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Home , Commercial diving, Media diving, Police diving, Professional diving

(A Clients Point of View)

Phil Keating BSc (Hons)

in one area had become so well organized that a payment scale for salvage work was established by law, acknowledging the fact that effort and increased with in one area had become so well organized that a payment scale for salvage work was established by law, acknowledging the fact that effort and risk increased with 1-2.1 Tubes. capabilities was providing an air supply that would permit him to stay underwater. Hollow reeds or tubes extending to the surface allowed a diver to remain submerged for an extended period, but he could accomplish little in the way of useful work. 1-2.1 Breathing Tubes. capabilities was providing an air supply that would permit him to stay underwater. approach to an enemy stronghold (). Hollow reeds or tubes extending to the surface allowed a diver to remain submerged for an extended period, but he could accomplish little in the way of useful work. approach to an enemy stronghold (). however, that any of these devices were actually constructed or tested. The result however, that any of these devices were actually constructed or tested. The result important factors in diving. Successful diving operations require that the be overcome or eliminated. Throughout history, imaginative devices were designed important factors in diving. Successful diving operations require that the pressure the problem of pressurebe overcome underwater or eliminated. was Throughoutnot fully understood history, imaginative and the devicesdesigns were were designed impractical. the problem of pressure underwater was not fully understood and the designs were impractical.

1-2.4.4 Salvage of the HMS Royal George. eral types of diving dress were being used in actual remains of the sunken warship, HMS Royal George. William operation was an ideal opportunity to formally and evaluate the various types of apparatus. Wary of the Deane apparatus because of the possibility of Siebe dress be adopted for future operations.

government historian noted that “of the seasoned divers, not a man escaped the repeated attacks Figure 1-1. Early Impractical Breathing Device. Figure 1-2. Assyrian Frieze (900 B.C.). Figure 1-3. Engraving of Halley’s Figure 1-2. Assyrian Frieze (900 B.C.). of rheumatism and cold.” The divers had Figure been 1-4. Lethbridge’s . This 1511 design showsFigure the 1-1. diver’s Early headImpractical encased Breathing Device. . Figure 1-5. Siebe’s First This 1511 design shows ’s head encased Enclosed Diving Dress and in a leather bag with a breathing tube extending to in a leather bag with a breathing tube extending to Helmet. the surface. the surface. not realize the implications of the observation. What appeared to be rheumatismminutes. was instead a symptom of a far more serious physiological problem that, within a few years, was to become of great importance 1-2 1-2 U.S. Navy DivingU.S. Navy Manual—Volume Diving Manual—Volume 1 1 to the diving profession. all had the same basic limitation as the diving bell—the diver had little freedom 1-2.5 Caissons. inventors were working to improve the diving bell by increasing its size and operated capable of delivering air under pressure was developed. of chambers 1-2 large.4. 2enough Deane’s to permit Patented several Diving men toDress. engage Several in dry men work produced on the a successful apparatus at footings or constructing tunnel sections where long periods of work were required. These dry chambers were known as caissons, a French word meaning “big boxes” (). Dress, consisting of a heavy suit for protection from the cold, a helmet with viewing Exhausted or surplus air passed out from under the edge of the helmet and posed Figure 1-6. French Caisson. 1-2.4.3 Siebe’s Improved Divingover Dress. the work site and dress has been given to lowered to the bottom by system (

Figure 1-8. MK 12 and MK V. Modern day sat divers

Figure 1-3. Engraving of Halley’s Figure 1-4. Lethbridge’s Diving Suit. CHAPTER 1—History of Diving 1-4 U.S. Navy1-5 Diving Manual—Volume 1 Diving Bell.

minutes.

