NUCLEAR POWER CORPORATION OF INDIA LIMITED (A Govt.of India Enterprise) KAKRAPAR ATOMIC POWER PROJECT#3&4
HAND BOOK ON RIGGING, LIFTING & MATERIAL HANDLING
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PREFACE
Various types of Material Handling Equipments like cranes, hoists are being used in Nuclear Power Plants. Safe and reliable operation of these Equipments is important from Personnel and Equipment safety point of view.
Many Accidents have taken place due to insufficient knowledge regarding operation and maintenance aspects of material handling Equipments. Though structured training and qualification programme exists for qualification of operators to operate the material handling Equipments, refresher training is required at regular intervals.
This hand book addresses the issue of refresher training by providing technical details, maintenance requirement, and operating instructions for various types of material handling equipment like EOT cranes, Hoists, Fork Lifts etc. Technical details and operational aspects of auxiliaries like wire rope slings and lifting tackles etc has also been explained in detail. Page 3 of 97
This pocket book is a handy guide for operators and maintainers alike. This hand book is developed for disseminations of information to the concerned based on the WANO SOER/2008-01 of rigging, lifting & material handling.
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Prepared by: R C Agrawal SO/E, MMU, KAPP#3&4
Checked by: Vijay Prakash SME (M), KAPP#3&4
: M.Chenthamarakshan MS, KAPP#3&4
Reviewed by: K.B. Patel, CS, KAPP#3&4
Approved by: R.R. Dani, Station Director, KAPP#3&4
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INDEX Page Section Contents no. 1.0 Standard Terminology 11 Electric operated overhead 2.0 traveling cranes 13 2.1 Introduction 13 2.2 Responsibilities of 17 qualified supervisor Responsibilities of 2.3 operator 18 2.4 Responsibilities of 20 signalman 2.5 Crane Inspection 21 2.6 Crane load testing 24 2.7 Hoist signal 25 2.8 Sound signals 26 2.9 Care of EOT cranes 28 3.0 Chain pulley block 30 3.1 Introduction 30 3.2 Test gauge for chain hoist 32
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3.3 Precautions for safe use of 35 chain pulley blocks: 3.4 Storage 37 4.0 Wire Ropes 38 4.1 introductions 38 4.2 Rope Lay 38 General Construction of 4.3 wire rope 40 4.4 Factor of Safety 41 4.5 Attachments on wire rope 42 4.6 Inspection of wire ropes 45 4.7 Precautions 46 4.8 Wire rope as sling 48 4.9 Storage of wire rope / sling 48 5.0 Fiber rope slings 50 5.1 introductions 50 5.2 Safety Provision 50 5.3 Selection Ropes 51 5.4 Classification of fiber ropes 52 5.5 Knots and Hitches 52 Page 8 of 97
5.6 Factor of Safety 65 5.7 Inspection of Fiber Ropes 67 5.8 Storage 69 5.9 Safety aspects on Fibre 69 Ropes 6.0 Lifting Tackles 71 6.1 Introduction 71 6.2 Shackles 71 6.2.1 D- Type Chain Shackle 73 6.3 Eye – Bolt 74 6.3.1 Coller – Less Eye bolt 76 6.3.2 Shoulder Type Eye Bolt 78 6.4 Orientation of Eyebolt 80 6.5 Hook 81 6.5.1 Hook inspection areas 82 6.6 Turnbuckles 82 6.7 Storage 84 Care of Material Handling 7.0 Equipement 85 7.1 Forklift 85 Page 9 of 97
7.2 Chains, Sling and "D" 87 shackles 7.3 Care of Mobile Cranes 90 7.4 Periodic inspection for 92 Mobile Crane Parking for Forklift and 7.5 Mobile crane 93 7.6 General Good Practices 93
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SECTION-1 1.0 STANDARD TERMINOLOGY: • Working Load Limit : It is the maximum mass which the block is designed to raise, lower or suspend in general service. • Safe Working Load : The maximum mass, which the block shall raise, lower or suspend in a particular service condition. It shall not be greater than the working load limit but it may be less. • Rigging : The use of mechanical load- shifting equipment and associated gear to move, place or secure a load including plant, equipment, or members of a building or structure and to ensure testability of those members. • Rigger: A person who has been instructed in the proper selection of slings and the slinging of loads, and who understands the capabilities of the crane
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with which he is working. A rigger is competent to carry out elementary slinging or lifting tasks and the directing and positioning of loads. • Signalman: A Qualified Rigger designated by the Work Team Leader to guide the lifting appliance operator using either hand signals or two-way radio. • Factor of Safety: The ratio between the ultimate strength and working load limit. • Lifting machine: Lifting machines (other than lift and hoist) such as cranes, crab winch, Chain pulley block are used for the purpose of raising or lowering goods or materials. • Lifting tackles: Lifting tackles such as wire rope sling /Nylon sling, hook, D- shackle, Eye Bolt, Eye Nut or similar appliances whether fixed or movable, used in connection with loads by use of lifting machines.
