Hong Kong Collection gift from Hong Kong (China). Labour Dept.

Transcription

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2 THE UNIVERSITY OF HONG KONG LIBRARIES Hong Kong Collection gift from Hong Kong (China). Labour Dept.

3 CODE OF PRACTICE FOR DIVING LABOUR DEPARTMENT HONG KONG AUGUST 1986

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5 CODE OF PRACTICE FOR DIVING Introduction Diving is a hazardous occupation and safety requires that the diver should be trained and fit, properly equipped and adequately supported. The aim of this code is to provide guidance on the principles of safe diving practice for the protection of the health of persons employed to work under water. The following government departments and organisations have been consulted during the preparation of the code of practice: Agriculture and Fisheries Department Fire Services Department Marine Department Water Supplies Department Hong Kong Divers Limited Hong Kong Underwater Service Williamson Marine The Committee on Industrial Safety and Accident Prevention, a tripartite industrial safety committee formed under the Labour Advisory Board and comprising representatives of employees, employers and the government, has also endorsed the code.

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7 CONTENTS Application of Code Employer (Diving Contractor) Responsibilities Diving Supervisor Responsibilities Diver Responsibilities Classification of Divers Certificate of Medical Fitness to Dive Diving Support Surface Compression Chamber Submersible Compression Chamber (Diving Bells) Use of Compression Chambers Decompression Treatment of Decompression Sickness Post Diving Precautions Flying Restrictions Diving Equipment Air Supply Cylinder Gas Breathing Apparatus Protection from Cold Equipment Testing Accidents First Aid Diving Operations Special Precautions References Advisory Service Appendix I Appendix II Appendix III Appendix IV Paragraph Matters in respect of which provision is to be made in diving instructions. Matters to be entered in the diving operations log book. Matters to be entered in the diver's log book. Medical certificate of fitness to dive

8 Appendix V Surface Compression Chambers. Appendix VI Submersible Compression Chamber (Diving Bells). Appendix VII Purity of compressed air. Appendix VIII Mouth-to-mouth respiration. Appendix IX References.

9 CODE OF PRACTICE FOR DIVING Application of Code 1. This code advises on the principles of safe diving practice and applies to all operations in which persons are employed to work underwater. Employer (Diving Contractor) Responsibilities 2. The employer (diving contractor) has the ultimate responsibility for ensuring the safety of his employees and should take all necessary steps to achieve safe diving practices. 3. He should appoint a suitably qualified person as supervisor for every diving operation. 4. He should give the supervisor detailed written instructions which provision relating to such matters as are specified in Appendix I as are relevant to the particular operation. 5. He should employ sufficient divers with adequate qualification and experience to undertake the work. 6. He should provide the appropriate plant and equipment for the operation and make sure that it is properly maintained and prepared for the task in hand. 7. He should provide a Diving Operations Log Book and ensure that the matters detailed in Appendix II are entered for each operation, The log book should be kept for at least two years after the last entry for reference purpose. 8. He should appoint a doctor with special experience in underwater medicine to provide medical cover for diving and carry out the examination required by divers. He should arrange for this doctor to be on call when diving operations involve regular decompression or other activity with high risk of illness or injury. 9. He should maintain a diver's fitness register with details of the dates and results of medical examinations including X-rays. 10. He should arrange emergency services, including in particular in diving operation using saturation techniques or at a depth exceeding 50 meters facilities for transferring the divers safely under a suitable person to a place where treatment can be given under pressure. Effective means of communication between the diving site and the emergency support services should also be established. Diving Supervisor Responsibilities 11. The diving supervisor is responsible for practical control of the operation for which he is appointed and for the safety of all persons involved. He should be fully competent and qualified for the task with adequate knowledge of the diving techniques to be used. Essentially he should have previous experience as a fully qualified diver in carrying out the type of work in the proposed operation.