all had the same basic limitation as the diving bell—the diver had little freedom operated pump capable of delivering air under pressure was developed. types: 1-2.4.2 Deane’s Patented Diving Dress. Several men produced a successful apparatus at water), Dress, consisting of a heavy suit for protection from the cold, a helmet with viewing Exhausted or surplus air passed out fromcircuit under types). the edge of the helmet and posed 1-3.1 Open-Circuit SCUBA. cylinder and the exhaust is vented directly to the surrounding water. 1-2.4.3 Siebe’s Improved Diving Dress. dress has been given to1 -3.1.1 Rouquayrol’s Demand Regulator. system ( cylinders strong enough to contain air at high pressure could not be built at the time, 1-4 U.S. Navy Diving Manual—Volume 1 1-3.1.2 LePrieur’s Open-Circuit SCUBA Design. to the constant manual control of his air supply. The lack of a demand regulator,

CHAPTER 1—History of Diving 1-9 Commercial Diving

• depth records • The diving depth record for off shore diving was achieved in 1988 by a team of professional divers of the Comex S.A. industrial deep-sea diving company performing pipe line connection exercises at a depth of 534 meters (1752 ft) of sea water (MSW) in the Mediterranean Sea during a record scientific dive.

• In 1992 Comex diver Theo Mavrostomos, achieved a record of 701 MSW (2300 ft) in an on shore hyperbaric chamber. He took 43 days to complete the scientific record dive, where a hydrogen-- gas mixture was used as New Depth Record Record Working Dive 2300ft 1752ft

OFFSHORE INJURY, ILL HEALTH AND INCIDENT STATISTICS 2009/2010

HID STATISTICS REPORT HSR 2010 - 1

Date of Issue: December 2010 Health and Safety Executive TABLE 8 – SEVERITY OF INJURY AND AGE OF INJURED PERSON – 2009/10

AGE OF INJURED SEVERITY OF INJURY ALL INJURIES PERSON FATAL MAJOR OVER-3-DAY Less than 20 0 0 0 20 – 24 4 6 10 25 – 29 4 19 23 30 – 34 5 7 12 35 – 39 6 24 30 40 – 44 9 14 23 45 – 49 8 13 21 50 – 54 4 10 14 55 – 59 5 8 13 60 – 64 4 4 8 65 – 69 0 2 2 Not recorded 1 3 4 TOTAL 0 50 110 160

TABLE 9 – SEVERITY OF INJURY AND WORK PROCESS ENVIRONMENT – 2009/10

SEVERITY OF IN JURY WORK PROCESS ENVIRONMENT ALL INJURIES FATAL MAJOR OVER-3-DAY DECK OPERATIONS 13 31 44 DRILLING 8 11 19 MANAGEMENT 6 15 21 PRODUCTION 7 13 20 MAINTENANCE / 15 38 53 OFFSHORE DIVING* 1 2 3 TOTAL 0 50 110 160 * HSE Offshore Division retains responsibility for all aspects of offshore diving and inshore diving. Statistics stated are for offshore diving and diving support activities only.

TABLE 11 – ILL HEALTH INCIDENTS APRIL 1998 – 17MARCH 2010

DESCRIPTION 1998/99 1999/00 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10 TOTAL 3 2 1 5 4 1 2 8 2 1 29 illness 1 1 1 3 Cramp 1 1 2 repetitive Beat knee 1 1 1 3 Inflamation of 1 1 1 2 1 6 tendons Hand-arm 1 2 4 3 10 vibration Occupational 4 2 5 2 1 3 17 dermatitis Chickenpox 6 7 10 6 13 6 8 6 9 4 7 4 86 Food poisoning 1* 1 3 2** 1 8 Malaria 1 1 Meningitis 1 1 1 3 Rubella 1 1 2 Mumps 1 1 6 1 1 10 Scarlet fever 1 1 Measles 1 1 Legionellosis 1 1 TOTAL 16 15 20 131 19 13 11 18 21 6 21 10 183 * This incident resulted in twelve people being affected ** One incident involved 21 workers, the other incident affected 16 workers

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TABLE 12 – DANGEROUS OCCURRENCES BY TYPE 2009/10

