Make First Line the Size You Eventually Will Use
The Volunteers Corner
A good precept to follow in an initial attack is to make the first line stretched the size that the volume of fire will eventually force you to use.
That may sound pretty obvious, but it is a prevalent weakness in initial attacks. The hidden trap is that officers become so accustomed to stretching a 1 1/2-inch line into buildings that they sometimes fail to recognize the 5 percent or fewer fires where a 1 1/2-inch line just won’t do the job. This is where habit blurs vision during size-up.
How do you know when you’ve been had? That’s easy. Think back and try to recall any times when a small line was the first one into a building and later on one or more 2 1/2-inch lines were used—or even a master stream. That’s like opening up a roof after a mushrooming fire has been brought under control.
The other side of the coin is the recollection of the times when a heavy application of water was made initially and a quick knockdown was made. These successes should bolster your confidence in using a large volume of water in the initial attack when the amount of fire requires it.
Demonstrating gpm effect: Hope and optimism cannot be substituted for an adequate water application rate in fighting a fire, and it’s not difficult to demonstrate this on the drill ground. Most drill grounds have a flammable liquids pit that requires two 1 1/2-inch lines for extinguishment and you can make that your testing medium.
Light off such a pit and attack the fire with a booster line. The hose crew can do everything they can think of, but when the volume of fire requires two 1 1/2-inch lines, the booster line can be used futilely until sufficient fuel has burned to leave a fire area that eventually is booster line size. However, there is no need to let the burning continue that long. The men on the line—and others watchingwill soon concede the ineffectiveness of the line.
That’s your cue to point out that flaming materials produce a certain amount of Btu per minute and hose streams are capable of absorbing certain amounts of Btu per minute. The objective is to apply a hose stream that will absorb more Btu than the fire is producing. When this is done, you obtain extinguishment.
Kireground examples: In critiquing the fires you fight, there inevitably will be times when additional hose streams were used. Emphasize why greater volumes of water were necessary and remind the men that they didn’t see flame start to diminish until a couple of 2 1/2-inch lines—or one or more master streams—were put into operation.
The best lessons are the professional initial attacks—by volunteer or paid fire fighters— when the use of a large initial attack line achieves a quick knockdown. It might be the use of a 2 1/2-inch line on a large room or a small store that was fully involved. It might be a deluge set that provided immediate exposure protection to buy time to set up attack lines. Or it might be a large line that protected a stairway so that the evacuation of occupants could be completed.
Point out that the initial line on the fireground may have other purposes than to hit the main body of fire and that the water application rate—the gpm—must be sufficient to attain the line’s objective.
Water damage: Sometimes you hear the objection that a large initial application of water means excessive water damage. There is no need for excessive water damage if you do two things—select the size line and nozzle for the proper water application rate and, most important, shut down the line the moment it has knocked down the fire. After knockdown, you can mop up by reducing the line to a smaller size—2 1/2 to 1 1/2-inch or master streams to hand lines-or you can crack open a nozzle on a 2 1/2-inch line just enough to give you the amount of water you need for overhaul.
Sometimes an officer hesitates to use a 2 1/2-inch line—or even a master stream—for fear of running out of booster tank water in an area without hydrants before more water is available from later arriving tankers or the setting up of a pumper relay.
This puts us back to paragraph 5 and the necessity for an adequate application rate. At 100 gpm, you can work off a 500-gallon booster tank for about five minutes. If the volume of fire is heavy, you will still have fire burning out of control at the end of five minutes and no more water in the tank. On the other hand, a 200 or 250-gpm application rate might well knock down the fire within a minute or less and you will have 250 or more gallons left in the tank for overhaul.
As far as water damage is concerned, try to remember the last time anyone complained of water damage when a building was destroyed by fire. Unless you extinguish the fire, the loss will be total, so your foremost objective must be to extinguish the fire.
It is only after you apply enough water to put out the fire that you have to worry about water damage, and this problem is nicely taken care of by a nozzleman who knows when to shut down. The water application rate in itself has nothing to do with water damage. It’s excessive length of application time that is the culprit.