Section 2(1)(g) in Petroleum and Natural Gas Regulatory Board (Technical Standards and Specifications including Safety Standards for Liquefied Natural Gas Facilities) Regulations, 2018
(g)"compressed gas" means any permanent gas, liquefable gas, or cryogenic liquid under pressure or gas mixture which in a closed pressure vessel exercise a pressure exceeding one atmosphere (gauge) at the maximum working temperature and includes Hydrogen Fluoride. In case of vessel without insulation or refrigeration, the maximum working temperature shall be considered as 550C ;