Keeping fire sprinkler pipes from freezing: a winter checklist for NJ buildings.
A frozen sprinkler pipe causes two problems at once: it can split and flood the building when it thaws, and a frozen section may not deliver water in a fire. October is the time to walk your building, before the first hard freeze reaches Warren County and the rest of North Jersey.
Why sprinkler pipes freeze
Most sprinkler systems in homes and smaller commercial buildings are wet-pipe systems: the pipes are full of water all the time, so a head can open the moment it senses heat. That's what makes them reliable, and it's also why any part of the pipe that runs through a cold space can freeze.
Water expands as it freezes. In a closed sprinkler pipe that pressure has nowhere to go, so fittings crack, pipes split, or a sprinkler head is pushed open. Often nothing shows until the ice melts, and then water pours out at full system pressure.
Buildings in unheated or partly heated areas sometimes use a dry-pipe system instead, where the pipes hold pressurized air until a head opens. Dry systems are built for the cold, but they can still freeze if water collects in low spots inside the pipe.
Where to look first
Walk the building and look for sprinkler pipe in any space that can get cold. The usual trouble spots:
- Attics and the space above top-floor ceilings, especially where insulation has been moved or is thin over the pipe.
- Exterior walls and soffits, including pipe that runs close to the outside sheathing.
- Garages, loading docks and vestibules, where doors open to the outside all day.
- Stairwells, crawl spaces and mechanical rooms that aren't on the building's main heat.
- Vacant units, closed-off wings and seasonal spaces where someone turned the heat down to save money.
- The sprinkler riser or valve room itself, if it's on an outside wall or has a door to the exterior.
- Pipe near broken windows, open vents or gaps where cold air blows straight in.
What owners and managers can safely do
- Keep heat on in every space that has wet sprinkler pipe, all winter, including vacant units, storage rooms and closed areas. Set thermostats so they can't be turned off by tenants or staff.
- Close and latch doors, windows and vents near sprinkler pipe. Repair broken glass, failed door closers and torn weatherstripping now, not in January.
- Don't move or remove insulation around sprinkler pipe in attics or ceilings. If work has been done up there, have someone check that the pipe is still on the warm side of the insulation.
- Make sure the riser or valve room is heated, the door closes, and nothing is blocking access to the control valve.
- Know where the sprinkler control valve is and who in your building is allowed to operate it. Write it down where staff can find it.
- Keep the phone numbers for your alarm monitoring company and your sprinkler contractor posted near the riser.
- Watch for warning signs: frost or sweating on a pipe, a sprinkler head with ice on it, stains on ceiling tiles under sprinkler lines, or a trouble signal on the fire alarm panel.
What not to do
- Never use an open flame, torch or heat gun on a sprinkler pipe or head. Sprinkler heads are designed to open with heat, and flame can also start a fire inside the ceiling.
- Don't shut off or drain the system yourself to avoid freezing. A building without working sprinklers is unprotected. Shutting a system down usually involves notifying your alarm company, the local fire official and often your insurer, and a qualified contractor should handle it.
- Don't hang anything from sprinkler pipe or paint sprinkler heads. Both can stop the system from working properly.
- Don't drain dry-pipe low points or auxiliary drains unless you've been trained. Opening the wrong valve on a dry system can trip it and fill the pipes with water, which is exactly what you're trying to avoid in the cold.
If a sprinkler pipe has already frozen or burst
- If water is pouring from a broken pipe or an open head, close the sprinkler control valve only if you know where it is and are authorized to operate it. Expect the alarm to sound and the fire department to respond.
- Call your alarm monitoring company so they know what is happening.
- Keep people away from water near electrical panels, lights and equipment.
- If you see frost on a pipe but no leak, keep the area as warm as you safely can with the building's normal heat and call a sprinkler contractor before it thaws.
- If there is any sign of fire or smoke, get everyone out and call 911.
- If you smell gas at any point, leave the building and call your gas utility or 911 from outside.
A frozen or damaged sprinkler system should be repaired and put back in service as soon as possible. Until it is, ask your local fire official what is required to keep the building occupied safely.
Homes with residential sprinklers
Many newer homes in Hunterdon, Morris and Somerset counties have residential sprinkler systems. The same rules apply on a smaller scale: keep the heat on, keep attic insulation over the pipe, and don't let a vacation or a vacant rental sit unheated. If you're leaving for the winter, ask a contractor what your particular system needs before you go.
Get it checked before the cold sets in
If you've added rooms, closed off space, changed the heat, or noticed any of the warning signs above, have the system looked at now. New Ark designs, installs and repairs residential and commercial fire protection systems alongside plumbing and HVAC, so the heat, the insulation and the sprinkler pipe can all be checked by one contractor.
Call 908-454-4043. Every call is answered 24/7 and emergencies go first. Or see fire protection and sprinklers.