading could refer to a number of activities, such as repeatedly bending the finger to activate triggers, or repeatedly bending the wrist to operate a hand tool. When the tissues of the wrist and hand are repeatedly bent, they can weaken over time and injury may result.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 182 Excessive Duration Another common way to injure the wrist and hand is from constant loading. Tissues under strain in the hand and wrist may deform and weaken. The risk of injury increases when high force or repetitive motions are applied to weakened tissues.

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 183 Examples of Loading on the Wrist and Hand Carpenter Tasks Load

Time Force Repetition Force Static Posture Awkward Posture

Carpenters may grip and Carpenters may operate Carpenters operate carry materials to their power tools, some of stationary tools, such as work area. which require repeated table saws and routers. trigger activation. Some of these tools may require prolonged gripping of handles or controls with the wrist in a bent position.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 184 Electrician Tasks Load

Time Repetition Repetition Force

Electricians may perform Electricians may Electricians may be computer work. Repeated manipulate hand tools required to forcefully bending of the fingers when wiring and rewiring. grasp and pull on wires occurs when keyboarding, This work may involve and cables spools. These and repeated movements repeatedly bending the activities may introduce of the wrist occur when wrist and/or fingers. high forces to the tissues using a mouse. of the wrist and hand.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 185 Heavy Duty Mechanic Tasks Load

Time Force Repetition Force Static Posture Awkward Posture

Heavy Duty Mechanics Heavy Duty Mechanics Heavy Duty Mechanics use many different hand use many different hand may use tools to loosen tools. Some of these tools tools. Some of these tools parts that are stiff or rusty. may require prolonged may require repetitive This activity may forceful gripping in order bending of the wrist or introduce large forces to to operate. fingers in order to the wrist especially if it is operate. bent.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 186 Machinist Tasks Load

Time Repetition Force

Machinist may repeatedly Machinists may grip controls with significant force bend the wrists when when operating the lathe. usinghandtools (e.g., wrench).

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 187 Millwright Tasks Load

Time Force Repetition Force

Millwrights may be Millwrights may Millwrights may grip required to work in a cold repeatedly move the wrist heavy objects and carry environment, with the and fingers when them. This loading can hands exposed, for a operating hand tools and introduce high forces to prolonged period of time. manipulating parts. the wrist and hand. The cold temperatures can result in decreased sensitivity and over- gripping.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 188 Oiler Tasks Load

Time Force Repetition Force Static Posture

Oilers may grip and carry Oilers may repeatedly Oilers may be required to containers of oil for pump grease guns when grip objects forcefully prolonged periods of time. greasing machinery parts. when moving oil drums or Tissue tolerance in the lifting objects. This wrist will decrease faster handling can introduce when the wrist is in a bent high forces to the tissues position while holding the of the wrist and hand. oil containers.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 189 Painter Tasks Load

Time Force Force Force Static Posture Static Posture Awkward Posture Vibration Static Posture

Painters may grip Painters may use power Painters may be required different hand tools, such hand tools to prepare to operate various hand as spray guns, for surfaces. With these tools that involve prolonged periods of time. tools, exposure to hand- prolonged gripping in an transmitted vibration may awkward posture. occur.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 190 Pipefitter Tasks Load

Time Force Repetition Force Static Posture

Pipefitters may use power Pipefitters may be Pipefitters may loosen hand tools. These tools required to use hand tools, valves. This work may may require prolonged such as a hammer. The require significant gripping of the tool, use of some hand tools gripping and pulling exposing the user to hand- may require repeated forces, which can arm vibration. bending of the wrist or introduce large forces to hand. the tissues of the wrist and hand.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 191 Plumber Tasks

Loosening Load

Time Repetition Force Awkward Posture Repetition Awkward Posture

Plumbers may be required to use hand Plumbers may loosen and tighten valves tools, such as a hammer. The use of and fittings when repairing and building some hand tools may require repeated lines. This work may require significant bending of the wrist. grippingandtwistingforces,whichcan introduce large forces to the tissues of the wrist and hand.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 192 Welder Tasks Load

Time Force Repetition Force Static Posture Awkward Posture Awkward Posture Vibration Static Posture

Welders may grip Welders may use hand Welders may be required welding guns for tools periodically. The to operate various prolonged periods of time. use of some tools, such as powered hand tools that hammers or wrenches, involve prolonged may require repeated gripping in an awkward bending of the wrist. posture. In addition, exposure to hand- transmitted vibration may occur.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 193 How to Prevent Wrist Injuries

Use the information below as your guide to prevent wrist injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time Decrease Demands Increase Capabilities • Optimise wrist position while working • To increase tissue tolerances, perform • Purchase tools with good design and stretching and strengthening exercises for optimal grip widths the hand and wrist • Minimise exposure to vibration and cold temperatures • Provide appropriate sized gloves • Use power grip rather than pinch grip for forceful exertions • Use jigs, fixtures, or slides to minimise holding time with hands

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 194 Risk Control Key

Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 195 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the hand and wrist. Examples for the Hand and Wrist

E Engineering Controls

Load

Loading the hand and wrist Time

The hand and wrist will experience To reduce loading on the hands/wrists, significant loading when manipulating use an overhead hoist to manipulate heavy objects. Tasks requiring the heavy objects. manipulation of heavy objects, following hand/wrist exposure to repetitive or static work, increase the likelihood of injury.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 196 Examples for the Hand and Wrist

WP Work Practice WP Work Practice Controls Controls

Load

Loading the hand and wrist Time

The hand and wrist are To reduce loading on the To reduce loading, use a under significant load hand and wrist, some torque multiplier wrench or when gripping tools to workers use metal bars to a bolt-loosening spray. loosen nuts or bolts. increase tool leverage.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 197 Examples for the Hand and Wrist

WP E

Using impact gun while Using impact gun while Usingimpactgunwitha standing–awkwardwrist kneeling – better wrist tool balancer – less force postures. postures. on hand and wrist tissues.

Load

Loading the hand and wrist Time

The hand and wrist are To reduce loading on the To further reduce loading, under significant loading hand and wrist, proper use a tool balancer to when using heavy tools. work positions should be reduce the weight of the adoptedtoallowformore tool. neutral body postures.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 198 Increasing Capabilities Exercises for the Hand and Wrist Follow the instructions on this worksheet to strengthen and stretch tissue. Exercises should be done daily. Exercise pain-free.

Wrist Curls Starting with the weight in fingers, slowly close the hand and lift weight. As condition improves use heavier weight. Note: Soup cans can be used as weights. Do3setsof10oneachside.

Wrist Extensions Slowly lift weight until wrist is straight. As condition improves use heavier weight. Do3setsof10oneachside.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 199 Low Back

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 200 Introduction

When will you learn to lift with your legs and not your back?

Back programs have been around for some time. Unfortunately, the success of these programs has been limited. This limited success is evidenced by the increases in number of compensation claims, and subsequent costs, each year.

Too often “band-aid” solutions are used to address complex problems. Through better understanding of how back injuries occur, more practical and effective solutions can be developed.

This manual covers the causes of back problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 201 Functional Anatomy

The spinal column consists of vertebra (bones) that are separated by soft discs. The discs have layered fibrous walls, much like the plies on a radial tire. The centre of these discs is filled with a jelly-like substance. The discs act as shock absorbers for the spinal column and allow the back to bend and twist.

Through the centre of the spinal column run bundles of nerves which carry messages to and from the body and brain.

Muscles actively produce movement and stabilise the loaded spine.

Ligaments prevent movement at the end range of motion.

Spinal Cord

Vertebra

Disc

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 202 Body Mechanics Teeter Totter Principle (Torque) The amount of force back muscles must generate to stabilise the spine depends directly on how close loads are to the body. When loads are held farther away from the body, muscles in the back have to work harder, soft tissues of the spine are compressed more, and the risk of injury increases.

Weight in hand

Muscle tension to counter- balance weight in hand

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 203 The Hidden Load People wrongly assume that the load being lifted or held is solely responsible for an injury. It is difficult to believe that something like a small wrench being picked up from off the floor could be responsible for causing an injury.

People often forget about the hidden load - the weight of the body. Half of the body’s weight is above the low back. When the torso is leaning forward, the tissues of the back have to support this hidden load. For a 90 kg (200 lb.) male, this load would be 45 kg (100 lb.). Consequently, it is not the 1 kg wrench that is of concern, but instead the 45 kg of upper body weight.

Body weight

Muscle tension to counter- balance body weight

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 204 Neutral Spine (3 curves) The body has postures in which it is stronger and more efficient. These postures are referred to as “power positions”. In sports, athletes train their bodies to perform in power positions, allowing them to achieve maximum results.

The back is strongest in the neutral position, when the three-curve spinal alignment is maintained. If possible, workers should try to maintain a neutral spine when working.

3-Curve Position Pelvic Tilt

When this three-curve shape is lost, the natural strength of the spine, especially the load bearing capability of the lumbar region, is not being properly used. Lifting with a pelvic tilt forces the spine into a C-shape, placing more load on the weaker supportive soft tissues in the back. With frequent or extended loading in this position, injuries can result.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 205 How Back Injuries Occur

Your body is similar to a lifting machine in the sense that it has load limits, which if exceeded, will cause damage. These load limits are referred to as tissue tolerances. An injury occurs when a load exceeds tissue tolerances. Excessive Force It is rare that a single lift would be of sufficient magnitude to independently load back tissues to the point of injury. More commonly, it is a lift of smaller (sub- maximal) magnitude, in combination with previous repetitive and/or static loading, which results in soft tissue injuries.

Back injuries due to a single incident of excessive force are most often caused by accidents. For example, if you slip and land on your tailbone, the impact forces can significantly load the tissues in the back. Spinal ligaments can also be damaged when overloaded during a slip.

Injury Tissue Tolerance

No injury

Load Slip and Fall

Time

Most injuries to the back are not due to a single overload event. Most back injuries are from repetitive and/or constant loading.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 206 Excessive Repetition Repeated bending of the back can weaken tissues, like the discs. Similar to repeatedly bending a coat hanger until it breaks, this repeated bending gradually weakens spinal tissue to the point of failure. Repetitive loading on the back also decreases tissue tolerances. It is this decreased tissue tolerance, and accumulated load, that leads workers to injure their backs lifting a light object, after safely lifting and handling all day.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 207 Excessive Duration Constant loading on the back can also weaken soft tissues, like discs. When the back is bent, the jelly centre of the discs puts pressure on the fibrous walls. Constant loading causes cracks to develop in the walls of the discs. In some instances, the jelly centre can push through these cracks and press up against the nerve root. Practical examples of this injury mechanism are workers who injure their back from constantly sitting in a forklift, or working bent over for long periods. In both of these cases, the tissues of the spine are constantly loaded, resulting in a gradual tissue tolerance decrease to the point of injury.

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 208 Examples of Loading on the Back Carpenter Tasks Load

Time Repetition Static Posture Repetition Awkward Posture Awkward Posture Awkward Posture

Carpenters repeatedly Carpenters may have to Carpenters have to reach bend forward to adjust bend over and hold this forward and bend machinery. position when using a repeatedly when cutting circular saw to cut plywood on a table saw. plywood.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 209 Chemical/Computer Attendant Tasks Load

Time Awkward Postures Awkward Postures Force Repetition Static Postures

Chemical Computer Chemical Computer Chemical Computer Attendants may work Attendants may bend over Attendants that check and below knee level when for extended periods to change chemicals and cleaning filters and clean filters and inspect filters have to lift filters inspecting for leaks. for leaks. and heavy bags of When working at or near chemicals. Lifting heavy ground level, Chemical items places increased Computer Attendants may loading on the back. repeatedly bend over to pick up materials and tools.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 210 Electrician Tasks

Both One sides side Load

Time Static Posture Force Force Awkward Posture

Electricians may spend Electricians may handle Electricians typically long periods of time bent heavy spools of electrical carry a lot of tools with over working on electrical cable and parts such as them. Electricians that panels. control panels during carry tools only on one installations. side of the body increase the loading on some back tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 211 Fire Watch Tasks Load

Time

Awkward Postures Awkward Postures Force Repetition Static Postures Awkward Postures

A Fire Watch person may A Fire Watch person may A Fire Watch person may repeatedly bend forward have to bend over for have to apply force to lift, to monitor work areas, cut extended periods to lower, push, pull, and metal, and prepare the monitor for fires or assist carry heavy materials. In work site for the Welder. aWelder. some work layouts, these activities may also require awkward postures.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 212 Heavy Duty Mechanic Tasks Load

Time Static Posture Force Force Awkward Posture Static Posture Awkward Posture

Mechanics may spend Mechanics lift heavy Mechanics operate heavy long periods bent over parts.Loadingonthe impact guns, which working on mobile back is increased when significantly load the low equipment. lifting heavy objects back, especially when the below knee height. back is held in a forward bent position.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 213 Machinist Tasks Load

Time Repetition Force Repetition Awkward Posture Awkward Posture

Machinists repeatedly Machinist may lift heavy Machinists repeatedly bend over when working parts like chucks into bend over to set up on the lathe. lathes. The back is equipment. significantly loaded when handling heavy objects and leaning into machinery.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 214 Millwright Tasks Load

Time

Force Force Static Posture Awkward Posture Repetition Awkward Posture

Millwrights frequently fix Millwrights frequently Millwrights frequently chains that become worn use a come-a-long to work in confined areas in down or misalign. move machinery and equipment and Millwright often work equipment. Millwrights machinery. Millwrights hunched over which repeatedly pull on come- may spend long periods increases the loading on a-long levers. Loading on bent over fixing the back. Pulling on the back muscles is equipment. crowbars while bent over increasedwhenapplying can significantly increase more pull force. loading on the back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 215 Oiler Tasks Load

Time Static Posture Awkward Posture Force Awkward Posture

Oilers may hold an oil can Oilers may bend over to Oilers may have to handle away from their body pour oil in to the oiling heavy oil drums. when lubricating can. equipment. Reaching farther away from the body increases the loading on the back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 216 Painter Tasks Load

Time Awkward Posture Force Force Static Posture Awkward Posture Static Posture

Painters may spend long Painters lift heavy pieces Painters may perform periods bent over working and materials. Loading heavy physical tasks, such at low levels. on the back is increased as assembling pieces after when lifting heavy objects painting, while in below knee height. awkward trunk postures. This activity can significantly load the low back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 217 Pipefitter Tasks Load

Time Repetition Static Posture Force Awkward Posture Awkward Posture

Pipefitters may work at Pipefitters may bend over Pipefitters may be ground level when for a prolonged period of responsible for opening installing new pipes, and timetoweldandcut and closing valves. will repeatedly bend over metal. Welding at lower Valves that are difficult to to pick up materials and levels will increase the open will increase loading tools. amount of back bending, on the back. and increase loading on the back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 218 Plumber Tasks Load

Time Awkward Posture Force Static Posture Awkward Posture Static Posture

Plumbers assume awkward trunk Plumbers typically carry tools or postures to work at low heights. materials when walking to job sites. Plumbers that carry tools only on one side of the body, or that lift heavy tools and materials from floor level increase the loading on some back tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 219 Welder Tasks Load

Time

Repetition Static Posture Static Posture Awkward Posture Awkward Posture Awkward Posture

Welders repeatedly bend Welders may have to Welders may have to forward to measure bend over to weld bend over to grind pieces. material. Typically, material. Grinding Welders have to hold usually requires Welders these positions. to maintain fixed positions.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 220 Load

Time

Force Force Awkward Posture

Welders often handle and Welders may have to lift Welders often bend lift heavy pieces of metal. heavy welding tanks, forward to adjust welding Handling bulky pieces of which places significant equipment. metal increases the loading on the back. loading on the back.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 221 How to Prevent Back Injuries

Use the information below as your guide to prevent back injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time

Decrease Demands Increase Capabilities • Reduce the weight of objects • When possible, maintain 3 curve • Adopt postures that reduce loading spinal alignment when working on the back • Use morning exercises to get the • When possible, avoid repetitive back back ready for work bending and working hunched over • Use maintenance exercises to keep for long periods the back healthy

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 222 Risk Control Key

Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 223 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the back. Examples for the Back

WP Work Practice E Engineering Controls Controls

Tissue Tolerance

36% 19% 3% Load

Loading on the low back Time (% of capacity)

The spine is under To reduce loading on the To reduce loading on the significant loading spine, some workers slide spine further, use an when bending forward the chuck onto a wooden overhead hoist. This toremoveachuck. base, and pull the wooden lifting aid will reduce base into their hip. This loading on the spine from close carrying technique 36%to3%ofcapacity. can reduce loading on the spine from 36 % to 19 % of capacity.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 224 Examples for the Back

WP Work Practice E Engineering Controls Controls

Tissue Tolerance

25 % 9% 4% Load

Loading on the low back Time (% of capacity)

The spine is under To reduce loading on the To significantly reduce significant loading when spine, some workers use a loading, use an overhead pushing a heavy oil drum. drum dolly to move a hoist with a drum drum. Using a dolly can attachment. This lifting reduce loading on the aid will reduce loading on spine from 25% to 9% of the spine from 25% to 4%. capacity.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 225 Examples for the Back

Impact gun with back Impact gun while Using a tool balancer bent. kneeling. while kneeling.

WP Work Practice E Engineering Controls Controls

Tissue Tolerance

50 %17 % 13 % Load

Time Loading on the low back (% of capacity)

The postures adopted To reduce loading on the To reduce loading even when using an impact gun spine, some workers kneel further, use a tool place the spine under while using the gun. This balancer to reduce the significant loading. reduces loading on the weight of the tool. This spine from 50 % to 17 % change will reduce of capacity. loading on the spine from 50 % to 13 %.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 226 Increasing Capabilities Exercises for the Back Follow the instructions on this worksheet to get the body ready for work. The exercises are designed to warm-up the hip and leg muscles to improve flexibility. Improving hip and leg flexibility will help maintain the three-curve alignment in the back.

Squats (low back) Place feet shoulder width apart, sit down and then stand back up. Repeat 5 times.

Don’t squat too deep!

Hamstring Stretch Place the heel of one foot in front of the body, and bend the other leg. Keep your back upright and in the neutral position. You should fell this stretch in the back of the thigh of the forward leg. Hold for 5 seconds. Repeat 3 times with each leg.

Calf Stretch With back leg straight, press heel into ground. Hold 30 seconds. Repeat 5 times each side Repeat stretch with back leg bent

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 227 Follow the exercises on this worksheet to keep the back healthy. Perform the exercises daily

Gluteal & Lumbar Strengthening Trunk Twisting Lying on back with knees bent, press heels into Lying on side, bring knees up to chest. Breath ground and raise buttock. Squeeze the buttock in and as you exhale roll shoulders back. This and keep back straight muscles. exercise should be done pain-free. Hold 30 seconds. Repeat 5 times each side Hold 30 seconds. Repeat 5 times each side

Lower Abdominal Stretching Hip Stretch Raise one bent leg about a foot off the ground. Lying on back with one leg crossed over, pull Keep breathing leg towards chest (can be done against wall). Hold 30 seconds. Repeat 5 times each side Hold 30 seconds. Repeat 5 times each side

Erector Spinae Strengthening Quadratus Lumborum Strengthening On all fours, lift opposite leg and arm. Avoid Lying on your side, raise straight leg about a arching neck and back. foot off the ground. Hold 30 seconds. Repeat 5 times each side Hold 30 seconds. Repeat 5 times each side

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 228 KNEE

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 229 Introduction

When visualising a knee injury, one typically thinks of a skier “blowing out” their knee, or a football player collapsing from a “chop block”. This type of sports injury is an acute injury, where a single event causes the damage. Chronic injury occurs when an accumulation of stress causes tissue to wear out. Studies have shown that patellofemoral syndrome accounts for up to 50% of overuse (chronic) injuries in the knee. Patellofemoral syndrome is caused by an irritation of the contact surface between the patella (kneecap) and femur (thighbone). Over a period of time, this contact surface can wear and become rough, increasing the level of knee pain.

This manual covers the causes of knee problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 230 Functional Anatomy

Muscles activate to produce movement and stabilise the knee when loaded. The main muscle group for the knee is the quadriceps. There are four muscles that make up the quadriceps muscle group. They are the rectus femoris, vastus lateralis, vastus intermedius, and the vastus medialis.

The rectus femoris arises from the hip; the other three originate from the femur. All four muscles of the quadriceps converge to asinglethicktendon that attaches to the tibia (shinbone). The patella (kneecap) is located within this tendon.

There are four ligaments that stabilise the knee joint by preventing extreme motions. Cartilage acts as a stabiliser, as well as a shock absorber, for the knee. Tracking of the patella and tendons over the knee joint depends on four factors; the pull of the quadriceps muscle on the patella and tendon, the strength of the patellar ligaments, the depth of the indentation at the end of the femur, and the shape of the patella.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 231 Body Mechanics

Two things can affect the amount of stress between the kneecap and thighbone: knee angle and muscle imbalance. The more the knee bends, the more stress there will be between the kneecap and thighbone. When the leg is straight, there is little or no stress on the kneecap. However, activities that require deep knee bends place a significant amount of stress on the kneecap, and can lead to premature wear. Premature wear can subsequently lead to an increase in stress as a result of muscle imbalance.

Knee straight Knee bent Knee bent Knee bent 45 120 degrees 90 degrees degrees

1800 1200 900 450

The arrows above indicate that the stress in the knee increases significantly when the knee is bent past 90 degrees.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 232 Tradespeople like Millwrights, Welders, and Pipefitters often kneel for prolonged periods, exposing their knees to a lot of “wear and tear”. This wear can produce inflammation in the knee, which changes the mechanics of movement. Even minor knee inflammation can cause the inner quadriceps muscle (vastus medialis) to shut off. To compensate for this shut down, the outer quadriceps muscle has to work harder. Over time, the outer muscle becomes over-developed, and the inner muscle wastes away. Because of this muscle imbalance around the knee, the patella tracks more towards the outside. This poor tracking increases the stress between the kneecap and the thighbone, and can lead to premature deterioration of the kneecap and thighbone.

Muscle Balance Degenerative cycle of patellofemoral Muscle Imbalance syndrome

Damage to the knee results in changes in knee mechanics, which in turn increases contact stress. Increased contact stress results in more damage. Consequently, if problems go unchecked, permanent damage can occur. Damage Inflammation Patella Tracking Increased Patella contact stress Muscle imbalance Changes to knee mechanics

“The key with preventing these injuries is to Femur develop muscle balance around the knee to Healthy patella that Femur and patella ensure that the knee cap tracks properly.” fits symmetrically in with premature the femoral groove. wear.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 233 How Knee Injuries Occur

Your body is similar to a lifting machine, in the sense that it has load limits. If these load limits are exceeded, damage can occur. These load limits are referred to as tissue tolerances. An injury occurs when a load exceeds tissue tolerances. Excessive Force If an applied force exceeds tissue tolerances, you can damage the tissue being loaded, resulting in an injury. An example of a single incident of high force leading to tissue damage is a ski fall where the skier injures their knee.

Injury Tissue Tolerance No injury Load Accidental fall

In the workplace, slips and falls are common causes of knee injuries. This document’s emphasis is on knee injuries due to overuse issues rather than traumatic-type injuries.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 234 Excessive Repetition In the workplace, the knee can also become injured from repetitive loading. This repetitive loading reduces tissue tolerances and increases cumulative stress, weakening the tissue to the point of injury.

