System Maintenance & Performance # 2004 Milan
Lifetime prediction of plastics piping systems plays an important key role when selecting new materials for pressure pipes. Practical experience during more than 50 years, demonstrates that PVC piping systems do not vanish after the lifetime as mentioned in the relevant national and international standards. PVC pipes have reached a strong competitive market position in the water industry, essentially based on long-term performance, cost effectiveness and sustainable development. Molecular oriented PVC (MOPVC) is still growing and still has to acquire a stable market position. Nevertheless, MOPVC is offering an excellent long-term performance and opens new horizons for higher pressures. In this paper, the MRS (Minimum Required Strength) pressure rating obtained with ISO 9080 of PVC-U and MOPVC pipes are discussed and evaluated. Renewed safety coefficients for PVC-U and MOPVC, based on the regression curves, the installation conditions and specific water company requirements, are proposed.