10 12. He should ensure that his team of divers and support staff is sufficient for the proposed operation and that individual workers are capable through training and experience of the work required of them. 13. He should allocate duties and in his selection should ensure that divers have valid medical certificates and are also in his opinion 4 fit to dive' at the time the operation starts. 14. He should make sure that all persons involved are fully instructed on the dive plan and understand their duties. 15. The supervisor is responsible for the preparation of diving plot, equipment and apparatus suited to the operation and should ensure the availability of adequate gas mixtures as required for the dive and possible emergencies. 16. The supervisor should start therapeutic decompression in accordance with appropriate tables for any diver with symptoms or signs of decompression sickness. He should remain responsible for the control of pressure and breathing mixtures unless a doctor qualified in underwater medicine assumes control. 17. The supervisor should enter the particulars specified in Appendix II in the diving operations log book. 18. He should countersign the entry relating to the operation in the diver's log book of each person who took part in diving. Diver Responsibilities 19. A person should not take part in any operation as a diver unless he meets the following requirements: (a) Is over the age of 18 years for all diving and is under the age of 45 years for deep dives in excess of 50 meters. (b) Has a valid certificate which shows that during the preceding 12 months he has been medically examined for diving fitness with the examination including chest and major joint X-rays. (c) Has been properly trained for the proposed dive and is competent to carry out safely the work he is expected to perform. 20. It is the diver's personal responsibility to keep himself fit for the work he undertakes. He should immediately inform the supervisor if he has any doubts about fitness. Even minor ailments may become serious under water and colds, sore-throats, toothaches, earaches or emotional upset no matter how slight are all contra indications to diving. 21. The diver is responsible for his personal equipment and should prepare and test his breathing apparatus before entering the water. If any fault is found or any inadequacy of the equipment for the task in hand is suspected this should be reported to the supervisor for further investigation and necessary action. 22. Dentures, if worn, should be removed before diving to avoid possible complication if emergency arises.

11 23. Alcohol should not be taken within 4 hours of a dive or a large meal within 2 hours although light snacks are permissible up to 30 minutes beforehand. 24. For deep diving in excess of 50 meters the diver should have made a number of dives to intermediate depths and be capable for performing the proposed task. During employment as a deep diver he should keep in date with at least one dive, either simulated or in water, to the maximum depth required every 30 days. 25. A diver should maintain a personal log book (diver's log book) in which he should enter his name with his signature and a passport type photograph of himself. The matters set out in Appendix III should be entered for each diving operation and he should sign the daily entry and have it countersigned by the supervisor. He should retain his diver's log book for at least two years after the last entry reference purpose. Classification of Divers 26. Training and experience are essential for safety in diving and in determining the competence of the diver for the task required, the following classification as advised in "The Principles of Safe Diving Practice" provided by the CIRIA Underwater Engineering Group, should be used as the standard. 27. Diver Class One A diver with broad experience, who has acted as a supervisor, instructor and as an active diver in all types of diving including SCUBA and SDBA with compressed air and mixed gases. He should be experienced in the use of compression chamber and the ancillary equipment to support those units. He should be capable of supervising therapeutic decompression. He should have been employed for a minimum of two years as a Diver Class Two. 28. Diver Class Two A diver who is competent to carry out all types of diving, including those requiring compressed air and mixed gases and who is competent to supervise diving under the direction of a Diver Class One. He may be employed as a supervisor for compressed air diving. He should have been employed as a Diver Class Three for a minimum of two years. 29. Diver Class Three A diver who is competent to carry out all types of diving using compressed air. Divers who have been employed for a minimum of two years as a Diver Class Three may be employed as a supervisor for diving operations where stops are not required in compressed air diving. 30. "Self-Employed" Diver It is the responsibility of a self-employed diver to produce evidence which will enable the employer to classify him. "Selfemployed" divers should not be employed in deep diving without training beforehand unless the employer is fully satisfied that the diver is qualified. 31. Diver under Training A person who is being trained to the standard required for Diver Class Three. 32. Out of practice Qualified Diver A diver who has not carried out any form of diving for a period of 12 months must be carefully supervised until the supervisor is satisfied he has reached the standard of proficiency required.