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SECTION-2 2.0 Electric operated overhead traveling cranes.(EOT) 2.1 Introduction: Crane is a specially designed structure equipped with mechanical means for moving a load by raising and lowering by electrical or manual operations and, whilst the load is in such a state of motion or suspension, transporting it. • Cab : The operator’s compartment on a crane. • Crane, Floor Operated : A crane which is controlled by means of suspension from the crane with the operator on the floor or on an independent platform. • Crane, Gantry : A crane similar to an overhead crane except that the bridge is rigidly supported in two or more legs. • Crane Manually Operated: A crane whose hoist and travel mechanism are driven by manual operation. • Crane Semi-gantry : A gantry crane with Page 13 of 97
one end of the bridge supported on one or more legs and other end of the bridge supported by an end truck connected to the girders and running on an elevated runway. • Cross Traverse Motion: The motion of the trolley or crab across the crane span is known as cross traverse motion. • Dead Load: The weight of the crane structured steel work moving on crane runway girder with all material fastened there to and supported permanently. • Deflection (Dead Load): The vertical displacement of a bridge girder due to its own-weight plus the weight of parts permanently attached thereto, such as foot walk, drive mechanism, motor and control panels. The dead load deflection is fully compensated for in the girder camber. • Deflection (Live Load): The vertical displacement of a bridge girder due to the
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weight of the trolley plus the rated load. • Hoist: A machinery unit that is used for lifting and lowering a load. • Hoist Auxiliary: A supplemental hoisting unit used to handle light loads. • Hoist ‘Main: The primary hoist mechanism provided for lifting and lowering the rated load of the crane. • Hook Approached (End): The minimum horizontal distance, parallel to the runway between the center line of the hook(s) and the face of the wall (-or columns) at the end of the building. • Hook Approach (Side) : The minimum horizontal distance, perpendicular to the runway, between the center line of a hook (main or auxiliary) and the center line of the runway rail. • Longitudinal Travel Motion : The motion of the whole crane on its gantry or tracks is known as the longitudinal travel motion. • Brake : The brake may be of purely
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mechanical, hydraulic or Electro-magnetic type. Set of brakes are provided for each motion i.e. in LT, CT and Hoisting. • Down shop Lead : it is the runway conductor for crane through which power supply is extended.
(Double Girder Crane)
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2.2 Responsibilities of qualified supervisor:
Ensuring proper rigging of the load and ensuring the loading within safe working load of the lifting device and lifting tackles. The supervisor shall station a mechanic on the crane to accomplish the work safely without any sign of distress. • Safety of all personnel in the work area of at all times. • That the signal man crane operator knows standard hand and sound signal. • Both the operator and signal man are familiar with the crane being operated. The crane operator is free from physical disability or temporary impairment that might render him incapable of safety in performing his duties. • The supervisor should be sufficiently knowledgeable to recognize fundamental deficiencies and possess the ability to correct the hazardous situation. He must Page 17 of 97
have wide experience in rigging and lifting activities. • Pre-job briefing shall be carried out by the Supervisor to all personnel involved in rigging and lifting activity. The pre-job briefing shall include identification of hazardous situation and necessary compensatory work in such condition so as to prevent personnel and equipment damage.
2.3 Responsibilities of operator
The operator shall be in charge of the crane and his duties and qualifications shall be followings: • A thorough knowledge of the standard hand and sound signals. • Operation of the crane in a safe manner and according to signals from the authorized signal man. • The movement of the crane shall not take place unless the signal is properly
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understood. If the operator loses contact with signal man, he will stop the movement of the crane until communications are restored. • The operator may question a signal or defer operations if any doubt arises so as to ensure his own safety, safety of others and the equipments, until given assurance of safe condition by the supervisor. • Remain alert at all times when a load is suspended. • Periodic inspection, including a thorough check of the crane prior to heavy load lift, to ensure that the crane is proper condition, i.e. Brakes are in good condition and Cables or ropes are in good condition. • The crane operator must ring the bell before resuming crane operation to alert the nearby personnel.
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• Operators of the Plant shall be trained and authorized by a committee appointed by the Station Director/Project Director for the purpose.
2.4 Responsibilities of signalman
• The signalman must understand and use standard hands signals for handling the load and the crane. • Only the designated signal man will direct the movement of the crane and operator shall not accept signal from any others except in case of emergency. • The signal man shall be located in position enabling him to obtain the best overall view of the operation and at the same time maintain constant communications with the crane operator throughout the operation. • Signalmen of the Plant shall be trained and authorized by a committee Page 20 of 97
appointed by the Station Director/Project Director for the purpose.
