This part of ISO 6993 specifies a code of practice for the design, handling and installation of high-impact poly(vinyl chloride) (PVC-HI) pipes and fittings intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 °C up to and including +30 °C and a maximum operating pressure of 1 bar (100 kPa) 1). The code of practice covers mains and service lines, and gives provisions for the design, installation, storage, handling, transportation and quality control of PVC-HI pipes and fittings up to and including an outside diameter of 400 mm, as well as backfilling, pipe system testing and commissioning. The pipes and fittings are suitable for those gases which do not contain potentially damaging components in such concentrations as to impair the properties of the pipe/fitting material.