12 Certificate of Medical Fitness to Dive 33. Before entering the water the diver should be in possession of a certificate of fitness issued within the preceding 12 months by a doctor with experience in underwater medicine. The certificate should contain the details specified in Appendix IV and should be entered in the diver's log book, A new certificate of fitness should be obtained if the diver is sick for a period of 14 days or over. Diving Support 34. An adequate and competent team is necessary to support underwater work. A stand-by diver should be available and provision of a life-line and signalling arrangements are other essentials. The implementation of the necessary support services will depend on the scope of the operation and should be covered by the employer in planning as advised in section 1 at Appendix I. As a guiding principle the planning should provide for: (a) Working element Diver or divers; (b) Surface team Supervisor and attendants; (c) Reserve element Stand-by diver ready to enter water. 35. A life line of adequate strength and suitable for recovering the diver and his equipment from the water is a normal requirement, and it also affords a minimum communication system. In circumstances when life lines are'not appropriate alternative arrangements should be made such as the use of a light line between divers standing by for one another, or for operations using swimmers a light line secured to the diver with a marker float. Whatever the circumstances may be the principle for operating safely demands provision be made to avoid the diver being lost underwater and to enable the supervisor to maintain contact with him. Surface Compression Chamber 36. A Surface Compression Chamber should meet the specification detailed in Appendix V and be made available during diving operation as follows: Operating Depth Compression Chamber Requirements 0-20 meters No requirement necessary, but the location of the nearest available chamber should be known meters (i) For short duration dives with stops unlikely to exceed 20 minutes: (a) One-man compression chamber on site complete with oxygen. (b) Two-compartment chamber available with 2 hours travelling time. (ii) Stops regularly being incurred: (a) Two-compartment chamber on site. (b) Working pressure available in chamber should equal to at least maximum depth of dive. 10

13 40-50 meters Two-compartment chamber on site with available working pressure equal to at least 50 meters. Over 50 meters Two-compartment chamber on site with available working pressure equal to maximum depth of dive. Submersible Compression Chamber (Diving Bells) 37. Submersible compression chamber if used should comply with the specification in Appendix VI. Use of Compression Chambers 38. Before use of a chamber the diving supervisor should check that: (a) The chamber is clean internally and free from combustible material. (b) Air and oxygen supply cylinders are fully charged and that the air is at the required pressure and adequately filtered. (c) When applicable, sufficient oxygen breathing apparatus is available and connected to the chamber supply points, and that this apparatus is tested. (d) Chamber doors are operating correctly and that any associated air-lock doors are securely closed. (e) Lighting and communicating systems are functioning correctly. (/) Exhaust outlets are clear. (g) Safety valves are fitted and in-date for test and set at correct override pressure. (h) Recording and time-keeping equipment is fitted and functioning. 39. When men are under pressure in a chamber they should always be supervised by a qualified person. 40. When no life support system is being used the chamber should be flushed through periodically to avoid build-up of carbon dioxide. Ideally a minimum flow of 300 litre of air should be delivered per man per minute (the volume being 300 litre at the appropriate depth). 41. Every precaution should be taken to prevent fire and combustible material and means of ignition should not be allowed in the chamber. Smoking in the chamber should be strictly prohibited. 42. Compression chambers should be maintained in a safe working condition and inspected at least monthly when pressure gauges, life support systems, clocks etc. should be checked and calibrated. Decompression 43. Decompression should be appropriate to the type of gas breathed and the depth and duration of the dive and should be carried out according to a recognized method which is in line with accepted practice. The decompression tables used should be strictly followed and the name of the table recorded in the operations and diver's log book. 11

