This part of ISO 22621 specifies the physical and mechanical properties of pipes made from polyamide (PA) in accordance with ISO 22621-1, intended to be buried and used for the supply of gaseous fuels at maximum operating pressures (MOP) up to and including 20 bar 1). It also specifies the test parameters for the test methods to which it refers. In addition, it lays down dimensional characteristics and requirements for the marking of pipes. Pipes conforming to this part of ISO 22621 are jointed typically by using mechanical, electrofusion or butt fusion (see Annex A) techniques, but not by solvent cement jointing.