This part of ISO 16486 specifies the physical and mechanical properties of pipes made from unplasticized polyamide (PA-U) in accordance with ISO 16486-1, intended to be buried and used for the supply of gaseous fuels. It also specifies the test parameters for the test methods to which it refers. ISO 16486 is applicable to PA-U piping systems the components of which are connected by fusion jointing and/or mechanical jointing. In addition, it lays down dimensional characteristics and requirements for the marking of pipes. Pipes conforming to this part of ISO 16486 are jointed typically by using mechanical, electrofusion or butt fusion (see Annex A) techniques, but not by solvent cement jointing.