14 Treatment of Decompression Sickness 44. All persons with sign or symptoms which could be attributed to decompression sickness should be recompressed in a chamber and treated in accordance with accepted therapeutic decompression tables. The diving supervisor is responsible for carrying out the treatment. The tables should be strictly adhered to and only altered on the authority of a doctor with experience in underwater medicine. 45. If treatment fails to relieve symptoms the patient should be kept at a minimum absolute pressure of 4 bar (30 meters) until medical advise or further action is received. 46. After treatment the diver should remain close to a compression chamber for 6 hours and within 1 hour travelling time for the next 18 hours. He should not dive again for at least 24 hours after an air dive and 5 days after a dive in excess of 50 meters. 47. When a compression chamber is not available on site a sick diver should be transferred to one as soon as possible. Action may be governed by circumstances but the following principles should be followed as far as possible: (a) Make contact with the nearest authority controlling a chamber and request it be made available. (b) Transfer the diver by the quickest means available. If he has to travel by air the effective cabin altitude should not exceed 300 m (1 000 ft.). (c) Oxygen if available should be breathed during transfer. (d) The supervisor should accompany the diver. 48. If it is not possible to get the diver to a compression chamber consideration should be given to sending him down again for compression and decompression in water. A rigid type helmet with communication system is most suitable for the operation. The efficiency of the support and the degree of exhaustion of the diver should be taken into account when deciding which table is appropriate. Post Diving Precautions 49. After diving the diver should remain within reach of a compression chamber as follows: Operating Depth Chamber Accessibility To 50 meters with stops within 1 hour travelling time for 12 hours after dive. In excess of 50 meters Immediately available (ready for use) for 4 hours after dive and within 1 hour travelling time for further 12 hours. 50. Divers should wear a personal label indicating that they are divers and the location of the recompression chamber (with contact telephone number) where they should be conveyed if taken ill. 12

15 Flying Restrictions 51. At least 2 hours should elapse between diving operations when no stops were necessary and flying in pressurised aircraft and this period should be extended to 24 hours if stops were used. If flying is essential the maximum altitude or effective altitude in pressurised aircraft should be kept as low as possible and preferably below 300 m (1 000 ft.) for at least 4 hours after diving. Diving Equipment 52. A diver should not be employed underwater unless he is provided with proper diving plant and equipment, including means of access to and from the water, suitable for the particular operation. Written instructions for the care and maintenance of underwater breathing apparatus should be readily available for divers and persons employed in the maintenance of such plant and equipment and all necessary routine inspections and checks should be carried out and recorded. Air Supply 53. A diver underwater should be supplied at all times with air which is fit for respiration, adequate in quantity and at suitable pressure for the plant or equipment and the circumstances in which he is working. 54. The air should comply with the minimum requirement of purity for breathing as specified in British Standard 4001 and detailed in Appendix VII. 55. Adequate precautions should be taken to avoid contamination of air supply and these should include; (a) Maintenance in accordance with manufacturer's instructions of compressors and cylinders. (b) Positioning compressor air intakes to avoid sucking in contaminated air e.g. from engine exhausts. (c) Compressor designed for other industrial purposes should not be used to supply air for diving, as the filter efficiency is inadequate. Previously used hoses which may be oil impregnated or otherwise contaminated should also be avoided. 56. The minimum air supply required for a standard diver is 45 litres/min. but if the diver is working hard about 75 litres/min. will be necessary. To decide the required total output of air, the diver's volume requirement should be multiplied by the absolute pressure in bars (atmospheres). Therefore hard work at 30 m (4 bars absolute) requires 75 litres x 4 bars = 300 litres/min. and a compressor with a minimum capacity of 300 litres/min. is required. The compressor capacity required for the operation in hand should be determined and adequate supply made. 57. A diver using surface demand equipment requires approximately 30 litres/min. per bar (atmosphere) and the compressor used should be capable of meeting the requirement. 13

