Determination of Environmental Stress Cracking Failure Mode in Investigation of CPVC Fire-Suppression Sprinkler Pipe Failures

摘要

This paper discusses three separate failure analysis case studies involving Chlorinated Polyvinylchloride (CPVC) fire suppression sprinkler pipe(s) alleged to have failed due to Environmental Stress Cracking (ESC) from exposure to an incompatible chemical. The investigations highlight the importance of the interpretation of fracture surface morphology, review of background information regarding service history, performing material characterization testing, as well as developing an understanding of the interaction of various chemicals with CPVC material when attributing a failure of CPVC sprinkler pipe to ESC. The case studies discussed are helpful in understanding the ESC mechanism in CPVC sprinkler pipes, which is a complex failure mode. This paper discusses the technical issues that should be addressed in determining whether ESC is the primary cause of failure in a CPVC fire suppression sprinkler pipe system.