The fire water network of all the buildings associated with the Liquefied Natural Gas Import (LNGI) facility had experienced several leaks due to corrosion. During visual inspection, it was noticed that the leaks were from the pipes/fittings through isolated pinholes in the base metal and adjacent to welds. Detailed analysis was conducted to determine the root cause of the failures. The entire piping was both shop and field fabricated using SS 304 piping materials. Desalinated water was used for the fire water lines. After the analysis, it was concluded that Microbiologically Influenced Corrosion (MIC) was the reason for the severe corrosion & leaks. It was observed that Hydrotest waster was not treated and not drained from the system.

In this paper, a case study of the failure that occurred in the Desalinated Fire (DF) water line is presented. A brief description of water quality, material of construction, existing site conditions and the failure analysis are included in this paper. The mitigating options which were implemented is also covered in this paper.