Compare Listed Antifreeze

Minimum Pressure Requirement

Why It's Important:

Minimum use temperature often dictates where a listed antifreeze product may be reliably used. But lower minimum use temperatures often require a higher minimum design pressure to push the extra-viscous liquid to the furthest points in the system. Pressure pumps are an extra expense and add complexity to an antifreeze loop.

freezemaster™ antifreeze has NO minimum pressure requirement other than that of the sprinkler head, which can eliminate the need to add a pressure pump. 

Volume Limitations

Why It’s Important:

Listed antifreeze must be able to keep a system from freezing even at its most remote locations. This is why UL puts system volume limitations on products. A higher volume limitation enables larger systems and reduces the number of valved-off sections needed to separate the system into smaller, compliant sections.

Note that the 2023 edition of NFPA 25 allows listed antifreeze to be used outside of its listing when replacing nonlisted antifreeze in an existing system as long as temperature requirements are met. Reference NFPA 25 for more detail.

UL Listing for Galvanized Piping

Why It's Important:

UL 2901 covers antifreeze solutions for use in wet-pipe sprinkler systems and includes compatibility testing with metals like ASTM A108, Grade 1010 steel, ASTM B16, H02 (Half Hard) brass and Type 304 stainless steel, but does not include galvanized steel. This means an antifreeze solution must undergo additional testing to prove suitable performance in galvanized steel piping and earn this extra listing component. Otherwise, the antifreeze could contribute to corrosion in a galvanized system.

freezemaster™ antifreeze sought and passed the additional UL test to become the first factory-premixed antifreeze UL listed for use with galvanized steel piping. 

UL Listing for CPVC Piping

Why It's Important:

There is a common misconception that listed antifreeze is incompatible with CPVC. Unlisted propylene glycol-based anti-freezing mixtures are known to cause a reaction with CPVC’s polymer chain that results in environmental stress cracking (ESC). In the time before listed antifreeze, the solution was to use glycerin-based mixtures in CPVC systems.

All listed antifreeze brands are compatible with and listed for use with CPVC systems. 

All listed antifreeze brands have been tested and proven compatible with BlazeMaster® CPVC as part of the FBC™ System Compatible Program.

Liquid Color

Why It's Important:

Water runs clear, and rusty water runs brownish or orange. It's difficult, if not impossible, to distinguish antifreeze from water when the two fluids are the same color. Testing different sample amounts would be the only sure method, which adds additional on-site time.

freezemaster™ antifreeze is tinted blue for easy visual identification.

Freeze Point Temperature

Why It's Important:

Differing from minimum use temperature, the freeze point indicates the temperature at which ice crystals begin to form in the antifreeze solution. The freeze point for all listed antifreeze products is about three degrees Fahrenheit below the minimum use temperature.

Minimum Use Temperature

Why It's Important:

Minimum use temperature is the freeze point of an antifreeze with about a 3 degrees Fahrenheit safety factor. Often, listed antifreeze products with very low minimum use temperatures are very viscous and therefore have higher minimum pressure requirements to ensure performance in the event of fire. freezemaster™ antifreeze is suitable for use in over 40 states in the U.S. and for partially conditioned spaces like temperate small parking garages in the 48 contiguous states and Canada, and has no minimum pressure requirements other than that of the sprinkler head. 

*To achieve these lower minimum use temperatures, these products require a minimum pressure to be constantly maintained, which usually requires the addition of a pressure pump.

Corrosion Inhibition

Why It's Important:

To earn a UL listing, factory-premixed antifreeze products must not cause corrosion to exceed 1.0 mils/year for ASTM A108, Grade 1010 steel, ASTM B16, H02 (Half Hard) brass and Type 304 stainless steel per UL 2901. A UL listing does not require protection against microbiologically influenced corrosion (MIC), a significant challenge responsible for up to 30% of corrosion a system undergoes.

freezemaster™ antifreeze is formulated by the material science experts at Lubrizol and underwent significant in-house testing to ensure a mixture that would not just meet but exceed UL 2901 requirements.

Testing Procedure

Why It's Important:

Testing listed antifreeze is more involved than a simple freeze point test for unlisted fluids. In the field, a hand-held refractometer to measure refractive index (RI) is often a more accurate test than using a hydrometer to measure specific gravity. Always test with clean instruments and with tools and antifreeze at the same ambient temperature.

Volume Calculator Tool

Why It's Important:

Listed antifreeze is more expensive than unlisted, site-mixed fluids. Accurate ordering can save both budget and time. A system volume calculator tool is a value-add support for customers to simplify order accuracy.

freezemaster™ antifreeze is available in 5-gallon buckets, 55-gallon drums or 275-gallon totes from our distribution partners across North America and is the only listed antifreeze brand with this supportive tool.

*As of November 2025