Failure Analysis of a Corroded Stainless-Steel Firefighting System

The present study covers the failure of a stainless-steel firefighting system after three months of completion and operation. The system used seawater with chemical foaming additions. The investigation revealed the low quality of the used material. Corrosion pits propagated by tunneling parallel to the pipe axis. Tunneling is a common mechanism of damage propagation in microbiologically influenced corrosion (MIC) in carbon steels, but interestingly tunneling is reported in this case in stainless steel. The root cause of this damage is the use of bacteria-infected water/fluid inside the piping system. To avoid such damages in the future, some recommendations are suggested. It is recommended that (i) the firefighting fluid is treated to reduce the aggressive contaminant levels; (ii) for the damaged piping system, it might be a solution to use a broad-spectrum biocide to penetrate and destroy the biofilms and stop the damage; and (iii) use of other alloys rather than the austenitic stainless steel may constitute a feasible remedy for this failure, as well.