The current research regarding corrosion in fire sprinkler systems suggests that the primary cause for corrosion related failures is dissolved oxygen in the water. Although microbiologically influenced corrosion (MIC) can be a contributing factor, there is strong evidence which indicates that MIC accounts for less than 10% of the corrosion related failures. Oxygen corrosion accounts for the vast majority of corrosion related pipe failures.
In other industries it is common to use water dispersible “filming amine” type chemical corrosion inhibitors to control oxygen corrosion in fresh water flowing environments. This approach achieves corrosion control through continuous low dosage injection of the inhibitor into the flowing stream of water. A thin inhibitor film protects the metal surface by forming a barrier which inhibits the action of oxygen on the metal.
The standard list of chemical corrosion inhibitors that provide excellent corrosion control in fresh water flowing environments have a much more difficult task in controlling corrosion in stagnant water based fire sprinkler systems and chemical suppliers are currently not required to prove that their corrosion inhibitor actually works in fire sprinkler systems. Proper dosage, even distribution, penetration beneath solids, and dilution from flow testing are all major concerns with applying chemical corrosion inhibitors to fire sprinkler systems.
There is currently no industry standard for performance, allowable toxicity, or compatibility with system components of chemical corrosion inhibitors used in fire sprinkler systems so there is no way to ensure that the chemical treatment is not doing more harm than good.