Section 66(11)(e) in The Punjab Factory Rules, 1952
(e)Water supply shall be provided to give flow of water as required under clause (a) for at least one hundred minutes. At least fifty per cent of this water supply or four lac and fifty thousand litres whichever is less, shall be in the form of static tanks of adequate capacities (not less than four lac and fifty thousand litres each) distributed round the factory with due regard to the potential fire risks in the factory. Where piped supply is provided, the size of the main shall not be less than fifteen centimetres diameter and it shall be capable of supplying a minimum of four thousand five hundred litres per minute at a pressure of not less than seven kilograms per square centimetre.