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Testing UL-Listed Antifreeze

By: Lainey Liotta on October 11th, 2023

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Testing UL-Listed Antifreeze

Installation  |  FAQs

It’s nearly winter again, and prepping for the cold typically includes testing antifreeze in wet fire sprinkler systems. The typical process for inspecting wet fire sprinkler systems involves:

  • Reviewing that year’s maintenance records.
  • Checking system design specs.
  • Visual inspection.
  • Testing alarm and control valves, water supply and flow.
  • Inventorying spare parts like extra sprinkler heads.
  • Updating all documentation.

The increased adoption of UL-listed antifreeze requires a bit more precision and equipment than testing unlisted antifreezes. When we were only testing unlisted fluids, a freeze point test with a thermometer was enough. If it performed at the right temperature, it was good to go. But the proprietary ingredients in UL-listed antifreeze products mean this method won’t provide accurate readings.

Here are some inspection tips to consider to make sure your system is in tip-top shape.

What You’ll Need (That You May Not Have Needed Before)

Precise, accurate testing requires the right tools for the job. You’ll need:

  • A vessel for holding the drained antifreeze to be tested.
  • A thermometer for confirming tools and liquids at the same ambient temperature.
  • The antifreeze’s installation and maintenance guide.
  • Testing tools.

The testing tools needed for the job depend on the UL-listed antifreeze product in the system (the installation and maintenance guide will specify which you need). For example, one UL-listed antifreeze brand specifies the use of a hydrometer only, which tests specific gravity. While a hydrometer is relatively inexpensive, the manual process is extremely difficult to produce an accurate reading in the field.

On the other hand, other UL-listed antifreeze brands, including freezemaster™ antifreeze, allow the use of a hydrometer or a refractometer, which tests the refractive index. There are several refractometer options, and all are designed for easy, on-site use. Two handheld brands we recommend for freezemaster™ antifreeze are Fisher Scientific’s Fisherbrand™ Handheld Digital Brix/RI Refractometer and MISCO brand handhelds.

Inspecting UL-Listed Antifreeze

The antifreeze testing process includes draining a sample, conducting tests and then replacing the sample. UL-listed antifreeze requires slightly more care to ensure the longest possible service life.

Before and after inspection and testing, thoroughly flush the well of the refractometer. It’s important to use distilled water because tap water has highly variable quality that can skew readings.

Once you arrive on-site: 

  1. Lay out your testing tool to bring it to ambient temperature to ensure the most accurate test reading. 

  2. Visually inspect the pipes and hang tag.

  3. Shut off the water source and drain a half-gallon of antifreeze from the most remote part of the system for testing. Let the test sample come to ambient temperature for the best results. If the system has multiple parts with stark temperature differences, it may make sense to pull half-gallon samples from each remote spot, properly label each, and set them out together to come to ambient temperature before testing. Never pull the antifreeze from near the water source, as this will yield a poor-quality reading.

  4. Test using your refractometer or hydrometer. If the fluid tests within specification, replace the drained UL-listed antifreeze, update the hang tag and continue your fire sprinkler system inspection.

If the sample tests out of specification, NFPA, UL and manufacturer standards are clear: “the system shall be emptied and vacuum-cleaned of any remaining fluid. Recharge the system with fresh listed antifreeze.” Even if the sample tests within the freeze point of your geographical area, the refractometer reading is the most accurate reading and should inform next steps.

It’s also important to note that freezemaster™ antifreeze is the only antifreeze listed for use with galvanized piping systems. If a galvanized system is filled with a fluid other than freezemaster™ antifreeze, a full drain and flush is required to bring the system into compliance before refilling with freezemaster™ antifreeze. How can you tell if the fluid in the system is freezemaster™ antifreeze? One easy identifier is its blue tint; if it’s not blue, it’s not freezemaster™ antifreeze and is not listed for galvanized piping systems.

Best Testing Practices, Longest Service Life

A properly designed, installed and maintained system that uses factory-premixed, UL-listed antifreeze like freezemaster™ antifreeze has a very long service life. And freezemaster™ antifreeze is backed by the expert support of Lubrizol and Viking SupplyNet: Local servicepeople are ready to answer your questions and discuss your use case, especially during annual testing and inspection time.

Our team is ready to help you learn how to choose and use a refractometer for proper testing of UL-listed freezemaster™ antifreeze.

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