2.5 CRANE INSPECTION
Crain should be inspected at regular interval as per the schedule as per the standard procedure. Before each operation of crane, following checks should be done.
• Condition of hoisting cable and hook block by visual checks. • Operability of the brake at no load and condition of brake shoe before handling loads weighing more than 50% of the SWL of the crane. • Operability of the hoisting limit switch. • Any visual oil leak from gear box. • Precautions for inaccessible locations: Due to the inherent location ; where it is not possible to access a crane or chain pulley block for radiological safety Page 21 of 97
reasons (inaccessible areas like pump room, moderator room etc), the following measures shall be ensured: o The custodian shall keep the crane/hoist isolated by removing its fuses and it shall be kept locked with information to the occupier. (Proper record on this with the signature of the competent person shall be maintained) o The key of such locked switches shall be with the custodian of the crane and the key shall not be available to anyone else without the approval of custodian and competent person under information to occupier. (Proper record on this with the signature of the competent person shall be maintained) o Such cranes/hoist shall be kept tagged as “Do not operate”.
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o Such crane/hoist shall be thoroughly inspected & load tested before its subsequent use or operation. A clearance for such use or operation shall be obtained from the competent person under information to occupier. • Display of Dates of testing: The date of load test and the next due date for testing shall be promptly displayed either on the crane or at an accessible location visible with the crane for ready reference.
• Precautions with idle cranes:
o In case a crane which was in use is idling for more than one month and less than six months a thorough inspection (properly recorded) need to be carried out before putting it into service again.
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o In case a crane, which was in use, is idling for more than six months; it should be thoroughly inspected and load tested before putting into service again.
2.6 CRANE LOAD TESTING:
Thorough inspection and load testing of a crane shall be done in presence of a competent person at least once in every 12 months at following loads (Atomic Energy Factory Rule 1996).
Safe working load Test load Up to 20 tons 25 % in excess 20 -50 tons 5 tons in excess Over 50 tone 10 % in excess
During overload test each motion in turn shall be maneuvered in both directions and crane shall sustain the load under full control. The specified speeds need not be attained. But the crane shall show itself capable of dealing with the over load without difficulty. Page 24 of 97
Deflection test at SWL shall also be done. Deflection allowable in [mm] = Span (in mm) / 900.
2.7 HOIST SIGNAL
To reduce to the absolute minimum the number of accident due to faulty or misunderstood signal when handling loads with cranes and hoists, it is deemed desirable to include this chapter. The signal should be thoroughly understood by the signal man the operator and only the approval signals should be used. It may be desirable to post a copy of the signal code in the crane cab and other copy where the signal man can occasionally refer to it.
The crane operator should take signal from no one but the authorized signal man. Where it is necessary signal man frequently, they should be provided with one arm bend conspicuous, hat, gloves, or other “badge " of authority, which will be in the possession of main in authority at the same time. Figure 1 indicates the hand signals adopted widely.
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Various standard signals:
2.8 SOUND SIGNALS
The derricks and special temporary hoist where the hoist engineer cannot observe the signal man, bell or whistle signal may be used, different sounding bells being
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for load hoist and boom hoist motions. The signals customarily used are as follow.
ACTION SIGNAL TO HOIST Two quick signals TO LOWER Three quick signals TO STOP One quick signal FOR EMERGENCY Series of quick Signals
For slow or cautions motions, use slower signals and hold the last signal until it is desired to stop the motion. Releasing the signal code indicates “STOP".
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2.9 CARE OF EOT CRANES
• Crane should be operated by authorized person. • Before lifting load in an EOT crane, test the travel brake. For testing hoist brake, lift the load a few centimeters off the floor and check before fully lifting. • Never overload and never leave a load in suspension. • Lifting of any person is strictly forbidden. • Ensure the passage is free from obstruction. • Do not rise or lower the crane hooks while it is out of sight unless directed by group leader. • While operating mobile crane, vertical or lateral distance between any part of the crane and any overhead power cable must not be less than 6 meters.
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• A clear space 18" wide must be maintained between any moving part of crane and any stationary part or object. • On mobile crane, driver must keep constant watch on the safe working load indicator. He should check the load and operating radius. • CO2, DCP or equivalent fire extinguishers should be kept in the cab. • While hoisting equipment is in operation, the operator should not be permitted to perform any other works and he should not level his position until the load has been safely landed. • To provide access to rail blocks of overhead traveling cranes, suitable passage wage of at least 50 cm width with toe board and double hand rail 90 cm high shall be provided alongside of the rail.
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SECTION-3
3.0 CHAIN PULLEY BLOCK
3.1 Introduction Chain hoist are portable equipment used for hoisting load in maintenance job or rigging. They may be used independently wherever required or may also be used as aid with other material handling equipment for specific jobs.
