Lifetime of Pipes # 1992 Eindhoven
The relatively high safety factors used in the design of PVC-U pressure pipes reflect concern about the possibility of brittle failure in service. Toughness may be improved by the addition of iinpact modifiers and plasticisers but normally strength is impaired. In this paper we show that pipes exhibiting a high resistance to crack growth may be obtained while still maintaining long term strength (50 yr) over 25 MPa. We also discuss new and alternative test procedures which we feel would be essential if a reduction in safety factor is to be justified.