In order to limit the thermal expansion of plastic materials at both high and low temperatures, a glass fleece reinforcement must be applied for air-conditioning applications involving hot and cold water. The structure of the PP-R pipe consists of 25% PP-R – 50% glass fleece – 25% PP-R. In this way, the thermal expansion coefficient α of the plastic pipe is reduced to 0.035 mm/mK, instead of 0.15 mm/mK for a standard PP-R pipe. Compliant with: UNI EN ISO 15874 – DIN 8077 – DIN 8078 – CSA B 137.11 – ASTM F 2389 – UNI EN ISO 15494 – ISO 4065