Abstract
Three unexpected failures of FRP components used in different environments have been investigated. The results showed that all the failures had occurred because of glass-fiber-related stress-corrosion cracking. The first occurred in a PVDF-lined FRP piping located between the mixer and the inlet to a chlorine-dioxide-stage bleach tower in a pulp mill. The line broke in a catastrophic manner after only about six years of service. The second case refers to FRP piping for hydrochloric acid in a chemical plant. In total, about 12 km of FRP piping is used for hydrochloric acid services in the plant. During 2–3.5 years of operation, more than ten failures of leakage due to wall-penetrating cracks have occurred. The latest leak developed in a line for cold acid after only 1.5 years of service. The cause of this failure has been a subject for further analysis. The third failure occurred in 2002 in a chemical plant producing iron sulphate/chloride. Leakage due to wall-penetrating cracks developed in a 5-year-old FRP pipeline intermittently transporting cold dry chlorine gas. Interestingly, the failures happened despite the fact that the structures were of high quality and were designed according to the current norms. Considering the numerous structures worldwide using FRP in aggressive environments, the risk of costly and harmful stress corrosion failure is obvious. We must therefore learn how to prevent and avoid such potential problems. The present paper is a step in that direction.