Tissue Tolerance

Load

Tissue tolerances decrease Time Tissue tolerances decrease With rest, more rapidly with a higher with repetitive loading. tissue tolerances are load. reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 235 Excessive Duration Another common way to injure the knee is from constant loading on the knee, such as kneeling for a long period of time. Under constant loading, tissues in the knee can weaken to the point of injury.

Tissue Tolerance

Load

Tissue tolerances decrease With rest, Tissue tolerances decrease Time with constant loading. tissue more rapidly with a higher tolerances are load. reset.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 236 Examples of Loading on the Knee Carpenter Tasks Load

Time Contact Stress

Carpenters may have to kneel, and hold this position, when building with plywood and other materials.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 237 Chemical Computer Attendant Tasks Load

Time Static Postures Contact Stress Awkward Postures Static Postures

A Chemical Computer Attendant may Chemical Computer Attendants may squat to check for leaks, clean filters, kneel for extended periods of time to mix and pour chemicals, and perform clean filters and perform maintenance. maintenance tasks. Kneeling on hard surfaces increases loading on the knees.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 238 Fire Watch Tasks

Load Time

Awkward Postures Contact Stress Repetition Awkward Postures Static Postures

A Fire Watch person frequently squats A Fire Watch person often has to to monitor for fires. Loading on the monitor for fire in hard-to-reach areas. knee is increased in the squatting In these conditions, a Fire Watch person position. may spend long periods kneeling or squatting.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 239 Heavy Duty Mechanic Tasks

Light Heavy Objects Objects Load

Time Static Posture Awkward Repetition Contact Stress Posture Awkward Posture

Mechanics may spend long Mechanics crouch down Mechanics kneel on one or periods crouched while to lift parts. Loading on both knees while working working on mobile the knee is increased when on machinery. Loading on equipment. lifting heavy objects the knee increases when below knee height. kneeling on a hard surface.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 240 Millwright Tasks

Time Load

Repetition Repetition Static Posture Awkward Posture Awkward Posture Contact Stress

Millwrights frequently Millwrights frequently Millwrights work in climb up on machinery to squat to check machinery confined areas in fix it. and equipment. equipment and machinery. Millwrights may spend long periods kneeling or squatting while fixing equipment.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 241 Oiler Tasks Load

Time Repetition Static Posture Contact Stress Awkward Posture

Oilers repeatedly climb Oilers may squat for Oilers may kneel for an stairs throughout the extended periods of time extended period of time shift. Walking on hard to pour oil into the oiling to grease machinery. surfaces and climbing can. Kneelingonhard stairs increases the load surfaces can increase the on the knees. loading on the knees.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 242 Painter Tasks Load

Time Awkward Posture Awkward Posture Static Posture Static Posture Contact Stress

Painters may squat to work at low Painters occasionally kneel to levels. Holding a squat position perform preparing and painting tasks leads to fatigue in the tissues of the at low heights. Stress is placed on lower extremities. the tissues of the knee when kneeling on hard surfaces.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 243 Pipefitter Tasks Load

Time Contact Stress Repetition Repetition Awkward Posture

Pipefitters may bend Pipefitters frequently Pipefitters repeatedly over to cut metal. crouch while installing climb ladders or stairs Kneelingonhard fittings on the end of a when installing or surfaces increases pipe, or performing repairing piping. loading on the knee. other work at low levels. Loadingontheknee increases as the depth of the crouch increases.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 244 Plumber Tasks Load

Time Repetition Awkward Posture Awkward Posture Contact Stress

Plumbers repeatedly climb ladders or Plumbers frequently crouch or kneel stairs when installing or repairing while installing fittings on the end of a piping. pipe, or performing other work at low levels. Loading on the knee increases as the depth of the crouch increases.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 245 Welding Tasks Load

Time Contact Stress Contact Stress

Welders may have to kneel on one In some cases, Welders may kneel on knee to weld material. both knees to perform some welding tasks.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 246 How to Prevent Knee Injuries

Use the information below as your guide to prevent knee injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time Decrease Demands Increase Capabilities • Where possible, sit instead of • Use daily exercises to improve crouching for extended periods kneecap tracking • Trytokeepworkandstorageat heights that do not require awkward knee postures • Use kneepads and anti-fatigue matting to protect the knee from contact stress

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 247 Risk Control Key

Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 248 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the knee. Examples for the Knee

PPE WP

Load

Loading on the knee Time

The knee is under To reduce the loading at To reduce loading on the significant loading when the knee, some workers knee, some workers will kneeling on hard surfaces. wear kneepads under, or sit instead of crouch or foam inserts in, coveralls kneel at a workstation. to prevent contact stress at the knee. Another method of reducing contact stress is to kneel on anti-fatigue matting. This mat will cushion the knee against hard surfaces.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 249 Increasing Capabilities Exercises for the Knee Follow the instructions on this worksheet to improve patella tracking. Exercises should be done daily. Let pain be your guide – do not overdo it.

Leg Extensions Place a soft ball or a rolled-up towel between the knees. Turn toes out slightly and gently squeeze knees together as you straighten legs. Repeat 10 times.

Step Downs Slowly step down keeping weight on the back foot. Keep kneecap over 2nd toe and try to minimise wobbling. Choose a small step and progress in height as knee strengthens. Repeat 10 times on each side.

Hip Abductor Stretch Cross one leg in front of the other and lean to the side. Gently stretch the outside muscles of the leg. Use a wall if needed to help your balance. Hold for 15 seconds. Repeat 5 times on each side.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 250 FOOT

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 251 Introduction

Feet may be the most abused part of the body. Day in and day out, the feet are subjected to harmful stresses. Over time, this stress can produce debilitating foot problems.

Plantar fasciitis is one of the more common foot problems found in industry. Typically, plantar fasciitis begins with a dull occasional pain in the heel and can progress to a sharp constant pain. The pain is worse in the morning or at the beginning of a shift.

This manual covers the causes of foot problems for workers with trades and maintenance duties. The manual also discusses areas of focus for ergonomic solutions, with problem-solving examples.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 252 Functional Anatomy

In the feet, there are many bones that combine to form a natural arch.

Ligaments in the bottom of the foot help to maintain this arch.

A tough fibrous band on the bottom of the foot starts at the base of the heel and travels down the foot towards the toes. This tissue is known as the plantar fascia. The role of the plantar fascia is to assist in walking by helping with the transfer of force through the feet.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 253 Body Mechanics

Alignment With good foot alignment, bones support the load transferred through the foot. With poor alignment, the soft tissues like ligaments and fascia are called upon to support more of the load. When soft tissue is loaded, it stretches and deforms. If this stretching is excessive, soft tissues can become permanently deformed.

Because of this reduced ability of soft tissue to withstand excessive or constant strain, people with pronation problems are at a higher risk of developing foot injuries. The poorer the alignment of the foot, the greater the risk of injury.

Good Alignment Poor Alignment (pronation)

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 254 If the ligaments in the bottom of the foot become permanently stretched, the natural arch in the foot will collapse. When this arch disappears, more strain is placed on the plantar fascia. Plantar fasciitis occurs when the fascia and the underlying musculature are damaged. Along with this damage comes inflammation. Heel spurs can develop where the underlying muscles attach at the heel. Because it is difficult to rest the foot, damaged tissue has difficulty healing properly. With every step, the fascia can become damaged further, allowing the injury to progress quickly.

Good Alignment Poor Alignment

With good alignment, With poor alignment, stress to the foot is thereismorestresstothe distributed evenly. inside.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 255 Tight heel cords Loading on the plantar fascia is increased when workers have tight heel cords (Achilles tendon). The two muscle groups that generate tension on the heel cord are the gastrocnemius and soleus. Gastrocnemius Gastrocnemius Thesemusclesarefoundinthecalfareaofthe leg. Soleus Soleus

Heel Cord (Achilles tendon)

To Check for Tight Heel Cords: • Sit on floor and pull the feet towards the body • If your ankle angle is greater than 90 degrees, you have tight heel cords • Use the heel cord stretch at the end of this section to reduce tightness

<900 >900

Angle greater than 90degrees Angle less than 90 degrees

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 256 Vibration Heavy machinery in sawmills produces vibration. This vibration can be very harmful to the body, especially at certain frequencies. The Tacoma Narrows Bridge collapse helps to explain how small levels of vibration can cause major damage.

Tacoma Bridge Collapse A light steady breeze was able to destroy the Tacoma Bridge structure. The bridge acted like a big spring. Depending on their dimensions, springs oscillate (move back and forth) at specific speeds or frequencies. This speedisreferredtoasthenatural frequency.

When the wind blew at the bridge’s natural frequency, the bridge began to oscillate.

The size of this oscillation continued to grow. Eventually, the oscillation was large enough to destroy the heavy deck structure of the bridge.

It was not the size of the windstorm, but the frequency, or speed, that caused the bridge to come down.

Vibration found in sawmills can have a similar effect on the human body. Even minor levels of vibration can be hazardous to workers if the vibration frequencies match the natural frequencies of body tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 257 How Foot Injuries Occur

Excessive Force Jumping from high levels onto hard surfaces puts excess force on the feet, which may result in an injury. Injuries occur when loading exceeds tissue tolerances of the feet.

Injury Tissue Tolerance

Load No injury

Time

Millwrights and other Trades/Maintenance workers may jump down from high levels, which places significant loading on the feet. If the load is large enough, an injury may occur.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 258 Excessive Repetition Most foot problems in industry do not occur from a single injury event like jumping from a high height. Generally, foot problems develop from repetitive loading, like walking. Just like a shoe, your foot can gradually wear out.

Tissue Tolerance

Load

Time Tissue tolerances With rest, Tissue tolerances decrease with tissue decrease more rapidly repetitive loading. tolerances with a higher load. are reset.

Oilers, Millwrights, and other Trades/Maintenance workers who walk for long periods may develop foot problems from repetitive loading.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 259 Excessive Duration Foot problems may also develop from constant loading, like standing in one place for an extended period of time. When standing still, the circulation of blood from the legs and feet to the heart is reduced. This reduced circulation leaves more metabolic waste products, typically removed in the return blood flow, in the legs, leading to increased fatigue and decreased tissue tolerances.

Tissue Tolerance

Load

Tissue tolerances With rest, Tissue tolerances Time decrease with constant tissue decrease more rapidly loading. tolerances with a higher load. are reset.

Machinists and other Trades/Maintenance workers who Trades/Maintenance workers who stand on ladders for long periods stand for too long can develop foot can develop problems with their problems. calves and feet.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 260 How to Prevent Foot Injuries

Use the information below as your guide to prevent foot injuries.

To tip the scales to avoid injury, decrease work demands and increase worker capabilities.

Work Worker Demands Capabilities

Injury No Injury

Tissue Tolerances Tissue Tolerances

Load Load

Time Time Decrease Demands Increase Capabilities • Reduce prolonged standing by using • Exercise to increase tissue tolerances sit/stand stools where practical • Remove/reduce harmful vibration • Place mats down on hard surfaces where workers stand all day • Foam insoles provide some cushion for workers who walk a lot • Replace shoes when they wear out

For additional solutions, see the solution sections on Workstation Design, Tools and Equipment, and Work Strategies.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 261 Risk Control Key

Risk control measures (solutions) are commonly grouped into four categories:

PPE Personal Protective Equipment These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In “Decreasing Demands”, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 262 Decreasing Demands

The following examples illustrate various methods of decreasing the demands for the foot.

Examples for the Foot

Engineering WP Work Practice E Controls Controls

Load

Loading on the Foot Time

Jumping down from high Stepping down from high Usingaladdertogeton levels can cause heights without jumping to and off of machinery excessive loading on the can reduce impact loading can significantly reduce feet. on the feet. loadingonthefeet.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 263 Examples for the Foot

Personal Engineering PPE Protective E Controls Equipment

Load

Loading on the Foot Time

Walkingonhardsurfaces The use of supportive Reduce the amount of for long periods can insoles with cushioning walking by using a bike cause foot problems from can reduce the wear and or truck to go longer repetitive loading. tear on the feet. distances, where feasible. Using a bike or truck also reduces any loads from carrying tools and materials.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 264 Examples for the Foot

E E

Load

Loading on the Foot Time

Standing for long periods The use of matting or When practical, using a of time on hard surfaces cushioning over hard sit/stand stool can can lead to fatigue in the surfaces where workers significantly reduce the tissues of the feet. stand for long periods of loadingonthefeet. time can reduce the static When the legs and feet loading on the feet by are unloaded, blood flow providing some and waste removal is cushioning. These floor increased. coverings also enable small movements of the legs, which allows for more return blood flow to the heart, and waste product removal.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 265 Increasing Capabilities

Purchasing the right shoe is an important first step in avoiding foot problems. A good shoe provides adequate support, and will help maintain proper foot alignment and reduce excessive wear and tear.

A good shoe will provide...

Good Arch Support People with very narrow feet may need custom- fitted footwear, or else risk ‘swimming around’ in their shoes.

OneFingerRule No less than one finger space in laces.

Good Heel Support

A strong heel counter helps keep your foot aligned. When a shoe wears out, pronation problems increase.

Old New Heel counter worn out

Buy durable shoes with a lot of support. Avoid buying lightweight work boots. Typically, the lighter the shoe, the less support it offers. Replace shoes on a regular basis. Invest in good footwear and allow your shoes to wear out, not your feet.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 266 Exercises for the Feet Follow the instructions on this worksheet to improve your foot alignment and strengthen foot muscles. Exercises should be done daily.

Toe Curls Place a towel down on a slippery surface and pull the towel in with the toes. To make it harder, place a weight on the end of the towel. Repeat 10 times on each side.

Toe Grabs Place feet together. Rotate knees outwards while using muscles in the feet to grab the ground. Hold for 10 seconds. Repeat 10 times.

Ball Rolling Roll a ball back and forth under the foot. Use gentle pressure. Continue for 2 minutes.

Heel Cord Stretch With your back leg straight, press your heel into the ground. Hold 30 seconds. Repeat 5 times on each side. Repeat stretch with back leg bent.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 267 Injury Prevention

The Injury Education section of the Work Manual explained that injuries might be prevented by decreasing the load on a tissue (decreasing demands) or by increasing the tissue tolerances (increasing capacities).

The focus of the Injury Prevention section is to provide problem-solving skills, in addition to specific solutions, to decrease loading on the tissues. These solutions, which include both general principles and job-specific recommendations, are divided as follows:

• Workstation Design Principles – how to make the workstation (e.g., layout, height, etc.) suit both the tasks and the workers.

• Tools and Equipment – guidelines for purchasing and/or modifying tools and equipment.

• Work Strategies – recommended work practices, administrative controls, and use of personal protective equipment.

Please note that exercises to stretch and strengthen the body, thereby increasing tissue tolerances, are given at the end of each body part module in the Injury Education section. This information has not been included in the Injury Prevention section.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 268 Risk Control Key

Risk control measures (solutions) are commonly grouped into four categories:

E ENGINEERING CONTROLS These include physical changes to workstations, equipment, materials, production facilities, or any other relevant aspect of the work environment, that reduce or prevent exposure to risk factors.

A ADMINISTRATIVE CONTROLS These include any change in procedure that significantly limits daily exposure to risk factors, by control or manipulation of the work schedule or manner in which work is performed. Examples include job rotation, rest breaks, alternative tasks, job enlargement, redesign of work methods, and adjustment of work pace. Some models of risk control include work practice controls within this category.

WP WORK PRACTICE CONTROLS These include techniques used to perform the tasks of a job, such as use of tools and equipment, manual material handling techniques, etc. Education and training are an integral part of ensuring effective work practice controls.

PPE PERSONAL PROTECTIVE EQUIPMENT These are devices worn by a worker to reduce the risk of injury, including gloves, kneepads, hearing protection, and leather aprons.

In this section, the icons next to the solution options indicate the type of risk control.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 269 Workstation Design Introduction

Trades/Maintenance workers may perform a variety of tasks at a number of workstations throughout a shift. The scope and organisation of these tasks often varies from day to day. Consequently, workers may find themselves in a variety of different work situations, with a different function and layout for each.

When laying out new workstations or modifying existing workstations, it is important to keep in mind these multiple users. Make sure work surfaces, tools, and controls are accessible to everyone who will use the workstation, and to anyone who has to repair the equipment. In the following pages, guidelines for laying out a workstation will be discussed from a general perspective. As well, a number of job-specific suggestions for Trades/Maintenance workers will be discussed.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 270 Introduction to design In general, all good design processes answer the same questions. These questions are:

1) What is the problem with the current design? Thorough knowledge of the existing design is critical to making solid changes. This information should include understanding the basis for the original design decision, as well as the strengths and weaknesses of that design. 2) What are possible solutions? Bringing together individuals from different backgrounds with a common interest in finding a solution creates a strong design group. Generating design alternatives should start as a wide-open brainstorming process, with the fine- tuning of ideas restricted to subsequent iterations. 3) Do any of these solutions already exist? Look for similar situations in other areas, either at your mill, another mill, or other industries. How has the problem been handled elsewhere? Has the solution been successful? Consult with specialists in the area for possible solutions. Speak with suppliers about products that could meet your needs. Use facts and research to understand the success of other solutions. 4) Which solutions could work for us? Identify solutions that would be appropriate for your situation. Narrowing your list of all possible solutions to a reduced set of logical possible solutions will allow your group to clearly consider each one. 5) Which solution is the most acceptable? The ideal design solution is individual to each situation. Weighing the impact factors (e.g., cost, acceptability, time to implement) for your group will allow you to choose the most appropriate solution. 6) How will the solution be implemented? Now that you have identified the solutions that are acceptable, locate the resources that are necessary to implement the solution(s). The IMIRP implementation guide should help you in this process. 7) Was the re-design successful? Follow up any change with an evaluation of the success, both short-term and long-term. Are injuries and discomfort down? Is productivity up? Respond accordingly to this new information.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 271 General Workstation Layout

Toooften,equipmentandmachineryareaddedtoanexistingworkstation,with little thought to layout and space. Without proper planning, new risk factors can be introduced into the worker’s environment, increasing the chance of the worker being injured.

New workstation design Ideally, the equipment for a workstation should be clearly defined by the requirements of the overall process. Once the necessary equipment and its uses have been identified, careful consideration should be given to the layout for this equipment. Issues such as workstation traffic patterns, order and frequency of equipment use, and material storage requirements should all be considered in arranging the workstation. Input from the workers is essential at this stage to develop a functional workstation. When the layout has been finalised, the design of the work area enclosure, including items like the locations for lights, doors, and electrical supplies, can be completed.

Existing workstation design Even when moving new equipment into a pre-existing space, it is important to understand the principles of proper work layout, and to have the flexibility to change the work area enclosure to suit changing needs. Items like double doors with a removable centre post and movable ceiling lights allow for workstations to be adapted for new equipment installations. Consult the workers at the workstation for ideas on proper layout and current needs, before making any changes.

Modifications may need to be made after the workstation is up and running, as small problems may arise. Feedback from the workers about the effectiveness of the workstation can pinpoint these problems and allow for quick and effective repairs.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 272 Example – Workstation layout

To illustrate the importance of workstation layout, consider the following series of tasks in repairing a cylinder:

1) Place cylinder on table 2) Get tools from locker 3) Secure cylinder in vise, and take apart cylinder 4) Drain fluids 5) Wash cylinder 6) Use grinder to smooth edges 7) Get parts 8) Use drill press to fabricate new part 9) Put cylinder back together

The original layout for the process, shown below, led to a lot of crossover in the flow of movement between tasks.

Unnecessary movements not only reduce work efficiency, but may lead to increased injury risk if they are performed while carrying heavy or awkward items. Frequent movements can also lead to general fatigue over the course of a shift.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 273 The new shop layout, shown below, improves the process flow for this task. In this case, the rinsing sink has been brought closer to the grinder to minimise the carrying distance. With fewer crossovers, there is less unnecessary movement.

Design workstation to be functional E Design the workstation to be functional and easy to clean up. For example, place waste bins and drainage containers in easily accessible locations, such as underneath counters or close to areas where the facilities are frequently needed.

Design workstation to minimise contact stresses E All sharp edges on work surfaces should be padded or rounded to eliminate contact stress. Good indicators of frequent contact with a surface are wear patterns in the paint, or areas where workers have installed secondary padding.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 274 GENERAL WORKSTATION ISSUES

Design workstations to fit different operators

Workstations should be adjustable to allow each worker to operate comfortably. Control locations, work surface heights, working reaches, and manual material handling requirements should accommodate comfortable ranges of movement for the full group of operators. Using general anthropometric tables can provide average size ranges. These ranges, however, may not be accurate for your working population. Using the dimensions of the mill population and/or specific workers can provide more accurate design dimensions for your specific workstation.

Designing workstations that encourage proper working postures can reduce loading of different tissues. For some tasks, specific postures may be more appropriate. As a guideline to tasks and postures:

Seated postures are most appropriate for lighter tasks, such as precision work, which require less force to be generated by the worker. A seated posture will isolate the muscles of the upper body, leaving these muscles to generate all of the force needed to complete the task without contribution from the lower body. Seated postures are also more stable because there are more points of contact with the floor, and the worker has a lower centre of gravity. Seated work is not conducive to movement across a large space.

Standing postures are more suited to tasks with greater force requirements, such as heavy lifting or hammering. The standing posture allows for motion and force to be transferred from the larger muscles of the legs to the upper extremities. Standing is also more suitable for tasks that cover large spaces.

Sit/Stand postures are best suited to tasks that require moderate force application. The sit/stand posture allows for some muscle force transfer from the lower body, yet provides the support and stability of a seated posture. Sit/Stand postures are also good for tasks where the operator is required to stand up and sit down frequently. The sit/stand stool should have a stable base in order to support this posture.

Designing some workstation areas or tasks for seated work, some for sit/stand, and some for standing allows an operator to alternate between postures, moderating the physical demands on individual tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 275 WORKING HEIGHTS –ISSUES

Any work that is too high leads to elevated shoulder postures and increased injury risk to the neck and shoulders. Work that is too low forces operators to use forward flexed neck and back postures, leading to possible overexertion of tissues in these areas.

The nature of the work also effects which heights will be suitable: • Precision work usually requires a high visual aspect, with little muscle force required. This work should be performed on surfaces slightly above elbow height, with support provided for the arms, bringing the work closer to the face.

• Manual work should be performed at levels slightly below elbow height, providing space for tools and materials. Bringing work to this height will allow more force to be used when necessary while still allowing the worker to see finer detail if needed.

• Heavy work should be well below elbow height, allowing for more force application from the upper body to tools and materials.

• Seated work should be light in nature, as previously discussed. Arm supports and adequate leg clearance should be provided.

• For visual tasks, displays should be raised (or angled) such that the operator does not have to bend forward at the back or neck. Viewing angles 0° to 30° below a horizontal line from the eyes allow for comfortable eye movement and focus.

An Electrican working on a computer in a An Electrician working on a computer in a standing posture. This working height puts seated position keeps the neck in a more the neck in an awkward posture. neutral posture.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 276 For manual lifting tasks, work should be kept at heights that do not require extreme postures. As loads increase, it is advisable to keep lifts near waist level, allowing for neutral trunk postures.