• All chain hoists are designed with their hooks as the weakest part. In other words, if the hoist is overloaded it is first indicated by the spreading opening up of the hook. As designed the inner contour of the hook is an arc of a circle. Any deviation from a circle is evidence of over loading.
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• Various components in CPB:
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3.2 Test gauge for chain hoist • In order to develop a standard for inspecting hook of chain hoist, a set of feeler gauge is developed as shown in figure. • The opening at the wide end of the gauge is used to caliper a chain link in order to make certain that the proper gauge is being used. • Then with chain hanging freely, attempt to insert the small end of the gauge between the links. If it is to wide, it indicates that the link has elongated and narrowed down due to over loading. • If the gauge enters the link of the first step only (stamped "OK") it indicates little or no wear on the links. If it enters to the second steps (stamped " R" to indicate recondition) There is an evidence of considerable wear and or stretch and the chain hoist should be sent to the maintenance shop for
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inspection and if gauge enters the link to the third step (stamped " C" for condemn) its shows excessive wear and or stretch and it should be condemned and replaced by new. • The wide end gauge is used to caliper the opening of the hoist hook. If the opening is in excess of the gauge, the hook should be condemned. TEST GUAGE FOR CHAIN HOIST
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TEST GUAGE FOR CHAIN HOIST 3.3 Precautions for safe use of chain pulley blocks:
• Lubrication of all the gears, bearings, chain and chain wheel, shaft, swivel etc should be done. But care should be taken not to lubricate the friction disc, ratchet wheel and ratchet pawl. • The chain link should not be in twisted fashion. • The load chain wheel should not be in worn out condition. Worn out load chain wheel would lead to jerks and may snap the chain. • The pitch of load chain and the load chain wheel groves should match, otherwise the chain would not fit in to the grooves and may cause jerks and snap the chain.
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• The friction discs should be regularly inspected and replaced if required to avoid slipping of the load. • The fitment of the check washer and check nut mounted on the pinion shaft should be checked to ensure that the hand wheel and check washer move together. • The ratchet pawl, ratchet wheel and ratchet spring should be in perfectly matching condition, without play. While hoisting, the ratchet mechanism should produce notching sound. • The gears should be checked for any abnormal wear out. • The hook assembly should be checked for free movement of the idle wheel, swivel etc. • The hook assembly should be checked for any abnormal wear out. • Expansion of the hook, if any should be replaced. The throat width should not be
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more than 0.75 to 0.9 times the saddle diameter of the hook. Excessive wear on the saddle of the hook should not be allowed.
3.4 Storage:
• The chain pulley blocks shall be stored in clean area free from dust and moisture. • It should be kept hanged with its hook on a stand with its load chain and hand chain properly wrapped.
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SECTION-4 4.0 WIRE ROPES
4.1 Introductions A wire rope is made up of strands and a strand is made up of one or more layers of wires. (figure - ‘a’).
(figure-‘a’)
4.2 Rope lay - This refers to the manner in which wires are helically laid into strands and strands into rope. If in the rope, the strands coil in the same direction as a right-hand screw- thread then the rope is said to be of the
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right-hand lay. If the strands coil around the rope in the same direction as a left- hand screw thread then the rope is said to be of left-hand. If the wires in a strand coil in the same direction as the strand, then the rope is a Lang’s lay and if coil in the opposite direction to that of the strand then the rope is regular or ordinary lay. Thus a rope can be either “Right-hand Lang’s lay or Left-hand Lang’s lay”, Right-hand ordinary lay or Left-hand ordinary lay as shown in figure below. a) Right hand Ordinary lay b) Right hand langs lay c) Left hand Ordinary lay d) Left hand langs lay
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4.3 General Construction of wire rope : There are a great number of different possible constructions of wire rope. These are described by indicating first the number of stands, then numbers of wires in each stand namely, 6 x 7, 6 x 19 or 6 x 37.
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4.4 FACTOR OF SAFETY
In order to ensure that a wire rope does not fail in service, which may cause disastrous consequences, the actual strain on the rope should be only a fraction of the breaking load.
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TABLE 2.3 Minimum safety factors for lifting tackles
Slings 8 Overhead electric hoist (small) 7
Overhead traveling crane 6.5 (small) Industrial truck crane 6 Derricks 6 Overhead traveling crane (large) 5.5 Hoisting tackles 5
4.5 Attachments on wire rope
Cross clips:
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Clips are used for attaching a wire rope to the equipment. The number of clips required is given in table (typical). These clips should be spaced not less than six rope diameters apart and all clips must be placed on the rope with U bolts bearing upon the shorter or dead end of wire rope. A heavy duty thimble should always be provided in the eye.
