Section 7 in The Static and Mobile Pressure Vessels (Unfired) Rules, 2016
7. Purging of pressure vessels used for flammable gases.
(1)Before using any new vessel or before the refilling of any existing vessel which has been made gas-free, air contained therein shall be purged by an inert gas or by the gas for which the vessel is to be used.(2)If the vessel is purged by means of a flammable gas, the flammable mixture so formed shall be vented from the vessel only after taking adequate precautions to prevent its ignition.