16 Cylinder Gas 58. Since colour codes are not yet internationally standardised, provision should be made to establish that cylinders contain the gas for which they are marked. 59. When Cylinder gas is used there should be a sufficient supply kept to cater for emergency use. Breathing Apparatus 60. Properly designed from a reputable manufacturer should only be used. The diver should be fully trained to operate the equipment and it should be maintained and tested strictly in accordance with the manufacturer's instructions. 61. Because of the dangers of oxygen self-contained breathing apparatus which is regenerative and works on a closed circuit should only be used with caution and in line with accepted practice. 62. The detailed procedures for preparing all breathing apparatus for diving should be carried out in accordance with the manufacturer's instructions and relevant equipment handbook. 63. The diver should personally check that, where relevant, bottles, cylinders and carbon dioxide canisters are charged and connections are correctly tightened and that self-contained equipment is tested for leaks by immersion in water. 64. The supervisor should carry out a final check for leaks after the diver has entered the water and before he descends. Protection from Cold 65. The diver should be protected from cold through too great a loss of body heat when in the water. If "wet" or "dry" suits are not adequate to achieve this they must be supplemented by some form of heating system which should allow the diver to control the temperature. Equipment Testing 66. Diving plant and equipment should not be brought into use until it has been tested. Manufacturer's recommended testing routines should be followed. Each piece should be thoroughly examined by a competent person at least once every 3 months and a signed report of the result attached to the general log of the operation, 67. Air pumps, compressor and cylinders and pipelines should be tested for leakage by a competent person within 24 hours of use to determine that pressure can be maintained within the system and the full working pressure of the dive after the pump and compressor has stopped. 68. The inlet and outlet valves in the diver's dress and any regulator and demand valves in the plant or equipment should be examined within 24 hours of use by a competent person and found to be efficient and in full working order. 14

17 Accidents First Aid 69. In serious cases it should never be assumed that the diver is dead. Mouth-to-mouth respiration and external cardiac massage should be given as detailed in Appendix VIII, together with any other treatment which seem appropriate. Resuscitation should be continued until medical assistance is obtained. 70. If the diver is unconscious on surfacing the following action should be taken: (a) Remove the mouthpiece and face mask; (b) Loosen tight clothing; (c) Check breathing and heart; (d) Ensure air passages are clear and start artificial respiration and cardiac massage if required; (e) Recompress in chamber if indicated; (/) Keep covered and lying on site; (g) Secure all equipment for later investigation; (h) Summon help from the emergency services. 71. A record should be kept of all accidents and incidents requiring first aid or medical intervention for reference purpose. It should also be noted that decompression sickness is a notifiable disease under the Factories and Industrial Undertakings (Notification of Occupational diseases) Regulations if the patient involved is employed in an industrial undertaking, and the case should be reported to the Director of Medical and Health Services. Diving Operations Special Precautions 72. This code deals with the principles of the safe diving practice in general but it should be noted that additional precautions may be necessary if the diving operation introduces special hazards as underwater welding, or cutting, explosion, cable or foundation laying, diving in sewers or near ship's propellors etc. The need for special precautions should be assessed in every operation and the necessary steps taken depending on circumstances to prevent or control the hazards. As with safe diving the basic requirements are personnel trained and experienced to deal with the task and adequate support. References 73. For detailed advice, as required, on special aspects of the various types of diving and associated work activity the relevant text-books and publications should be consulted. A list of sources of information is attached at Appendix IX. Advisory Service 74. Advice on the safety and health aspects of diving is available from the Factory Inspectorate (Tel ) and the Occupational Health Division (Tel ) of the Labour Department, Harbour Building, Central, Hong Kong. 15

