2.6 Breathing gas supply, storage and temperature control

  2.6.1 Each surface compression chamber and diving bell should be fitted with adequate equipment for supplying and maintaining the appropriate breathing mixtures to its occupants at all depths down to maximum operating depth. When adding pure oxygen to the chamber, a separate piping system should be provided.

  2.6.2 In addition to the system mentioned in 2.6.1 each surface compression chamber and diving bell should contain a separately controlled built-in breathing system for oxygen, therapeutic gas or bottom mix gas with at least one mask per occupant stored inside each separately pressurized compartment and means should be provided to prevent any dangerous accumulation of gases.

  2.6.3 The diving bell should be designed with a self-contained breathing gas system capable of maintaining a satisfactory concentration of breathing gas for the occupants for a period of at least 24 hours at its maximum operating depth.

  2.6.4 Oxygen bottles should be installed in a well-ventilated location.

  2.6.5 Oxygen bottles should not be stored near flammable substances.

  2.6.6 The diving system and breathing gas storage facilities should not be sited in machinery spaces if the machinery is not associated with the diving system. Where, due to the requirements of diving operations, systems are sited in hazardous areas, the electrical equipment should comply with the requirements for such equipment in hazardous areas. Diving systems should not be permitted in hazardous areas designated as zone 0.

  2.6.7 A diving system should include adequate plant and equipment to maintain the divers in safe thermal balance during normal operations.

  2.6.8 There should be means to maintain the divers within the diving bell in thermal balance in an emergency for at least 24 hours. Such requirements may be satisfied by the use of passive means carried in the bell.

  2.6.9 For piping systems and gas storage bottles/pressure vessels the following colour code should be used:

In addition, each bottle/pressure vessel should be marked with the name and symbol given above of the gases it contains. The marking and colour coding of the gas storage bottles should be visible from the valve end.