TYPE DESCRIPTION NUMBER 01 Failure of lifting machinery etc. 38 02 Failure of pressure systems. 1 05 Electrical short circuit or overload. 13 08 Radiation. 5 09 Malfunction of breathing apparatus. 4 10 Diving operations. 15 11 Collapse of scaffolding. 0 13 Well operations. (See Table 12(a)) 24* 14 Pipelines and pipeline works. 0 73 Release of hydrocarbon. 187 74 Fire or explosion other than hydrocarbon. 28 75 Release or escape of a dangerous substance other than 9 hydrocarbon. 76 Collapses. 0 77 Failure of equipment required to maintain a floating installation on station. Objects dropped on an installation, attendant vessel or 102 into water. Weather damage. 78 Collision between a vessel or aircraft and an installation. 5 79 Possible collision offshore. 0 80 Subsidence or collapse of seabed. 1 81 Loss of stability or . 1 82 Evacuation of an installation. 1 83 Falls into water. 0 TOTAL 434 * Excludes one well incident that occurred in the Falkland Islands. HSE currently acts on behalf of the Falkland Islands Government in the regulation of offshore activities in island waters.

Table 12(a) - WELL RELATED DANGEROUS OCCURRENCES 2009/10

TYPE DESCRIPTION NUMBER 13(a) Blowout (Uncontrolled flow from a well) 0 13(b) BOP / Diverter operation to control flow 17 13(c) Unanticipated H2S released 3 13(d) Precautionary measures following failure to maintain 0 minimum separation between wells 13(e) Mechanical failure of a Safety Critical Element (SCE) 4(7)** of a well Total 24(27) ** Figure in brackets comprises events under 13(e) plus additional events that relate to failure of a SCE of a well that resulted in a hydrocarbon release. Additional events were reported as dangerous occurrence (DO) type 73 and are included in Table 12 under this category.

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548 MALES 353 FEMALES

37.5 50.0 0 12.5 25.0 23 STUDENT 21

BASIC 20 23

SPECIALITY 13 11

RESCUE 10 11

DIVEMASTER 15 11 INSTRUCTOR 16 10 ACCIDENT % BY

Category Title CAVE/TECH 3 7 QUALIFICATION SCIENTIFIC1 7 COMMERCIAL11 MILITARY11

SOURCE P.A.D.I (2010) Value Title

WRECK

WINDFARM

INLAND DIVE

NWERU Recompression Chambers Approved Uses:

Current Diseases Approved for Treatment Hyperbaric : A Committee Report Ed. Camporesi EC. UHMS, Kensington MD, 1996 Gas Embolism Carbon Monoxide and Smoke Inhalation Gas Gangrene Selected Aerobic and Anaerobic Soft Tissue Infections Radiation Injury Exceptional Blood Loss Anaemia Crush Injury and Other Acute Traumatic Peripheral Ischaemias Skin Grafts and Flaps Healing of Selected Problem Wounds Thermal Burns Decompression Sickness (DCS). A diver’s blood and tissues absorb additional nitrogen (or helium) from the lungs when at depth. If a diver ascends too fast this excess gas will separate from and form bubbles. These bubbles produce mechanical and biochemical effects that lead to a condition known as decompres- sion sickness. Signs of DCS - Skin may show a blotchy rash - Paralysis, muscle weakness - Difficulty urinating - Confusion, personality changes, bizarre behavior - Amnesia, tremors - Staggering - Coughing up bloody, frothy sputum - Collapse or unconsciousness Note: Symptoms and signs usually appear within 15 minutes to 12 hours after surfacing; but in severe cases, symptoms may appear before surfacing or immediately afterwards. Delayed occurrence of symptoms is rare, but it does occur, especially if air travel follows diving. Symptoms of DCS - Unusual fatigue - Skin itch - Pain in joints and / or muscles of the arms, legs or torso - Dizziness, vertigo, ringing in the ears - Numbness, tingling and paralysis - Shortness of breath 23yr old female with facial burns from flaming petrol and tar

12 hrs after the injury

Diagnosis Arterial Treatment of Arterial Gas Embolism Gas Embolism or or Serious Decompression Sickness Decompression Sickness Consider use of and Table 6 in capabilities available Yes accordance with within 10 min. paragraph 20-2.3 (Note 3) (Note 4) Pulse No present? No

