# 2004 Milan
To heat buildings and houses, a common source of heat with a large ‘district heating’ distribution system is used more and more. This system is both economic and ecological as it avoids the generation of heat by thousands of private heating systems. Such networks are currently made mainly with steel coated with PU foam layer and an external casing pipe in polyethylene. Steel pipes may be subject to corrosion under the combined action of water transported and temperature. New solutions are now investigated. One of these new materials is crosslinkable PEX, which is based on silane technology. By crosslinking the PEX pipes during operation, the installation and welding of pipes can be made as for standard PE pipes. This paper brings all the elements necessary to understand and take into account all the key points of such a network and its good use.