A model for crack-growth in PVCU mains, implemented in Comsima - Executive Summary - Slow crack-growth and residual stress modelled in Comsima provides clearer picture of pipe failure causal factors

Slow crack-growth and residual stress are two important aspects that contribute to the premature failure of pipes made from PVCU, which is the material most used in the Dutch drinking water distribution network. By modelling these aspects in Comsima, a pipe-condition calculation tool, the tool can make a better estimate of the failure probability of a PVCU pipe. A sensitivity analysis with this tool, once it has been extended in this manner, reveals which information is crucial for a good assessment of the pipe condition. The extent of the flaws, the water pressure, the residual stress all strongly influence the premature failure of PVCU pipes, as do combinations of extreme values, for example, for wall thickness, pressure, pipe depth and the size of the flaw.

Interest: understanding PVCU failure and degradation is crucial for asset management PVCU (unplasticized PVC, also known as ‘hard PVC’) is the pipe material that is most used in the Netherlands. It has been used since 1950 and now accounts for more than half (60,000 km) of the country’s drinking water distribution network. Understanding the failure and degradation behaviour of this extensively used pipe material is therefore important for the good asset management of the drinking water distribution network.

Report – This research is described in the report Een model voor scheurgroei in PVCU buizen, toegepast in Comsima (BTO 2020.001).