Extend the life of fire sprinkler systems with the most corrosion resistant antifreeze

Water-filled pipes for fire sprinkler systems, such as those made of metal or CPVC, must remain above 40° F (4.44° C) to prevent freezing that can cause severe damage, leaks or pressure drops. Using glycerin and propylene glycol-based antifreeze solutions had been the industry standard for many years, enabling sprinkler systems to protect lives and property despite severe cold, particularly in northern climates.

Since 2012, National Fire Protection Association (NFPA) standards have required that all new antifreeze systems use a listed antifreeze product that also has corrosion resistance properties to protect sprinkler pipes against premature degradation, costly repairs and possible system failure. In addition, the 2014-2020 Editions of NFPA 25 require that nonlisted glycerin and propylene glycol antifreeze solutions used in existing wet sprinkler systems be drained and replaced with a listed antifreeze solution by September 30, 2022.

Download the free white paper to learn more about how antifreeze can be instrumental in resisting corrosion.

Global specialty chemical company The Lubrizol Corporation has developed and acquired a broad range of corrosion-inhibiting additives over the past century that give it a core competency and a leadership position in the metal protection industry, making the organization uniquely qualified to bring to market a freeze protection technology with a breakthrough corrosion inhibitor. Lubrizol formulated freezemaster™ antifreeze, which not only meets UL corrosion resistance requirements, but also achieves elevated levels of corrosion protection through the development of a corrosion inhibitor that outperforms an other UL-listed alternative in the required corrosion performance.

Let’s take a look at how corrosion compromises fire sprinkler performance, how antifreeze can be instrumental in resisting corrosion, and how commercially available listed products compare in corrosion protection properties as determined by lab testing.

Galvanic Corrosion Safeguards

Fire suppression systems are rarely comprised of only one metal type, or identical grades of a single metal. When dissimilar metals are in direct contact with one another or connected by a conductive fluid, a galvanic cell can form in the sprinkler system where one of the dissimilar metals will corrode preferentially over the other. The second metalworking test derives from ASTM G71 “Standard Guide for Conducting and Evaluating Galvanic Corrosion Tests in Electrolytes.” This test establishes the behavior of two dissimilar metals in electrical contact in an electrolyte under low-flow conditions. If corrosion is not present, color changes and sediment in the antifreeze solution will not occur.

Lubrizol built and tested several galvanic cell couples to measure electrical current over time while immersed. UL requires monitoring for 90 days, but in only seven days, it was possible to tell that the voltage versus time curves were radically different between the two solutions, indicating galvanic corrosion occurred more readily in one instance. In addition, the commercial product took on a blue color during the test, indicating that copper was being leached into the solution. This color change did not occur with Lubrizol’s new antifreeze, which is listed for use in galvanized piping systems, unlike the other UL-listed product.

A long-term pipe storage test was also conducted to simulate real world fluid-pipe contact. Using Schedule 40 pipe capped with half-hard brass fittings, a sample port was drilled in the top for ease of filling and sampling and sealed with a nylon screw. Samples of Lubrizol’s new antifreeze and the other commercially available antifreeze were added to the pipes and stored at 25 degrees Celsius and 40 degrees Celsius. At the end of 90 days, the pipes were cut open and visually inspected. Corrosion began to appear in the competitive listed solution in that time; Lubrizol’s antifreeze inhibited the formation of corrosion.