.-(1) Every tank or receptacle for the storage of petroleum in bulk other than a well-head tank shall be constructed of iron or steel in accordance with the codes or specifications approved by the Indian Standards Institution or any other code or specification approved in writing by the Chief Controller:Provided that if the properties of petroleum to be stored, so required or for any other reason it is necessary to do so, tanks or other receptacles may be built of materials other than iron or steel.(2)The tanks or other receptacles shall be erected on firm foundations or supports of non-combustible material in accordance with sound engineering practice.(3)The height of a storage tank shall not exceed one and a half times its diameter or twenty-metres, whichever is less.Explanation .-For the purpose of this sub-rule, the height of a tank shall be the height from its bottom to top curb angles.(4)An air space of not less than five per cent. of the total capacity of the tank or the space prescribed in the code or specification referred to in sub-rule (1), whichever is less, shall be kept in each tank.
