Corrosion Control Inside Water-filled Steel Fire Sprinkler Piping

This article is a guide for sprinkler contractors, facilities managers, and their technical advisors who sometimes have to deal with the consequences of iron-water corrosion inside pressurized, low-carbon steel fire protection systems that contain water. The consequences include: (1) pinhole leaks and (2) build-up of insoluble corrosion residues on the interior pipe wall that increases pipe friction losses. A reference is made to sections of the National Fire Codes/NFPA 13 that address pipe materials, protection of steel piping against corrosion, and pipe friction losses. Electrochemical metal-water corrosion processes that can occur inside pressurized, low-carbon steel fire protection systems that contain water are discussed, as is microbiologically influenced corrosion. Corrosion control measures arising from the electrochemical science underlying both metal-water corrosion and microbiologically influenced corrosion are suggested.