18 Matters in respect of which provision is to be made in diving instructions Planning 1. Consideration of Appendix 1 (a) meteorological conditions, including forecasted conditions; (Z?) tidal information including local tide tables and indications of speed of current to be expected; (c) proposed shipping movements; (d) air and water temperatures; (e) underwater hazards of the diving site, including any culverts, penstocks, sluice valves or areas where differences in hydrostatic pressure may endanger the diver; (/) depth and type of operation; (g) suitability of plant and equipment; (A) availability and qualifications of personnel; (/) the effect on a diver of changes of air pressure if he flies after diving; (j) the activities of any person who will be diving in connection with the diving operation whether or not he is a diver. Preparations 2. (a) Consultation with persons having any control over or information related to the safety of any diving operations; and in particular persons having control of lifting appliances or having control of or information about shipping movements; (b) selection of the breathing apparatus and mixtures; (c) check of plant and equipment; (d) allocation of personnel; (e) personal fitness of divers for underwater operations; (/) precautions against cold in and out of the water; (g) signalling procedures; (h) precautions against underwater hazards of the diving site. Procedures during diving 3. (d) Responsibilities of diving supervisor, divers and surface support; (b) use of all types of personal diving equipment; (c) supply of gas and gas mixture, including maximum and minimum partial pressure of gases; (d) operations direct from an installation, work site or craft; (e) operations in relation to diving bell; (/) working in different locations; (g) operations and use of equipment under water; (A) limits on depth and time under water; 16

19 (f) descent, ascent and recovery of divers; (j) descent, ascent and recovery of diving bell; (k) diving tables for use in decompression procedures for both single and repetitive diving and in therapeutic decompression procedures; and for inland waters the need to take account of the effect on pressure of the altitudes at which the diving takes place; (/) control in changing conditions; (ra) time for which divers are to remain in vicinity of the surface compression chamber; (n) maintenance of log books. Emergency procedure 4. (a) Emergency signalling; (b) emergency assistance under water and on the surface; (c) therapeutic recompression and decompression and the availability of chambers for that purpose; (d) first aid; (e) medical assistance; (/) calling assistance from emergency services including advance liaison with those services where appropriate; (g) precautions in the event of evacuation of the installation, work site, vessel, hovercraft or floating structure; (h) provision of emergency electrical supplies. 17

20 Matters to be entered in the Diving Operations Log Book Appendix II The following matters shall be entered in the diving operations log book in respect of each diving operation: (a) the name of the diving contractor; (b) the dates on which and the period during which the diving operation was carried on; (c) the name or other designation of the craft or offshore installation or work site in connection with which the diving operation was carried on and the location of that craft or offshore installation of work site; (d) the name of the diving supervisor and the period for which he is acting in that capacity in respect of that diving operation; (e) the names of the other persons engaged in the diving operation including those operating any diving plant or equipment and their respective duties; (/) the arrangements for emergency support; (g) the procedures followed in the course of the diving operation including details of the decompression schedule used; (A) the maximum depth reached in the course of the operation for each diver; (/) for each diver, in respect of each dive he makes, the time he leaves the surface, his bottom time (that is the period from the time he leaves the surface until he starts to ascend) and the time he reaches the surface; (j) the type of breathing apparatus and mixture used; (k) the nature of the diving operation; (/) any decompression sickness, other illness, discomfort or injury suffered by any of the divers; (m) particulars of any emergency which occurred during the diving operation and any action taken; (72) any defects that are discovered in any plant or equipment used in the diving operations; (0) particulars of any environmental factors affecting the diving operation; (p) any other factors relevant to the safety or health of the persons engaged in the operation. 18

21 Matters to be entered in the Diver's Log Book Appendix HI The following matters shall be entered in the diver's log book in respect of each diving operation in which he takes part: (a) the name and address of the diving contractor; (b) the date; (c) the name or other designation and the location of the offshore installation, work site, craft or harbour from which the diving operation was carried on; (d) the name of the diving supervisor; (e) the maximum depth reached on each occasion; (/) the time he left the surface, his bottom time and the time he reached the surface on each occasion; (g) where the dive includes time spent in a compression chamber, details of any time spent outside the chamber at a different pressure; (/z) the type of breathing apparatus and mixture used by him; (z) any work done by him on each occasion and the equipment (including tools) used by him in that work; (j) any decompression schedules followed by him on each occasion; (k) any decompression sickness or other illness, discomfort or injury suffered by him; (/) any other factor relevant to his safety or health. 19

