Frozen Fire Sprinkler Pipes: Prevention and What to Do After a Burst

A sprinkler pipe above the ceiling of a closed office freezes on a Saturday night. On Sunday afternoon the temperature climbs, the ice melts, and the cracked fitting opens up. By Monday morning water has run through two floors.

Frozen fire sprinkler pipes can shut a building down for days. Here’s why they freeze, where to check before a cold snap and what to do in the first hour if one bursts.

Why sprinkler pipes freeze

Most sprinkler systems are full of water all the time. That way they’re ready the second a head opens. But water in a cold pipe can freeze. The National Fire Sprinkler Association says water-filled sprinkler piping must be kept at a minimum ambient temperature of 40°F. It also calls frozen piping one of the most common winter service calls.

Spaces that can’t stay at 40°F usually get a dry system or an antifreeze system instead. Those need care in winter too. A national standard called NFPA 25 covers how all of these systems get checked and maintained.

Where frozen sprinkler pipes usually happen

NFSA lists common trouble spots that are easy to miss in summer:

• Vestibules and entryways.
• Stairwells.
• Unoccupied rooms and mechanical spaces.
• Attics and areas with skylights.
• Poorly insulated wall cavities.

NFSA also warns that a warm spell followed by a sudden cold snap is when systems freeze unexpectedly. Its winter post opened by pointing to minus 24 degree temperatures in Minnesota.

Before the first hard freeze, walk these spots with your fire protection contractor. Low-temperature alarms in the riskiest areas give you a warning before the pipe freezes.

Buildings that sit empty

Vacant suites and buildings that close for the holidays are at higher risk. Heat gets turned down, nobody walks through and a frozen pipe can go unnoticed for days. Check the thermostat settings and have someone walk the space during cold spells.

What to do in the first hour after a sprinkler pipe bursts

1. Get people out of the wet area

Water and electricity don’t mix. Keep people away from ceilings that sag and from wet electrical equipment.

2. Call your fire protection contractor and alarm company

A burst pipe usually sets off the alarm, and the fire department may come. Let your sprinkler contractor or trained staff shut the system down. While it’s off, the building has no sprinkler protection. Fixing the system is their job.

3. Protect what you can

Move inventory, files and electronics out of the water’s path. Cover equipment with plastic.

4. Take photos

Photograph the broken pipe, the ceilings, the floors and damaged inventory before cleanup starts.

5. Call a restoration contractor

Sprinkler water spreads fast. It soaks ceiling tiles, drywall, insulation and floors. The sooner drying starts, the less has to be torn out.

Cleaning up after frozen fire sprinkler pipes burst

Kiser Construction handles the water damage while your fire protection contractor fixes the system. We extract water, remove ceiling tiles and wet materials that can’t be dried, dry the structure and track moisture readings every day. Then we rebuild. Our fire sprinkler water damage page covers the full process.

We work on commercial buildings of any size, and we phase the job so you can keep part of the building open. Loud work moves to evenings and weekends where the building allows it. Read more about our commercial restoration services.

We photograph the loss, log moisture readings daily and write a scope your adjuster can follow. We don’t interpret your policy or adjust your claim.

What to save for the claim

• Photos of the broken pipe and every wet area.
• The sprinkler contractor’s repair report.
• A list of damaged inventory and equipment.
• Our daily moisture readings and written scope.

Homes have frozen pipes too

If you’re dealing with a frozen pipe at home rather than a sprinkler line, see our page on frozen pipe damage repair.

Common questions

Call us

Frozen fire sprinkler pipes don’t wait for business hours. If a sprinkler line burst in your building, call (612) 518-8852. A real person answers 24/7, including holidays. To plan a commercial project, call our Elk River office at (763) 633-2010.