Welders lifting oxygen tanks will lift from Lifting objects from or near waist height, low levels. This places the back in an like this Millwright, places the back in a awkward posture. much more neutral posture.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 277 WORKING HEIGHTS –SOLUTIONS

Adjustable work surfaces E Adjustable height work surfaces (e.g., scissor tables) can meet the needs of most tasks and workers. Any adjustable features should have solid locking mechanisms to prevent accidental collapse.

Multi-level work surfaces E Multi-level work surfaces can allow workers to easily transfer tasks from one height to another as required.

Lifting the worker E Lifting the worker, using ladders, stools, Man-lifts, or custom steps, can bring tasks to a more appropriate height. Similarly, equipment jacks, lifts, or floor pits allow a worker to work on low height items without extreme forward bending.

Adjusting keyboard height Adjust your keyboard so that your wrists are straight when your fingers are E WP on the middle row of keys. This position is also good for hunt-and-peck typists. If your work surface doesn’t adjust, raise or lower your chair so that your wrists are at the right height. Keeping your wrists straight will reduce your risk of injury.

Addingafootrest E If your feet are dangling above the floor because your seat and work surface are high, you may want to get a foot rest. Supporting your feet prevents the front edge of your seat from cutting off the blood circulation to the lower half of your legs.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 278 Extensions E Extensions on low height controls or fittings can reduce forward bending by bringing the action closer to the worker. In the example below, extended grease fittings have reduced the bending of the Oiler.

Oiler greasing rollers below floor level. By extending hoses from the rollers to The Oiler has to kneel on both knees and waist level, the Oiler can grease without bend forward at the back and neck. kneeling or bending forward.

Screen height E Adjust your screen height so that the top line of text on your computer WP screen is at eye level. Simply putting a book or other flat object under the screen can increase the height, while placing the monitor on an adjustable arm provides more flexibility in positioning. Adjusting your screen height can reduce the neck discomfort and fatigue of constantly looking down or up at the screen.

Note: For bifocal glasses wearers, you may want to lower your screen so that it is more easily viewed through the bottom of your lenses.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 279 WORKING REACHES –ISSUES

Working reaches that are too far can require stressful shoulder, elbow, wrist, and back postures, increasing tissue loading. Reaching to the side, behind, or too far in front of the body can put stress on the smaller muscles.

The nature of work also effects which reaches will be suitable:

Working reaches should be within a normal reach envelope, as shown below, with the controls, materials, and tools that are handled most often closest to the body. Generally, the most frequently used items/tools should be placed within a forearm’s reach (1), this will prevent awkward postures of the shoulders and low back while working. Less frequently used items/tools should be placed within a comfortable arm’s reach (2), and infrequently used items/tools placed within a fully extended arm’s reach (3). Since these items are used less frequently, awkward postures would be assumed less often.

1 = Controls/items most frequently used 2 = Controls/items less frequently used 3 = Controls/items least frequently used

Controls for equipment, should be close to the worker and should be grouped together to decrease awkward reaches and hand postures. This is especially true for controls that have similar or combined functions.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 280 WORKING REACHES –SOLUTIONS

Angled work surfaces E Angled work surfaces, especially control consoles, can maintain the same control spacing while bringing the farthest controls closer to the operator, as compared to the same console in a horizontal orientation. Workbenches angled towards the worker also provide variable working heights and reaches for different tasks. Clamps or stops should be provided to hold the work object in the desired position on the angled bench surface.

Low friction work surfaces E Low friction work surfaces allow a worker to slide an object using less force. Sections of rollers or polyethylene plastic inserted into a bench can provide an area where easier reaching for and handling of an item can be performed.

Cut-outs E Bench and machinery cut-outs allow the worker to get closer to the task as required. This will reduce awkward postures of the shoulder and the low back from reach distances.

Double-sided benches E Double-sided benches and tables (islands) allow the worker to reach pieces from either side. This flexibility will reduce reaching distance when working from either side of the table, in turn reducing awkward postures of the low back and shoulders. Each side could be of slightly different height to accommodate for varied user heights.

Double-sided bench

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 281 Turntables E Countertop turntables can be used when operators need to work on multiple sides of a large item. The operator can simply rotates the turntable to work on one side of the item, and turn it back when finished.

Slide-out drawers E Slide-out drawers will help to eliminate reaching underneath benches and tables and into tool or parts cabinets. Keeping these drawers at waist level can also reduce the loading during lifting.

Open-top storage cabinets E Storage cabinets that open from the top, as well as from the front, reduce the need to reach under horizontal surfaces to retrieve large tools or materials, such as buckets of oil and shovels. These storage cabinets are especially useful when the storage is low in height.

Open-top storage cabinet

Viewing distance E Viewing distance to a computer screen should be about arm’s length. WP Sitting any closer could potentially cause neck and eye fatigue.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 282 Location of computer mouse E Re-position the mouse so that it is close to the keyboard and at the same height. If the mouse is used much more than the keyboard, re-position the mouse so that it is on the desk directly in front of the shoulder of the arm that uses the mouse. If armrests are not present, move everything back on the table so the worker’s arms can rest on the table while using the mouse. Supporting the arms will help to reduce shoulder and upper arm fatigue.

Position for Position for mainly keyboard mainly mouse use use

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 283 MANUAL MATERIAL HANDLING –ISSUES

Trades/Maintenance personnel have to handle a variety of heavy, large, and awkward-to-handle equipment. Lifting, lowering, pushing, pulling, carrying and gripping are all ways that workers may have to manually handle items.

• Lifting and lowering large loads increases the demands on the tissues of the back and shoulders, which increases the risk of injury. These injury risks are even greater when the lift starts or ends at extreme working heights, either high or low. Repeated handling of loads also increases the risk of injury as the tissue fatigues.

• Forceful gripping of items increases the risk of injury to the tissues of the elbow and wrist. Forceful gripping is required when objects have no handles, inappropriately designed handles, or when objects are too small (e.g., fine screws) or too heavy to be safely handled. Hand tools that do not provide sufficient mechanical advantage (e.g., short handled wrenches, jammed grease guns) also increase the force required to complete a task.

• Pushing or pulling large loads also increases the demands on the tissues of the back, shoulders, elbows, and wrists, which increases the risk of injury.

• Carrying large loads long distances increases the demand on the tissues of the shoulder, elbows, and wrists, which increases the risk of injury. The risk could be greater if the load is unstable or the floor surface is slippery or uneven.

Combining any of these risk factors, a common situation in most manual material handling tasks, leads to a subsequent increase in the risk of MSI.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 284 MANUAL MATERIAL HANDLING –SOLUTIONS

Mechanical lifts E Provide mechanical lifts to reduce the force required for handling. Lifting WP heavy objects can place large loads on the tissues of the shoulders and back. Using overhead hoists, rolling carts, stacked pallets, scissor tables, and waist level storage can reduce the work of lifting and carrying by keeping loads at waist level. Workstations should be designed with mechanical lifts. These can be:

On tracks – e.g., electric overhead hoists, swinging gantry cranes to lift and lower, as well as carry, objects Wheeled – e.g., engine lifts, fork trucks, dollies to push, pull, carry, lift, and lower objects Stationary – e.g., overhead hoists, ramps to lift and lower items

Low friction work surfaces E Low friction work surfaces can be used to minimise the force required for handling items on a bench. Examples include angled workbenches, bench- top rollers, and polyethylene plastic work surfaces. These surfaces will not be appropriate for some tasks, such as welding or soldering.

Subdividing large loads E Subdividing large loads, or storing large or frequently used items closer to their location of use, can reduce the magnitude and duration of loading during handling.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 285 SEATING –ISSUES

For some tasks, seated postures may be more appropriate. As a guideline to tasks and postures:

Seated postures are most appropriate for lighter tasks, such as precision work (e.g., soldering or working on a computer), which require less force to be generated by the worker. Seated postures are more stable because there are more points of contact with the floor, and the worker has a lower centre of gravity. Seated work is not conducive to movement across a large space.

Sit/Stand postures are best suited to tasks that require moderate force application (e.g., a Millwright sharpening a chainsaw). The sit/stand posture allows for some muscle force transfer from the lower body, yet provides the support and stability of a seated posture. The sit/stand stool should have a stable base in order to support this posture. Sit/stand stools are also good at workstations where operators often change from sitting to standing, even within one task.

Where applicable, designing some workstation areas or tasks for seated work, some for sit/stand, and some for standing allows an operator to alternate between postures, moderating the physical demands on individual tissues.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 286 SEATING –SOLUTIONS

Design considerations E Provide well-designed and suitable chairs for the task, and maintain them. When providing a new chair, make sure that workers know how to adjust and use it properly. Any work seating needs to be properly installed to provide maximum benefit. For Trades/Maintenance jobs two types of seating may be needed:

1. Office seating used for computer programming, inventory keeping, and other office work should have an adjustable backrest with lumbar support, adjustable seat pan height and tilt, and adjustable armrest height and angle. The chair should also have a footrest, a contoured waterfall edge on the front of the seat pan, breathable fabric, and five casters.

2. Industrial seating used in workshops, such as stools, benches, and sit/stand stools, should be appropriate for the task at hand. For example, when moderate force is required to accomplish the work, a sit/stand stool may be more appropriate than a bench, as the sit/stand stool allows for force generation in the leg muscles. The seating should also be stable, adjustable in height when possible, and made of a material that is comfortable and durable.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 287 FLOORING –ISSUES

Many Trades/Maintenance people stand continuously while working at machines. Static standing on rigid flooring can lead to blood pooling in the legs, and discomfort in the feet. Standing on uneven flooring can lead to increased muscle activity to maintain balance. This prolonged muscle activity can lead to fatigue.

Walking on uneven, vibrating, or slippery flooring can increase fatigue in the lower body because muscles are constantly working to maintain balance. Also, increased force is required to pull or push carts and dollies on uneven flooring.

FLOORING –SOLUTIONS

Anti-fatigue flooring E Anti-fatigue flooring reduces the static component of standing by continually allowing the feet to experience micro-movement. These micro-movements increase blood circulation in the lower extremities and decrease foot tissue fatigue.

Repair and maintain walkways E Repair and maintain walkways to prevent slipping hazards, vibrating, or uneven surfaces. This maintenance reduces the risk of injury to the lower extremities.

Anti-fatigue insoles PPE Anti-fatigue insoles may help to combat fatigue and discomfort in the lower extremities for Trades/Maintenance workers that walk a great deal of the shift. Anti-fatigue insoles act as extra cushioning and support for the worker’s foot.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 288 ENVIRONMENTAL CONDITIONS -ISSUES

Trades/Maintenance personnel may have to work in unusual or extreme environmental conditions. These conditions may not directly contribute to an injury but may indirectly contribute to one.

Poor ventilation can leave workers exposed to fumes, dusts, and other irritants. This can cause difficulty in breathing or just irritation and added stress for the worker. The worker could then tense up and increase the force required to perform atask.

Lighting at low levels can lead to awkward postures as workers attempt to get closer to their tasks when performing precision work. Too much illumination, however, can cause glare, either directly from the light source, or indirectly off reflective surfaces. Shadows are also created by too much illumination. Glare or shadowing can cause eyestrain or result in workers adopting awkward postures to see around the glare or shadows.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 289 ENVIRONMENTAL CONDITIONS –SOLUTIONS

Local ventilation E Local ventilation on articulating arms can remove irritants from specific work areas.

Task lighting E Task lighting can be installed on shop machines to improve illumination. This lighting should be on some sort of adjustable arm so the light can be focussed where required.

Headlamps A Lightweight headlamps can PPE be used to provide hands- freelightinginclosedwork areas, such as machines.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 290 Improve lighting

E • Add task lighting. Focus the lighting on areas where it is needed.

• Add indirect lighting. Glare is reduced with indirect lighting.

• Add or improve diffusers or shields. These devices will help reduce glare.

• Use materials that are less reflective to reduce indirect glare.

• Use “warm” coloured lighting to provide tones closer to natural light.

• Make sure you have good placement of lights.

• Using a light background with darker lettering on computer screens to reduce glare. It is good to avoid the following: • Using too many colours on your screen at once. Too many colours can be confusing. • Extreme colour contrasts, such as red and blue. These extreme contrasts can fatigue your eyes more quickly. • Colours with minimal contrast, such as white on yellow. • The combination of yellow on green, which creates a vibrating effect on the screen.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 291 Job-Specific Workstation Design Suggestions

CARPENTER

Increase table surface on stationary machines E To decrease awkward postures and force on the shoulders and back, build a larger surface around table saws. This increased table area will provide more support and stability for cutting larger pieces of wood. The larger table surface should be designed not to increase working reaches or obstruct the operator’s access to the saw. Sawhorses, portable roller stands,orcartscanalsobeusedtosupportwoodwhilecutting.

Storage for plywood E To reduce forceful and awkward postures of the shoulder and back, WP plywood should be stored in brackets, organised by thickness and size. This form of storage will reduce the need to sort through numerous sheets of plywood to find the right size.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 292 CHEMICAL/COMPUTER ATTENDANT

Bike E In order to decrease repetitive motion of the ankle/foot, use a bike to get from place to place when monitoring systems around the mill.

A three-wheeled bicycle with a basket allows a Chemical Computer Attendant to move safely around the mill with tools and materials.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 293 ELECTRICIAN

Armrests E Make armrests available at workstations where precision work (e.g., soldering) is done. These armrests can be permanent or removable, and can help reduce static work of the shoulders as well as contact stress on the forearms (e.g., when working at a bench for extended periods of time).

Seated posture WP Prolonged seated postures (e.g., when Electricians program the computers) can contribute to fatigue and discomfort of the back and lower extremities, due to the awkward and static nature of the posture.

To decrease the chance of fatigue and discomfort, encourage the worker to change their posture throughout the day. This change can be easily done while in the seated posture by simply adjusting the chair to different positions. To change postures, the worker can change the positioning of any adjustable feature on the chair, such as tilting the seat forward, moving the backrest back, adjusting the seat height, or even angle of the armrests so they support the arms more. It is also important to occasionally get up and stretch for a few minutes. This stretching will help reduce the risk for injury by restoring tissue tolerances.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 294 HEAVY DUTY MECHANIC

Portable work surfaces E Moveable tables, carts, or other items can be used as a table surface for parts and/or tools when working on machinery. Storing tools and parts on a portable table can reduce working reaches.

Working on taller machinery E Heavy Duty Mechanics can use stepladders to raise themselves up to taller machinery. Shown here is a stepladder with weight- responsive rollers. Locking mechanisms on the wheels will be necessary.

Creepers E In order to keep Heavy Duty Mechanics at appropriate work heights, creepers can be provided for work under machinery. Creepers should have appropriate head and neck support. Six wheels are more stable than four. Lightweight equipment E In order to reduce the loads handled, make sure tools and equipment are lightweight. For example, fibreglass ladders should be chosen over steel ladders. Seating for low height tasks E In order to reduce contact stress on the knees when working lower down on machinery (e.g., when greasing some parts) provide the Heavy Duty Mechanics with a rolling stool or chair. This seating may also aid the mechanics in varying their work postures throughout a task.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 295 MACHINIST

Working at machinery E Machinery that requires forward flexed postures to operate (e.g., lathe, drill press) should be raised to minimise these postures. If machinery cannot be raised for structural reasons, pits can be created around machines to allow machinists to work at comfortable heights. The edges of pits need to be clearly marked to prevent trips and falls.

Secondary tool bin E Setting up a secondary tool bin in the mill can reduce heavy carrying and repeated trips for Machinists who generally work out of a shop.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 296 MILLWRIGHT

Access panels E To decrease awkward postures of the wrist, hand, and elbow, cut access panels into machines or equipment, such as unscramblers, so that the Millwright can get at problem areas more easily.

Hinged motor mounts E To decrease the force required when fixing belts, place the motor base on a hinge. When the belt has to be changed, the motor can be swung free after one bolt has been loosened. With this system, the Millwright will not have to pry the belt on with a screwdriver.

Motor on regular base Motor on hinged base

Accessible motor locations E To decrease awkward postures of the shoulder, neck, and low back, extend shafts so that motors are out from under chains and off to the side. This should allow for easier access when belts have to be changed or motors fixed.

Warning light panel E A warning light panel or phone system can identify which trade/maintenance person is required where. Efficiency can be improved with these systems.

Area warning system Tradesperson warning system

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 297 OILER

Whiplines E The installation of whiplines throughout the mill will reduce the amount of lubricants that must be manually transported. Whiplines allow lubricants to be pumped from a central storage location to all areas of the mill.

Pumping stations E To decrease the distance that the lubricants have to be manually transported, set up several pumping stations around the mill. These stations can be barrels that are set up in the basement (transported into place with dollies or Bobcats) that the Oiler can access throughout the shift, to retrieve the necessary lubricants.

Lifting aids E Provide dollies, loaders, or hoists to move oil barrels from one location to another.

Portable lighting A To improve lighting, the Oiler PPE can wear a lightweight headlamp when working under and in machinery.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 298 PIPEFITTER

Lifting workers E Pipefitters may spend long periods of time on ladders working overhead on pipes in compromised working conditions. Where possible, scaffolding or a Man-lift should be used to provide a more stable support. Man-lifts are most desirable because they allow for changes in working height and working posture.

Pipefitter working at ceiling height.

Pipe holders E To reduce bending of the back and neck when working on pipe, use pipe holders or stands, and adjust the height to above waist level.

A Pipefitter cutting a piece of pipe on Tripod Stand the floor with a circular saw

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 299 WELDER

Automatic cutting table E In order to reduce static and awkward postures of the neck, shoulder, and low back, an automatic cutting table may be used. The metal to be cut is placed on the table, secured, and then the desired dimensions are programmed into the machine. This solution is most appropriate for situations where there is a lot of fabricating or cutting of metal.

Material holders E In order to reduce awkward postures of the neck and shoulder region, objects (e.g., hog fuel hammers) can be placed in an adjustable holder or jig for welding. The holder is made from a pipe fixed in a vise, along which a hammer is inserted. Two bracket templates made of brass are placed on either side. Once the hammer unit is in the desired position, it is held in place by tightening the end plug (screw mechanism).

Fire retardant anti-fatigue matting E Welders often stand in one place on steel floors for extended periods of time. When welding torches fall onto the steel floor, there is the potential for a spark to occur. In the workshop, the area around the workbench should have fire retardant flooring that has some anti-fatigue component. When a Welder is not in the shop, and welding is required, it may be desirable to carry a piece of the matting on a cart to the welding area.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 300 Rest stand for torch E Welders often place torches on tables or other machinery when they are not in use. This can make the torches more susceptible to falling and being damaged. When torches fall, Welders bend down to retrieve them. An adjustable stationary stand would be useful around a workbench, while a clip-on device would be handy in areas outside of the shop.

Proper ventilation E Welders may work in environments that require proper ventilation to remove harmful fumes from the welding/brazing process. In the shop environment this is somewhat easier to contend with. For enclosed areas, where sufficient ventilation is not available, portable ventilation systems should be used.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 301 Tools and Equipment Introduction

Trades/Maintenance workers perform a variety of tasks using a number of different hand tools, power tools, and pieces of equipment in the process. It is important that the tools and equipment available be evaluated properly, as they can have a substantial impact on the risk of musculoskeletal injury. The following pages provide guidelines for purchasing and/or modifying tools and equipment from a general perspective, as well as job-specific suggestions.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 302 Tools

Hand tools and power tools are used for a variety of applications in Trades/Maintenance jobs. Before purchasing new tools or modifying existing tools, the following questions should be asked: What is the purpose of the tool? The tool should suit the task at hand. When inappropriate tools are used to perform a task, the tissues of the neck, shoulder, elbow, wrist, and hand can experience increased loading. Whowillbeusingthetool? If both men and women will be using certain tools, the hand dimensions and grip strength of both groups should be considered when evaluating the tools. Generally, women tend to have smaller hands and less grip strength than men. Howwillthetoolbeused? The orientation of the work and the work surface should be considered when deciding on the tool to be used and the orientation of the tool handle. Tools of proper design will allow workers to use “power positions”. Willthetoolbeusedwithgloves? If a tool is to be used with gloves, careful evaluation of the tool grip and gloves will be required. Gloves can increase the grip force required to maintain control of tools or equipment. Ensuring that the gloves are as thin as possible, with a good grip, and that the tool handle accommodates the glove thickness is important for gloved work with hand tools. How long will the tool be used for? If the tool is to be carried or held frequently and/or for long periods of time, the tool should be lightweight, and a very careful evaluation of the hand postures required to operate the tool will be needed. If the tool is to be used infrequently and/or for short periods of time, these factors may be less important. Having clear answers to the above questions will aid the Trades/Maintenance worker in focusing on important aspects of tool design, making sure these tools are suited to the task and situation at hand. Once a clear understanding of the purpose, intended use, and length of use of the tool is gained, the factors outlined on the following pages should be reviewed.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 303 GUIDELINES FOR TOOL PURCHASING,MODIFICATION, AND USE

The size and shape of the tool and the tool handle can have a direct effect on the amountofgripstrengthrequiredtooperatethetool,andthusontheloadingonthe structures of the hand, wrist, and forearm. When evaluating the size and shape of the tool there are four main factors to keep in mind: wrist and arm postures, tool grip, handle size, and tool weight.

WRIST POSTURES When operating tools, the wrist may be forced into a bent position. Most commonly, the handling of tools requires the operator to bend the wrist so that the pinky finger moves closer to the forearm (ulnar deviation). When the wrist is placed in this bent position, the force generated in the muscles of the forearm increases, leading to an increased risk of injury in the soft tissues Ulnar Deviation of the elbow, forearm, wrist, and hand.

Bent handled tools E In order to keep the wrist in a neutral posture when handling tools, bent handled tools may be considered for situations where bent wrist postures might otherwise result. There are a number of common tools that are available with bent handles. For example, bent handled hammers or pliers are now available. A Millwright would use a bent handle wrench to get into tight spaces. Using this tool would allow the wrist to maintain a neutral posture, decreasing the risk of injury to the worker.

The bottom hammer in this picture has a slight curve at the end of the handle. This curve allows a more neutral posture of the wrist to be maintained when using the hammer, as compared to regular handles. This handle orientation is most effective for hammering on horizontal surfaces.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 304 Orientation of tool handle E In order to keep the wrist in a neutral posture while operating tools, the grip style of the tool (pistol grip, in-line grip) should be considered together with the orientation of the work/work surface.

Pistol Grip In-line Grip

In general, pistol grip tool handles may be more appropriate when the work is vertically oriented in front of the worker, while in-line tool handles may be more appropriate when the work is horizontally oriented in front of the worker. Keep in mind the direction of force required with the tool (e.g., forward or down).

Use of pistol grip drills on a horizontal work surface, leading to awkward postures of the shoulder, elbow, and wrist while applying downward force.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 305 ARM POSTURES

If extreme wrist postures are required when operating a tool, the operator may elevate the arm to reduce some of the stress on the wrist area. This elevation can introduce increased loading on the shoulder joint. If the tool is not too heavy, a small amount of arm elevation may be acceptable. However, it may be necessary to consider the use of pistol vs. in-line tool grips, and to evaluate the height and orientation of the work surface in relation to arm postures.

