20 mm PERT Aluminum Pipe ISO9001/14001 standard/CE Plastic bag ... 50 years life time 20 mm High quality PERT Aluminum Pipe1. Reduced thermal expansion2. For other special request, ... Due to the existence of the middle layer of aluminum, the expansion co-efficient a samll metal pipe with ... pipes used for heating installation on floor and wall, snow-melting devices for buildings in northern, park, airport, ...