3.1.1 Each compartment of a surface compression chamber is to be equipped with
suitable means for extinguishing a fire in the interior by providing for the rapid
and efficient distribution of the extinguishing agent to any part of the
chamber.
3.1.2 The fire extinguishing system is to be designed and constructed in such a
way that it can safely deal with every conceivable outbreak of fire under all the
environmental conditions for which the diving system is designed. Actuation of the
fire extinguishing system may not cause any unacceptable pressure change inside the
chamber. The extinguishing system may be actuated by hand. It must at all times be
possible to stop the extinguishing operation from the chamber and from the control
room.
3.1.3 Fresh water is the preferred extinguishing agent. Extinguishing agents
with a toxic or narcotic effect are not permitted.
3.1.4 Any required fixed pressure fresh water spraying or water mist
fire-extinguishing system is to be designed to ensure rapid and efficient
distribution of water throughout the chambers to be protected. It is to operate
effectively in all hyperbaric conditions which may occur in the chamber that are
capable of sustaining combustion.
3.1.5 Pressure control of the water spray is to be provided by a tracking
regulator which constantly monitors the chamber pressure.
3.1.6 A water application rate of 25 litre/m2/min of internal
surface area of the chamber shell is required or 80 litre/m2/min relevant
to walking surface at ¼ of internal diameter, whichever is larger. The system is to
be capable of manual operation from inside the chamber and from a continuously
manned diving centre room.
3.1.7 Water spray nozzles are to provide coarse droplets of water under all
pressure conditions and are to be located to provide reasonably uniform special
coverage in all parts of the chamber.
3.1.8 There is to be sufficient water supply for the system to operate for one
minute at the required application rate without recharging the system. It is to be
possible to manually stop the discharge of the system at any time before the water
supply is exhausted.
3.1.9 Where the quantity of water is required to protect more than one chamber,
the quantity of water available need not be more than the largest quantity for any
one chamber so protected.
3.1.10 A second fire-hose based fire-fighting system is to be provided in every
hyperbaric chambers compartment. Such systems shall be better supplied through an
independent pipe from nebulised stationary distribution system, alternatively a
suitable pressurised/portable water extinguisher to each hyperbaric chamber
compartment is to be provided (two extinguishers in large chambers and only one in
each entry lock).
3.1.11 Alternative to water spray system, approved high pressure water mist
system with due water capacities, securing equivalent reliable levels (extinguishing
time, discharge density etc.) based on NFPA 750 or BS EN 16081 principals will be
considered.
3.1.12 Upon fire-fighting system start up, the oxygen supply to the chamber is
to be discontinued immediately and general safety policy provided by emergency plan
shall be implemented.
3.1.13 Whenever a fire-fighting system is started, all electric systems working
inside the hyperbaric chamber are to be disconnected and emergency communication and
lights is to be set to work.
3.1.14 Maximum overall time from fire detection to discharge start is to be four
seconds.