Yes NOTES: Compress to 60 feet Commence oxygen breathing consulted before committing to a at 60 feet Treatment Table 4 or 7. 2. Treatment Table 6A may be extended if necessary at 60 and/or 30 feet. Complete Unchanged 3. Cardiac arrest requires early or worsening No Treatment severe symptoms on Table 6 (Note 5) chance of resuscitation consultation with a Diving Medical Yes possible (see paragraph 20-2.3). 4. Recompression chamber must be Compression on Complete 30 min air to depth of period breathing air or treatment gas on 5. Assessment of patient must be improvement not to Table 6A (Note 7) exceed 165 fsw made within 20 minutes. If the stricken diver remains pulseless after 20 minutes, termination of Remain at resuscitation may be considered. treatment depth Yes More time not to exceed needed at depth of 6. Additional time may be required relief (Note 1) 120 min. total according to paragraph 20-5.6. 7 Enter Treatment Table 6A at depth No Decompress on Table 4 Decompression to 60 feet to 60 feet not to exceed 3 ft/min Complete Treatment Table 6A (Note 2)

Life threatening No Complete symptoms and Table 4 more time needed (Note 1) at 60 feet (Note 1) Yes

Remain at 60 ft Decompress at least 12 hours on Table 7 (Note 6) (Note 1)

Figure 20-1. Treatment of Arterial Gas Embolism or Serious Decompression Sickness.

CHAPTER 20—Diagnosis and Treatment of Decompression Sickness and Arterial Gas Embolism 20-37 Treatment of Symptom Recurrence Recurrence During Treatment Recurrence Following Treatment

Diagnosis: Diagnosis: Recurrence Recurrence During Following Treatment Treatment

Symptom Diver on oxygen No Treat according onset 60 feet compress to to Fig. 20-1 or deeper? 60 feet

Yes Complete three 20 min. oxygen Deeper breathing periods recompression No at 60 feet needed? (Note 1)

Continue and/or Yes Symptoms Yes Decompress extend relieved? on Table 6 Table

No

Compress to depth of Yes Deeper relief (165 feet recompression maximum) with needed? patient off O NOTES: 2 should be consulted No before committing to a Treatment Table 4 or 7. Life 2. Treatment Table 6 may threatening symptoms or Decompress be extended up to more time needed on Table 6 two additional oxygen at 60 feet? No Extended breathing periods at 30 (Note 2) Remain at depth and/or 60 feet. :30 min. on air or Yes treatment gas if 3. Additional time may be required according to available Remain at paragraph 20-5.6. 60 feet at least Decompress 12 hours (Note 1 on Table 7 and Note 3) (Note 1) Enter Treatment More time No Table 6A at needed at treatment depth treatment depth? and decompress (Note 1) accordingly Yes Yes

Symptoms Decompress still present & No Complete to 60 feet more time needed Table 4 on Table 4 at 60 feet? (Note 1) (Note 1)

Figure 20-3. Treatment of Symptom Recurrence.

CHAPTER 20—Diagnosis and Treatment of Decompression Sickness and Arterial Gas Embolism 20-39 Treatment Table 5 1. Descent rate - 20 ft/min. 5. Treatment Table may be extended two oxygen- breathing periods at the 30-foot stop. No air break 2. Ascent rate - Not to exceed 1 ft/min. Do not compensate for slower ascent rates. Compensate for required between oxygen-breathing periods or prior to faster rates by halting the ascent. ascent. 6. Tender breathes 100 percent O during ascent from the 3. Time on oxygen begins on arrival at 60 feet. 2 30-foot stop to the surface. If the tender had a previous 4. If oxygen breathing must be interrupted because hyperbaric exposure in the previous 18 hours, an of CNS , allow 15 minutes after the additional 20 minutes of oxygen breathing is required reaction has entirely subsided and resume schedule at prior to ascent. point of interruption (see paragraph 20-7.11.1.1)

Treatment Table 5 Depth/Time Profile

0

15

30

Depth Ascent Rate (FSW) 1 Ft/Min. 45 Descent Rate 20 Ft/Min. Ascent Rate 1 Ft/Min. 60 3205 20 30 5 20 5 30

Total Elapsed Time: Time at Depth (minutes) 135 Minutes 2 Hours 15 Minutes (Not Including Descent Time)

Figure 20-4. Treatment Table 5.

