Water Flow Alarm

Water flowing through pipes of a sprinkler system causes the transmission of a water flow alarm. A water flow alarm can be triggered by a fire, causing a sprinkler head to discharge water, or a leaking sprinkler system due to frozen pipe expanding and breaking, or a worker accidentally damaging a pipe in the system. A water flow alarm can also be triggered when there is a water pressure surge in the sprinkler system. A so-called pressure surge is a temporary increase in water pressure inside a water main that supplies a sprinkler system. The momentary increase in water pressure causes an alarm valve to temporarily open and shut. This temporary opening and closing of the alarm (clapper valve) causes a water flow alarm to be transmitted to the alarm company, which relays the information to the fire department. The problem presented to the incident commander responding to a water-flow alarm is determining whether this alarm is being caused by a sprinkler discharging on a fire, by a broken sprinkler system or by a pressure surge. A search of the building is required when there is an alarm of water flow. If the exact cause of the water flow alarm is not determined and the fire department leaves the scene, a disaster may occur. For example if the cause of the water flow is a fire and it is not discovered, the fire may grow. If the cause of the water flow alarm is a broken pipe and it is not discovered, there will be flood damage to the property.

A thorough search of a building must be conducted to locate the cause of a water flow alarm:

First - Check the alarm panel to pinpoint, if possible, the exact floor of the water flow alarm and search this area. In many buildings the exact location or floor is not indicated on the alarm panel; it just shows a water flow alarm somewhere in the building.

Second -By radio or telephone, contact the alarm company and ask it to reset the alarm, and then see whether the system stays reset or another water flow alarm triggered. If the alarm comes on again, this would indicate water is continuing to flow in the system and the cause was not a pressure surge. There may be either a fire or a leak. Or it could also indicate a defective alarm.

Third - Search the building. Start in the cellar; examine the sprinkler water pumps. If there are no water pumps, check the water main feed gauge. See if there is water flowing into the sprinkler system from the water main: Feel the pipe for vibration, listen to the pipes for flowing water by putting your ear to the pipe.

Fourth - Send a firefighter to the roof to check for a gravity tank supply; check this for water flow to the sprinkler system. Water flow can sometimes be heard indicating water from the tank is supplying water to the sprinkler. Water leaking on the roof from an overflowing gravity tank can be the cause of a water flow alarm if there are no leaks and no water sounds, check over the sides of building from the roof and check the shafts for signs of smoke coming out a window of a lower floor. Also, look for water discharging from a water scupper or side wall drain.

Fifth - The firefighters after checking the roof, walks down the stairs, checking each door for sounds of a sprinkler discharge or smell of smoke. During or after freezing weather, sprinkler piping on outside truck-loading platforms, unheated stairs and halls should be examined for frozen and leaking pipes.

Sixth - A person from the sprinkler alarm company should be requested to respond. That person should check the alarm for possible defects and proper working parts. Locating a cause of a water flow alarm is difficult and time consuming. It must be done thoroughly. It takes time patience and experience.