• Installation of clips (typical) Rope No of Spacing diameter Clips between (inch) clips (inch) 1/4 2 1 1/2 5/6 2 2 3/8 2 2 1/4 7/16 2 2 1/2 1/2 3 3
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5/8 3 4 1/4 4 4 `/2 7/8 4 5 1/4 1 4 6 1 1/8 5 7 1 1.4 5 8
• Position of U-bolts in clip:
←Correct
←Incorrect
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4.6 Inspection of wire ropes
All wire ropes shall be inspected visually every time before taking into use and thoroughly checked at least once in 12 months for • Broken wire. • Corrosion. • Wear and tear. • Twisting and • Kinking.
Wire rope shall be discarded if:
• In any length of 8 diameters, the no. of visible broken wires exceeds 10% of the total no. of wires. • There are 6 or more randomly distributed broken wires in one rope lay or 3 or more broken wires in one strand in one rope lay. • The wear of the outer wires exceed 1/3 rd of the original diameters of the wires.
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• The reduction in rope diameter is 6% or more. • The elongation of the rope length is more than 5%. • The rope gets corroded internally or externally. • Other defects like crushed, flattened, kinks, stranding, un-laying, bulges, birds caging, unbalanced wear locations etc.
4.7 PREACAUTIONS :
Wire ropes required careful use, handling and maintenance for satisfactory performance, long life and adequate safety. Some of the precautions to be observed to meet this requirement have been stated below. • Ensure that the correct rope is used. • Never ove rload or subject rope to check load. • Protect rope from sharp corner or edges with padding.
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• Avoid dragging the rope from under loads or obstacle. • Avoid dropping rope from heights. • Ensure that rope spools properly on the drum. • Use thimbles in eye fittings. • Lubricate regularly according the rope manufacturer's recommendations. • Store in clean dry place.
• Measurement of diameter of Wire rope sling:
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4.8 Wire rope as Sling: Wire rope slings find wide use in handling load because of their adaptability over a wide range of loads.
• Thumb rule for new wire rope sling:
Safe working load of a new wire rope sling can be approximately calculated from the following formula: SWL (in Kg): = 8 d 2 d = diameter of wire rope in mm. The above thumb rule applies for a new wire rope sling made of steel wire with ultimate tensile strength of 1960 kg/cm 2. 4.9 Storage of wire rope / sling:
Wire rope should be stored in a cool dry place away from fumes, chemicals, local heat, dampness etc. It should be kept on the reel or spool until used. If it is to be stored for a long period of time the outer layer of rope should be coated with a
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good moisture resistant lubricant. Tar or asphalt in any form should not be used.
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SECTION-5 5.0 FIBRE ROPE SLINGS
5.1 Introduction Fiber rope slings are used for material handling in factories and docks and also form as a part of lifting tackle or gear . 5.2 Safety Provision
Safety provision for ropes requires the followings: • The rope should be of good construction, sound material and adequate strength and free from defects. • Properly maintained • Thoroughly examined by a competent person. • Not to be over loaded. • Safe working loads to be marked and or displayed.
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5.3 Selection of ropes Description Manila Nylon Polyester Strength 0.90 2.6 2.3 Weight 1.00 0.95 1.15 Change in 5% 10% - strength when wet Resistance to a) Repaired Poor Poor Good bonding b) Abrasion Good Fair Very Good c) Chemical Poor Poor to (Except alkalis, solvents) excellent to acids, fair to oils and solvents Working 1 1 1 Elasticity Melting Point Loosen 250 0C 260 0C strength
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5.4 Classification of fiber ropes :
Types of Natural fiber ropes:
• Manila • Hemp • Sisal • Coir
Types of Synthetic fiber ropes:
• Nylon • Polyester • Polypropylene • Polyethylene
5.5 Knots and Hitches
• Knot: A “Knot" is the intertwining of end of rope with a portion of the rope.
• Hitch: A hitch is the attachment of a rope to a pole ring hook or other object.
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Few of the important knots are given below for ready reference:
Knot/Hitch Image Trucker's hitch
Description A compound knot commonly used for securing loads on trucks or trailers.
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Knot/Hitch Image Anchor bend Description A knot used for attaching a rope to a ring
Knot/Hitch Image Barrel hitch Description The "barrel hitch" and "barrel sling,", are a simple yet effective way to suspend an object.
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Knot/Hitch Image Becket hitch Description Any hitch that is made on an eye loop, i.e., on a becket.
Knot/Hitch Image Boom hitch Description A rather robust and secure method of attaching a line, or rope to a fixed object like a pipe, post. Page 55 of 97
Knot/Hitch Image Cat's paw Description A knot used for connecting a rope to an object.
Knot/Hitch Image Chain hitch Description A knot used to connect a rope to a cylindrical object. formed with successive Clove hitch knots.
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Knot/Hitch Image Clove hitch Description A clove hitch is two successive half-hitches around an object.
