This Technical Specification presents a code of practice dealing with polyethylene (PE) pipes and fittings for buried pipeline systems outside buildings and designed to distribute gaseous fuels 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 jointing by scraping and/or machining, and gives instructions for the design, storage, handling, transportation, laying conditions and fusion quality control of PE pipes and fittings up to and including 630 mm outside diameter, as well as subsequent joint testing, backfilling, pipe system testing, commissioning and decommissioning. The jointing methods covered by this Technical Specification are heated-tool fusion jointing (butt, socket and saddle fusion), electrofusion jointing and mechanical jointing. No special precautions are necessary for areas exposed to the influence of mining and earthquakes other than those precautions mentioned in this code of practice. Existing and new national regulations take precedence over this Technical Specification.