Isolating valves to separate the section of the fire main within the machinery space containing
the main fire pump or pumps from the rest of the fire main are to be fitted in an easily
accessible and tenable position outside of the machinery spaces. The fire main is to be so
arranged that when the isolating valves are shut, all of the hydrants on the vessel, except
those in the machinery space referred to above, can be supplied with water by another fire
pump or an emergency fire pump.
This requirement applies to a machinery space of category A only. Any part of the fire main
routed through a machinery space of category A is to be fitted with isolating valves outside of
the space.