22 Medical Certificate of Fitness to Dive Appendix IV 1. After appropriate examination by a doctor with experience in underwater medicine a certificate should contain the following: (a) Name of person to whom it relates; (6) Date of medical examination; (c) Date and result of chest X-ray (annual X-ray required); (d) Date and result of major joint X-ray (annual X-ray required); (e) Any limitation in the diving or compression for which the person is considered fit; (/) Name, qualification, address and telephone number of the doctor issuing the certificate; (g) Signature of doctor. 2. The certificate should be entered in the diver's log book. 20

23 Surface Compression Chambers A surface compression chamber shall: Appendix V (a) have at least two compartments with doors each of which acts as a pressure seal and can be opened from either side ("a two-compartment chamber"); or alternatively a single compartment chamber may be used where (i) the divers do not go to a depth exceeding 50 metres, and (ii) the diving operations are not carried on from or in connection with an offshore installation or pipe-line works, and (iii) facilities are provided for transferring persons under pressure from that chamber to a two-compartment chamber within four hours; (b) in the case of a two-compartment chamber, have sufficient space in at least one of its compartments to enable two adults to lie down inside the chamber without difficulty and if the chamber is to be used in circumstances in which a person is intended to remain inside under pressure for a continuous period of 12 hours or more, excluding any therapeutic decompression, it shall have a minimum internal diameter of two metres; (c) where a diving bell is used, be capable of allowing a person to transfer under pressure from the bell to the surface compression chamber and vice versa; (d) provide a suitable environment and suitable facilities for the persons who are to use it, having regard to the kind of operation in connection with which it is used and the period during which the pressure is raised; (e) be so designed as to minimise the risk of fire; (/) have a lock through which food and medical supplies may be passed into the chamber while its occupants remain under pressure; (g) be equipped with such valves, gauges and other fittings (which are to be made of suitable materials and so designed as to minimise the noise inside the chamber during rapid pressurisation) as are necessary to control and indicate the internal pressures of each compartment from outside the chamber; (h) be fitted with adequate equipment, including reserve facilities, for supplying and maintaining the appropriate breathing mixture to persons inside it; (z) be equipped with a two-way oral communication system; (j) have means for heating or cooling the chamber as appropriate and for lighting and adequate first aid and sanitary facilities. 21

24 Submersible Compression Chamber (Diving Bells) A diving bell shall: Appendix VI (a) be equipped with means by which each diver using the bell is able to enter and leave it without difficulty; (b) be capable of allowing a person to transfer under pressure from it to a surface compression chamber and vice versa; (c) be equipped with doors which act as pressure seals and which may be opened from either side; (d) be equipped with such valves, gauges and other fittings (which are to be made of suitable materials) as are necessary to control and indicate the pressure within the bell and to indicate to those inside the bell and to the diving supervisor the external pressure on the bell; (e) be fitted with adequate equipment including reserve facilities for supplying the appropriate breathing mixture to persons occupying or working from the bell; (/) be equipped with a two-way oral communication system which enables contact to be maintained both with persons at the place from which the diving operation is carried on and with divers while they are outside the bell; (g) be fitted with equipment for lighting and heating the bell; (h) contain adequate first aid facilities and be fitted with lifting equipment sufficient to enable an unconscious or injured diver to be hoisted into the bell by a person inside it; (/) be provided with means by which, in the event of any emergency, it can be rapidly located by through water signals from the stricken bell and the lives of trapped persons can be sustained for at least 24 hours or, where that is not practicable, sustained for as long as is practicable; (j) be used in association with lifting gear which enables the chamber to be lowered to the depth from which the diving operations are to be carried.on, maintained in its position and raised, in each case without excessive lateral, vertical or rotational movement taking place; and (k) be provided with a means by which, in the event of failure of the main lifting gear, the chamber can be returned to the surface; if those means involve the shedding of weights, they shall be capable of being shed from the bell by.a person inside it and a means shall be incorporated to prevent their accidental shedding. 22

