Fire sprinkler systems can be prone to a specific category of corrosion plaguing the industry known as microbiologically influenced corrosion, or MIC. According to the FM Global report “Corrosion and Corrosion Mitigation in Fire Protection Systems,” MIC is responsible for 10-30% of corrosion in all piping systems in the U.S.
Fire sprinkler contractors who have an inspection, testing and maintenance (ITM) business are looking at new protocols for water-based fire protection systems.
Have you ever wondered why antifreeze in water-based fire sprinkler systems requires yearly testing before the onset of freezing weather? Simply put, testing ensures that the antifreeze maintains its proper concentration and freeze point. It must always remain in a liquid state and address the life safety issues associated with antifreeze use. To ensure this, the concentration of antifreeze solution should always be no more than the least amount necessary for the anticipated minimum temperature. In the event of leaks, pressure surges or temperature changes to the system, antifreeze can flow out of the system or water can flow into the system, leading to changes in the freeze temperature and antifreeze concentrations. If concentration conditions deviate from allowable tolerances, as illustrated by the chart below for freezemaster™ antifreeze, the fluid must be replaced. Because freezemaster™ antifreeze is a UL-listed, safe to use, factory premixed antifreeze, the percent concentration by volume would always be 100 percent.
As you select an antifreeze for your fire sprinkler system, it is important that you consider these questions: Does it meet the rigorous technical challenges of becoming listed as required by NFPA? Is it listed and approved for use with the application and the size of the system? Will it protect the system against damage from exposure to the severe cold? How does it contribute to the prevention of corrosion and microbiologically influenced corrosion (MIC)? In this blog post, I address why the answers to these questions are so critical, and the advantage freezemaster™ antifreeze offers for fire sprinkler systems in Residential, Light Hazard, Ordinary Hazard and Storage applications.
The 2014 edition of NFPA 25, the standard for the inspection, testing and maintenance of water-based fire protection systems, was written to specifically include emergency changes regarding the use of antifreeze. Those changes were based on events in which activated sprinkler systems, fortified with antifreeze, actually intensified blazes rather than extinguished them. This was likely due to onsite errors in mixing the solutions that introduced excessive amounts of the active ingredients glycerin and propylene glycol, both of which increase flammability when present in high concentrations.
UL 2901 was established in December 2013, outlining certification requirements for antifreeze solutions for wet pipe fire sprinkler systems. To meet the UL 2901 requirements, antifreeze products must prove corrosion resistance (important for metal-based fire sprinkler systems), fire performance (i.e., flammability), hydraulic characteristics, human health and environmental impact, and meet marking and installation specifications.
When a fire sprinkler system activated as designed in 2009 to suppress a cooking fire – and instead intensified the blaze, killing one and injuring four – the use of antifreeze in sprinkler systems changed forever. The sprinkler system contained antifreeze that had been mixed improperly before application. A high concentration of the antifreeze agent caused the flames to virtually explode when the sprinkler system activated.
NFPA 25 is the standard for the inspection, testing and maintenance of water-based fire protection systems. Once adopted by local code bodies, authorities having jurisdiction (AHJs) require strict adherence to NFPA 25 – and frankly, there is no reason not to design, repair or maintain a system to the standard.