When evaluating wrist postures during the use of particular tools, it would be wise to note what arm postures are adopted as well. Aim to minimise both bent postures of the wrist and elevation of the arm.

TOOL GRIP

When tools must be gripped with high force, greater loading is placed on the soft tissues of the elbow, forearm, wrist, and hand. Tools should have handles that minimise the grip force required to grasp them. The following features can help to reduce the grip force required by the operator.

Maximise friction between hand and tool E Try to maximise the friction between the hand and the tool handle. If WP gloves are worn, ensure that gloves are close fitting with a “sticky” palm surface. Wrapping the tool handles with foam, rubber, or medical/ athletic tape, or modifying the surface of the tool handle (e.g., gritty paint or grooves) can also increase the friction between the operator’s glove and the tool handle. Grooves have been carved into the wooden handle of this hammer. The presence of the grooves allows for greater friction between the worker’s gloves and the tool handle, decreasing the grip force required to hold on to the tool.

While surface finishing of handles is suggested to reduce grip force requirements, rough modifications like these grooves should be used only on an interim basis. Other injuries, such as contact stress damage in the hand due to irregular loading on the groove edges, can sometimes result from extended use of makeshift solutions.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 306 Flared handles E Tools with flared handles provide a stop for the fingers and thumb while using the tool. This stop prevents slipping and helps to decrease the grip force used by the worker when operating the tool.

The flare at the base of the handle provides a stop for the fingers and the thumb. This flare can help to reduce the grip force required to maintain control of the tool.

Tool handle grip E In order to reduce contact stress on the palm and to facilitate ease in gripping tools, tool handles should have a cushioned grip with no sharp edges.

The tool handles are narrow and may dig into The pliers have wide cushioned handles, with the palm and fingers when gripped tightly. flared grip stops to prevent slipping.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 307 Spring return mechanism Tools which require a grip and release motion (e.g., pliers) should have a E spring return mechanism. This will help to reduce the repetitious gripping motion required when using these tools.

The pliers shown here have a spring return mechanism. Once the grip on the tool is released, the handle will return to its original position.

Keep tools clean WP In order to reduce the force required to grip tools, ensure that tool handles are kept clean of slippery fluids and debris.

HANDLE SIZE

Tool handle length E In order to distribute the force of gripping and operating the tool evenly across either side of the palm and fingers, handle length should not be so short that the handle rests on the soft area of the palm, which can lead to increased stress on the hand. Handles also need to be long enough to provide adequate leverage to perform required tasks.

Tool handle width E The size of the handle can effect how much grip force is required to grasp the tool. There is an optimal grip width at which the force on the tissues of the elbow, forearm, wrist, and hand is minimised. Anything wider or narrower than this optimal width will require larger grip forces, and will increase the loading on the elbow, forearm, wrist, and hand. • For tools which require a grip and release motion (e.g., pliers) the maximum grip span should be equal to a comfortable open span of the hand(approximately5to8cm). • For cylindrical handles, the maximum diameter of the tool handle should allow for a slight overlap of the thumb and index finger. • If gloves are to be worn when operating the tool, the amount of clearance left for fingers must be increased.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 308 TOOL WEIGHT

There are no specific guidelines regarding appropriate weights for tools. In general, the heavier the tool, the greater the loading on the elbow, forearm, wrist, and hand. If the tool places the wrist and arm into awkward postures, loading may be increased further. Keep in mind that powered hand tools tend to be heavier than manual hand tools.

Lightweight tools E In order to minimise loading on the shoulder and wrist, purchase the A lightest tool that will do the job properly. For example, grinders and sanders used on horizontal surfaces work more efficiently, with less operator force, if they have some weight. This recommendation should be kept in mind for both hand tools and power tools.

If a tool has significant weight, or is used with the arm elevated, consider the use of a tool balancer and/or padded arm (elbow) supports.

Cordless power tools E In order to decrease the likelihood of tripping over power cords or to A increase the accessibility of tools in varying work environments, cordless power tools can be used. Keep in mind that cordless tools may be slightly heavier than regular power tools. When considering the use of cordless tools, be sure to assess the weight of the tool in comparison to regular power tools, think about the orientation that the tool must be used in, and the frequency and duration of the tool use.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 309 Tool balancers E The use of a tool balancer can help to reduce loading on the wrist, hand, elbow, and shoulder by decreasing the weight of hand held equipment and minimising over-gripping. Tool balancers are best suited to areas where powered tools are repetitively used in the same area.

Repetitive use of a pneumatic nailer increases loading on the wrist, hand, elbow, and shoulder. A tool balancer would decrease the effect of the tool weight on the operator, therefore reducing the amount of muscle contraction required to stabilise and control the nailer. Placing the balancer on a swinging arm would allow the worker to use the tool at various locations on a workbench.

The following points should be considered when investigating the use of tool balancers at a workstation:

• Tool balancers are most appropriate for workstations that require repetitive use of hand operated equipment, such as a pneumatic nail gun, air impact gun, or drill. • Tool balancers should allow easy access to the tension controls, and the controls should be easy to adjust. • The appropriate style of tool balancer should be investigated and selected. This investigation process should include the users of the equipment. • The placement of tool balancers should be discussed with the individuals who will be using them.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 310 Padded arm supports In order to reduce loading on the shoulder when operating heavy tools or E tools that require the arm(s) to be elevated, support the arms with padded rests.

Padded arm supports, as shown above, can help to reduce loading on the shoulder when operating heavy power tools.

HAND-TRANSMITTED VIBRATION

An important consideration in the selection or modification of powered hand tools is exposure to hand-transmitted vibration. Exposure to hand-transmitted vibration can lead to ‘Vibration White Finger’ and bone and joint disorders of the hand, wrist, elbow, or shoulder. Hand-transmitted vibration may also lead to an earlier onset of MSIs in the wrist and elbow.

Tool design E In order to minimise exposure to hand-transmitted vibration, ensure that A tool design limits the transmission of vibration to the operator. Many tool manufacturers now design hand tools with vibration damping and/or anti- kickback mechanisms. It is also wise to check that powered hand tools do not blow cold exhaust air over the wrist or hand.

Tool maintenance A To reduce the level of exposure to hand-transmitted vibration, ensure that WP tools are maintained. Tools in need of repair can increase the amount of vibration that is transmitted to the operator’s hand/arm.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 311 Handle wrap E In order to reduce the level of vibration that the hand is exposed to while operating powered tools, the handles of the tools can be wrapped with a vibration-damping material. This protection may be more appropriate for powered hand tools that are frequently used.

Vibration-damping gloves PPE In order to reduce the level of vibration that the hand is exposed to while operating powered hand tools, workers can wear vibration-damping gloves. These gloves are most appropriate for workers who use a number of vibrating hand tools.

Work surface design E Benches and tables in mill workshops can also be subject to process vibration, which is subsequently transmitted through materials and tools to the worker. Isolating these tables on dampers or cushions can reduce the vibration transmitted to the operator.

TOOL BELTS

Many Trades/Maintenance workers use tool belts to transport their tools from work area to work area, while keeping the hands free. The following guidelines should be considered when selecting and loading tool belts.

Balance tools in tool belt WP In order to reduce loading on the back, ensure that tools are balanced evenly on both sides of the tool belt. To further reduce loading on the back, pack only the most frequently used tools.

Tool belts with shoulder straps E In order to reduce loading on the back, provide Trades/Maintenance A workers with shoulder straps for their tool belts. Suspenders attached to existing tool belts and/or tool belts with leather shoulder straps attached to them are two options to consider.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 312 Shown above is a regular tool belt with weight Shown above is a tool belt with both sides on one side of the body (belt is slung over the balanced and with suspenders for additional shoulder). This distribution can increase the support. In this situation, loading on the soft loading on the back, as the opposite side of the tissues of the back is minimised as the weight torso must counterbalance the weight of the is balanced on either side of the spine. tool belt.

Carry tools on person WP Frequently used tools can be carried in coverall pockets, making a tool belt A unnecessary for many smaller jobs. For larger jobs, a hunting/fishing vest might be preferable to a tool belt. Keeping the tools in pockets closer to the body, evenly distributed around the torso, reduces the loading on the muscles of the back. Contact stress and irritation between tool belt and hips is also eliminated with a vest.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 313 Equipment

Equipment such as lifting aids and carts are used for material lifting, lowering, and transportation, and as portable worksurfaces in Trades/Maintenance positions. Often, equipment is introduced to reduce forceful loading on the body. Before purchasing new equipment or modifying existing equipment the following questions should be asked:

How do I know what kind of equipment I need? Look at the tasks performed at the job of concern and try to identify high- risk tasks where new or modified equipment could assist the worker. Tasks requiring heavy manual handling of objects (lifting, carrying, pushing, and pulling) are often good starting points.

What will be the equipment’s main purpose? Consider when and where it will be used, who will be using it, and if it can be used for other tasks.

What will be the constraints of using the equipment? It will be important to know whether workers will accept and use the new equipment right away, how much time must be invested into training workers on the appropriate use of the equipment, and if time must be invested into creating ‘buy-in’ for the new change. It is also important to research whether any safety restrictions or barriers may prevent the equipment from being used.

If it says ‘ergonomic’, is it a good purchase? There are no regulations on the use of the word ‘ergonomic’. In many cases, the word is used for marketing purposes. Take a thorough look at any equipment that is being considered, and see if it meets your requirements and reduces loading on the body. Often suppliers will provide a trial period for users to test an item. This trial suggests that the suppliers have confidence in their product, and it is a good way for potential purchasers to introduce equipment and get feedback from workers.

Having clear answers to the above questions will help to streamline your research efforts. On the following pages, a few of the more common equipment recommendations will be discussed.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 314 LIFTING AIDS

The availability and use of lifting aids in a work environment can significantly reduce loading on the body. The following common lifting aids are appropriate to consider for the sawmill environment.

Hoists & Cranes Lifting aids such as hoists and cranes can help to reduce loading on the E WP back, shoulders, elbows, wrists, and hands by eliminating the need to manually lift and manoeuvre heavy objects.

For example: A Machinist may be required to lift heavy lathe chucks, using awkward body postures to position the chuck on the lathe properly. This task places a significant load on the back and shoulders. The use of a hoist can significantly decrease loading on the back and shoulders.

Manually handling heavy objects can By using a hoist to manoeuvre heavy objects, significantly increase loading on the back and loading on the back and shoulders is reduced shoulders. dramatically.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 315 Typesofhoistsandcranes:

Shown above is a manually operated chain Two types of electric overhead cranes are hoist. shown above.

The following points should be considered when purchasing or modifying a hoist or crane: • The capacity should be great enough to lift all possible weights for all tasks performed. • The controls for the hoist/crane need to be sensitive enough for fine movements, while the action of the motor needs to be rapid enough to be practical for frequent use. A motor with two speeds could provide slower motion for an initial interval, automatically increasing in speed after constant activation of some set duration (e.g., 5 seconds). • Beams or tracks for the hoist/crane should be planned out prior to installation, to ensure the beam length and orientation is sufficient to reach all necessary areas. Planning is especially important when hoists are intended to lift and lower equipment that needs to be properly aligned. • The location of the hoist/crane controls should be located at elbow height or slightly higher. • The size of the control box should be small enough for operators to grip comfortably. • The buttons on the control box should not require high force to operate. • Directions should be clearly labelled above or below each button to minimise error. • The users of the hoist or crane should be consulted regarding all items above.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 316 Lift tables E The use of lift tables can decrease the amount of loading experienced on WP the back and shoulders while working at lower heights, or lifting heavy objects.

Shown above is a height-adjustable lift table. A weight-responsive lift table is shown above. Height adjustable lift tables are commonly These lift tables are commonly used to store used to raise heavy work to a more heavy parts and equipment at appropriate appropriate working height. heights. As the height, and weight, of the load decreases, the height of the working surface stays at a relatively consistent level.

Consider the following when purchasing lift tables or modifying existing equipment: • Determine the size, shape, height, and capacity required for tasks at individual workstations. • Portable lift tables could be shared among departments. • Examine the various heights of workers at a workstation. Lift tables are available in a wide range of heights and weight capacities. Lift tables are very suitable in areas that have varying worker heights, as they can easily be adjusted among people and even among tasks. • The controls for the table can be either foot-operated or hand-operated. Examine the nature of the task and the environment to determine which wouldbemoresuitable.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 317 TRANSPORTING AIDS

The availability of aids to help with transporting objects can dramatically reduce the risk of injury to the back and arms from carrying heavy objects.

Portable carts and tables E The availability and use of portable carts and tables can help to reduce WP loading on the back, shoulders, elbows, wrists, and hands when the carts are used to transport heavy objects from one area to another.

Examples of different carts and tables:

The cart above can be used to transport heavy A workbench with locking wheels can be used items from one work area to another. both as a work surface and as a means of transporting heavy objects.

A small cart with extended handle allows the Having frequently used equipment on wheeled worker to move heavier objects while carts eliminates the need to lift and carry it remaining in a neutral posture. from one area to another.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 318 When purchasing carts or tables, or modifying existing equipment, the following points should be considered:

• The handles for the cart should be round, and the worker should be able to close their hand around them. • The handles for the cart should be at or above waist level. • If pushing heavy objects, handles should be padded to minimise contact stress on the hand. • Larger wheels decrease the amount of force required to push heavy carts. • Carts should have two or four wheels that swivel 360o. ♦ Two swivelling wheels provide more control with less manoeuvrability. ♦ Four swivelling wheels provide more manoeuvrability with less control. • Consider the material the wheels are made from. For example, pneumatic tires provide better shock absorption on rough floors. • To prevent objects from sliding off the cart, surfaces should have a raised lip. For heavy objects, one side can remain flush so heavy items can be slid off the cart and onto the workstation. • Carts should have locking mechanisms built into the wheels. Locking the wheels will increase the stability of the cart when unloading. • Keep floors and wheels well maintained, as this will reduce the amount of force required to move carts from one location to another.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 319 Miscellaneous Equipment

Lightweight equipment E In order to reduce the force required to manoeuvre equipment, ensure that A any moveable equipment that is purchased is lightweight. For example, fibreglass ladders could be chosen over steel ladders.

Step ladders and/or stools In order to reduce awkward shoulder postures, provide step ladders and/or E stools to workers who may need to work higher up on equipment or machinery.

A stepladder on weight-responsive rollers can Astepstoolcanalsobeusedtoraisethe be used to raise the worker. worker.

Rolling chair/stool E In order to reduce contact stress on the knees when working closer to ground level, provide workers with a rolling stool or chair to sit on.

A small, rolling chair allows the worker to lower themselves to equipment or machinery that needs to be worked on at lower heights. Locking mechanisms on the wheels will be necessary.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 320 Job-Specific Tools and Equipment Suggestions

CARPENTER

C-clamps WP When cutting pieces of lumber, use a C-clamp to secure the lumber to the workbench. This will reduce the amount of force required to stabilise the lumber.

When cutting pieces of lumber, one hand is often used to stabilise the lumber while the other hand is used to complete the cut. Using a C-clamp to secure the lumber on the workbench can eliminate the force applied through the hand to stabilise the lumber.

CHEMICAL/COMPUTER ATTENDANT

Ultrasonic detector E In order to decrease awkward and static postures of the low back and shoulder, use an ultrasonic detector to check for leaks in systems.

This ultrasensitive sound wave detector can help the Chemical Computer Attendant locate leaks more quickly.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 321 ELECTRICIAN

Come-a-longs E Use a lightweight come-a-long to pull two wires together rather than WP manually pulling on the wires. This would take the tension off the line when making a connection, significantly reducing the loading on the hand, wrist, elbow, and shoulder.

HEAVY DUTY MECHANIC Creepers E Heavy Duty Mechanics should have creepers readily available for sliding WP under machinery. A creeper with six wheels is preferable, as these designs are more stable and durable than those with four wheels. A creeper with adequate neck support can help to minimise loading on the neck muscles when working under machinery.

Creepers can aid the Heavy Duty Mechanic in manoeuvring themselves under machinery with ease. It is important to ensure that creepers have adequate neck support for working under machinery. At times, it may be necessary to secure additional padding to the neck area of the creeper in order to provide better support for the head while working under machinery.

Carts for power units E In order to eliminate the need to lift and carry power units into and around machinery, place the power units on wheeled carts and provide longer lines (e.g., welding apparatus).

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 322 Moveable jacks and lifts E In order to reduce the need to lift and handle engines and other heavy parts, provide the Mechanics with moveable jacks and lifts. These lifting aids may be especially useful in areas where hoists and cranes cannot be used or do not reach.

A moveable lift, such as the one on the left, can be used to safely transport heavy machine parts.

MILLWRIGHT

Come-a-longs E Use come-a-longs to pull chains in the required direction rather than WP manually pulling on the chain. The mechanical advantage of a come-a- long can significantly reduce loading on the hand, wrist, elbow, and shoulder.

The mechanical advantage provided by a come-a-long reduces loads on the hand, wrist, elbow, and shoulder when pulling chains and equipment.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 323 OILER

Contoured handle E Attach a contoured handle, such as a bicycle handle, to the arm of the grease gun to allow for a better grip. The increased friction between the hand and the handle will reduce the force needed to grip the grease gun handle.

The arm of a grease gun may be smooth and slippery. In order to improve the friction between the arm and the hand, place a padded handle over the arm.

Oil can handle E The handle of the oil can should have rounded edges, rather than flat sharp edges, to prevent contact stress to the fingers and hands.

The oil can shown has hard, sharp edges on the handle. This handle design can lead to contact stress on the palm of the hand and the fingers. To eliminate contact stress in the hand, purchase oil cans with more rounded, smooth handles, or modify existing tool handles by wrapping foam and tape around rough edges.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 324 Barrel opener E The barrel opener should be designed to allow for effective gripping.

The barrel opener on the right requires awkward wrist postures and high forces to operate. A T-handled barrel opener, with cushioned handles, would balance the force across both arms, and reduce required grip forces.

Electric grease gun E In order to decrease the loading on the shoulder, elbows, wrist, and hands of the Oiler, use an electric grease gun in instances where a lot of grease needs to be added to a machine. This change will reduce the repetitive and forceful nature of the job.

PAINTER

Extended spray gun nozzle In order to keep the trunk and shoulder in a more neutral posture, use an E extended spray gun nozzle or ‘wand’ when painting at low heights.

Extreme trunk and shoulder flexion when Neutral trunk and shoulder posture when using painting at floor level with conventional spray ‘wand’ extension to paint at floor level. gun.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 325 Working on high surfaces E To decrease the force required when preparing and painting high surfaces, WP use the appropriate lifting device to reach the work area. Ladders are suitable for mid-height work, while scaffolding or man-lifts are more stable for work at greater heights.

Awkward neck and shoulder postures and More neutral postures used when worker lifted extreme force necessary to paint high surface to appropriate height with man-lift. from ground level.

PIPEFITTER

Angled pipe wrench In order to keep the wrists in a more neutral posture, use an angled pipe E wrench (e.g., 90-degree, 45-degree) to improve access to pipes that are tight against walls.

The use of an angled pipe wrench allows the Pipefitter to gain better access to pipes and fittings that are close to the wall. This wrench also allows the Pipefitter to maintain more neutral wrist postures.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 326 Valve wrench E To decrease the force needed to open difficult valves, use a valve wrench. Using larger wrenches or a bar to extend the handle can increase the mechanical advantage even further.

A valve wrench can decrease the force required to open difficult valves. Consider extending the tool handle to decrease the required force even further.

The wrench shown here has other ergonomic problems, including narrow handle diameter and poor grip design, which should be improved.

Maintenance truck vise E Install a vise on the back of the maintenance truck to hold fittings and pipes. This will allow the Pipefitter to transport materials using the maintenance truck, reducing the loading on the back and shoulders.

Larger valve handles/Automatic valve opener E In order to reduce loading on the hand, wrist, and elbow, install larger valve handles or automatic valve openers on large valves that are difficult to open.

Large valves that must be opened manually Installing larger valve handles can reduce can significantly increase the loading on the loading on the hands, wrists, and elbows by hand, wrist, and elbow. increasing the mechanical advantage. Automatic valve openers can be installed on difficult-to-open valves.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 327 Automatic pipe cutter E Use an automatic pipe cutter to reduce the operator force required to cut pipe, in turn reducing loads on the hand, wrist, elbow, and shoulder.

An automatic pipe cutter can significantly reduce the loading on the hand, wrist, elbow, and shoulder.

PLUMBER

Largepipewrench E To decrease the force needed to remove and tighten large fittings, large pipe wrenches should be available. Using larger wrenches or a bar to extend the handle increases the mechanical advantage, and allows the Plumbertousebotharmstoapplyforce.

A large wrench can decrease the force required to remove and tighten larger fittings. Both hands can be placed comfortably on the handle of a larger pipe wrench.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 328 WELDER

Large view, lightweight face shields/helmets PPE In order to minimise the amount of neck flexion, large view, lightweight face shields/helmets should be used. Larger view areas will encourage Welders to move their eyes rather than their necks in order to view the welding area. Ideally, a clear shield could be worn over protective eyewear. With polarised helmets, such as quick flash or gold leaf, the neck flexion is eliminated.

Prescription welding helmets Wearing prescription welding helmets can decrease awkward postures of PPE the neck, since the helmet will be set up for the optimal viewing range of the worker.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 329 Work Strategies

Introduction

Trades/Maintenance workers perform a variety of tasks in many different postures and working spaces throughout a shift. The work tends to be self-paced, and because they have a lot of control over how they perform various tasks, work strategies can play an important role in reducing the risk of musculoskeletal injuries. These strategies include work practices (techniques used to perform the tasks of a job), use of personal protective equipment, and administrative controls.

Earlier in the Work Manual, it was explained that musculoskeletal injuries could occur due to excessive force, repetition, or duration. When awkward postures are combined with any of these three mechanisms, the risk of injury is increased.

The Work Strategies solutions are divided into the following sections:

• General Work Practices that apply to more than one Trades/Maintenance job. The following risks are addressed:

• Excessive force (including mechanical advantage and manual material handling) • Excessive repetition • Excessive duration (static postures) • Awkward postures • Environmental concerns

• Administrative Controls and Personal Protective Equipment

• Following the general work practice guidelines, additional job-specific work practices have been included.

When any changes are made to a job or work environment (e.g., a new tool or workstation is introduced), it is important to remember that work strategies may have to change. The guidelines have been developed to help workers adapt to a changing work environment.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 330 General Work Practices

WP PREVENTING INJURIES DUE TO EXCESSIVE FORCE

Injuries can occur from a single event when the loads or forces are so great they exceed tissue tolerances. This type of injury is more common with trips and falls, but can also occur with forceful exertions (e.g., heavy lifting, pushing, pulling).

Power positions Use power positions when handling loads or exerting force on objects. Using larger and stronger muscles when doing heavy or forceful work reduces the risk of muscle strain. For lifting, a power position is adopted when a worker remembers to ‘lift with the legs, not the back’. This phrase is based on the fact that the muscles of the thighs are larger and more powerful than the muscles of the low back.

