Phoenix Fire & Systems
An antifreeze sprinkler loop needs a test every year before freezing weather. An older factory premixed solution that is within the strength limits can stay. A refill, or a solution that is too strong, takes a listed antifreeze solution. Have a person qualified for that work test the loop early in the fall, so there is time to fix what the test finds.
What an antifreeze loop is
Most commercial buildings use wet-pipe sprinklers, with water in the pipes at all times. Where a small area cannot be kept warm, such as an unheated vestibule, a loading dock, a canopy, an attic, or a cooler, a short section of piping may be filled with an antifreeze solution instead of plain water. That section is the antifreeze loop. It usually connects to the wet system through a valve and backflow arrangement.
Dry-pipe systems are different and have their own winter prep: see dry-pipe sprinkler winterization.
What the annual test involves
NFPA 25 (2023 edition, as adopted in Ohio) requires the antifreeze solution to be tested every year before freezing weather. A person qualified for that work takes samples from the top and bottom of the loop and checks the concentration. A solution that has separated, been diluted by water, or drifted out of range may not protect the piping when temperatures drop, and it may not perform as intended in a fire.
The contractor records the results, notes any deficiencies, and tells you what needs correcting. If the loop needs work, it is far easier to schedule in early fall than after the first hard freeze.
Is your old antifreeze still allowed?
Under NFPA 25 (2023 edition, as adopted in Ohio), an older antifreeze solution can stay in an existing system only if it is a factory premixed solution within set strength limits. If the system is drained, or the solution is too strong, it must be refilled with a listed antifreeze solution. Many older loops were filled years ago, some with solutions mixed on site.
If the test shows the solution is too strong, or the contractor cannot tell what type of antifreeze is in the loop, NFPA 25 calls for draining the loop and refilling it with a listed antifreeze solution. That is contractor work. It involves handling and disposing of the old solution and putting the loop back in service correctly.
What the owner does
The building owner stays responsible for making sure inspection, testing, and maintenance happen. See building owner sprinkler ITM responsibilities for the full picture. For antifreeze loops specifically:
- Know where every loop is. Docks, vestibules, and canopies are easy to forget.
- Schedule the annual test early, before cold weather.
- Keep the test results and any refill records with your sprinkler paperwork.
- Do not add antifreeze yourself, and do not top off a loop with water.
- Call your contractor if you see leaks, a damaged pipe, or a valve that looks out of position near a loop.
Where this fits in the full schedule
The antifreeze test is one item in the larger NFPA 25 schedule. For annual and longer-interval sprinkler work, see NFPA 25 sprinkler inspection.
Phoenix Fire & Systems tests and refills antifreeze sprinkler loops. Call (937) 637-7768, or see fire sprinkler service and request a quote.
