NFPA’s September 30, 2022, deadline specifies that all wet sprinkler systems must use factory pre-mixed, UL-listed antifreeze. Listed antifreeze addresses important life safety concerns associated with unlisted fluids. To ensure optimal performance, qualified ITMs will subject a listed product like freezemaster™ antifreeze to many different tests, including testing the refractive index using a refractometer.

What is a Refractometer?
A refractometer is a common tool for testing a liquid’s refractive index (RI), or how much a material bends light, which confirms that the liquid hasn’t thickened or been diluted. Refractometers are an essential tool for testing factory pre-mixed, UL-listed antifreeze to ensure that the product is performing as designed and tested to help save lives and property.

Choosing the Right Refractometer
Refractometers are a common tool among ITMs. A lab benchtop refractometer has excellent resolution, but a handheld device is easy to transport and use in the field. The guide offers advice on selecting the best refractometer for your usage needs.

Testing freezemaster™ Antifreeze with a Refractometer
Essential to maintaining any listed antifreeze product on your property is careful attention to the manufacturer’s installation guide. The guide will contain information on the correct refractive index value for the product when tested at a given temperature, as thermal changes affect the refractive index your refractometer will read. Proper testing can help ensure life safety and can help avoid unnecessary system drain, flush and refills.