An Oiler uses straight legs and a hunched back A Heavy Duty Mechanic lifts an impact wrench to pull an oiling cart up stairs. Excessive force from the floor. Bent legs and a neutral spine can be placed on the tissues of the back when help to minimise the loading on back tissues. lifting and lowering in this position. Lifting the tool in front of the body, instead of at the side, would even the loading on the left and right sides.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 331 MECHANICAL ADVANTAGE

When possible, use leverage, or another method of mechanical advantage, to help move heavy objects. Using mechanical advantage will help decrease the force, or effort, necessary to move an object.

A Millwright uses leverage to prop up a metal panel while another worker is welding.

Torque multiplier/bolt-loosening spray To reduce the force required from the hands, arms, shoulders, and back when loosening bolts, use a torque multiplier or a bolt-loosening spray where possible.

Extend tool handles In order to reduce the amount of force required to loosen bolts or parts, increase leverage by extending tool handles. The examples below show metal pipes placed on the end of a wrench to allow for greater leverage when loosening bolts.

A Millwright loosens a bolt with a regular A Millwright uses a wrench with an extension wrench. pipe to loosen a bolt.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 332 A Heavy Duty Mechanic uses a wrench extension to loosen a bolt in an awkward space

Use both hands for forceful movements To reduce the risk of overexerting smaller muscle groups of the arms, use both hands to exert force on objects (e.g., using a hand crank). Using two hands distributes the required force across the wrists, forearms, and shoulders.

An Oiler uses one arm to pump lubricant from Using both hands where possible can a storage barrel. Repeated use of tissues can distribute the load across tissues in both arms, lead to fatigue and injury. Alternating arms decreasing the risk of injury due to repetition can reduce the cumulative fatigue on any one or force. side.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 333 Work in pairs To reduce force and repetition on all muscles of the body, work in pairs when performing heavy tasks. For example, when ‘chasing whistles’ Millwrights should be able to call for help (e.g., radio contact with other Millwrights) with lifting heavy materials.

Proper maintenance of tools Proper maintenance of tools can reduce the amount of force required, therefore reducing loading on many muscle groups. For example, using dull wire cutters requires more force from the hand and forearm muscles than using sharp wire cutters.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 334 MANUAL MATERIAL HANDLING

The following work practices refer specifically to manual material handling tasks. These tasks include lifting, lowering, pushing, pulling, carrying, and holding objects. • Use the entire body, especially the large muscle groups of the lower body, to perform a movement. • To reduce loading on the soft tissues of the back, lift heavy objects with a neutral back posture while maintaining the 3-point curve. Refer to the Back Section in the Injury Education portion of this document. • Do not twist while holding or moving a load. Twisting places the back in a weaker posture, increasing the risk of injury. • When possible, balance loads being carried on each side of the body. This minimises loading on the soft tissues of the back and hips.

Oilers carrying oil buckets/cans around the mill should carry one in each hand to balance the load.

• When lifting, carrying, or holding objects, keep them as close to the body as possible. The farther the load is away from the body, the more stress it puts on the back. • When carrying only one object (e.g., one container of oil), alternate hands periodically to balance the load on the muscles. This will also allow one side to rest while the other side works.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 335 A Heavy Duty Mechanic using an impact By lowering the body, the Heavy Duty wrench with the above posture puts undue Mechanic is able to hold the impact wrench loading on the back muscles. closer to the body, reducing stress on the back.

• Ask for help with lifting large, heavy objects. For example, use a two- person lift if necessary. Remember that communication is important during a two-person lift. A poorly timed two-person lift can cause the load to be unbalanced, or unevenly distributed between the two people, which can lead to overexertion.

Lifting some objects unassisted may A two-person lift can reduce the risk of require awkward postures or excessive injury when a mechanical lifting device is force. not available.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 336 • Handle objects with as little force as possible. For example, roll objects (e.g., oil barrels) whenever possible rather than lifting and carrying them. If appropriate, allow objects to drop instead of supporting the weight of the object to lower it.

An Oiler rolls oil barrels into place.

An Electrician lowers a spool of cable by allowing it to carefully drop to the ground, rather than supporting its weight. To prevent potential damage to the spool, alternate methods of removal can be used, such as rolling the spool down an incline to the ground.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 337 • To reduce loading on many areas of the body, particularly the back and shoulders, use mechanical lifting aids when available.

a) b)

c) d)

e) Examples of mechanical aids used to manoeuvre heavy objects: a) dolly, b) small front-end loader, c) hoist, d) overhead crane, and e) cart to transport objects around the shop.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 338 WP PREVENTING INJURIES DUE TO EXCESSIVE REPETITION

Injuries can occur from repeated loading on the same tissues, weakening them to the point of failure. This type of injury can progress to the point where even light loads can cause increased discomfort, and risk of further injury. The following work practices reduce repetitive stress on soft tissues.

Alternate using both sides of the body Alternating sides will reduce the risk of muscle imbalance, fatigue, and/or injury. For example, try to change hands when using an impact wrench for prolonged periods of time.

Task rotation Trades/Maintenance workers may have the ability to rotate to different tasks throughout the day, reducing their exposure to certain risk factors. Consider the following points when determining a task rotation schedule:

• Consider the physical demands of each task (e.g., tools used, working postures, weights handled). Rotate between tasks that have different physical demands. • To give muscles recovery time, arrange for lighter tasks (e.g., soldering, light assembly) to follow physically demanding tasks (e.g., heavy lifting and carrying). • The length of time each task is performed should be based on the most demanding task. For heavy, demanding tasks, shorter time periods may be required. • Alternate low-level crouching and stooping tasks with ones that require standing or reaching overhead.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 339 WP PREVENTING INJURIES DUE TO EXCESSIVE DURATION

Excessive duration refers to constant loading on the same tissues (static loading), weakening them to the point of failure. This type of injury is more common with tasks that require workers to adopt static or awkward postures for extended periods. Consider the following work practices to prevent loading of excessive duration from leading to injury.

Change positions often Changing work positions often can reduce static loading on all body areas. For example, to reduce static postures of the trunk and lower body, alternate between standing, sitting, and walking.

Look down with the eyes To reduce static loading on the neck when working at a bench or table, look down with the eyes when possible, instead of bending the neck forward. If the task requires precision work, the working height may need to be increased.

Reduce the duration of overhead work Working with the arms above shoulder height for prolonged periods of time can cause discomfort to the shoulders, neck, and arms. When working overhead, take stretch breaks every few minutes, or alternate overhead work with other tasks that can be done with the shoulders in a more neutral position.

An Oiler may have to fill lubricant Pipefitters may work overhead for long containers that are located above periods of time when installing and shoulder height. maintaining pipes.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 340 Head support/neck cushion To prevent neck muscle fatigue in workers who perform tasks lying down, provide a cushion to support the head and/or neck. This support will allow the muscles of the neck to remain more relaxed.

Heavy Duty Mechanics often work lying down when repairing and maintaining mobile equipment, trucks, and machines. Creepers should be outfitted with head supports that can provide relief for the muscles and soft tissues of the neck. The head support on this creeper is too small to be effective in this posture.

Support the arms when using tools for prolonged periods When using tools for prolonged periods of time (e.g., soldering or welding), muscles have to maintain static postures, leading to discomfort and fatigue. When possible and safe, support the arms using part of the workbench, or with added armrests.

Padded arm supports, as shown above, can help to reduce loading on the shoulder when operating heavy power tools.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 341 WP AWKWARD POSTURES

Awkward postures, in combination with overexertion, repetition, and/or duration, can lead to increased risk of injury. The following recommendations can decrease the risk of injury associated with awkward postures.

Adjustable workstation Be aware of how to adjust the workstation(s), chairs, tools, etc. Improper working heights and reaches tend to cause awkward postures for one or more body parts. If the workstation is not adjustable, try to make safe changes. For example, if a workbench is too high, a step stool can be used to raise the height of the worker. For more recommendations on how to prevent awkward working postures, refer to the Workstation Design section.

Sit when working at low levels for a prolonged period To decrease awkward postures of the lower body when working at low levels for prolonged periods, try to sit instead of crouching or kneeling.

In this picture, one worker bends his back, A Millwright sits while working at a low level. while the other one kneels to work at low levels.

Be aware of how bifocals can cause awkward postures Wearing bifocals can cause awkward postures of the neck, since wearers must look out of the lower part of their glasses. If you wear bifocals, position work so that it is in the proper viewing range, or see your eye-care professional for appropriate glasses to wear when performing certain tasks.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 342 WP ENVIRONMENTAL CONCERNS

The following work practices address environmental concerns that may affect the risk of musculoskeletal injury for Trades/Maintenance workers. For additional recommendations relating to environmental factors, refer to the General Risk Factors Solutions Manual.

Appropriate clothing for the weather Trades/Maintenance workers should wear appropriate clothing during weather extremes. Layer clothing, and consider advanced clothing materials.

Fluids for hot weather To minimise muscle strain and cramping from overexertion during hot weather conditions, drink plenty of fluids, and stay in cooler locations. For extremely hot weather, drinks with an electrolyte component should be consumed to prevent mineral loss. During hot weather conditions, muscles fatigue at a faster rate, and are at a less optimal level of strength.

Warm-up exercises To minimise muscle strain from stiffness due to cold weather conditions, perform exercises to warm up muscles. Walking is an excellent warm up for muscles of the low back.

Portable heaters Where appropriate, use portable heaters to maintain the body’s core temperature.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 343 PPE PERSONAL PROTECTIVE EQUIPMENT

Appropriate gloves Wear appropriate gloves when working in cold environments. Well-insulated gloves are ideal for cold weather, but close-fitting gloves may be a requirement for precision work (e.g., wiring), to prevent over-gripping or over-pinching.

Kneepads and foam inserts Wear kneepads or foam inserts in coveralls to prevent contact stress when kneeling and crawling. Kneeling reduces the need to bend from the back when working at low levels.

An Oiler may kneel to grease machinery or fill lubricant containers.

Elbow pads and padding on arms of coveralls To reduce contact stress on forearms and elbows, protective padding may be sewn inside coveralls. For example, the tissues in the forearm are compressed when Welders lean against hard or sharp surfaces to brace themselves while welding. Padding would alleviate some of the pressure on these tissues. Elbow pads can also be worn over or under coveralls.

Large view, lightweight face shields/helmets In order to minimise the amount of neck flexion while welding and grinding, large view, lightweight face shields/helmets should be used. Larger view areas will encourage workers to move their eyes rather than their necks to view the appropriate area. Ideally, a clear shield could be worn over protective eyewear.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 344 A ADMINISTRATIVE CONTROLS

Stock materials together based on similarities (size, length, weight) Materials should be stocked together based on similarities. Stocking a variety of sizes may be easier in areas where there are routine parts/items of a known size being used by trades people such as Carpenters, Machinists, Pipefitters, and Welders. Stocking shorter lengths of materials, such as metal rods, pipes, and lumber, reduces the load on the musculoskeletal system during handling.

Routine preventative maintenance To reduce the frequency and severity of equipment and machinery breakdowns, thorough preventative maintenance efforts can be routinely scheduled.

Examples: Millwrights can be responsible for routine maintenance of all machines in an area of the mill. A schedule of checks and tasks can be done on a daily or weekly basis.

HeavyDutyMechanicscan periodically take samples of oil and fluid from their equipment, and send these samples to labs for testing. Based on the analysis of the fluids, recommendations are given on what repairs should be made to the machinery, and when they should be made.

The main activity of concern with Heavy Duty Mechanics is the need to fix broken down machinery in the field. Field breakdowns can be expensive both in terms of damage to the machinery and lost production time. In this situation, weather extremes may be encountered, tools and equipment are not as readily available as in the shop environment, and increased time pressures may be felt. A preventative approach can help to decrease the number of field breakdowns, leading to a decreased risk of injury for the Heavy Duty Mechanic and decreased cost to the company.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 345 Job-Specific Work Practices

WP ELECTRICIAN

Electric motor to pull cable To reduce loading on the shoulders for Electricians doing construction work, heavy cablecanbefedbytyingthinwirearoundtheend,thenusinganelectricmotorto pull the cable through joists, etc.

Get help feeding heavy cable To reduce loading on the back and shoulders, have two people feed heavy cable. One person should be positioned close to the spool to feed cable up to the other person, who may be on a ladder. This method significantly decreases the pulling and lifting forces for the person on the ladder, who may already be working in awkward overhead postures.

Pull wire with power position To decrease loading on the shoulder joint, try the following technique: when pulling smaller wire (e.g., through ceiling joists), position yourself so that you can pull the wire towards the body (power position), rather than pulling away and to the side of the body with the arm extended (awkward posture).

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 346 WP HEAVY DUTY MECHANIC

Use jacks to manoeuvre objects underneath machinery In order to reduce loading on the back due to lifting, use jacks (with straps if needed) when manoeuvring heavy parts or objects into place underneath machinery. Using a jack can eliminate the need to lift heavy objects while working under machinery.

A wheeled jack can be used to manoeuvre heavy objects into place under mobile equipment.

WP MACHINIST

Rotate tasks while machines are running If machines can operate automatically (e.g., lathe, milling machine), Machinists can organise work so that other shop tasks can be performed while machines are running. Performing other tasks will reduce static sitting or standing, and will lead to a more even distribution of physical demands.

WP MILLWRIGHT

Carry smaller loads when cleaning up spills When using absorbent material to clean up spills, only pack as much of the material as you need to use. Bring a small bucketful to the spill site instead of carrying the whole bag. Also, purchasing smaller bags of the material will help in moving the material from place to place.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 347 WP OILER

Effective lubricant container sizing When purchasing lubricants, keep in mind how the lubricants will be transported around the mill. For greater lubricant quantity requirements, larger containers that can remain in one location and be mechanically pumped to different areas in the mill may be more cost effective and easier to handle than smaller quantities that need to be manually moved around the mill.

WP PIPEFITTER

Preventative measures to remove fittings To reduce the force required to remove fittings from pipes, use self-penetrating oil, or hit the pipe with the hammer to break rust. Teflon tape and/or grease can be used when assembling pipes to prevent future problems with rust seizing.

Teflon tape on pipe thread.

Move work Awkward postures of the back, neck, shoulder, elbow, and wrist can result when Pipefitters assume awkward positions to work on sections of existing pipe networks. Where possible, Pipefitters should remove the work piece and take it to a shop, where they can work on a bench or table at a comfortable height. After the work has been completed, the pipe system can be reconnected.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 348 WP WELDER

Angle welding rods whenever possible In order to reduce loading on the neck, shoulder, wrist/hand, and to reduce back flexion, Welders are encouraged to angle the position of the welding rods in order to maintain more neutral postures.

Angling the welding rod, when possible, helps Welders maintain neutral postures, particularly of the shoulders.

Avoid snapping the neck to lower welding helmet Often Welders will ‘snap’ the neck forward to lower the welding shield/helmet as they prepare to weld. The speed of the movement, with the additional weight of the helmet and the weight of the head, puts increased stress on the tissues of the neck. To reduce loading on the neck muscles, Welders should be encouraged to use the hand to move the shield/helmet.

The above sequence of pictures shows a Welder lowering the flash helmet by snapping the neck forward.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 349 Lowering the flash helmet by hand.

Alternative welding helmets These helmets can be considered when doing work that requires multiple short welds with visual inspection in between. One consideration with these types of helmets is the increased heat discomfort from having the shield down in front of the face for long durations. a) Quick Flash welding helmet – The Quick Flash helmet eliminates the need to flick the helmet down, as the glass polarises when exposed to the welding flash. b) Gold Filter welding helmet – The Gold Filter helmet also does not need to be pulled down, as these masks filter light continuously. They are different than the Quick Flash helmet in that they do not need a flash to trigger the filtering of the light. However, the glass in these helmets can be scratched when cleaning. Scratching reduces the filtering performance of the glass.

Wear dark clothing Welders should be encouraged to wear dark clothing to reduce the reflection of UV rays under the helmet to the face.

Refer to the Body Manual for details on specific body parts, stretches, and strengthening exercises.

Refer to the General Risk Factors Solutions Manual for information that can be used by any sawmill worker.

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 350 Index of Solutions Workstation Design 270 Design workstation to be functional 274 Design workstation to minimise contact stresses 274 Design workstations to fit different operators 275

Working Heights 278 Adjustable work surfaces 278 Multi-level work surfaces 278 Lifting the worker 278 Adjusting keyboard height 278 Adding a footrest 278 Extensions 279 Screen height 279

Working Reaches 281 Angled work surfaces 281 Low friction work surfaces 281 Cut-outs 281 Double-sided benches 281 Turntables 282 Slide-out drawers 282 Open-top storage cabinets 282 Viewing distance 282 Location of computer mouse 283

Manual Material Handling 285 Mechanical lifts 285 Low friction work surfaces 285 Subdividing large loads 285

Seating 287 Design considerations 287

Flooring 288 Anti-fatigue flooring 288 Repair and maintain walkways 288 Anti-fatigue insoles 288

Environmental Conditions 290 Local ventilation 290 Task lighting 290 Headlamps 290 Improve lighting 291

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 351 Job-Specific Workstation Design Suggestions 292 Carpenter Increase table surface on stationary machines 292 Storage for plywood 292 Chemical/Computer Attendant Bike 293 Electrician Armrests 294 Seated posture 294 Heavy Duty Mechanic Portable work surfaces 295 Working on taller machinery 295 Creepers 295 Lightweight equipment 295 Seating for low height tasks 295 Machinist Working at machinery 296 Secondary tool bin 296 Millwright Access panels 297 Hinged motor mounts 297 Accessible motor locations 297 Warning light panel 297 Oiler Whiplines 298 Pumping stations 298 Lifting aids 298 Portable lighting 298 Pipefitter Lifting workers 299 Pipe holders 299 Welder Automatic cutting table 300 Material holders 300 Fire retardant anti-fatigue matting 300 Rest stand for torch 301 Proper ventilation 301

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 352 Tools and Equipment 302

Guidelines for Tool Purchasing, Modification, and Use 304

Wrist Postures 304 Bent handled tools 304 Orientation of tool handle 305

Arm Postures 306

Tool Grip 306 Maximise friction between hand and tool 306 Flared handles 307 Tool handle grip 307 Spring return mechanism 308 Keep tools clean 308

Handle Size 308 Tool handle length 308 Tool handle width 308

Tool Weight 309 Lightweight tools 309 Cordless power tools 309 Tool balancers 310 Padded arm supports 311

Hand-transmitted Vibration 311 Tool design 311 Tool maintenance 311 Handle wrap 312 Vibration-damping gloves 312 Work surface design 312

Tool Belts 312 Balance tools in tool belt 312 Tool belts with shoulder straps 312 Carry tools on person 313

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 353 Lifting Aids 315 Hoists & cranes 315 Lift tables 317

Transporting Aids 318 Portable carts and tables 318

Miscellaneous Equipment 320 Lightweight equipment 320 Step ladders and/or stools 320 Rolling chair/stool 320

Job-Specific Tools and Equipment Suggestions 321 Carpenter C-clamps 321 Chemical/Computer Attendant Ultrasonic detector 321 Electrician Come-a-longs 322 Heavy Duty Mechanic Creepers 322 Carts for power units 322 Movable jacks and lifts 323 Millwright Come-a-longs 323 Oiler Contoured handle 324 Oil can handle 324 Barrel opener 325 Electricgreasegun 325 Painter Extended spray gun nozzle 325 Workingonhighsurfaces 326 Pipefitter Angled pipe wrench 326 Valve wrench 327 Maintenance truck vise 327 Larger valve handles/Automatic valve opener 327 Automatic pipe cutter 328

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 354 Plumber Largepipewrench 328 Welder Large view, lightweight face shields/helmets 329 Prescription welding helmets 329

Work Strategies 330

Preventing Injuries Due to Excessive Force 331 Power positions 331

Mechanical Advantage Torque multiplier/bolt-loosening spray 332 Extend tool handles 332 Use both hands for forceful movements 333 Work in pairs 334 Proper maintenance of tools 334

Manual Material Handling 335

Preventing Injuries Due to Excessive Repetition 339 Alternate using both sides of the body 339 Task rotation 339

Preventing Injuries Due to Excessive Duration 340 Change positions often 340 Look down with the eyes 340 Reduce the duration of overhead work 340 Head support/neck cushion 341 Support the arms when using tools for prolonged periods 341

Awkward Postures 342 Adjustable workstation 342 Sit when working at low levels for a prolonged period 342 Be aware of how bifocals can cause awkward postures 342

Environmental Concerns 343 Appropriate clothing for the weather 343 Fluids for hot weather 343 Warm-up exercises 343 Portable heaters 343

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 355 Personal Protective Equipment 344 Appropriate gloves 344 Kneepads and foam inserts 344 Elbow pads and padding on arms of coveralls 344 Large view, lightweight face shields/helmets 344

Administrative Controls 345 Stock materials based on similarities (size, length, weight) 345 Routine preventative maintenance 345

Job-specific Work Strategy Suggestions 346 Electrician Electric motor to pull cable 346 Get help feeding heavy cable 346 Pull wire with power position 346 Heavy Duty Mechanic Use jacks to manoeuvre objects underneath machinery 347 Machinist Rotate tasks while machines are running 347 Millwright Carry smaller loads when cleaning up spills 347 Oiler Effective lubricant container sizing 348 Pipefitter Preventative measures to remove fittings 348 Move work 348 Welder Angle welding rods whenever possible 349 Avoid snapping the neck to lower welding helmet 349 Alternative welding helmets 350 Wear dark clothing 350

 2000 IMIRP Society Trades/Maintenance Work Manual (revised) 356 CARPENTER MSI SAFETY GUIDE

OBJECTIVE: To identify ergonomic risks involved in carpentry, and to reduce the potential for musculoskeletal injuries. More detailed information about risk-reducing recommendations can be found in the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Shoulder Force • When working overhead, take stretch breaks every • The rotator cuff stabilises the shoulder joint when objects few minutes. A Carpenter may are pushed, pulled, and manipulated. The heavier the • Alternate overhead work with other tasks that can use various tools object, or the larger the force required, the greater the load be done with the shoulders in a more neutral for carpentry tasks. on the rotator cuff. position. Carpenters may • If the force placed on the rotator cuff exceeds the tissue • When using tools for prolonged periods of time, also manually tolerances, injury may occur. support the arms using part of the workbench, or handle various Awkward Postures with arm rests. sizes of different • • Consider the physical demands of each task. Rotate materials, such as The rotator cuff stabilises the shoulder joint when the arms are away from the body. The farther away the arms are between tasks that have different physical demands. lumber, plywood, • from the body, the greater the load on the rotator cuff. To give muscles recovery time, arrange for lighter sheet metal, and tasks to follow more physically demanding tasks plastic. Static Postures (e.g., heavy lifting, carrying). • When the arms are repeatedly held away from the body, the • Alternate low-level crouching and stooping tasks muscles of the neck and shoulder must remain tense to with tasks that require standing or reaching support the weight. If the duration of constant tension is overhead. excessive, and recovery is not adequate, the tissues may • Materials should be stocked in a variety of sizes, if fatigue to the point of injury. feasible, allowing carpenters to handle pieces Repetition which are not unnecessarily large. Handling • When the arms are repeatedly raised, the rotator cuff is smaller pieces of material reduces tissue loads. subjected to repeated stress with little time for recovery. If • For exercises that can increase tissue tolerances and the repetitive stress is excessive, and recovery is not prevent shoulder injuries, see the Shoulder Injury adequate, the tissues may fatigue to the point of injury. Education section of the Trades/Maintenance Work Manual.

