Wolters, Wikkerink
Standards & Specs # 2006 Washington DC
The use of plastic pipeline materials in gas distribution systems is still increasing. Presently PE and high impact PVC are the dominating materials in gas distribution networks up to 4 bar. Most of these networks operate at these pressures, only a limited part of the network operates at higher pressures, up to 10 to 20 bar. The performance of the plastic gas distribution systems is excellent, also caused by the availability of (ISO) specifications for these systems.Within ISO TC 138/SC4, which is responsible for defining requirements for plastics used in gas supply systems, many organizations from all over the world are involved. In this paper an overview is given of the status of all specifications in this area.For PE pipeline systems a full set of specs is available, covering all aspects from requirements on resins, pipes, fittings up to the jointing methods and code of practice. These specifications are regularly updated. Recently, also a full set of specifications has become available for high impact PVC pipes aimed to be used at lower pressures (<0.1 bar).For higher demanding applications (higher pressures, higher and lower temperatures, rocky soils, etc. ) tailor-made plastic pipeline systems have or are being developed. For crosslinked PE (PEX) now a complete set of ISO specifications is available. For higher pressure applications, up to 16 to 20 bar, polyamide (PA) and fibre-reinforced thermoplastic pipeline (RTP) systems have been developed. For these materials ISO TC 138/SC4 has also defined specifications or is drafting specs. For multilayer pipes this is also in progress.Altogether this means that in due time a complete set of specifications will be available for all plastics to be used in gas supply systems, defining requirements to resins, pipes, fittings and jointing techniques. This will certainly contribute to the successful, safe and reliable use of plastics in gas distribution systems.
