The building in this example
- Type
- Two-story professional office building from the 1980s, about a dozen suites, one owner.
- Sprinklers
- Wet-pipe system: the pipes are always full of water, so any section that freezes can split.
- Weak point
- A mechanical room against an outside wall, heated only by the equipment in it, with a louvered vent to the outdoors.
- Timing
- A long January cold snap over a weekend, with the building closed and the heat set back.
What happened
Illustrative example. Not a real job or customer.
Illustrative example. On Sunday afternoon, the temperature climbs above freezing after three bitter nights. A sprinkler branch line near the exterior louver, which froze and split overnight, thaws and starts spraying. The water-flow alarm reports to the monitoring company, which calls the fire department and the owner's after-hours contact.
- Firefighters confirm there is no fire and, with the owner's maintenance contractor on the phone, close the system control valve and drain the affected zone.
- Water has run under the mechanical room door, into the first-floor corridor and into two suites. Ceiling tiles in the suite below a second-floor riser are also wet.
- The owner arranges a fire watch, as the fire department requires, until a licensed fire-protection contractor replaces the split pipe and restores the system the next day.
- A water mitigation company extracts the corridor carpet, removes wet ceiling tiles and the bottom of affected drywall, and sets drying equipment.
- The owner notifies tenants by email on Sunday evening, telling them which suites are closed on Monday and what to do about computers and files in the affected rooms.
Because the alarm was monitored, water ran for well under an hour. The corridor and two suites were dried and repaired within about two weeks. The owner later insulated and heated the mechanical room wall and closed off the louver in winter.
What owners can take from it
Sprinkler pipes freeze in the same places water pipes do: against exterior walls, near vents and louvers, above ceilings in unheated spaces, and in rooms where the heat is turned down. A building that is closed and set back over a holiday weekend during a cold snap is exactly the risk.
A monitored water-flow alarm limits the damage. Without one, a release in a closed building can run until someone walks in on Monday. If your building has sprinklers, it is worth knowing whether the alarm is monitored, who gets called, and whether that person can get to the building at night.
Before the next cold snap
- Walk the building with your fire-protection contractor and mark any sprinkler piping in cold spots.
- Keep heat in mechanical rooms, stairwells and above-ceiling spaces, not just in occupied suites.
- Confirm the monitoring company has a current after-hours contact list.
- Know where the control valve is and who is trained and allowed to close it.
- Have a tenant notification template ready for a closure.
Common questions
Why not use a dry-pipe system everywhere?
Dry systems are used in unheated areas but are more complex and costly to maintain. Most heated buildings use wet-pipe systems and rely on keeping the pipes warm.
General information for Englewood, not a quote or professional advice. In an emergency, call 911.