Elbow/Wrist Force • Alternate tool use between both arms. For example, try • Gripping an object requires activation of the forearm to periodically change hands when using an impact A Carpenter may muscles, which generates tension at the tendon/bone wrench for prolonged periods of time. grip various tools, connection of the elbow. The harder that an object • Proper maintenance of tools can reduce the amount of such as hammers, must be gripped, the greater the load on the force required to use them. For example, more force is saws, and drills, tendon/bone connection. required when using a dull saw to perform a cutting when assembling task. materials. A Awkward Postures Carpenter also • The width of an object affects how much muscle • Use only necessary gripping force when handling manually grips tension needs to be generated. Using either an overly objects or tools. Be aware that cold temperatures and pieces of material, large or a small grip requires more muscle force, and tool vibration can lead to decreased sensitivity and such as lumber, can lead to tissue fatigue at the tendon/bone increased grip forces. plywood, sheet connection. • Maintain a straight wrist position when gripping or metal, and plastic. • The position of the wrist also affects how much manoeuvring tools and objects. muscle tension needs to be generated. Gripping • Whenever possible, use both hands for forceful objects with the wrist bent increases the tension movements. Using both hands distributes the required generated by muscles. force. Repetition • For exercises that can increase tissue tolerances and • Repeated stress to the elbow without adequate rest prevent elbow and wrist injuries, see the Elbow and could fatigue tissues to the point of injury. Wrist Injury Education sections of the Trades/Maintenance Work Manual.

Wrist/Hand Contact Stress • Alternate tool use between both arms. For example, try to • Contact between hard or sharp surfaces and the periodically change hands when using an impact wrench A Carpenter may base of the palm places stress on the tendons and for prolonged periods of time. grip the handles of nerves in the carpal tunnel. • Proper maintenance of tools can reduce the amount of various tools and • Continual contact may damage the nerve and/or force required to use them. Make sure tools and handles equipment, such as gradually weaken the tendons and cause injury. are well maintained. Handles should be free of sharp hammers, edges. pneumatic guns, Vibration radial arm saws, • • Carve grooves into smooth wooden handles. Textured and circular saws. Exposure to vibration, through power tools or other grooves increase the friction between hands/gloves and the These tools may vibrating objects, places a unique form of tool handle, reducing the force required to grip the handle. also transmit mechanical stress on the tissues of the hand and • Use only necessary gripping force when handling objects vibration to the wrist. Factors like vibration level and vibration or tools. Be aware that cold temperatures and tool hand or hands. frequency influence the amount of stress. • vibration can lead to decreased sensitivity and increased Continual exposure to hand/arm vibration may grip forces. gradually damage neurovascular tissue (nerves and blood vessels) in the hand, and may contribute to • Maintain a straight wrist position when gripping or problems in the wrist. manoeuvring tools and objects. • Whenever possible, use both hands for forceful movements. Using both hands distributes the required force. • Wear appropriate gloves. Gloves that are too large may cause overgripping. Gloves that are too small may constrict blood flow to the working muscles in the hand. • For exercises that can increase tissue tolerances and prevent wrist injuries, see the Wrist Injury Education section of the Trades/Maintenance Work Manual.

Low Back Force • Consider the physical demands of each task. Rotate between • Lifting increases the loading on the spine. tasks that have different physical demands. A Carpenter may Weight held in the hands is transmitted to the low • To give muscles recovery time, arrange for lighter tasks (e.g., bend forward to back. The greater the weight, the greater the soldering, light assembly) to follow physically demanding use equipment, to loading on the structures of the low back. tasks (e.g., heavy lifting, carrying). manually handle • The length of time each task is performed should be based on material, and to Awkward Postures the level of tissue demand. For heavy, demanding tasks, perform other • Back muscles must support the weight of the shorter time periods may be more acceptable. various tasks. upper body when leaning forward. Increased • Alternate low-level crouching and stooping tasks with ones bending of the back increases the loading on the that require standing or reaching overhead. spine and increases the pressure on the walls of • Changing work positions often can reduce static loading on the discs. all body areas. For example, to reduce static postures of the trunk and lower body, alternate between standing, sitting, Static Postures and walking. • Extended periods of forward or side bending can • Use the entire body, especially the large muscle groups of the gradually fatigue the structures of the low back. lower extremities, to perform handling motions. If the stress is excessive, and recovery is not • To reduce loading on the soft tissues of the back, lift heavy adequate, muscles and other tissues may fatigue objects with a neutral back posture while maintaining the 3- to the point of injury. point curve. • Do not twist while holding or moving a load. Twisting Repetition places the back in a weak posture and can lead to injury. • Repeated forward bending and lifting can • To minimise muscle strain due to stiffness in cold weather gradually fatigue the structures of the low back. conditions, perform exercises to warm up muscles. Walking If the repetitive stress is excessive, and recovery is an excellent warm up for muscles of the low back. is not adequate, the disc walls may fatigue to the • When possible, balance loads being carried on each side of point of injury. the body. This minimises loading on the soft tissues of the back.

Low Back • When lifting, carrying, or holding objects, keep them as (continued) close to the body as possible. The farther the load is away from the body, the more stress it puts on the back. • Ask for help when lifting large, heavy objects. Remember that communication is important during a two-person lift. A poorly timed two-person lift can cause the load to be unbalanced, or unevenly distributed between the two people, which can lead to overexertion. • To reduce loading on the back, use manual material handling aids, such as mechanical lifts or dollies, to assist in manoeuvring materials. • Be aware of how to properly adjust workstations, chairs, tools, etc. Improper working heights and reaches can cause awkward postures for one or more body parts. If a workstation is not adjustable, try to improvise. For example, if a workbench is too high, a well-balanced step stool can be used to raise the height of the worker. For more recommendations on how to prevent awkward working postures, refer to the Workstation Design Principles section of the Trades/Maintenance Work Manual. • For exercises that can increase tissue tolerances and prevent back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Awkward & Static Postures • Try to sit, instead of crouching or kneeling, when • Bending the knee increases the contact stress between working at low levels for prolonged periods. A Carpenter may the kneecap and the thigh bone. Contact stress • Wear kneepads or foam inserts in coveralls to prevent kneel when increases significantly when the knee is bent over 90 contact stress when kneeling and crawling. working at low degrees. levels. • For exercises that can help prevent knee injuries, see the Contact Stress Knee Injury Education section of the • Kneeling on a hard surface increases the contact stress Trades/Maintenance Work Manual. between the kneecap and the thigh bone.

Repetition • Repeated squatting and kneeling may gradually irritate the knee. Irritation of the knee may lead to muscle wasting, which in turn leads to poor tracking of the knee cap on the thigh bone and increased contact stress between these bones. Foot Static Postures • Wear footwear that is in good condition and provides • While standing, the weight of the body loads the cushioning and good support. A Carpenter may plantar fascia. If the duration of standing is excessive, • Place anti-fatigue inserts into shoes to provide extra be required to and recovery is not adequate, the fascia may deform to cushioning. stand or walk for the point of injury. long duration. • For exercises that can increase tissue tolerances and prevent foot injuries, see the Foot Injury Education section of the Trades/Maintenance Work Manual.

OBJECTIVE: To identify ergonomic risks involved in Chemical Computer Attendant tasks and reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck/Shoulder Force • Use mechanical lifting aids when available. • Neck and shoulder muscles support the weight of • Use the larger muscles of the lower extremities to help A Chemical objects held in the hands. The heavier the object, the handle and manoeuvre heavier objects Computer greater the load on muscles and tendons. Attendant may lift • For exercises that can increase tissue tolerances and • If the force placed on the rotator cuff exceeds the tissue heavy objects prevent neck and shoulder injuries, see the Neck and tolerances, injury may occur. when maintaining Shoulder Injury Education sections of chemicals and Trades/Maintenance Work Manual. checking filters. Shoulder Awkward Postures • When working overhead, take stretch breaks every few • The rotator cuff stabilises the shoulder joint when the minutes. A Chemical arms are away from the body. The farther away the • Alternate overhead work with other tasks that can be Computer arms are from the body, the greater the load on the done with the shoulders in the neutral position. Attendant may rotator cuff. perform work with • For exercises that can increase tissue tolerances and the shoulder in an prevent shoulder injuries, see the Shoulder Injury awkward posture. Education section of the Trades/Maintenance Work Manual.

Low Back Force • To reduce loading on many areas of the body, • Lifting increases the loading on the spine. Weight particularly the back and shoulders, use mechanical A Chemical held in the hands is transmitted to the low back. The lifting aids when available. Computer greater the weight, the greater the loading on the • Ask for help with lifting large, heavy objects. Attendant may structures of the low back. work with • For more recommended work techniques for Manual awkward and/or Awkward Postures Material Handling, refer to the Work Strategies section repetitive postures • Back muscles must support the weight of the upper of the Trades/Maintenance Work Manual. of the back while body when leaning forward. Increased bending of the • For exercises that can increase tissue tolerances and performing various back increases the loading on the spine and increases prevent Back injuries, see the Back Injury Education duties. They may the pressure on the walls of the discs. section of the Trades/Maintenance Work Manual. also manually handle objects in Repetition these postures. • Repeated forward bending and lifting can gradually fatigue the structures of the low back. If the repetitive stress is excessive, and recovery is not adequate, the disc walls may fatigue to the point of injury.

Knee Awkward Postures • Wear kneepads, or foam inserts in coveralls to prevent Static Postures contact stress when kneeling and crawling. A Chemical • Bending the knee increases the contact stress between • Change positions often. These changes reduce static Computer the knee cap and the thigh bone. Contact stress loading on all body areas. For example, to reduce static Attendant may be increases significantly when the knee is bent over 90 postures of the trunk and lower body, alternate between required to kneel degrees. standing, sitting, and walking. or crouch for long during Contact Stress • For exercises that can help prevent knee injuries, see the maintenance • Kneeling on a hard surface increases the contact stress Knee Injury Education section of the duties. These between the knee cap and the thigh bone. Trades/Maintenance Work Manual. positions increase loading on the knee.

OBJECTIVE: To identify ergonomic risks involved in Electrician tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck/Shoulder Force • Use mechanical lifting aids when available. • Neck and shoulder muscles support the weight of • When feeding heavy cable, tie thin wire around one end, An Electrician objects held in the hands. The heavier the object, the then use an electric motor to pull the line through joists may lift heavy greater the load on muscles and tendons. and narrow openings. objects, work with • • If the force placed on the rotator cuff exceeds the When pulling smaller wire through ceiling joists, the arms raised, or tissue tolerances, injury may occur. position yourself so that you can pull the wire towards work with the the body (power position), rather than pulling away and arms overhead. Awkward Postures to the side of the body with the arm extended (awkward posture). • Neck and shoulder muscles must support the weight of • the arms when they are away from the body. The When using tools for prolonged periods of time (e.g., farther away the arms are from the body, the greater soldering), support the arms on the workbench or the load on the muscles and tendons. portable arm rests. • When working overhead, take stretch breaks every few Repetition and Static Postures minutes. • • When the arms are repeatedly held away from the Alternate overhead work with other tasks that can be body, the muscles of the neck and shoulder must done with the shoulders in the neutral position. remain tense to support the weight. If the duration of • For exercises that can increase tissue tolerances and constant tension is excessive, and recovery is not prevent neck and shoulder injuries, see the Neck and adequate, the tissues may fatigue to the point of injury. Shoulder Injury Education sections of Trades/Maintenance Work Manual.

Shoulder Force • Have two people feed heavy cable. One person standing • The rotator cuff stabilises the shoulder joint when close to the spool can feed the cable up to the other An Electrician objects are pushed, pulled, and manipulated. The person, who may be on a ladder. Using a second person may perform work heavier the object, or the larger the force required, the significantly decreases the pulling and lifting forces with the shoulder greater the load on the rotator cuff. Excessive forces required for the person on the ladder, who may already in an awkward can cause injuries. be working in awkward overhead postures. posture (e.g., • For exercises that can increase tissue tolerances and installing heavy Awkward Postures prevent shoulder injuries, see the Shoulder Injury cables). • The rotator cuff stabilises the shoulder joint when the Education section of the Trades/Maintenance Work arms are away from the body. The farther away the Manual. arms are from the body, the greater the load on the rotator cuff. Elbow/Wrist Force • When loosening bolts, use a torque multiplier or a bolt- • Gripping an object requires activation of the forearm loosening spray to reduce required force. An Electrician muscles, which generates tension at the tendon/bone • To loosen bolts or parts, increase leverage by extending may perform connection of the elbow. The harder that an object tool handles. For example, longer metal pipes placed on forceful must be gripped, the greater the load on the the end of a wrench allow for greater leverage when movements tendon/bone connection. loosening bolts. affecting muscles of the elbow/wrist Repetition • To reduce contact stress on the forearms, protective (e.g., installing or • Repeated stress to the elbow without adequate rest padding may be placed inside or outside of the building control could fatigue tissues to the point of injury. coveralls. panels, consoles, • For exercises that can increase tissue tolerances and etc.) prevent elbow and wrist injuries, see the Elbow and Wrist Injury Education sections of the Trades/Maintenance Work Manual.

Wrists/Hands Force • Wear appropriate gloves when working in cold • Gripping an object requires activation of the forearm environments. Well-insulated gloves are ideal for cold An Electrician muscles, which generates tension in the tendons and weather, but close-fitting gloves may be a requirement may install lights, tendon sheaths running through the wrist. The harder for precise work (e.g., wiring) to prevent over-gripping consoles, etc. an object is gripped, the greater the tension in the and over-pinching. outside the mill, tendons, and the pressure in the carpal tunnel. which can expose Environmental factors, namely cold work the wrists and environments, can lead to increased gripping forces hands to cold due to reduced sensitivity in the hands. temperatures. Low Back Force • To reduce loading on many areas of the body, • Lifting increases the loading on the spine. Weight particularly the back and shoulders, use mechanical An Electrician held in the hands is transmitted to the low back. The lifting aids when available. may work with greater the weight, the greater the loading on the • Ask for help with lifting large, heavy objects. awkward and static structures of the low back. postures of the • For more recommended work techniques for Manual back while Awkward Postures Material Handling, refer to the Work Strategies section performing various • Back muscles must support the weight of the upper of the Trades/Maintenance Work Manual. maintenance duties body when leaning forward. Increased bending of the • Change positions often, by rotating tasks or taking (e.g., crawling into back increases the loading on the spine and increases stretch breaks. Changing position reduces static loading machines or under the pressure on the walls of the discs. on the back. conveyors). They may also have to Static Postures • For exercises that can increase tissue tolerances and manually handle • Extended periods of forward or side bending can prevent back injuries, see the Back Injury Education objects in these gradually fatigue the structures of the low back. If the section of the Trades/Maintenance Work Manual. postures. stress is excessive, and recovery is not adequate, the disc walls may fatigue to the point of injury.

Knee Awkward & Static Postures • Wear kneepads, or foam inserts in coveralls to prevent • Bending the knee increases the contact stress between contact stress when kneeling and crawling. An Electrician the knee cap and the thigh bone. Contact stress • Change positions often. These changes reduce static may be required to increases significantly when the knee is bent over 90 loading on all body areas. For example, to reduce static kneel or crouch for degrees. postures of the trunk and lower body, alternate between long periods of standing, sitting, and walking. time during Contact Stress maintenance duties • Kneeling on a hard surface increases the contact stress • For exercises that can help prevent knee injuries, see the or installations. between the knee cap and the thigh bone. Knee Injury Education section of the These positions Trades/Maintenance Work Manual. increase loading on the knee.

OBJECTIVE: To identify ergonomic risks involved in Fire Watch tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • Change the position of the neck whenever possible. • Neck muscles must support the weight of the head When tasks allow, try to bring the neck back to neutral AFire while in a forward bent position. The more the neck position. Watchperson often bends, the greater the load on the muscles and tendons. • Attempt to look down with the eyes rather than the works with the neck. neck bent forward Static Postures and/or twisted for • When the neck is held still in a forward bent position • For exercises to improve the endurance of neck muscles, extended periods the muscles of the neck must remain tense to support to improve posture, and to prevent neck discomfort, see while monitoring the weight of the head. If the constant stress is the Neck Injury Education section of the for fires. sufficient, and recovery is not adequate, the tissues may Trades/Maintenance Work Manual. fatigue to the point of injury.

Neck/Shoulder Awkward Postures • Try to get as close to the area as possible when spraying • Neck and shoulder muscles must support the weight of downanarea. AFire the arms when they are away from the body. The • Keep upper arm close to the body while performing Watchperson may farther away the arms are from the body, the greater the tasks hold the fire hose load on the muscles and tendons. away from the • Alternate with other tasks that can be done with the body as the work Static Postures shoulders in a more neutral position. site is being • When the arms are repeatedly held away from the • For exercises that can increase tissue tolerances and prepared. body, the muscles of the neck and shoulder must prevent neck and shoulder injuries, see the Injury remain tense to support the weight. If the duration of Education section of the Trades/Maintenance Work constant tension is excessive, and recovery is not Manual. adequate, the tissues may fatigue to the point of injury.

Shoulder Force • Use the larger muscles of the lower extremities to help • The rotator cuff stabilises the shoulder joint when handle and manoeuvre heavier objects. AFire objects are pushed, pulled, and manipulated. The • Use mechanical lifting aids when available. Watchperson may heavier the object, or the larger the force required, the lift, lower, push, greater the load on the rotator cuff. • Handle objects with as little force as possible. For and pull objects • If the force placed on the rotator cuff exceeds the tissue example, roll objects (e.g., oil barrels, welding tanks) throughout the day tolerances, injury may occur. whenever possible rather than lifting and carrying them. in order to aid the • Where possible, allow objects to drop, instead of Welder. Awkward Postures supporting the weight of the object while lowering it. • The rotator cuff stabilises the shoulder joint when the arms are away from the body. The farther away the • Ask for help with lifting large, heavy objects. arms are from the body, the greater the load on the Remember that communication is important during a rotator cuff. two-person lift. A poorly timed two-person lift can cause the load to be unbalanced, or unevenly distributed between the two people, which can lead to overexertion. • Work in pairs on heavy physical tasks. • For exercises that can increase tissue tolerances and prevent shoulder injuries, see the Shoulder Injury Education section of the Trades/Maintenance Work Manual.

See Disclaimer in PDA & Work Manual © 2000 IMIRP Society Trades/Maintenance Fire Watch MSI Safety Guide (revised) 372 ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS Low Back Repetition • Adopt power positions while in a bent forward position. • Repeated forward bending and lifting can gradually In all cases, maintain the 3-point curve, bend with the AFire fatigue the structures of the low back. If the repetitive knees, and keep work as close to the body as Watchperson may stress is excessive, and recovery is not adequate, the comfortable. repeatedly bend disc walls may fatigue to the point of injury. • To minimise muscle strain due to stiffness in cold the low back in an weather conditions, perform exercises to warm up awkward posture Awkward Postures muscles. Walking is an excellent warm up for muscles monitoring for • Back muscles must support the weight of the upper of the low back. fires, aiding the body when leaning forward. Increased bending of the Welders, or back increases the loading on the spine and increases • For exercises that can increase tissue tolerances and preparing the work the pressure on the walls of the discs. prevent low back injuries, see the Back Injury site. Education section of the Trades/Maintenance Work Manual. AFire Force • Use dollies to move large objects around the work area. Watchperson may • Lifting increases the loading on the spine. Weight • Use the large muscles of the lower body as much as be required to lift held in the hands is transmitted to the low back. The possible. heavy, awkward greater the weight, the greater the loading on the objects. structures of the low back. • Do not twist the back while lifting. • Keep items as close to the body as possible while lifting. Awkward Postures • Back muscles must support the weight of the upper • Roll items whenever possible. body when leaning forward. Increased bending of the • Use leverage or mechanical aids to lift items. back increases the loading on the spine and increases the pressure on the walls of the discs. • Seek assistance. • For exercises that can increase tissue tolerances and prevent low back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Repetition • Adjust the height of the work surface to avoid frequent • Repeated squatting and kneeling may gradually irritate bending of the knees. Depending on the the knee. Irritation of the knee may lead to muscle • If squatting occurs, try not to adopt a deep squat (e.g., height of the weld wasting, which in turn leads to poor tracking of the back of heels touching the back of the thigh). relative to a Fire knee cap on the thigh bone and increased contact Watchperson’s stress between these bones. • Sit while working at low heights for prolonged periods viewing height, a of time. Fire Watchperson Awkward Posture • For exercises that can help prevent Knee injuries, see may be required to • Bending the knee increases the contact stress between the knee Injury Education section of the repeatedly bend the kneecap and the thighbone. Contact stress Trades/Maintenance Work Manual. down to view the increases significantly when the knee is bent over 90 welded area. degrees. AFire Awkward Postures • Use kneepads or foam inserts while working in a Watchperson often Static Postures kneeled position. kneels in order to • Bending the knee increases the contact stress between • For exercises that can help prevent Knee injuries, see monitor the the kneecap and the thighbone. Contact stress the knee Injury Education section of the welding area for increases significantly when the knee is bent over 90 Trades/Maintenance Work Manual. fires. degrees.

Contact Stress • Kneeling on a hard surface increases the contact stress between the kneecap and the thighbone.

OBJECTIVE: To identify ergonomic risks involved in the Heavy Duty Mechanic position, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • If possible, use the cushion of the creeper to help support the • Neck muscles must support the weight of the head when working under machinery. Additional cushioning A Heavy Duty head while working under machinery. The in the neck region of the creeper may aid in reducing strains Mechanic may hold longer the head must be held in this position, the of the neck. their head up greater the load on the muscles and tendons. • Use task rotation to periodically move away from working unsupported while under machinery. This rotation will give the muscles of the working under Static Postures neck time to recover. machinery. • When the head is held still in a bent position, the muscles of the neck must remain tense to support • For exercises to improve the endurance of neck muscles, to the weight of the head. This constant state of improve posture, and to prevent neck discomfort, see the tension in the neck muscles, with no time Neck Injury Education section of the Trades/Maintenance allowed for recovery, can cause fatigue. Work Manual.

Shoulder Force • Increase leverage by extending tool handles. For example, • The rotator cuff stabilises the shoulder joint place a longer metal pipe on the end of a wrench to allow for A Heavy Duty when objects are pushed, pulled, and greater leverage when loosening bolts. Mechanic may lift, manipulated. The heavier the object, or the • Use both hands to exert force on objects (e.g., pulling on a lower, carry, push, larger the force required, the greater the load on large wrench). This distributes the required force across pull, and the rotator cuff. Excessive forces can cause wrists, forearms, and shoulders. manipulate objects injuries. If the force placed on the rotator cuff with the arms away exceeds the tissue tolerances, injury may occur. • Use overhead cranes and hoists to move objects around the from the shop. body. Awkward Postures • • When using hand tools for prolonged periods of time (e.g., The rotator cuff stabilises the shoulder joint soldering or welding), support the arms on the workbench, or when the arms are away from the body. The use arm rests. farther away the arms are from the body, the greater the load on the rotator cuff. • For exercises that can increase tissue tolerances and prevent shoulder injuries, see the Shoulder Injury Education section of the Trades/Maintenance Work Manual.

