Dry Standpipe Supply Operations

For urban areas, standpipe operations are basic day-to-day operations that must be understood and kept simple so that in the heat of the fire, water can be delivered at the pressure and volume needed to mount an effective fire attack.

Pre-fire planning of buildings is great if time allows. However, we know that such is often not possible. With this fact in mind, we must be prepared to use dry standpipe systems that could be as tall as thirteen stories or more, depending on the age of the building, and have a basic effective method identified to supply such Fire Department Connections (FDC).

Sseveral methods are used in the fire service to charge dry standpipe systems. Some pump instructions advise pumping into the FDC at pump-idle pressure. Another method recommends an established pump r.p.m. setting.

My experience with fire apparatus has been that neither of the above methods worked effectively nor did they produce uniform results among different apparatuses. Each engine type can have different idle pressures, resulting in different static pressures when a supplied dry standpipe system was filled. But this means more math and thinking on the fire ground, which, when added to other considerations on the fire ground, runs counter to the basic fire-service principle: “Keep it simple.”

Establish the flow rate, determined by your handline nozzle choice, and pressure desired at the fire floor. The basic rule of thumb here is 100-psi nozzle pressure, with a desired minimum fire flow rate of 150-gpm. Factor in friction loss for the diameter of hose being used on the fire floor and the standard length of that fire-floor hose. Factor in 25-psi friction loss for the FDC, with the assumption that your standpipes will be flowing more than 350 gpm. Add in friction loss for the standard number of hose lengths supplying the FDC, which should be a minimum of two for any working fire.

This will be your pump panel starting pressure. The pump operator need only factor in the head pressure that must be overcome by adding 5 psi per floor for the number of floors to the fire floor. Different references will subtract or count the first floor — a minor consideration. (Continued below box.)

Example:

Fire floor hose: 1¾ inches, hose pack length of 100 feet

FDC supply hose: 2½ inches, minimum two, each 50-foot length

Friction loss of 22 psi: Used for 1¾-inch hose, reference Angus Fire North America Hi Combat II. (This hose type uses a through-the-weave liner. Should your fire agency not have it, you need to use 30 psi per 100 feet for friction loss. Your hose supplier can advise, should you not know.)

Friction loss of 12 psi: Used for 2½-inch hose, reference Angus Fire North America, double jacket

Fog nozzle tip pressure: 100 psi

Solid bore nozzle pressure: Consideration should be given to pressure regulation at the standpipe outlet control valve.

2½-inch fire attack hose: Friction loss is considered 12.5 psi per 100 feet

100 psi NP (fog)
+22 psi FL fire floor 1¾-inch small line.
+25 psi FL FDC
+12 psi FL 2 ½” supply hose
160 psi (rounded off)
+ 5 psi HP per floor to fire floor
_ = Engine pressure

(FORMULA KEY: NP=nozzle pressure; FL=friction loss; EP=engine pressure; HP =head pressure; FDC=fire department connection)

The supply engine moves within 50 feet (if safe to do so) of the Class I standpipe FDC to lead a minimum of two 2½-inch (in San Francisco 3-inch) supply lines into the Class I dry standpipe Siamese. Immediately supply the standpipe from the engines 500-gallon tank supply via two leads with 160 psi.

Make sure you have removed all inlet caps. Once you have charged the standpipe, if there is a leaking clapper valve in an inlet, you won’t be able to remove that inlet cap that has not been removed when the pressure has been applied to the standpipe system.

Charging the standpipe should be done whenever there is smoke showing or other reasonable indication of a working fire. Investigation mode requires a minimum of a dry supply line hooked up with the engine ready to supply at any indication of a working fire.

Supply one pump discharge supply at a time, slowly opening the discharge gate as the standpipe fills. The key point is opening the discharge gate slowly, to avoid water hammer in the standpipe system.

The master pump pressure gauge will drop down to about 60 psi as the standpipe fills. This is because the effect on the pump is as if it were pumping through an open coupling and therefore moving a large volume of water, which will take about 30 seconds. When the standpipe is filled, the pump’s static pressure will come back up to 160 psi. Note the rpm to create this pressure discharge. This will be your starting pressure. To finish the fire ground math and achieve your overall engine pressure setting, add 5 psi per floor to the fire floor to overcome head.

With this procedure, the standpipe will be charged long before the initial attack team has been able to connect to an outlet to begin their hose stretch and fire attack.

Should the static pressure not return to the established starting pressure within the 30-second time, the pump operator needs to realize that a standpipe outlet is either open and flowing water out into the building or the standpipe has failed in some other way. Consideration needs to be given to shutting down the supply until this situation has been investigated. The IC and attack team need to be made aware of this immediately.

Prior to admitting external supply to the fire engine, the pump operator must throttle the pump pressure down to 60 psi, admit external supply, and then adjust back to fire floor engine pressure.

Throttling down to 60 psi is advised with the realization that, in most municipal areas, 100 psi or higher hydrants are common.

Suction supply should always be into the main suction inlet, not the gated or auxiliary suction inlet. Such auxiliary inlets are greatly restricted in their size, whereas the main inlet quickly forms into a six-inch rectangular inlet for maximum suction supply.

The pump operator needs to be prepared to supply additional FDC supply lines should the fire progress beyond the room-and-contents size. Constant attention to the residual pressure showing on the compound gauge is needed in order to know if the pump has the ability to supply additional FDC supply lines, and/or the need for the pump operator to secure an additional suction supply into his/her pump.

DRY STANDPIPE SUPPLY OPERATIONS