This part of ISO 16486 specifies a code of practice dealing with unplasticized polyamide (PA-U) pipes and fittings for buried pipeline systems outside buildings and designed to transport gaseous fuels (as defined in part-1 of this standard, e.g.: methane, LPG, manufactured gas and hydrogen) within the temperature range – 20 °C to + 40 °C and gives appropriate temperature-related requirements. The code of practice covers mains and service lines whose components are prepared for fusion or mechanical jointing and gives instructions for the design, storage, handling, transportation, laying conditions and fusion quality control of PA-U pipes and fittings as well as subsequent joint testing, backfilling, pipe system testing, commissioning. NOTE Principal information for rehabilitation can be found in ISO 11295 [41] for classification, ISO 11299 [42, 43] for renovation and ISO 21225 [44],[45] for trenchless replacement. PA-U may be considered in future editions. More detailed national standards or codes of practice might exist in the ISO member countries. This part of ISO 16486 is intended to be applied in association with those national standards or codes of practice related to the above-mentioned basic principles. The jointing methods covered by this part of ISO 16486 are: - butt fusion jointing (see Annex A); - electrofusion jointing (see Annex B) and - mechanical jointing (see Annex C). In the case of ground movement or shaking (e.g.: earthquakes, etc.) precautions mentioned in this code of practice may need to be implemented following guidelines provided by authorities (e.g.: Eurocode 8 [13], Annex A of EN12007-1 [14], etc.), Existing and new national regulations take precedence over this standard. Workers health and safety issues are outside the scope of this document