Shoulder Awkward Postures • When working overhead, take stretch breaks every few • A rotator cuff tendon may rub up against bone minutes. A Heavy Duty (impingement) when the arms are lifted • Alternate overhead work with other tasks that can be done Mechanic overhead. The friction between the tendon and with the shoulders in a more neutral position. frequently works the bone increases as the arm is lifted higher. In with the arms held addition, the rotator cuff must stabilise the • For exercises that can increase tissue tolerances and prevent overhead. weight of the arms when working overhead, shoulder injuries, see the Shoulder Injury Education section increasing the tension in the tendon. The of the Trades/Maintenance Work Manual. combination of impingement and tension increases the stress on this tendon.

Elbow/Wrist Force • Use a torque multiplier or a bolt-loosening spray to reduce the • Gripping an object requires activation of the amount of force required to loosen bolts. A Heavy Duty forearm muscles, which generates tension at the • Carve grooves into smooth wooden handles. Textured Mechanic tendon/bone connection of the elbow. The grooves increase the friction between hands/gloves and the repeatedly grips harder that an object must be gripped, the tool handle, reducing the force required to grip the handle. and manoeuvres greater the load on the tendon/bone connection. tools and objects. • Use only necessary gripping force when handling objects or Awkward Postures tools. Be aware that cold temperatures and tool vibration can • The width of an object affects how much lead to decreased sensitivity and increased grip forces. muscle tension needs to be generated. Using • Maintain a straight wrist position when gripping or either an overly large or a small grip requires manoeuvring tools and objects. more muscle force, and can lead to tissue fatigue at the tendon/bone connection. • Whenever possible, use both hands for forceful movements. Using both hands distributes the required force. • The position of the wrist also affects how much muscle tension needs to be generated. Gripping • For exercises that can increase tissue tolerances and prevent objects with the wrist bent increases the tension elbow injuries, see the Elbow Injury Education section of the generated by muscles. Trades/Maintenance Work Manual.

Repetition • Repeated stress to the elbow without adequate rest could fatigue tissues to the point of injury.

Wrist Force • Use a torque multiplier or a bolt-loosening spray to reduce the • Gripping an object requires activation of the amount of force required to loosen bolts. A Heavy Duty forearm muscles, which generates tension in the • Carve grooves into smooth wooden handles. Textured Mechanic may tendons and tendon sheaths running through the grooves increase the friction between hands/gloves and the grip tools and wrist. The harder an object is gripped, the tool handle, reducing the force required to grip the handle. objects with the greater the tension in the tendons, and the wrists bent. pressure in the carpal tunnel. • Use only necessary gripping force when handling objects or tools. Be aware that cold temperatures and tool vibration can Awkward Postures lead to decreased sensitivity and increased grip forces. • As the wrist is bent, the tendon sheaths will rub • Maintain a straight wrist position when gripping or up against the walls of the carpal tunnel. The manoeuvring tools and objects. further the wrist is bent, the more friction experienced in the tendon sheaths. • Whenever possible, use both hands for forceful movements. Using both hands distributes the required force. Repetition • For exercises that can increase tissue tolerances and prevent • Repeated bending of the wrist and gripping wrist injuries, see the Wrist Injury Education section of the causes stress to the tendon sheaths. If the Trades/Maintenance Work Manual. repetitive stress is excessive, and recovery is not adequate, the tendon sheaths may fatigue to the point of injury.

Wrist/Hand Vibration • Maintain a straight wrist position when operating vibrating • Exposure to vibration, through power tools or hand tools. A Heavy Duty other vibrating objects, places a unique form of • Try not to operate vibrating tools for prolonged periods of Mechanic may mechanical stress on the tissues of the hand and time. When possible, break-up the use of these tools into operate vibrating wrist. Factors like vibration level and vibration smaller time periods. hand tools. frequency influence the amount of stress. • Use only necessary gripping force when handling objects or • Continual exposure to hand/arm vibration may tools. Be aware that cold temperatures and tool vibration can gradually damage neurovascular tissue (nerves lead to decreased sensitivity and increased grip forces. and blood vessels) in the hand, and may contribute to problems in the wrist. • Ensure that vibrating power tools are properly maintained. Tools in need of repair often vibrate more, or at more critical frequencies, than properly maintained tools.

Low Back Force • Use the entire body, especially the large muscle groups of the lower • Lifting increases the loading on the limbs, to perform manual handling. A Heavy Duty spine. Weight held in the hands is • Lift heavy objects with a neutral back posture while maintaining the 3- Mechanic may lift, transmitted to the low back. The point curve. lower, carry, push, greater the weight, the greater the • Do not twist while holding or moving a load. This places the back in a pull, and loading on the structures of the low weaker posture, which can lead to injury. manipulate heavy back. • When possible, balance loads being carried on each side of the body. objects. Balanced loads place more even loading on the soft tissues of the Awkward Postures back. • Back muscles must support the weight • When lifting, carrying, or holding objects, keep them as close to the of the upper body when leaning body as possible. The farther the load is away from the body, the forward. Increased bending of the back more stress it puts on the back. increases the loading on the spine and • Ask for help when lifting large, heavy objects. Remember that increases the pressure on the walls of communication is important during a two-person lift. A poorly timed the discs. two-person lift can cause the load to be unbalanced, or unevenly distributed between the two people, which can lead to overexertion. • Use overhead cranes and hoists as much as possible to move objects around the shop. • Use jacks (with straps if needed) when manoeuvring heavy parts or objects into place underneath machinery. These lifting aids can eliminate the need to manually lift heavy objects while working under machinery. • To minimise muscle strain due to stiffness in cold weather conditions, perform exercises to warm up muscles. Walking is an excellent warm up for muscles of the low back. • For exercises that can increase tissue tolerances and prevent back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Awkward & Static Postures • When working at low levels for prolonged periods, try to sit • Bending the knee increases the contact stress instead of crouching or kneeling. A Heavy Duty between the knee cap and the thigh bone. • Wear kneepads or foam inserts in coveralls to prevent contact Mechanic Contact stress increases significantly when the stress when kneeling and crawling. frequently kneels knee is bent over 90 degrees. on hard surfaces in • For exercises that help prevent knee injuries, see the Knee order to work on Contact Stress Injury Education section of the Trades/Maintenance Work machinery. • Kneeling on a hard surface increases the contact Manual. stress between the knee cap and the thigh bone.

OBJECTIVE: To identify ergonomic risks involved in Machinist tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • To reduce static loading on the neck when working at a • Neck muscles are required to turn the head to the side. workbench or table, look down with the eyes when Machinsts are The further the head is turned to the side, the greater possible, instead of bending the head forward. If work frequently in the load on muscles and tendons. is precise, this may also require an increase in working forward flexed height. • Neck muscles must support the weight of the head neck postures while in a side bent position. The more the neck • Alternate prolonged bench and machine work with other while working at bends, the greater the load on the muscles and tendons. tasks that can be done with the neck in the neutral various machines position. and benches. Static Postures These postures can • For wearers of bifocals, position work so that it is in a • When the neck is held still in a forward bent, side be static or proper viewing range that does not require forward neck bent, or twisted position, the muscles of the neck must repetitive, flexion, or see your eye-care professional for remain tense to support the weight of the head. If the depending on the appropriate glasses to wear when performing bench constant stress is sufficient, and recovery is not nature of the task. tasks. adequate, the tissues may fatigue to the point of injury. • Use task lighting to improve illumination inside Repetition machines, reducing awkward neck postures. • When the head is repeatedly turned to the side, the • For exercises to improve the endurance of neck muscles, muscles of the neck are subjected to repeated stress to improve posture, and to prevent neck discomfort, see with little time for recovery. If the stress is excessive, the Neck Injury Education section of the and recovery is not adequate, tissues can fatigue to the Trades/Maintenance Work Manual. point of injury.

Neck/Shoulder Force • Use mechanical lifting aids when available. • Neck and shoulder muscles support the weight of • When using tools for prolonged periods of time (e.g., Machinists often objects held in the hands. The heavier the object, the grinding), support the arms on the workbench or hold their arms in greater the load on muscles and tendons. portable arm rests. unsupported • If the force placed on the rotator cuff exceeds the elevated postitions • When working with the lathe and other machinery, tissue tolerances, injury may occur. while working at support the arms on flat machine surfaces or portable different machines arm rests. Avoid supporting the arms on sharp, Awkward Postures and benches. uncomfortable, or unsafe surfaces. • Neck and shoulder muscles must support the weight of the arms when they are away from the body. The • When working with the arms extended for prolonged farther away the arms are from the body, the greater periods, take stretch breaks every few minutes. the load on the muscles and tendons. • Alternate prolonged forward arm extension work with other tasks that can be done with the arms and shoulders Static Postures in a more neutral position. • When the arms are repeatedly held away from the body, the muscles of the neck and shoulder must • For exercises that can increase tissue tolerances and remain tense to support the weight. If the duration of prevent neck and shoulder injuries, see the Neck and constant tension is excessive, and recovery is not Shoulder Injury Education sections of the adequate, the tissues may fatigue to the point of injury. Trades/Maintenance Work Manual.

Wrist Force • Use a torque multiplier or a bolt-loosening spray to • Gripping an object requires activation of the forearm reduce the amount of force required to loosen bolts and Machinists may muscles, which generates tension in the tendons and other fasteners. adopt awkward tendon sheaths running through the wrist. The harder • Carve grooves into smooth wooden handles. Textured wrist postures an object is gripped, the greater the tension in the grooves increase the friction between hands/gloves and while setting and tendons, and the pressure in the carpal tunnel. the tool handle, reducing the force required to grip the adjusting the lathe. handle. Awkward Postures • Use only necessary gripping force when handling A Machinist may • As the wrist is bent, the tendon sheaths will rub up objects or tools. Be aware that cold temperatures and grip tools and against the walls of the carpal tunnel. The further the tool vibration can lead to decreased sensitivity and objects with the wrist is bent, the more friction experienced in the increased grip forces. wrists bent. tendon sheaths. • Maintain a straight wrist position when gripping or manoeuvring tools and objects. Repetition • Whenever possible, use both hands for forceful • Repeated bending of the wrist and gripping causes movements. Using both hands distributes the required stress to the tendon sheaths. If the repetitive stress is force. excessive, and recovery is not adequate, the tendon • For exercises that can increase tissue tolerances and sheaths may fatigue to the point of injury. prevent elbow and wrist injuries, see the Elbow and Wrist Injury Education sections of the Trades/Maintenance Work Manual.

Low Back Force • When working for prolonged periods in forward flexed • Lifting increases the loading on the spine. Weight positions, take stretch breaks every few minutes. Machinists may be held in the hands is transmitted to the low back. The • Alternate forward flexed work with other tasks that can required to assume greater the weight, the greater the loading on the be done with the trunk in a more neutral position. forward flexed structures of the low back. • Use the entire body, especially the large muscle groups postures while of the lower limbs, to perform manual handling. working at Awkward Postures • Lift heavy objects with a neutral back posture while different machines • Back muscles must support the weight of the upper maintaining the 3-point curve. and benches. body when leaning forward. Increased bending of the • Do not twist while holding or moving a load. Twisting back increases the loading on the spine and increases places the back in a weak posture. A Machinist may the pressure on the walls of the discs. • When possible, balance loads being carried on each side lift, lower, carry, of the body. Balanced loads place more even loading on push, pull, and Static Postures the soft tissues of the back. manipulate heavy • Extended periods of forward or side bending can • When lifting, carrying, or holding objects, keep them as objects and gradually fatigue the structures of the low back. If the close to the body as possible. The farther the load is materials. stress is excessive, and recovery is not adequate, the from the body, the more stress it puts on the back. disc walls may fatigue to the point of injury. • Ask for help when lifting large, heavy objects. Remember that communication is important during a two-person lift. A poorly timed two-person lift can cause the load to be unbalanced, or unevenly distributed between the two people, which can lead to overexertion. • Use overhead cranes and hoists as much as possible to move objects around the shop. • For exercises that can increase tissue tolerances and prevent back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

OBJECTIVE: To identify ergonomic risks involved in Millwright tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • To reduce static loading on the neck when working at a • Neck muscles must support the weight of the head workbench or table, look down with the eyes when Millwrights may while in a bent position. The more the neck is bent, possible, instead of bending the head forward. If work frequently look up, the greater the load on the muscles and tendons. is precise, this may also require an increase in working down, or to the height. side in order to Static Postures • When working overhead, take stretch breaks every few repair or maintain • When the neck is held still in a forward bent, side minutes. machinery. bent, or twisted position, the muscles of the neck must remain tense to support the weight of the head. If the • Alternate overhead work with other tasks that can be constant stress is sufficient, and recovery is not done with the shoulders in the neutral position. adequate, the tissues may fatigue to the point of injury. • For wearers of bifocals, position work so that it is in a proper viewing range that does not require forward neck flexion, or see your eye-care professional for appropriate glasses to wear when performing bench tasks. • For exercises to improve the endurance of neck muscles, to improve posture, and to prevent neck discomfort, see the Neck Injury Education section of the Trades/Maintenance Work Manual.

Neck/Shoulder Force • When working overhead, take stretch breaks every few • Neck and shoulder muscles support the weight of minutes. Millwrights may objects held in the hands. The heavier the object, the • Alternate overhead work with other tasks that can be work overhead or greater the load on muscles and tendons. done with the shoulders in the neutral position. in front of their • If the force placed on the rotator cuff exceeds the bodies in order to • When using tools for prolonged periods of time (e.g., tissue tolerances, injury may occur. maintain and soldering, welding), support the arms using the repair machinery workbench or arm rests. Awkward Postures • Neck and shoulder muscles must support the weight of • Alternate tool use between both arms. For example, try the arms when they are away from the body. The to change hands when using an impact wrench for farther away the arms are from the body, the greater prolonged periods of time. the load on the muscles and tendons. • Use the larger muscles of the lower extremities to help handle and manoeuvre heavier objects. Static Postures • When the arms are repeatedly held away from the • To reduce the force required in the hands, arms, body, the muscles of the neck and shoulder must shoulders, and back when loosening bolts, use a torque remain tense to support the weight. If the duration of multiplier or a bolt-loosening spray. constant tension is excessive, and recovery is not • Extend tool handles to increase leverage and reduce adequate, the tissues may fatigue to the point of injury. required muscle force. Repetition • Proper maintenance of tools can reduce the amount of • When the arms are repeatedly lifted, the muscles of the force required to use them, therefore reducing muscle neck and shoulder are subjected to repeated stress with loading. little or no time for recovery. If the stress is excessive, • For exercises that can increase tissue tolerances and and recovery is not adequate, the tissues may fatigue prevent shoulder injuries, see the Shoulder Injury to the point of injury. Education section of the Trades/Maintenance Work Manual.

Shoulder Force • Use the larger muscles of the lower extremities to help • The rotator cuff stabilises the shoulder joint when handle and manoeuvre heavier objects. Millwrights lift, objects are pushed, pulled, and manipulated. The • To reduce the force required in the hands, arms, lower, push, and heavier the object, or the larger the force required, the shoulders, and back when loosening bolts, use a torque pull many objects greater the load on the rotator cuff. multiplier or a bolt-loosening spray. throughout the day • If the force placed on the rotator cuff exceeds the in order to • Extend tool handles to increase leverage and reduce tissue tolerances, injury may occur. maintain and required muscle force. repair machinery. Awkward Postures • Use mechanical lifting aids when available. • The rotator cuff stabilises the shoulder joint when the • Handle objects with as little force as possible. For arms are away from the body. The farther away the example, roll objects (e.g. oil barrels, welding tanks) arms are from the body, the greater the load on the whenever possible rather than lifting and carrying them. rotator cuff. • Where possible, allow objects to drop, instead of Repetition supporting the weight of the object while lowering it. • When the arms are repeatedly raised, the rotator cuff is • Ask for help with lifting large, heavy objects. subjected to repeated stress with little time for Remember that communication is important during a recovery. If the repetitive stress is excessive, and two-person lift. A poorly timed two-person lift can recovery is not adequate, the tissues may fatigue to the cause the load to be unbalanced, or unevenly distributed point of injury. between the two people, which can lead to overexertion. • Work in pairs on heavy physical tasks. • For exercises that can increase tissue tolerances and prevent shoulder injuries, see the Shoulder Injury Education section of the Trades/Maintenance Work Manual.

Elbow/Wrist Force • Proper maintenance of tools can reduce the amount of • Gripping an object requires activation of the forearm force required to use them, and therefore reduce loading Millwrights may muscles, which generates tension at the tendon/bone on many muscle groups. grip and connection of the elbow. The harder that an object • To reduce the force required in the hands, arms, repetitively handle must be gripped, the greater the load on the shoulders, and back when loosening bolts, use a torque tools and tendon/bone connection. multiplier or a bolt-loosening spray. equipment. Awkward Postures • Extend tool handles to increase leverage and reduce • The width of an object affects how much muscle required muscle force. tension needs to be generated. Using either an overly • Carve grooves into smooth wooden handles. Textured large or a small grip requires more muscle force, and grooves increase the friction between hands/gloves and can lead to tissue fatigue at the tendon/bone the tool handle, reducing the force required to grip the connection. handle. • The position of the wrist also affects how much • Use only necessary gripping force when handling muscle tension needs to be generated. Gripping objects or tools. Be aware that cold temperatures and objects with the wrist bent increases the tension tool vibration can lead to decreased sensitivity and generated by muscles. increased grip forces. Repetition • Maintain a straight wrist position when gripping or • Repeated stress to the elbow without adequate rest manoeuvring tools and objects. could fatigue tissues to the point of injury. • Whenever possible, use both hands for forceful movements. Using both hands distributes the required force. • For exercises that can increase tissue tolerances and prevent elbow injuries, see the Elbow Injury Education section of the Trades/Maintenance Work Manual.

Low Back Force • Use the larger muscles of the lower • Lifting increases the loading on the spine. Weight held in the extremities to help handle and manoeuvre Millwrights lift, hands is transmitted to the low back. The greater the weight, the heavier objects. lower, push, and greater the loading on the structures of the low back. • Use mechanical lifting aids when available. pull many objects • Awkward Postures Handle objects with as little force as possible. throughout the day • Back muscles must support the weight of the upper body when For example, roll objects (e.g., oil barrels, in order to leaning forward. Increased bending of the back increases the welding tanks) whenever possible rather than maintain and loading on the spine and increases the pressure on the walls of lifting and carrying them. repair machinery. • the discs. Where possible, allow objects to drop, instead of supporting the weight of the object to lower Static Postures it. • Extended periods of forward or side bending can gradually • Ask for help with lifting large, heavy objects. fatigue the structures of the low back. If the stress is excessive, Remember that communication is important and recovery is not adequate, the disc walls may fatigue to the during a two-person lift. A poorly timed two- point of injury. person lift can cause the load to be Repetition unbalanced, or unevenly distributed between • Repeated forward bending and lifting can gradually fatigue the the two people, which can lead to structures of the low back. If the repetitive stress is excessive, overexertion. and recovery is not adequate, the disc walls may fatigue to the • Work in pairs on heavy physical tasks. point of injury. • To minimise muscle strain due to stiffness in cold weather conditions, perform exercises to Vibration • warm up muscles. Walking is an excellent Whole body vibration is usually transmitted through the seat into warm up for muscles of the low back. the low back. Exposure to whole body vibration introduces a • For exercises that can increase tissue unique mechanical stress to the structures of the spine that can tolerances and prevent back injuries, see the significantly increase the loading on the low back. Prolonged Back Injury Education section of the sitting on a vibrating surface may contribute to the gradual Trades/Maintenance Work Manual. weakening of the lumbar discs.

Knee Awkward & Static Postures • When working at low levels for prolonged periods, try • Bending the knee increases the contact stress between to sit instead of crouching or kneeling. Millwrights may the knee cap and the thigh bone. Contact stress • Wear kneepads or foam inserts in coveralls to prevent kneel, climb, or increases significantly when the knee is bent over 90 contact stress when kneeling and crawling. squat while degrees. repairing or • For exercises that can help prevent knee injuries, refer to maintaining Contact Stress the Knee Injury Education section of the machinery. • Kneeling on a hard surface increases the contact stress Trades/Maintenance Work Manual. between the kneecap and the thighbone.

Repetition • Repeated squatting and kneeling may gradually irritate the knee. Irritation of the knee may lead to muscle wasting, which in turn leads to poor tracking of the knee cap on the thigh bone and increased contact stress between these bones. Foot Repetition • Buy appropriate supportive footwear to decrease foot • During walking, impact between the ground and the discomfort. Millwrights may feet loads the plantar fascia. If the duration of walking • Place anti-fatigue inserts into shoes to provide extra walk long is excessive, and recovery is not adequate, the fascia cushioning. distances around may fatigue to the point of injury. the mill while • For exercises that can increase tissue tolerances and whistle chasing. Vibration prevent foot injuries, see the Foot Injury Education • Vibrating floors can increase the loading on the foot. section of the Trades/Maintenance Work Manual. Factors like vibration level and vibration frequency increase the amount of loading on the foot, and could lead to irritation.

OBJECTIVE: To identify ergonomic risks involved in oiling, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck/Shoulder Force • Where possible, support the arms on a stationary object • Neck and shoulder muscles support the weight of while pouring lubricant (e.g., on a handrail while oiling An Oiler may objects held in the hands. The heavier the object, the chain). work with the greater the load on muscles and tendons. • When lifting and carrying an oil bucket, keep the load as arms away from • If the force placed on the rotator cuff exceeds the close to the body as possible. the body, or above tissue tolerances, injury may occur. shoulder height, to • When repeatedly reaching overhead, try to alternate fill lubricant arms. Awkward Postures vessels or grease • • For exercises that can increase tissue tolerances and machinery. Neck and shoulder muscles must support the weight of the arms when they are away from the body. The prevent neck and shoulder injuries, see the Neck and farther away the arms are from the body, the greater Shoulder Injury Education sections of the the load on the muscles and tendons. Trades/Maintenance Work Manual.

Static Postures • When the arms are repeatedly held away from the body, the muscles of the neck and shoulders must remain tense to support the weight. If the duration of constant tension is excessive, and recovery is not adequate, tissues may fatigue to the point of injury.

Elbow/Wrist Force • Use only necessary gripping force. • Gripping an object requires activation of the forearm • Maintain a straight wrist position where possible. An Oiler may muscles, which generates tension at the tendon/bone grease machinery connection of the elbow. The harder that an object • Choose a grease gun with an appropriate size handle. using a manual must be gripped, the greater the load on the • If operating a manual hand crank, alternate arm use. grease gun. tendon/bone connection. • For exercises that can increase tissue tolerances and An Oiler may Awkward Postures prevent wrist and elbow injuries, see the Wrist and operate a manual • The width of an object affects how much muscle Elbow Injury Education sections of the hand crank to tension needs to be generated. Using either an overly Trades/Maintenance Work Manual. pump lubricants large or a small grip requires more muscle force, and into machinery. can lead to tissue fatigue at the tendon/bone connection. • The position of the wrist also affects how much muscle tension needs to be generated. Gripping objects with the wrist bent increases the tension generated by muscles.

Repetition • Repeated stress to the elbow without adequate rest could fatigue tissues to the point of injury.

