The Risks of Performing Maintenance in Dry Fire Sprinkler Systems

Posted by Brad Wood on Oct 5, 2021 10:15:00 AM

A building’s fire protection system, something that frequently goes unnoticed to the standard human eye, plays a vital role in the safety of both the building and those who inhabit it. Although the fire sprinkler system is typically “out of sight, out of mind” - there are vital maintenance procedures to ensure that this life safety system performs as designed. However, these safety test procedures can simultaneously contribute to corrosion in the case of dry fire sprinkler systems. Learn why this happens and what you can do to maintain your system without putting it at risk for further corrosion.


Dry Fire Sprinkler System Tests

Several practices exist to test the functionality of dry pipe systems. Some of these methods include hydrostatic testing of the system after installation (required by NFPA 13) and periodic trip testing of the fire sprinkler system every three years (required by NFPA 25). Those in the fire protection industry realize that testing a system is necessary to ensure proper function. Unfortunately, this testing can help exacerbate corrosion-related issues in dry pipe fire sprinkler systems. 


How Testing Jeopardizes Dry Pipe Systems 

These tests introduce liquid water into the systems that cannot be completely drained by gravity, regardless of the pitch of the piping. The trapped water is problematic because it now leaves the system prone to the number one cause of fire sprinkler degradation: oxygen corrosion. Hydrostatic testing and full flow trip tests aren’t the only systematic procedures that introduce this liquid water to the system internally. Water that condenses from the moist air injected by the air compressors is also a source of liquid water that can be found in a system. The use of desiccant and regenerative dryers has been implemented with these compressors to try to prevent the additional moisture. However, the dryers are not capable of removing the previously trapped water from system testing. The bottom line – the internal environment of the dry or pre-action system is never completely dry.


How Inspections Introduce Corrosion

There are also additional systemic practices that are essentially “destructive” to the internal integrity of the fire sprinkler piping. For example, NFPA 25 provides some basic requirements for the five year internal inspection, which calls for an in-depth investigation into the status of an aging system. While it seems like an efficient method to give owners an idea of the remaining life of their system, in respect to corrosion, it only compounds the rate at which corrosion occurs. It is inevitable that a system with trapped water, unprotected steel, and regular compressed air will experience corrosion to some degree. The opening of this system is sure to do one thing – reintroduce fresh oxygen throughout the system piping that will further the chemical process of corrosion.


Maintaining Your Dry Pipe System Risk-Free

The dry pipe sprinkler system maintenance practices currently in place are not doing your system any favors. Since liquid water and inherently corrosive steel are here to stay, it could be time to look at a method that safely provides full preventative maintenance to your system. What other avenues can count out the #1 pipe killer, oxygen corrosion? Removing the corrosive oxygen and replacing this gas with inert gas such as nitrogen is a tried-and-true method that will stop the degradation of your pipes in its tracks. 

If you have any questions about corrosion in your dry pipe fire sprinkler system, contact our team of experts.

Brad Wood

Written by Brad Wood

Project Engineer