25 Purity of Compressed Air Appendix VII Compressed air supplied to divers should not contain impurities in excess of the limits as follows: Carbon monoxide 10 parts per million Carbon dioxide 500 parts per million Oil Water 1 mg/m 3 Odour and cleanliness The air should be as dry as possible and should not give rise to condensation of moisture and the maximum filling pressure at a minimal service temperature of 5 C. The air should be free from all odours and contamination by dust, dirt and metallic particles and should not contain any other toxic ingradient Note: Odour and cleanliness of compressed air are difficult to check accurately without special equipment. A rough check may be made by opening the cylinder valve and smelling the escaping air and by noting any discolouration or matter when the air is passed through tissue or filter paper. 23

26 Appendix VIII Mouth-to-Mouth Respiration If the casualty is not breathing start mouth-to-mouth respiration as soon as possible: (a) Make sure airway is clear, support the nape of the neck and press the top of the head so that it is tilled backwards push the chin upwards: (b) Open your mouth wide and take a deep breath; (c) Pinch casualty's nostrils together with your fingers; (d) Seal your lips over his mouth; (e) Gently blow into his lungs until the chest rises; (/) Remove your mouth and watch the chest fall; (g) Repeat and continue inflates at your natural breathing rate; (/?) Continue until medical help is available or until the patient is breathing without assistance. External Cardiac Massage If the heart is not beating as shown by absence of pulsation at wrist and over hear and wide dilation of the pupils: (a) Put him on his back on a firm surface; (b) Place yourself at the side of the casualty; (c) Feel for the lower half of the breast bone; (d) Place the heel of your hand on this part of the bone, keeping the palm and fingers off the chest; (e) Cover the hand with the heel of the other hand; (/) With arms straight rock forward pressing down on the lower half of the breast bone to push it towards the spine about 2 inches; (g) Repeat this once per second; (A) Continue until expert help is available to take over or until the heart is beating strongly without assistance. 24

27 References I 1 SEr IC2 " " Appendix IX U.K. Government Publications (available from HMSO London): Admiralty Diving Manual Revised Ed B.R British Standards and Codes (available from British Standards Institute, London): B.S. 4001: Recommendations for the care and maintenance of underwater breathing apparatus: Part I 1966 Compressed air open circuit type Standard diving equipment. B.S. 4532: 1969 Snorkels and face masks. B.S. 4667: 1974 Breathing apparatus: Part 1 Closed-circuit breathing apparatus. Part 2 Open-circuit breathing apparatus. Part 3 Fresh air hose and compressed air line breathing apparatus. Other Publications: The Principles of Safe Diving Practice 1975 CIRIA Underwater Engineering Group, London. U.S. Navy Diving Manual Navy Department, Washington D.C. Guide for Classification of Manned Submersible American Bureau of Shipping (New York). Safety and operational guidelines for undersee vehicles (1968) Marine Technology Society, Washington D.C. The Physiology and Medicine of Diving and Compressed Air Work by BENNETT PB and ELLIOTT DH. Bailliere, Tindall, London. The British Sub Aqua Club Diving Manual, London. Man Beneath the Sea by PENZIAS W. and GOODMAN MW. Wiley Inter- Science, New York. Business of Diving by KENNY JE. Gulf Publishing Co. Houston. Underwater Medicine by MILES S. Staples Press, London. Submersibles: Rules, regulations and guidance for the construction, classification and planned inspection of submersibles. Lloyd's Register of Shipping, London. Chamber Fire Safety by SCHMIT TC, DOOR VA and HAMILTON RW. Ocean Systems Inc. Technical Memorandum UCR

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29 X1S31E3SD HKP C6 Code of practice for diving Hong Kong : Labour Dept., [1986] Date Due OT FQIi LO

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