20-40 U.S. Navy Diving Manual — Volume 5 Treatment Table 6

1. Descent rate - 20 ft/min. 6. Tender breathes 100 percent O2 during the last 30 2. Ascent rate - Not to exceed 1 ft/min. Do not min. at 30 fsw and during ascent to the surface for an compensate for slower ascent rates. Compensate for extension at 30 or 60 feet. If there has been more than faster rates by halting the ascent. one extension, the O2 breathing at 30 feet is increased 3. Time on oxygen begins on arrival at 60 feet. to 60 minutes. If the tender had a hyperbaric exposure

4. If oxygen breathing must be interrupted because within the past 18 hours an additional 60-minute O2 of CNS Oxygen Toxicity, allow 15 minutes after the period is taken at 30 feet. reaction has entirely subsided and resume schedule at point of interruption (see paragraph 20-7.11.1.1). 5. Table 6 can be lengthened up to 2 additional 25-minute periods at 60 feet (20 minutes on oxygen and 5 minutes on air), or up to 2 additional 75-minute periods at 30 feet (15 minutes on air and 60 minutes on oxygen), or both.

Treatment Table 6 Depth/Time Profile

0

15

Depth 30 (fsw) Ascent Rate 1 Ft/Min. 45 Descent Rate Ascent Rate 20 Ft/Min. 1 Ft/Min. 60 3205 20 5 20 5 30 15 60 15 60 30

Total Elapsed Time: Time at Depth (minutes) 285 Minutes 4 Hours 45 Minutes (Not Including Descent Time)

Figure 20-5. Treatment Table 6.

CHAPTER 20—Diagnosis and Treatment of Decompression Sickness and Arterial Gas Embolism 20-41 Rapid Ascent Incident Health and Safety Executive

Differential pressure in diving

Prepared by QinetiQ for the Health and Safety Executive 2009

RR761 Research Report !

Basic formula = Pressure x Area The example below calculates the force acting on an object blocking a 0.3 m diameter pipe connecting two bodies of water with a difference in level of 3.5 m.

!

F = D x density x A Where: F = Force (kgf) (kgf is kilogramme force) D = Difference in level (m) -3 density = 1025 kg ·m for sea water -3 or = 1000 kg ·m for fresh water A = Area (m2) ( x (d/2)2 (approx. 0.79 x d x d) where d is diameter in m) 10 x 1025 x (0.4 x 0.4) Force = 3.5 x 1025 x x (0.3/2)2 = 254 kgf Figure 6.1: Force due to differential pressure calculation = 1.640 tonnes

Note: To estimate the force due to differential pressure across an opening into a gaseous void substitute D with the depth of the void below the water surface. For a pump intake substitute D with the depth of the intake below the water surface. (Increase the depths further (up to 10 m) if the gas in the void is at a pressure below or the pump is capable of generating negative below atmospheric pressure. Look-up tables are provided in Annex F (Tables F.1 and F.2), showing the differential pressure force generated at a variety of depths of water over a range of areas derived from common pipe diameters and areas of openings mentioned in incident reports. 21 DELTA P Introduction: summarise important elements:

that may be helpful to persons involved with hiring, organising or controlling diving operations conducted by specialist diving contractors.

Diving is a potentially hazardous activity in any environment.