Knot/Hitch Image Farrimond friction hitch Description A quick release adjustable friction hitch for use on lines under tension.
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Knot/Hitch Image Cow hitch Description A hitch knot used to attach a rope to an object.
Knot/Hitch Image Double overhand noose Description A hitch knot used to bind a rope to a carabiner.
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Knot/Hitch Image Gripping Sailor's hitch Description A secure, jam-proof hitch used to tie one rope to another or a rope to a pole, boom, spar, etc., when the pull is lengthwise along the object.
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Knot/Hitch Image Ground-line hitch Description A type of knot used to attach a rope to an object.
Knot/Hitch Image Half hitch Description A simple overhand knot, where the working end of a line is brought over and under the standing part.
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Knot/Hitch Image Halter hitch Description A type of knot used to connect a rope to an object.
Knot/Hitch Image Highpoint hitch Description A type of knot used to attach a rope to an object.
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Knot/Hitch Image Munter hitch Description A simple knot, commonly used by climbers and cavers as part of a life-lining or belay system
Knot/Hitch Image Sailor's hitch Description A secure, jam-proof hitch. Page 62 of 97
Knot/Hitch Image Pile hitch Description A kind of hitch, which is a knot used for attaching rope to a pole or other structure.
Knot/Hitch Image Taut-line hitch Description An adjustable loop knot for use on lines under tension. Page 63 of 97
Knot/Hitch Image Tensionless hitch Description A knot used to attach a single length of rope to a cylindrical object.
Knot/Hitch Image Two half- hitches Description A type of knot, specifically a binding knot or hitch knot. Page 64 of 97
Knot/Hitch Image Killick hitch Description A type of hitch knot used to attach a rope to oddly shaped objects.
5.6 FACTOR OF SAFETY
The following are the important reasons considered for fixing up a factor of safety to arrive at safe working load of fiber rope.
• To account for wear and tear arising out of ordinary usage.
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• Extra loads on ropes by way of vibration jerk and material friction • Inaccuracies in the weight of load • Reduction of strength due to bending • To account for rot mildew. • To account for abrasion due to grits and dust.
The factor of safety of fiber ropes depends on all the condition of use and varies from 6 to 12.
SWL = (Minimum breaking load) / (Factor of safety)
Safe Working Loads: Safe working load are to be arrived at by dividing the minimum breaking load quoted by manufacturer by appropriate factor of safety depending on the use. Factor of safety as below is recommended in relation to their diameter.
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Dia of 12 14 18- 24- 40 & rope(mm) - 23 39 above 17 Factor of 12 10 8 7 6 safety
It is also recommended that fiber ropes of diameter less than 12mm should not be used for a sling or part of fittings appliance.
5.7 Inspection of Fiber ropes:
• To ensure safety, fiber ropes and slings should be inspected before taken into every time. The main points to be inspected are the external and internal wear. • The external defects can be broken fiber yarns, cuts, nicks, signs of abrasion un- lying and reduction in diameter. Each of
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these defects contributes to reduction in strength. • Open up the rope by untwisting of stands, but take care to not link them. The inside of rope should be as bright and clear as when it was new. Check for broken yarns, excessively loose stands and yarns or an accumulation of powder like dust, which indicates excessive internal wear as the rope is flexed back and forth. If the rope is overloaded the interior yarns fail. • If the core of a four- stand rope comes out in pieces if pulled, it is also an indication of overloading. • If the fibers pulled from the rope break, it shows that they have become brittle and the rope needs replacement. • If the inside of the rope is dirty and the strands have begun to unlay, the rope should not be used for lifting purpose.
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5.8 STORAGE • Store the ropes in cool dry room having good air circulation. • Hang the rope up in loose coiled on pegs. • Protect from sun, weather , dampness • Protect the ropes from attack of pests and rats. • Clean the rope after use, dry them before storing.
5.9 SAFETY ASPECTS ON FIBRE ROPES
• Select proper rope for use. • Inspect the rope before use. • Keep rope clean and dry, wash them in cool water and dry them thoroughly. • Use ropes away from heat, fumes, chemicals and exhaust gases. • Never over load ropes, apply safety factors. • Never drag a rope.
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• Avoid using rope against sharp edges. • Protect them by padding. • Use thimble for making eyes in ropes. • Observe proper slinging rules. • Do not exceed safe slinging angles. • Check for fiction heating while using synthetic ropes. • Take care not to damage the load by the rope, also let the load not damage the rope. • Properties of fiber and Synthetic ropes: Diameter of rope v/s Safe working load in Kg Dia in Poly Nylon Manila Polyester MM propylene 8 78 87 41 104 12 191 238 120 291 16 318 424 225 513 20 577 772 379 908 24 817 1144 527 1280 28 1071 1507 699 1725 32 1371 1961 876 2188 36 1734 2415 1080 2747 40 2097 2951 1308 3337
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SECTION-6
6.0 Lifting Tackles
6.1 Introduction: Lifting tackles are accessories which are used with slings and other material handling equipment for rigging. Following tackles are mainly used.
