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Dry Air Proven to Mitigate Corrosion in Dry and Pre-Action Sprinkler Systems: An Alternative to Nitrogen Generators

We put Dry Air to the test to find out just how much it can help deter corrosion in dry pipe and pre-action fire sprinkler systems.

For decades, Dry Air has been used to fill dry pipe and pre-action fire sprinkler systems in special circumstances that necessitated the removal of moisture from standard compressed air entering the system – most commonly, freezer rooms. Specifically, our Dry Air Pac™ has been FM Approved and used for its prevention of ice plugs in freezer rooms and cold storage applications for almost 30 years.

Dry Air Prevents corrosion in dry and pre-action fire sprinkler systems. Inside of a 13 year-old galvanized pipe sample (magnified) showing no evidence of corrosion when supervised by a General Air Products Dry Air Pac™.

While freezer rooms and coolers are concerned with moisture removal to eliminate ice plugs, the rest of the dry pipe sprinkler industry’s primary concern has recently shifted toward corrosion prevention and mitigation. In response, the use of a number of corrosion mitigation methods, including nitrogen generators, has grown substantially. As a result, a number of high-end applications and long-standing structures are beginning to see the benefit of investing in protecting their pipes from corrosion.

Here's the catch: not every dry pipe or pre-action fire sprinkler system is best served by a nitrogen generator. A number of factors limiting their effectiveness, efficiency and ROI include the life span of the building, the required maintenance cost, system leakage, and up-front cost of the nitrogen generator itself. This begs the question: is there an alternative for preventing corrosion in dry and pre-action fire sprinkler systems?

Turns out, Dry Air Does Help Mitigate Corrosion

General Air Products recently collected pipe samples straight from the field in sites around the country using our Dry Air Pacs – air compressor / air dryer packages - that are FM Approved for fire sprinkler systems. Those pipe samples were sent to a 3rd party metallurgical testing laboratory in Maryland to be investigated for signs of corrosion:

Pipe Samples collected by General Air Products to test Dry Air for corrosion mitigating effected in fire sprinkler systems. Galvanized pipe sample, shown as collected.

The results from the lab (Table 1) concluded that 3 of the 4 pipe samples, ranging from 3 – 13 years old, showed no signs of corrosion with the use of Dry Air as the supervisory gas. Where corrosion had occurred, was in exposed pipe on a salt water pier. Even then, the lab estimated the life expectancy of the pipe at 60 – 70 years until the occurrence of the first pinhole leak. By reducing the dew point in the fire sprinkler system to the standard -40°F that the Dry Air Pac™ is rated to provide, corrosion has been effectively mitigated in the piping network.

Results form a 3rd party lab testing for corrosoin in pipe samples supervised by a General Air Products Dry Air Pac™. Table 1: Results form a 3rd party lab testing for corrosoin in pipe samples supervised by a General Air Products Dry Air Pac™.
Pipe Samples collected by General Air Products to test Dry Air for corrosion mitigating effected in fire sprinkler systems. Inside of a 13-year old pipe sample, shown in as-split condition, showing a smooth surface and no evidence of corrosion having been supervised by Dry Air.

Many more samples are currently being collected and evaluated to substantiate this finding in the field. The mounting evidence suggesting Dry Air may be an alternative method to nitrogen as a corrosion-inhibiting supervisory gas in dry pipe sprinkler systems is promising.

If you would like to learn more about the corrosion mitigating effects of Dry Air, check out our latest white paper on the topic. If you have any questions about this research or how Dry Air or Nitrogen gas can help mitigate corrosion, please give us a call at 1-800-345-8207, or shoot us a comment down below!

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