PVC-U Pipes: Optimal Extrusion Conditions for a 100+ Year Design Lifetime (Part II)

Presenter: Joaquín Lahoz Castillo, CEISLAB.

The presentation is based on a research project launched in 2020 by CEIS and PVC4Pipes, now VinylPlus Pipes, to generate public data demonstrating that pressure PVC-U pipes can deliver a service life of more than 100 years.

The study examines how extrusion temperature and quality control testing relate to the long-term performance of PVC-U 250 pressure pipes. Calcium-based stabilised pipes were extruded under different processing conditions and assessed using DSC onset temperature, degree of gelation, resistance to dichloromethane and long-term hydrostatic strength prediction according to ISO 9080.

The results indicate that an extrusion temperature of 180°C is sufficient to achieve MRS250 classification. Moderate increases in processing temperature can improve predicted long-term performance, while higher temperatures offer only marginal gains and increase the risk of material degradation.

The findings support the possibility of extending MRS250 classification to a 100+ year design lifetime, allowing designers of pressurised water supply networks to plan for longer service lives using design stress and design coefficient values typically applied for 50-year designs.