1) Shackles 2) Eye bolt 3) Turn buckle
6.2 Shackles: Shackles are used to join fittings to chain kink. Two common types of shackles are shown in the figure they are: 1) D type chain shackle 2) Bow type anchor shackle
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Bow shackle D-shackle
It is common to find the anchor shackle used at the upper and of a chain sling where the hoisting rings is located whilst the chain shackle would be found on the hook end. Both vary in the type of bolt or pin arrangement used to close the shackle opening. The arrangement commonly used are: The screw pin is most common. The round pin is also used. The two type of shackle commonly used are.
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6.2.1 D-TYPE CHAIN SHACKLE
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6.3 EYE-BOLT
Eyebolt are used to provide facility to attachment of slings, chains etc. to the equipment for handling purpose. Eye bolt have a ring at one end and a threaded bolt at other end with a shoulder in between. A threaded hole is provided in the equipment at a suitable location where an eye bolt can be fitted. Slings or chains can be attached to the eye bolt through shackle.
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The strength of eye bolt to which a sling can be attached is also of utmost importance. As it is influenced greatly by the direction of pull, an angular pull should be always be in the line with shank of the eye bolt.
Eye bolt Eye nut
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6.3.1 COLLER-LESS EYE BOLT
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USE OF EYE BOLTS
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6.3.2 SHOULDER TYPE EYE BOLT The shoulder type eye bolt should be screwed tightly with the shoulder bearing firmly against the boss or pad on the casting. This type of eye bolt has an angular strength several times greater than conventional eyebolt
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and collar type eye bolt hole should have enough depth about 1.5 times of bolt diameter. During tightening, collar should be in contact with plan surface. If not contacting with plan surface, pack it with washers. The gap between eye bolt collar and surface should not be tapered as shown below:
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6.4 ORIENTATION OF EYEBOLT
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6.5 Hook: A hook is a device for grabbing and lifting loads by means of a device such as a hoist or crane. A lifting hook is usually equipped with a safety latch to prevent the disengagement of the lifting wire rope sling, chain or rope to which the load is attached.
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Figure of Hook 6.5.1 Hook inspection areas
6.6 TURNBUCKLES Turnbuckles are used to give stretch to a sling rope. They consist of a central body having threaded holes at both ends. Each side is having an opposite hand threads (i.e. LH threads on one sides and RH threads on other sides) and is provided with matching threaded bolt having ends in form of eye, jaw, stub or hook. The turnbuckle is installed between two
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slings. When the central body of the turnbuckle is rotated it increases / loosens the stretch of the slings. Turnbuckles are available with various end type as shown figure.
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The safe loads (typical) on buckles are given below:
Size Load ( mm) (kgs) 6 400 12 680 25 3000 32 4820 38 7090 50 12545 56 16455
6.7 Storage: Lifting tackles should be stored in a cool dry place away from fumes, chemicals, local heat, dampness etc. in a clean area.
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SECTION-7
7.0 CARE OF MATERIAL HANDLING EQUIPMENT
7.1 Forklift : Forklift is a good servant in the hand of well trained and careful operators and a very useful and versatile materials handling device. But misuse of the forklift for carrying mean, lifting men to higher elevation and many odd jobs for which forklift is not designed is responsible for many accident. • Do not operate a forklift unless authorized to do so. Check the following things before taking load. • Fuel level, leaks any in fuel line and drips in hydraulic system. • Inspect the liquid level in the battery and see that connections are tight.
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• Check the steering and hydraulic system, horn etc. • Safe working load is marked on the vehicle and should not exceed in any case. • Slow down when going round corners. • When driving with load on slop, ensure center of gravity of load falls on the vehicle. • Keep the fork about 10 - 15 cm above the ground while driving • Always tie with rope if gas cylinders are loaded. • Always keep the top level of the load below your eye level. • Before you lift the load, the correct weight of the load should be known. • Never carry passengers - look out for pedestrians. • Never raise or lower the load while in motion.
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• Forklift should not be moved on ramps or grades exceeding 1 in 10. • Report the condition of the truck whenever you hand over the truck to the other operator. • Adjust the forks to match the width of the load and ensure the load should butt the mast. • Do not drive at a speed exceeding 28 Kmph.
7.2 Chains, Sling and "D" shackles
• Do not attempt to use deformed chain or corroded links. • Each change should be tested prior to use for the first time and safe working load is to be tagged. • Chain and other slings are to be stored properly in their assigned place away from moisture, corrosive fumes and heat.
