Leakage of submerged piping in sewage treatment plant was investigated. Leakage occured through perforation of bent connectors.

The investigation found the failure to be a result of improper material selection: connectors were made of AISI304 stainless steel, contrary to design requirement of AISI316L employment for the entire piping system (pipes and connectors).

Consequently, galvanic corrosion developed between the two different materials, leading to the observed perforation of the connectors.