Notwithstanding the above statement, when a good level of planning and preparation are applied and strict controls implemented to supplement the information and procedures set out at the planning stage, the can be mitigated and the majority of underwater activity can be completed safely, successfully and economically. The Diving at Work Regulations 1997 (DWR) came into force in 1998:

•Supported by five Approved Codes of Practice (ACOP’s) covering:

•Commercial Diving Projects Offshore •Commercial Diving Projects Inland / Inshore. (L104) •Scientific and Archaeological Diving Projects. • Projects. • Projects •Military and Projects

Each of which gives advice on meeting the requirements of The Diving at Work Regulations 1997 (referred to as the ) for the appropriate diving project. The ACOP for Inland / Inshore Diving Operations applies when the activity occurs;

(a) Inshore within United Kingdom territorial waters adjacent to Great Britain (generally 12 nautical miles from the low water mark). (b) Inland in Great Britain including docks, harbours, rivers, culverts, canals, lakes, ponds and reservoirs. new offshore ACoP:

For the purposes of this presentation all references will be based on the assumption that the works fall under the category of the Inland/Inshore ACOP. The Regulations: Regulation 4 states that;

“Every person who to any extent is responsible for, has control over or is engaged in a diving project or whose acts and omissions could adversely affect the health and safety of persons engaged in a such a project, shall take such measures as is reasonable for a person in his position to take to ensure that these regulations are complied with.” In a coastal or marine construction environment this could include:

•The employer, •A or harbour master, •Vessel master, •Main contractor, •Designer, •Specialist service supplier •Any operator instructed to use plant or equipment in support of the diving or associated operation.

Whilst the level of responsibility will vary from person to person, all should retain an interest in the diving operation and will need maintain an element of liaison with the chosen diving contractor and their appointed personnel. Insurances:

The provision of an in date Employers Liability Compulsory Insurance (ELCI) certificate, specifically including clear reference to the coverage of diving operations is a mandatory requirement and sight of a valid certificate should be expected at both the pricing stage and immediately prior to commencement of work on site.

Where the chosen diving contractor fails to provide a valid insurance cover and a claim results, the employer - the individual or client commissioning the works - is likely to find they and their insurers are liable for the deficiency. Responsibilities:

The employer who requests the work must ensure that:

(1) The appointed contractor is competent to carry out the proposed work.

(2) The proposed work site is safe and any known hazards, underwater restrictions or associated operational information is made known to the diving contractor.

(3) That other appropriate facilities or persons will be made available to the appointed should an emergency situation necessitate. The competent diving contractor: carrying out the works must ensure that:

(1) A detailed diving project plan is prepared and all risks fully assessed

(2) Details of the plan are made known to anyone directly or indirectly involved in the diving operation or its support activities.

(3) That an adequate number of personnel, diving and essential support are available, that sufficient plant and equipment is available and adequate arrangements for or emergency medical support are in place. 4) That the immediate area of the dive site is safe to conduct diving operations and adequate arrangements for the access and recovery of the diver even in an emergency are in place.

(5) That the supervisor or supervisors are appointed in writing and details of the appointment are available on site for inspection.

(6) That accurate records are maintained and all other appropriate regulations are adhered too. The appointed diving supervisor: in addition to being confirmed in writing by the contractor and properly qualified to carry out the task must ensure that:

(1) Everyone involved in or required to support the diving operation are fully briefed and aware of the diving plan and any emergency arrangements that are applicable.

(2) That all information, local conditions, weather, , current or similar used in assessing the risks on the site remain valid during the period of the dive.

(3) That adequate records are kept and persons involved in the support of or working close to the dive site are fully apprised of progress as the operation progresses. Team Size: Number of personnel in a ?

Whilst Regulation 6 and the ACOP indicate the minimum team size to be four, Supervisor, diver, stand-by diver and tender, the Diving Project Plan in addition to detailing the scope of the task and associated risks, should address the requirement for diving team numbers and justify the team size necessary for a particular task.

Basic underwater tasks in controlled circumstances can be safely completed using a four man diving team, however as both the complexity in terms of tools, equipment use and depth of the dive increase so to is the likely need for additional members of the dive team Diving Project Plan: (DPP) Emergency Arrangements: Consistent with other H&S legislation the DPP is intended to “... so far as reasonably practical,” identify the hazards and risks existing on or at a site and detail how these will be controlled.

In addition the DPP will look specifically at the range of support equipment that will be necessary to cover all foreseeable eventualities on the dive site.

The DPP should make clear reference to the working methods that will be used and detail the control measures that will be implemented for dealing with water flows, underwater currents, low visibility, weather conditions, vessel movements, use of tools as well as specifying any special precautions that may be required to ensure liaison between the dive team and others vessels operating in the area.

