Section 18(2)(xiii) in The Static And Mobile Pressure Vessels (Unfired) Rules, 1981
(xiii)[ relief valves shall be tested by a competent person for correct operation not less than once in a year and a record of such test shall be maintained. The test certificate shall be issued in the prescribed pro forma .] [ Substituted by G.S.R. 264(E), dated 10.3.1993.]