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• Make sure that chain is not kinked or twisted. • Check the safe working load of the shackle before use. • Do not use any shackle which is not marked with the safe working load. • Ensure that the correct size of pin is used with the shackles. • Examine bow and pin for damage or distortion. Destroy if doubtful. Destroy when wear is more than one tenth of original diameter. • Ensure slings are properly tested and the safe working load is to be tagged. Never exceed the safe working load. • Never drag slings under load. • Lubricate the slings, chains, regularly. • Spare slings must not be carried on the hook
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• Ensure that pads are placed across or around sharp edges where the ropes are placed. • Do the hammer out a link (if not authorized) or do repairs on change and slings. • A wire rope becomes unserviceable when 5% or more broken Wires are showing in any of 10 diameters length.
Example: For 12.7 mm dia rope of 6 x 19 rope construction: No. Of wires = 6 x 19 = 114 5% of 114 = 6 (approx.) Length of 10 dia = 10 x 12.7 mm = 127mm. i.e. a rope showing 6 broken wires or more in a length of 12.7 cm is to be discarded. • Chain should not be joined by bolting or wiring links together. They should not be shortened by tying knot. Proper eye
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splices should be used to attach to the chain hooks. • While using multi- legged slings, each sings or leg should be loaded evenly and the slings should be of sufficient length to avoid a wide angle between the legs.
7.3 MOBILE CRANES • Crane should be operated by authorized person. • Never overload and never leave a load in suspension. • Lifting of any person is strictly forbidden. • Ensure the passage is free from obstruction. • While operating mobile crane, vertical or lateral distance between any part of the crane and any overhead power cable must not be less than 6 meters. • A clear space 18" wide must be maintained between any moving part of crane and any stationary part or object.
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• On mobile crane, driver must keep constant watch on the safe working load indicator. He should check the load and operating radius. • CO2, DCP or equivalent fire extinguishers should be kept in the cab. • In case of power failure, move the controller off position until power is available again. • Thorough inspection and load testing of crane shall be done by a competent person at least once in a year. • All control mechanisms shall be inspected for mal function on daily basis. • All control mechanism for excessive wear of components and contamination by lubricants or other foreign materials shall be inspected. • All safety devices for malfunction shall be inspected.
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• Deterioration or leakage in the air or hydraulic system shall be inspected on daily basis. • Crane hooks for deformation or cracks shall be inspected. • All running ropes shall be inspected. • Electrical apparatus for malfunction, signs of deterioration, dirt and moist accumulation shall be inspected.
7.4 Periodic inspection for mobile crane :
• Deformed, cracked or corroded members of crane structure and Jib. • Loose bolts or rivets. • Cracked or worn sheaves and drums • Worn, cracked or distorted parts such as pins, bearings, shafts, gears, rollers. • Excessive wear of brake or clutch parts, linings, pawls and ratchets. • Diesel, electrical or other power units for improper performance.
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• Excessive wear or chain drive, sprockets and excessive chain stretch. • Travel, steering, braking and locking devices for malfunction • Excessive worn or damaged tires.
7.5 Parking of Forklift / Mobile crane:
Forklift and Mobile crane shall be parked in shed meant for it to protect it from direct sunlight and rain.
7.6 General Good Practices:
• Lift plans is to be prepared for complex nature of jobs or while carrying out the job at critical area e.g. movement of loads over the Safe shutdown equipment area, S/D Pumps, over the Turbine Generator etc. The lift plan shall include the movement path, minimum clearance from the obstruction in the path, proper
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cordoning off area etc. Movement should be restricted over the critical equipments. While carrying out rigging work near Safe shutdown equipments, the rigging personnel involved must be briefed about the regulatory and design limits regarding maximum weight, required clearance etc. and the supervisor involved must ensure that these limits are not exceeded during the work. • Any special rigging or lifting tools / tackles brought to the site shall be reviewed thoroughly for safety adequacy and tested before taking into use. • The crane and monorail / Electrical hoist shall be parked in parking area only after use. • Wrapping bags shall be wrapped over the chain and hook after use. If wrapping bag is missing, it is to be reported to
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Material Handling group, MMU for provision of spare wrapping bag. • Whenever there is any probability of load binding or dragging in the rigging and lifting work, crane weighing scale / load cell must be used. The weight of the load shall be calculated prior to start of work and the weight appearing in the load measuring scale should be monitored continuously where there is potential of binding or dragging and work must be stopped immediately in case of any load binding or dragging. • Edge protectors and softeners shall be used at sharp corners while slinging. Following types of edge protector may be used: o Wooden sleepers for Load less than 2 Te. o Specially fabricated metal protectors for load more than 2 Te.
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Standard type of edge protectors shall be arranged by Material Handling group and handed over to MMU sub store for further issue. However special type edge protectors shall be arranged by User group depending upon the weight and shape of the load. User group should ensure availability of this before start of work.
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