Section 16(3) in The Static and Mobile Pressure Vessels (Unfired) Rules, 2016
(3)The water capacity of the cryogenic pressure vessel shall be rated in terms of gross water capacity and the allowable water capacity in litres at 15°C. The usable water capacity shall not exceed 95% of the gross water capacity. An overflow pipe shall be provided at the maximum allowable capacity level as a safeguard against filling the vessel beyond the maximum usable capacity.
