There are two major types of fire sprinkler systems; wet pipe and dry pipe. Wet pipe systems means the sprinkler pipes are always filled with water. Dry pipe systems means that most pipes are filled with pressured air – these systems may contain some water from condensation or improper draining of the system after testing.

When water inside pipes freezes, the ice will expand and that expansion can break pipes and fittings, causing leaks and loss of water or air pressure (loss of air pressure in a dry pipe system will cause water to flow into the pipes). The expansion could also force open sprinkler heads, causing accidental activation when these pipes thaw out. All wet pipe and dry pipe control valves must be kept at 40 degrees Fahrenheit to prevent freezing. NFPA 25 requires a daily inspection of enclosures to monitor temperatures around dry-pipe valves. If you have a low temperature alarm installed, then a weekly inspection is required.

If leaks are suspected, the best and easiest way to determine the location of these leaks is through visual inspection. Inspect every piping joint and sprinkler head on the entire system and while doing so, try to determine how well the sprinkler heads are connected to the system (DO NOT DAMAGE SPRINKLER HEADS).

If a sprinkler system is leaking water, contact the sprinkler company immediately. Most likely, the sprinkler company will give instructions to shut the water supply off to the system to prevent or reduce the water damage to the facility. If the sprinkler system is not in full service within 4 hours the facility is required to institute a fire watch. (It would be prudent to start a fire watch prior to this time frame if you know it could be some time before the sprinkler system is on line again.) When instituting a fire watch, the facility is required to contact the Section for Long-Term Care Regulation and the local fire authorities in order to coordinate a response to any fire event.