Section 56(6)(a) in The West Bengal Factories Rules, 1958
(a)No new pressure vessel or plant shall be taken into use in a factory after coming into force of this rule unless it has been hydrostatically tested by a competent person at a pressure at least 1.3 times the design pressure, and no pressure vessel or plant which has been previously used or has remained isolated or idle for a period exceeding 6 months or which has undergone alterations or repairs shall be taken into use in a factory, unless it has been the roughly examined by a competent person externally, and internally, if practicable, and has been hydrostatically tested by the competent person at a pressure which shall be 1 .5 times the maximum permissible working pressure;