2.5.1.: Definition

2.5.1.1. ►M4 Gases under pressure are gases which are contained in a receptacle at a pressure of 200 kPa (gauge) or more at 20 °C, or which are liquefied or liquefied and refrigerated. ◄

They comprise compressed gases, liquefied gases, dissolved gases and refrigerated liquefied gases.

2.5.1.2. The critical temperature is the temperature above which a pure gas cannot be liquefied, regardless of the degree of compression.