Fighting Fires in Buildings With Sprinkler Systems
The Volunteers Corner
The constant movement of industry to rural areas makes it increasingly important for all fire departments to make the use of sprinkler systems part of their training program. Supplementing the sprinkler system water supply with water from a pumper is the first step in the attack on fire in a sprinklered occupancy.
The first-in engine company should connect parallel lines to the sprinkler Siamese, stretch to the nearest hydrant and start pumping. With the production of a large amount of smoke by even a modest size fire, you may not know exactly where the fire is when you reach the building. But the sprinkler system does, and heads already are putting water on the fire. Therefore, you can buy some time for getting men and equipment into the area by having the first-in engine company make certain that the sprinkler heads do not run out of water.
But first, a word of caution. If some buildings in your area are only partially sprinklered, make certain that this has been noted in pre-fire plans given to the first-due companies. It doesn’t make much sense to commit an engine to supplying a sprinkler system when the fire is in an unsprinklered area. In that case, the first-in engine company should make a quick attack directly on the fire, and if the sprinklered area is threatened, then another engine can supply the sprinkler system for that area.
Pressure at Siamese: If the engine supplying the sprinkler system is reasonably close to the sprinkler Siamese, an engine pressure of 100 psi is generally recommended, although NFPA Standard No. 13E, “Recommendations for Fire Department Operations in Properties Protected by Sprinkler and Standpipe Systems,” advises 150 psi at the pump. The lower pump pressure is used as a precaution against excess pressure in old sprinkler system piping.
Parallel lines to the Siamese have two advantages. They assure the capability of flowing double the amount of water that one line can provide, and if a hose bursts, the other line can continue to feed the sprinkler system.
In making his size-up, the first-in officer must observe the effect the sprinklers are having on the fire and if no heads are operating, he must make certain that any sectional OS&Y or post indicator yard valves are open. Their locations should be noted in the pre-fire plan.
Shutting off sprinklers: The only man who should give the order to shut down a sprinkler system or a section of it is the officer in charge of the fire. The fire fighter who closes the valve should remain at the valve until overhauling is finished and the companies are ready to leave. This is to ensure immediate restoration of the sprinkler system in the event that the fire breaks out again during the overhaul.
The fused sprinklers may be shut off individually to minimize water damage. Either sprinkler tongs or wooden wedges are used to plug the open sprinkler heads and leave the other heads ready to operate.
Sprinkler wedges can be made from 1-inch (actually 3/4-inch) pine or other soft wood. The wedge should be 6 inches long and shaped like a door stop, 1% on one end and tapered toW inch on the other.
Restoring sprinkler system: There are two schools of thought on restoring a sprinkler system to operating condition after a fire. Some fire departments replace the fused heads and reset the sprinkler valve. This might lead to legal difficulties if the sprinkler system later failed to operate properly.
The better course, I think, is to tell the owner or tenant that he must have his sprinkler maintenance service restore the system as soon as possible and he must keep a watchman in the area until the system is operable. The watchman should have ready access to a telephone and know the fire department number so that there will be no delay in reporting another fire in the area—or a rekindle.
If conditions make it advisable for fire fighters to replace a few sprinkler heads, the replacements must be the same color (indicating fusing temperature) as the original heads. But the system should still be checked out by qualified sprinkler service personnel.
Overheating of pump: When supplying sprinkler systems, pump operators should know if water is actually passing through the pump. If a sprinkler valve is closed or the check valve associated with the Siamese fails to open for any one of several reasons, then no water will flow through the pump, which will begin to heat. To avoid overheating the pump, open one or two hose gate bleeder valves (or attach a length of hose to a gate) to discharge water to the ground.
An operator can tell if water is flowing through his pump by closing a hose gate. If the pressure remains the same, no water has been flowing through the pump. If water has been flowing, the pump pressure will rise as the gate is closed.