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By: Lainey Liotta on September 28th, 2021

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Codes, Standards & Approvals

Before July 2021, a listed antifreeze approved for use in Ordinary Hazard 1 & 2 sprinkler systems larger than 40 gallons did not exist, even though many of these buildings require a system with significantly more antifreeze. This limitation made it difficult and expensive for antifreeze-based fire sprinkler systems in larger applications to maintain compliance with NFPA requirements.

But compliance is now easier than ever before: freezemaster™ antifreeze is the only UL-listed antifreeze approved for use in Ordinary Hazard 1 & 2 systems up to 375 gallons, using NFPA 13 dry system hydraulic design criteria for systems between 40 and 375 gallons.


NFPA standards require the use of listed antifreeze in all newly constructed antifreeze sprinkler systems now and in all existing antifreeze systems by September 30, 2022. This requirement presents a challenge to building owners of new and existing larger Ordinary Hazard facilities like parking garages, canneries, cereal mills, distilleries, and paper and pulp mills.

Until now, contractors and building owners faced the same two time-consuming, expensive options, whether designing a new system or working with an existing one:

  1. Convert to a dry system (or other freeze protection method), which are costly to install and maintain.
  2. Use a listed antifreeze and “valve off” high volume systems into smaller subsystems that do not exceed 40 gallons – meaning very big systems would require more sections, driving up installation and maintenance costs.

But now there’s a third, better option for listed antifreeze.


As a leading name in research and development for products that meet safety and regulatory needs, Lubrizol is committed to creating a quality listed antifreeze product that meets market needs. In May 2021, we conducted an industry-wide survey, and a common unmet need was listed antifreeze for large-volume systems because nearly 1/3 of freeze-protected systems require more than 40 gallons of antifreeze.

To meet market demand, we completed additional certification testing for freezemaster™ antifreeze and became the first and only antifreeze that is UL-listed for use in Ordinary Hazard 1 & 2 systems up to 375 gallons.

The updated listing for Ordinary Hazard Groups 1 & 2, as defined by NFPA 13, states:

freezemaster™ antifreeze is approved for ≤40 gal; in accordance with NFPA 13 design criteria or >40 gal to ≤375 gal; in accordance with NFPA 13 using the dry system hydraulic design criteria, where the system hydraulics are designed as a dry system even though the system is filled with antifreeze.

Not only does this expanded volume listing allow more systems to easily be brought into compliance with NFPA requirements, but it also saves contractors the hassle of valving off a system every 40 gallons. Annual testing is the same as before, as are the steps to switching from an unlisted fluid to listed antifreeze.


freezemaster™ antifreeze is a great freeze protection option for many other types of systems. For example, freezemaster™ antifreeze is listed for use up to 500 gallons in NFPA 13R, 13D, Light Hazard systems, and up to 40 gallons in Storage applications. Along with its unique Ordinary Hazard listing, freezemaster™ antifreeze is the only antifreeze listed for use in galvanized piping systems. Additionally, freezemaster™ antifreeze does not have minimum design pressure requirements, unlike a competitively listed antifreeze that requires a minimum operating pressure of 20 psi at the most hydraulicly remote sprinkler, in addition to the hydraulic calculations. You can find all the details, including volume allowances of freezemaster™ antifreeze across applications, in our Installation Guide. Always reference the antifreeze manufacturer’s installation guidelines, as listings can vary across products.

Simplify the Switch with freezemaster™ antifreeze

freezemaster™ antifreeze is the sprinkler industry's most popular listed antifreeze for a reason. Our unique volume listing, superior corrosion protection, and blue color for easy visual verification during system flushes aim to simplify installation and maintenance as much as possible as you work to meet the NFPA 25 deadline.

Need more information or support for your project? We’re ready to help.


Freezemaster Technical Support