Section 56(6) in The West Bengal Factories Rules, 1958
(6)(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;Provided, however, that the pressure vessel or plant Which is so designed and constructed that it cannot be safely filled with water or liquid or is used in service where even traces of water cannot be tolerated, shall be pneumatically tested at pressure not less than the design pressure or the maximum permissible working pressure, as the case may be, subject to the condition that-(i)where the source of pressure is higher than the test pressure. precaution against over-pressurisation of vessel or plant under test shall be taken by the use of suitable reducing valve, pressure gauge and safety valve of adequate size:(ii)steps shall be taken to ensure that people are not likely to be injured in the event of bursting either by containing the vessel under test within a blast pit, or by retaining wall, or by ensuring that such personnel are adequately protected; and(iii)the vessel under test should not be approached for close inspection until after the test the pressure has been reduced:Provided further that the pressure vessel or plant which is lined with glass shall be tested hydrostatically or pneumatically as required at a pressure not less than the design pressure or maximum permissible working pressure, as the case may be.Explanation- Design pressure shall be not less than the maximum permissible working pressure and shall take into account the possible fluctuation of pressure during actual operation.(b)No pressure vessel or plant shall be used in a factory unless there has been obtained from the maker of the pressure vessel or plant or from a competent person a certificate specifying the design pressure or maximum permissible working pressure thereof, and starting the nature of tests to which the pressure vessel or plant and its fitting (if any) have been subjected, and every pressure vessel or plant so used in a factory shall be conspicuously marked so as to enable it to be identified as to be the pressure vessel or plant to which the certificate relates and the certificate shall be kept available for perusal by the Inspector.(c)No pressure vessel or plant shall be permitted to be operated or used at a pressure higher than its design pressure or maximum permissible working pressure as shown in the certificate.