Low Back Force • Use hoists, dollies, or small mobile equipment to move • Lifting increases the loading on the spine. Weight heavy objects such as oil barrels around the mill. An Oiler may held in the hands is transmitted to the low back. The • When lifting objects such as oil buckets, hold them manually move greater the weight, the greater the loading on the close to the body. large barrels full of structures of the low back. oil. • Use a two-person lift when necessary. Awkward Postures • When carrying oil bucket/cans around the mill is An Oiler may • Back muscles must support the weight of the upper necessary, carry one in each hand to balance the load. shovel grease from body when leaning forward. Increased bending of the large containers to back increases the loading on the spine and increases • For exercises that can increase tissue tolerances and smaller portable the pressure on the walls of the discs. prevent back injuries, see the Back Injury Education containers. section of the Trades/Maintenance Work Manual. Static Postures An Oiler may • Extended periods of forward or side bending can carry oil buckets gradually fatigue the structures of the low back. If the around the mill. stress is excessive, and recovery is not adequate, the disc walls may fatigue to the point of injury.

Knee Awkward & Static Postures • Wear kneepads when kneeling on hard surfaces. • Bending the knee increases the contact stress between • For exercises that can help prevent knee injuries, see the An Oiler may the knee cap and the thigh bone. Contact stress Knee section of the Trades/Maintenance Work kneel on hard increases significantly when the knee is bent over 90 Manual. surfaces such as degrees. catwalks to lubricate Contact Stress machinery. • Kneeling on a hard surface increases the contact stress between the kneecap and the thighbone. Foot Repetition • For exercises that can increase tissue tolerances and • During walking, impact between the ground and the prevent foot injuries, see the Foot section of the An Oiler may walk feet loads the plantar fascia. If the duration of walking Trades/Maintenance Work Manual. on hard surfaces is excessive, and recovery is not adequate, the fascia for long duration. may fatigue to the point of injury.

OBJECTIVE: To identify ergonomic risks involved in painting tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • When working at a workbench or table, look down with • Neck muscles must support the weight of the head the eyes when possible, instead of bending the head Painters may while in a bent position. The more the neck is bent, forward. If work is precise, this may also require an frequently look up, the greater the load on the muscles and tendons. increase in working height. down, or to the • When working overhead, take stretch breaks every few side in order to Static Postures minutes. prepare and paint • When the neck is held still in a forward bent, side pieces. bent, or twisted position, the muscles of the neck must • For wearers of bifocals, position work so that it is in a remain tense to support the weight of the head. If the proper viewing range that does not require forward neck constant stress is sufficient, and recovery is not flexion, or see your eye-care professional for adequate, the tissues may fatigue to the point of injury. appropriate glasses to wear when performing bench tasks. • For exercises to improve the endurance of neck muscles, to improve posture, and to prevent neck discomfort, see the Neck Injury Education section of the Trades/Maintenance Work Manual.

Neck/Shoulder Awkward Postures • When working overhead, take stretch breaks every few • Neck and shoulder muscles must support the weight of minutes. Painters may work the arms when they are away from the body. The • Alternate overhead work with other tasks that can be overhead or in farther away the arms are from the body, the greater done with the shoulders in the neutral position. front of their the load on the muscles and tendons. bodies in order to • Alternate tool use between both arms. For example, try prepare and paint Static Postures to change hands when using a spray gun for prolonged surfaces. • When the arms are repeatedly held away from the periods of time. body, the muscles of the neck and shoulder must • Use the larger muscles of the lower extremities to help remain tense to support the weight. If the duration of handle and manoeuvre heavier objects. constant tension is excessive, and recovery is not adequate, the tissues may fatigue to the point of injury. • Extend tool handles to increase leverage and reduce required muscle force. Repetition • Proper maintenance of tools can reduce the amount of • When the arms are repeatedly lifted, the muscles of the force required to use them, therefore reducing muscle neck and shoulder are subjected to repeated stress with loading. little or no time for recovery. If the stress is excessive, and recovery is not adequate, the tissues may fatigue • For exercises that can increase tissue tolerances and to the point of injury. prevent shoulder injuries, see the Shoulder Injury Education section of the Trades/Maintenance Work Manual.

Shoulder Awkward Postures • Extend tool handles to increase leverage and reduce • The rotator cuff stabilises the shoulder joint when the required muscle force. Painters assume arms are away from the body. The farther away the • Alternate hands when performing tasks with hand tools. extreme shoulder arms are from the body, the greater the load on the postures, often rotator cuff. • Use mechanical lifting aids when available. while holding hand • Ask for help with lifting large, heavy objects. tools, to prepare Static Postures Remember that communication is important during a and paint surfaces, • When the arms are held in a raised position, loading two-person lift. A poorly timed two-person lift can and to clean work occurs in the tissues of the shoulder. Prolonged cause the load to be unbalanced, or unevenly distributed areas. exposure to this loading leads to tissue fatigue and risk between the two people, which can lead to overexertion. of injury. • Work in pairs on heavy physical tasks. Repetition • For exercises that can increase tissue tolerances and • When the arms are repeatedly raised, the rotator cuff is prevent shoulder injuries, see the Shoulder Injury subjected to repeated stress with little time for Education section of the Trades/Maintenance Work recovery. If the repetitive stress is excessive, and Manual. recovery is not adequate, the tissues may fatigue to the point of injury.

Elbow/Wrist Force • Proper maintenance of tools can reduce the amount of • Gripping an object requires activation of the forearm force required to use them, and therefore reduce loading Painters repeatedly muscles, which generates tension at the tendon/bone on many muscle groups. grip and handle connection of the elbow. The harder that an object • Extend tool handles to increase leverage and reduce tools and must be gripped, the greater the load on the required muscle force. equipment. For tendon/bone connection. some tasks, the • Use only necessary gripping force when handling duration of this Awkward Postures objects or tools. Be aware that cold temperatures and gripping can be • The width of an object affects how much muscle tool vibration can lead to decreased sensitivity and prolonged. tension needs to be generated. Using either an overly increased grip forces. large or a small grip requires more muscle force, and • Maintain a straight wrist position when gripping or can lead to tissue fatigue at the tendon/bone manoeuvring tools and objects. connection. • • Whenever possible, use both hands for forceful The position of the wrist also affects how much movements. Using both hands distributes the required muscle tension needs to be generated. Gripping force. objects with the wrist bent increases the tension generated by muscles. • For exercises that can increase tissue tolerances and prevent elbow and wrist injuries, see the Elbow and Vibration Wrist Injury Education sections of the • Exposure to vibration, through power tools or other Trades/Maintenance Work Manual. vibrating objects, places a unique form of mechanical stress on the tissues of the hand and wrist. Factors like vibration level and vibration frequency influence the amount of stress.

Low Back Force • Use the larger muscles of the lower extremities to help • Lifting increases the loading on the spine. Weight handle and manoeuvre heavier objects. Painters assume held in the hands is transmitted to the low back. The • Use mechanical lifting aids when available. awkward trunk greater the weight, the greater the loading on the postures to prepare structures of the low back. • Handle objects with as little force as possible. For and paint surfaces, example, roll or slide whenever possible rather than especially in cases Awkward Postures lifting and carrying them. where the work • Back muscles must support the weight of the upper • Ask for help with lifting large, heavy objects. must be done in body when leaning forward. Increased bending of the Remember that communication is important during a the mill. back increases the loading on the spine and increases two-person lift. A poorly timed two-person lift can the pressure on the walls of the discs. cause the load to be unbalanced, or unevenly distributed Painters handle between the two people, which can lead to overexertion. materials and Static Postures pieces throughout • Extended periods of forward or side bending can • Work in pairs on heavy physical tasks. the day. gradually fatigue the structures of the low back. If the • To minimise muscle strain due to stiffness in cold stress is excessive, and recovery is not adequate, the weather conditions, perform exercises to warm up disc walls may fatigue to the point of injury. muscles. Walking is an excellent warm up for muscles of the low back. • For exercises that can increase tissue tolerances and prevent back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Awkward Postures • When working at low levels for prolonged periods, try Static Postures to sit instead of crouching or kneeling. Painters may • Bending the knee increases the contact stress between • Wear kneepads or foam inserts in coveralls to prevent kneel, climb, or the kneecap and the thighbone. Contact stress contact stress when kneeling and crawling. squat while increases significantly when the knee is bent over 90 preparing and degrees. • For exercises that can help prevent knee injuries, refer painting surfaces, to the Knee Injury Education section of the and while handling Contact Stress Trades/Maintenance Work Manual. materials and • Kneeling on a hard surface increases the contact stress pieces. between the kneecap and the thighbone.

OBJECTIVE: To identify ergonomic risks involved in pipefitting, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Shoulder Static Posture • To reduce loading on the shoulders, use an appropriate • When the arms are held above shoulder height, the size ladder or manlift to avoid working with the arms A Pipefitter must muscles of the neck and shoulder must remain tense to extended overhead. work with their support the weight of the arms. If the duration of • For exercises that can help prevent shoulder injuries, see arms above constant tension is excessive, and recovery is not the Shoulder section of the Body Manual. shoulder height adequate, the tissues may fatigue to the point of injury. when installing pipes in ceilings. Elbow Force • To reduce loading on the elbow, use gloves that fit properly, and use appropriate size wrenches. • Gripping an object requires activation of the forearm A Pipefitter must muscles, which generates tension at the tendon/bone • To reduce loading on the elbow, when removing grip pipe wrenches connection of the elbow. The harder that an object fittings, hit the fittings with a hammer to break away forcefully when must be gripped, the greater the load on the rust. installing or tendon/bone connection. removing fittings. • For exercises that can help prevent elbow injuries, see the Elbow section of the Body Manual. Repetition • Repeated stress to the elbow without adequate rest could slowly fatigue tissues to the point of injury.

Low Back Force • To reduce loading on the back when repairing fittings, • Pushing and pulling on pipe wrenches and valves use teflon tape on threads during installation. A Pipefitter must requires back muscles to stabilise the spine. The • To increase back tolerances for work, lightly contract forcefully push greater the force, the greater the tension developed in trunk muscles, and keep the back straight. and pull on pipe the muscles. wrenches and • For exercises that can help prevent back injuries, see the • If the force placed on the back muscles exceeds the valves when Back section of the Body Manual. tissue tolerances, injury may occur. installing or repairing lines. Knee Awkward Posture • To reduce loading on the knee, wear kneepads or use • Bending the knee increases the contact stress between foam inserts in coveralls, and avoid deep knee squats. A Pipefitter must the kneecap and the thighbone. Contact stress • For exercises that can help prevent knee injuries, see the squat or kneel on increases significantly when the knee is bent over 90 Knee section of the Body Manual. hard surfaces when degrees. installing new lines at floor level. Contact Stress • Kneeling on a hard surface increases the contact stress between the kneecap and the thighbone.

OBJECTIVE: To identify ergonomic risks involved in plumbing tasks, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Shoulder Force • Use an appropriate size ladder or man-lift to avoid • Applying excessive force with the arms can lead to working with the arms extended overhead. Plumbers fatigue and injury in the tissues of the shoulders. • For exercises that can help prevent shoulder injuries, see frequently push the Shoulder Injury Education section of the and pull on Awkward Postures Trades/Maintenance Work Manual. wrenches to • The rotator cuff stabilises the shoulder joint when the remove and install arms are away from the body. The farther away the fittings on new and arms are from the body, the greater the load on the existing lines. rotator cuff.

A Plumber may Static Postures work with their • When the arms are held above shoulder height, the arms above muscles of the neck and shoulder must remain tense to shoulder height support the weight of the arms. If the duration of when installing constant tension is excessive, and recovery is not pipes in ceilings. adequate, the tissues may fatigue to the point of injury.

Repetition • Repetitive movements of the arm, especially in combination with high force, place increased load on the tissues of the rotator cuff.

Elbow Force • Use gloves that fit properly, and use appropriate size wrenches. • Gripping an object requires activation of the forearm A Plumber must muscles, which generates tension at the tendon/bone • When removing fittings, hit the fittings with a hammer grip pipe wrenches connection of the elbow. The harder that an object to break away rust. and other hand must be gripped, the greater the load on the tools forcefully • For exercises that can help prevent elbow injuries, see tendon/bone connection. when installing or the Elbow Injury Education section of the removing fittings. Trades/Maintenance Work Manual. Repetition • Repeated stress to the elbow without adequate rest could slowly fatigue tissues to the point of injury.

Wrist Force • Proper maintenance of tools can reduce the amount of • Gripping an object requires activation of the forearm force required to use them, and therefore reduce loading Plumbers muscles, which generates tension at the tendon/bone on many muscle groups. repeatedly grip and connection of the elbow. The harder that an object • Extend tool handles to increase leverage and reduce handle tools and must be gripped, the greater the load on the required muscle force. equipment. For tendon/bone connection. some tasks, the • Use only necessary gripping force when handling duration of this Awkward Postures objects or tools. Be aware that cold temperatures and gripping can be • The width of an object affects how much muscle tool vibration can lead to decreased sensitivity and prolonged. tension needs to be generated. Using either an overly increased grip forces. large or a small grip requires more muscle force, and • Maintain a straight wrist position when gripping or can lead to tissue fatigue at the tendon/bone manoeuvring tools and objects. connection. • • Whenever possible, use both hands for forceful The position of the wrist also affects how much movements. Using both hands distributes the required muscle tension needs to be generated. Gripping force. objects with the wrist bent increases the tension generated by muscles. • For exercises that can increase tissue tolerances and prevent wrist injuries, see the Wrist Injury Education Repetition section of the Trades/Maintenance Work Manual. • Repetitive movement of the wrist can lead to tissue fatigue and injury, especially when movements include awkward postures.

Low Back Force • Use the larger muscles of the lower extremities to help • Pushing and pulling on pipe wrenches and valves handle and manoeuvre heavier objects. A Plumber must requires back muscles to stabilise the spine. The • Use mechanical lifting aids when available. forcefully push greater the force, the greater the tension developed in and pull on pipe the muscles. • Handle objects with as little force as possible. For wrenches and example, roll or slide whenever possible rather than • If the force placed on the back muscles exceeds the valves when lifting and carrying them. tissue tolerances, injury may occur. installing or • Ask for help with lifting large, heavy objects. repairing lines. Awkward Postures Remember that communication is important during a • two-person lift. A poorly timed two-person lift can Plumbers also Back muscles must support the weight of the upper cause the load to be unbalanced, or unevenly distributed perform heavy body when leaning forward. Increased bending of the between the two people, which can lead to manual handling back increases the loading on the spine and increases overexertion. of tools and the pressure on the walls of the discs. materials. • Work in pairs on heavy physical tasks. Static Postures • • When repairing fittings, use Teflon tape on threads Extended periods of forward or side bending can during installation. gradually fatigue the structures of the low back. If the stress is excessive, and recovery is not adequate, the • For exercises that can help prevent back injuries, see disc walls may fatigue to the point of injury. the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Awkward Postures • Wear kneepads or use foam inserts in coveralls, and • Bending the knee increases the contact stress between avoid deep knee squats. A Plumber must the kneecap and the thighbone. Contact stress • For exercises that can help prevent knee injuries, see the squat or kneel on increases significantly when the knee is bent over 90 Knee Injury Education section of the hard surfaces when degrees. Trades/Maintenance Work Manual. installing new lines at floor level, Contact Stress or when retrieving • Kneeling on a hard surface increases the contact stress materials from low between the kneecap and the thighbone. storage spaces. Repetition • Repeated squatting and kneeling may gradually irritate the knee. Irritation of the knee may lead to muscle wasting, which in turn leads to poor tracking of the knee cap on the thigh bone and increased contact stress between these bones.

OBJECTIVE: To identify ergonomic risks involved in welding, and to reduce the potential for musculoskeletal injuries. More detailed information about risk reducing recommendations can be found in the Injury Prevention section of the Trades/Maintenance Work Manual.

ACTIVITY OF RISK POTENTIAL HAZARDS SUGGESTED SOLUTIONS

Neck Awkward Postures • Change the position of the neck whenever • Neck muscles must support the weight of the head while in a possible. When tasks allow, try to bring the Welders often forward bent position. The more the neck bends, the greater neck back to neutral position. work with the neck the load on the muscles and tendons. • Attempt to look down with the eyes rather than bent forward the neck. and/or twisted for Static Postures extended periods • When the neck is held still in a forward bent position the • If tasks are performed while lying down, use a while cutting muscles of the neck must remain tense to support the weight cushion behind the head/neck to provide support. metal, forming of the head. If the constant stress is sufficient, and recovery is • For exercises to improve the endurance of neck welds, painting not adequate, the tissues may fatigue to the point of injury. muscles, to improve posture, and to prevent neck pieces, or using discomfort, see the Neck Injury Education stationary grinders. section of the Trades/Maintenance Work Manual. Welders drop the Force • Use the hand/arm to lower the helmet/shield. welding • The weight of the head and helmet/shield increases loading • For exercises that can increase tissue tolerances helmet/shield over when the neck is flicked forward to lower the helmet/shield. and prevent neck injuries, see the Neck Injury the head/face by Education section of the Trades/Maintenance quickly flicking Repetition Work Manual. the head forward. • When the head is frequently snapped forward, the muscles of the neck are subjected to repeated stress with little time for recovery. If the stress is excessive, and recovery is not adequate, tissues can fatigue to the point of injury.

Neck Awkward Postures • Adjust working height to avoid backward bending of the • Neck muscles must support the weight of the head neck. Welders check the while in a backward bent position. The more the neck • Wear appropriate eyewear with proper focal length. quality of the bends, the greater the load on the muscles and tendons. welds frequently. • Avoid wearing bifocals if neck extension results. If bifocals are Repetition Consult an eyecare professional for further help. worn, the neck • When the head is repeatedly bent backward, the • For exercises that can increase tissue tolerances and may be bent muscles of the neck are subjected to repeated stress prevent neck injuries, see the Neck Injury Education backwards to view with little time for recovery. If the stress is excessive, section of the Trades/Maintenance Work Manual. the weld. and recovery is not adequate, tissues can fatigue to the point of injury. Neck/Shoulder Awkward Postures • Try to get as close to the area as possible when grinding. • Neck and shoulder muscles must support the weight of • Keep upper arm close to the body while performing Welders may hold the arms when they are away from the body. The tasks a hand-held farther away the arms are from the body, the greater grinder away from the load on the muscles and tendons. • Alternate with other tasks that can be done with the the body as metal shoulders in a more neutral position. is being ground. Static Postures • • For exercises that can increase tissue tolerances and When the arms are repeatedly held away from the prevent neck and shoulder injuries, see the Injury body, the muscles of the neck and shoulder must Education section of the Trades/Maintenance Work remain tense to support the weight. If the duration of Manual. constant tension is excessive, and recovery is not adequate, the tissues may fatigue to the point of injury.

Shoulder Force • Take stretch breaks every few minutes. • The rotator cuff stabilises the shoulder joint when • Keep upper arms close to the body while performing When Welders objects are pushed, pulled, and manipulated. The tasks shape or bend heavier the object, or the larger the force required, the • Alternate with other tasks that can be done with the metal pieces, the greater the load on the rotator cuff. Excessive forces arms in a more neutral position. arms may be can cause injuries. • Use mechanical aids to accomplish tasks. extended away • If the force placed on the rotator cuff exceeds the • Support the arms whenever possible when working from the body tissue tolerances, injury may occur. away from the body. while extreme • Use both hands at a time for forceful movements, or if force is applied. Awkward Postures this is not possible, alternate between hands. • The rotator cuff stabilises the shoulder joint when the • For exercises that can increase tissue tolerances and arms are away from the body. The farther away the prevent shoulder injuries, see the Shoulder Injury arms are from the body, the greater the load on the Education section of the Trades/Maintenance Work rotator cuff. Manual. Wrist/Hand Vibration • Proper tool maintenance can help to reduce vibration. • Exposure to vibration, through power tools or other • Wear anti-vibration gloves if available. Welders are often vibrating objects, places a unique form of mechanical exposed to stress on the tissues of the hand and wrist. Factors • Wrap handles with anti-vibration material. vibration for like vibration level and vibration frequency influence • Alternate between tasks to reduce exposure. extended periods the amount of stress. of time when using • For exercises that can increase tissue tolerances and • Continual exposure to hand/arm vibration may tools such as hand- prevent wrist and hand injuries, see the Wrist and Hand gradually damage neurovascular tissue (nerves and held grinders or Injury Education sections of the Trades/Maintenance blood vessels) in the hand, and may contribute to tools required for Work Manual. assembly. problems in the wrist.

Low Back Awkward Postures • Adopt power positions while in a bent forward position. • Back muscles must support the weight of the upper In all cases, maintain the 3-point curve, bend with the Welders may hold body when leaning forward. Increased bending of the knees, and keep work as close to the body as the low back in an back increases the loading on the spine and increases comfortable. awkward posture the pressure on the walls of the discs. • For exercises that can increase tissue tolerances and for extended prevent low back injuries, see the Back Injury periods of time Static Postures Education section of the Trades/Maintenance Work while cutting metal • Extended periods of forward or side bending can Manual. or painting items. gradually fatigue the structures of the low back. If the stress is excessive, and recovery is not adequate, the disc walls may fatigue to the point of injury. Welders are often Force • Use dollies to move large objects around the work area. required to lift • Lifting increases the loading on the spine. Weight • Use the large muscles of the lower body as much as heavy, awkward held in the hands is transmitted to the low back. The possible. objects. greater the weight, the greater the loading on the • Do not twist the back while lifting. structures of the low back. • Keep items as close to the body as possible while lifting. • Roll items whenever possible. Awkward Postures • Use leverage to lift items. • Back muscles must support the weight of the upper • Seek assistance. body when leaning forward. Increased bending of the • Use mechanical aids for lifting. back increases the loading on the spine and increases • For exercises that can increase tissue tolerances and the pressure on the walls of the discs. prevent low back injuries, see the Back Injury Education section of the Trades/Maintenance Work Manual.

Knee Awkward Posture • Adjust the height of the work surface to avoid frequent • Bending the knee increases the contact stress between bending of the knees. Depending on the the kneecap and the thighbone. Contact stress • If squatting occurs, try not to adopt a deep squat (e.g., height of the weld increases significantly when the knee is bent over 90 back of heels touching the back of the thigh). relative to a degrees. Welder’s viewing • Sit while working at low heights for prolonged periods height, a Welder Repetition of time. may be required to • Repeated squatting and kneeling may gradually irritate • For exercises that can help prevent knee injuries, see the repeatedly bend the knee. Irritation of the knee may lead to muscle Knee Injury Education section of the down to view the wasting, which in turn leads to poor tracking of the Trades/Maintenance Work Manual. welded area. knee cap on the thigh bone and increased contact stress between these bones. Welders often Awkward & Static Postures • Use kneepads or foam inserts while working in a kneel in order to • Bending the knee increases the contact stress between kneeled position. perform welding the kneecap and the thighbone. Contact stress • For exercises that can help prevent knee injuries, see the tasks. increases significantly when the knee is bent over 90 Knee Injury Education section of the degrees. Trades/Maintenance Work Manual. Contact Stress • Kneeling on a hard surface increases the contact stress between the kneecap and the thighbone.