13.5.2 Arrangements of Free-standing Tanks
The use of free standing fuel oil tanks in the machinery spaces of category A is to be avoided as far as possible, see the general intent in 4-6-4/13.5.1(a). Where this is unavoidable, free-standing fuel oil tanks in machinery spaces of category A are to be kept to a minimum and their installation is to be as follows:
• The fuel oil tanks are to be placed in an oil tight spill tray of ample size (e.g., large enough to cover leakage points such as manhole, drain valves, gauge glass, etc.) with a drainage facility to a suitable drain tank.
• The fuel oil tanks are not to be situated where spillage or leakage therefrom can constitute a hazard by falling on heated surfaces. In particular they are not to be located over boilers.
13.5.3 Valves on Fuel Oil Tanks
13.5.3(a) Required valves. Every fuel oil pipe emanating from any fuel oil tank, which, if damaged, would allow fuel oil to escape from the tank, is to be provided with a positive closing valve directly on the tank. The valve is not to be of cast iron, although the use of nodular cast iron is permissible, see 4-6-2/3.1.4. The positive closing valve is to be provided with means of closure both locally and from a readily accessible and safe position outside of the space. In the event that the capacity of the tank is less than 500 liters (132 US gallons), this remote means of closure may be omitted.
If the required valve is situated in a shaft tunnel or pipe tunnel or similar spaces, the arrangement for remote closing may be effected by means of an additional valve on the pipe or pipes outside the tunnel or similar spaces. If such an additional valve is fitted in a machinery space, it is to be provided with a means of closure both locally and from a readily accessible position outside of this space.