Why Use Nitrogen

Why Use Nitrogen?

Actual corrosion found during an NFPA 25 internal pipe inspection.
The interior of preaction and dry sprinkler piping is subject to corrosion, which can lead to clogged sprinkler heads, leaks, and pipe failure. This corrosion can be of two distinct types. Oxidation corrosion takes place in the presence of oxygen and is accelerated by the presence of water. Microbiologically influenced corrosion (MIC) takes place in the presence of certain microbes that attack metal, again in the presence of water and in many cases oxygen. Reducing the damaging effects of this corrosion is best accomplished by greatly reducing or eliminating the amount of water and oxygen left in the pipe.


Section of pipe removed from a preaction sprinkler, showing overall internal corrosion with accelerated corrosion at the bottom from standing water. This also shows edge corrosion from improper coupling groove placement. Not shown: pinhole leak in the area of accelerated corrosion.
Ordinary air compressors that are used to provide supervisory pressure keep the oxygen concentration inside the pipe the same as normal air—ideal for oxidation corrosion to take place. Ordinary compressors also do not dry the air—residual water system testing remains in low points, and moist air can actually increase standing water within pipes from condensation. The introduction of high-purity dry nitrogen with a low dew point reduces or eliminates these two problems. The interior of the pipe remains dry, with very little oxygen remaining to attack the metal.
Contact Our Team
Did You Know?
  • Your dry-pipe or preaction fire sprinkler system can be infected! That’s right – microbes can be lurking inside your sprinkler pipes and causing damage.  Microbiologically influenced corrosion (MIC) occurs when the right combination of moisture and microbial organisms produces rapid corrosion of steel piping from the inside out. MIC is not the only cause of steel pipe corrosion, but it is important to know about and mitigate this problem BEFORE it causes pitting, pinholes, and thinning of pipe walls. Take steps to prevent both rust and MIC by using NITROGEN-PAC.