Internal Pressure Testing as a Tool for Life Cycle Management of Piping Systems

摘要

Beside its use for quality control, hoop stress testing proved to be a valuable method to assess the condition of plastic piping systems. The presented applications show the benefit of the methodology but also the pitfalls. More than 30 years experience showed that internal pressure testing is a useful tool to monitor the degradation of thermoplastic piping systems. It can be used for quality control as well as for the decision making on investments by estimating the remaining lifetime. Substantial savings were achieved by delaying investments for several years. However, the field data clearly demonstrate that the information about changes in the conveyed chemicals is key to a successful lifetime extrapolation. More severe conditions will result in unexpected failure. The experience from field applications shows that 5% remaining life time in the lab test is a lower limit. Below this limit in lab test the pipe may fail at any time, hence the pipe should be replaced immediately.