I In particular, the need to address the method of recovering the diver after completing the work or in an emergency situation when he may be unconscious. Entry tends to be quite simple but having completed an element of work the ability to climb a vertical ladder may be seriously impaired and some other form of controlled recovery may be necessary.

The DPP will be used to brief the divers and any other persons involved in the diving operation and a copy of the plan should be available to any interested party.

Checklists are commonly used as part of a DPP to ensure all aspects of the duties of the employer, contractor, diving supervisor and divers have not been omitted. A sample has been appended to this document for use by employers checking that all aspects of the planning have been completed. Equipment: All commercial diving work should be carried using equipment that is routinely maintained and certificated as part of planned maintenance system and suitable for the work in hand

Whilst DWR 1997 does not specifically exclude the use of Self Contained Underwater Breathing Apparatus (SCUBA), the need to provide communications between the diver and the surface as well as the requirements for an independent air supply reserve tend to reduce the scope for use of SCUBA and actively encourages the diving contractor to adopt a Surface Supplied (SSDE) spread. In addition to the benefits of having a larger reserve of air provided from the surface, SSDE provides the working diver with modern lightweight air helmets which can afford a high degree of head protection whilst working in the water.

The proposed use of SCUBA equipment in most commercial diving environments, other than in benign conditions such as a swimming pools or tanks should be very carefully monitored. Should a contractor propose the use of SCUBA as his intended primary equipment, an employer should seek guidance from an independent specialist before sanctioning the diving operation. Emergency Arrangements: Consistent with other H&S legislation the DPP is intended to “... so far as reasonably practical,” identify the hazards and risks existing on or at a site and detail how these will be controlled. In addition the DPP will look specifically at the range of support equipment that will be necessary to cover all foreseeable eventualities on the dive site.

The DPP should make clear reference to the working methods that will be used and detail the control measures that will be implemented for dealing with water flows, underwater currents, low visibility, weather conditions, vessel movements, use of tools as well as specifying any special precautions that may be required to ensure liaison between the dive team and others vessels operating in the area. ACOP Availability of compression chambers

110 The diving contractor has a responsibility to ensure the provision of facilities so that a diver can be recompressed in an emergency, should this be necessary. Treatment of DCI in a compression chamber should commence as soon as possible. The provision of a recompression chamber should be in accordance with the decompression procedures selected as part of the diving project plan.

111 In addition, the following minimum standards should also be applied:

(a) for dives with no planned in-water decompression and that are less than 10 metres the diving contractor should identify the nearest suitable operational two-person, two-compartment chamber. Under no circumstances should this be more than 6 hours travelling distance from the dive site;

(b) for dives over 10 and up to 50 metres with either:

- no planned in-water decompression; or

- with planned in-water decompression of up to 20 minutes,

a suitable two-person, two-compartment chamber should be no more than 2 hours travelling distance from the dive site;

(c) for dives with planned in-water decompression greater than 20 minutes a suitable, operational, two-person, two-compartment chamber should be provided for immediate use at the site of the diving project. The diver should be able to leave the water quickly and easily and be pressurised within the chamber to the appropriate recompression pressure as defined by the time in the decompression schedule being used. The controls of a surface compression chamber should only be operated by persons competent to do so. Such competence will be achieved by a combination of training and experience. The degree of supervision provided should reflect the experience of the operator.

112 In all cases where the recompression chamber is not located on the site, the diving project plan should include arrangements to ensure that in an emergency a diver will be able to be transported and recompressed to ensure, so far as is reasonably practicable, his or her safety. The diving project plan should record the suitable chambers which have been identified and the arrangements which have been made for emergency recompression throughout the course of the diving project.

Suitability of compression chambers

113* Two-person, two-compartment compression chambers should be suitable for the purposes intended and comply with the recognised standard appropriate to this Code.

Transporting an injured diver under hyperbaric pressure

114 A diving contractor who is responsible for transporting a diver to

6(3)(b) *See Annex 5 for relevant industry technical guidance

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