The service life of plastic pipe in the polyurethane foam insulation, used for heating systems

The interest in the polymer (plastic) pipes in terms of their use in district heating networks of large cities settlements and neighborhoods as flexible pre-insulated pipes in the polyurethane foam insulation channel free laying increased in Russia during the last decade. Pipes made of PE-RT (polyethylene of Raised Temperature Resistance) and PE-X (cross-linked polyethylene) are the most promising plastic pipes. Pipes made of PE-RT have long term hydrostatic resistance (ability to prevent the liquid expiration under pressure) at high temperatures, without molecular cross-linking. This resistance provides significant technological advantages (the ability to weld) comparing with the crosslinkable systems (PE-X), as well as pipes cost reduction. The paper presents the method of determining the service life of polymer heat pipelines made of PE-RT and PE-X at a temperature of 110 °C, based on domestic and foreign standards. The analysis of heat pipelines performance made of PE-RT and PE-X and the plastic pipes service life calculation at temperatures up to 110 °C indicate obvious advantages of PE-RT Type II DOWLEX ™ 2388. In addition, the article gives the guidance to developers of the standard GOST R 52134 next edition, based on European regulations and essential for the laying plastic pipe improvement.