Section 18(3)(v) in The Static and Mobile Pressure Vessels (Unfired) Rules, 2016
(v)for static vessels, operational fitness examination of excess flow valves shall be carried out during periodic hydraulic test under rule 19 to check physical condition of the parts and its proper operations. For compressed gas tankers operational fitness examination of excess flow valves/internal valves shall be done once in a year. Closing flow rate testing of excess flow valves/internal valves of compressed gas tankers shall be done during the periodic hydraulic test. The excess flow valves/internal valves shall be repaired/replaced by a new ones if found defective on examination or during operation.