Water Application Rate Of Your First-In Pumper
The Volunteers Corner
With enough time, manpower and pumpers, it’s no big deal to eventually pump all the water available in a hydrant system supplying the fireground. Unfortunately, when this amount of fire flow is used, you have a tremendous loss on your record.
Ironically, most fire fighters can tell you the capacity of their pumper, but few can tell you the maximum water application rate of their engine company in the first three to five minutes on the fireground. Yet, the water application rate that the first-in engine company can develop in various periods of time is a vital bit of information that the company officer and the first alarm chief need to determine the strategy for handling the fire.
For example, the first-in engine company at 2 a.m. finds a ground floor store fully involved in fire that looks as though it may or may not have started to extend to the apartments on the upper two floors of the threestory building. There obviously are people sleeping or trying to get out of the upper floors, so there is a rescue problem. The threat of extension, or the actual but unverified extension, of the fire intensifies the rescue problem. While considering these facts and possibilities, the company officer also concludes that a 500-gpm stream can darken down the fire in the store.
Application rate: The company officer must rapidly—we’ll give him a few seconds—review his resources and select alternatives. The first alternative he has to select is where to position his pumper—at the fire or at a hydrant. In order to make the proper decision, he has to know the water application rate his company can develop immediately.
Factors affecting the application rate include the rate of flow of water to the pump—from the booster tank, through inline pumping supply lines from a hydrant, from a direct hydrant hookup and through supply lines from a second pumper at a hydrant— the number and types of nozzles carried, the number of men in the company, and the capability of the second-due engine company.
In the fire situation described, a four-man engine company that has no deluge set would have to man two lines to apply the 500 gpm needed to darken down the fire in the store. With 2 1/2-inch lines, at least one line would have to be looped so the nozzleman could handle it alone and then two man would have a struggle to get the second line in operation while the fourth man operated the pump. Manpower loads would be eased with the use of 1 ¾-inch lines with automatic nozzles.
Meanwhile, time is ticking away. Furthermore, the rescue problem is increasing. Not only the company officer, but also the first alarm chief must consider the time it takes to put the necessary rate of water application on the fire. The first-in company officer must position his pumper where it is most effective not only as an individual unit but also as part of the chiefs strategy.
Learn the facts: Water application rates in terms of gpm, time for their establishment and manpower necessary to develop them have to be determined through drills.
Did your first-in engine have piping that was large enough to permit a 500-gpm drop from the booster tank? If this capability existed and if the engine carried a deluge gun that could be used in its mount on the apparatus, then the officer might well have decided to position his pumper in front of the store, ordered one man to operate the gun while he and another man took a line up the stairs. The quick operation of the master stream would hopefully darken down the main body of fire and buy some time for the two-man hose crew and the second-in company to work on the search and rescue and fire extension problems.
You find out whether your pumper can supply 500 or 600 gpm from its booster tank by trying to do just that during a drill. Have the men work at a normal fireground pace so you don’t get some false data and time the operation from the moment the pumper comes to a stop until a stream is developed.
After you do this several times with two men, try the same evolution with the pump operator working both the pump and the deluge set. Find out whether in your department the average times for one and two-man operation are significantly different. The results will influence your development of a standard operating procedure for this evolution.
Stretching lines: Working with a pump operator and two, three or four men, time the various hose line evolutions you use in your department—and then see if some others might be more effective. How long does it take two men to get a 100-gpm, 1 1/2-inch line—or a 250-gpm 2 ½ or 1 ¾-inch line—in operation on the second and then the third floor? How long does it take to get a line in operation off a standpipe?
Take a look at the fires you have fought during the last several years and select the hose line evolutions most frequently used. What were the flows from these lines?
Set up the drills so that you can determine whether a company can develop a water application rate of 250,500 or even 1000 gpm in one, two or three minutes under the conditions that exist in your municipality. Find out how much more four men can do than three by stretching lines and getting water. Then try five men—or even two if that’s all you generally have.
In the same time and manpower study method, learn how much water you can get over various distances with inline pumping, direct hydrant hookup and through supply lines (the sizes available) from a second pump at the hydrant.