March-April 2009 Issue

	March-April 2009

Estimating the Stretch

By the late Andrew A. Fredericks

Reprinted from the June 2000 issue of Fire Nuggets

We have previously discussed the selection of handlines based on required fire flow and proper placement of the first handline to ensure its effectiveness as a life-saving tool. In this issue we will present several formulas for estimating the amount of hose needed to reach and cover the fire area.

Estimating a handline stretch is a two-step process. Step 1 is to determine the amount of hose needed within the fire building and Step 2 is to determine how much hose is needed between the fire building entrance and the engine. The objective is to have sufficient hose to reach the most remote room in the fire area without unrolling too much hose, which will increase the required pump discharge pressure, as well as the potential for kinks.

Some fire departments—New York City and Detroit among them—do not use preconnected handlines. Rather, they perform reverse hose lays using "static" or "bulk" hose loads. As an example of how a reverse lay is executed, consider a top-floor fire in a narrow, three-story multiple dwelling. Based on the size of the building, the location of the fire, and the initial position of the engine, the nozzle firefighter and officer immediately remove four lengths of hose. (A length is considered to be 50 feet, although some fire departments use 100-foot handlines.) Why four lengths? The distance between the entrance door and the point where the engine initially stops, just past the fire building, is about one length of hose. Three more lengths are needed in the fire building to reach and cover the "railroad flat" apartment on the third floor.

Once the hose needed for the fire building (plus one additional length to reach the building entrance from the street) is unloaded, the apparatus operator (chauffeur or engineer) drives to the nearest serviceable hydrant as additional lengths play out of the hose bed. If the engine is already positioned at a hydrant when the order to stretch is received, the hose needed to reach the fire building is determined by "eyeballing" it. Landmarks such as parked autos, sidewalk markings, building widths, and lot dimensions may be used to gauge the amount of hose required.

The use of preconnected handlines requires that the engine apparatus be positioned close to the fire building (generally within a length or two). Both parts of the stretch—the hose needed to reach the fire building and the hose needed inside the fire building—must be properly estimated. Particularly when engine apparatuses are equipped with preconnected lines of various lengths, deciding which line to "pull" requires a sound foundation in handline estimation. While an extra length of hose is rarely a problem and acts as an insurance policy, not stretching enough hose can be disastrous. Stretching "short" is probably the most common mistake made when employing preconnected handlines.

Obviously, having enough hose to reach the fire building is important, but it is actually the second step in the handline estimation process. The first step is to estimate the amount of hose needed within the fire building and to ensure this amount of hose is removed from the engine. The question then is how do we determine this amount of hose? Since there are many families of buildings that share similar characteristics, developing hose estimation formulas beforehand is fairly straightforward. Generally speaking, hose estimation formulas depend on a building's frontage, depth, and stair configuration.

For small multiple dwellings, the fire floor is the key. A fire on the third floor of a small apartment house would require three lengths of hose. A fourth-floor fire would require four lengths, and so on. This formula may be referred to as the "fire floor formula," and it works well for multiple dwellings with a frontage of 40 feet or less and depths up to about 85 feet.

In the case of large multiple dwellings (up to 100 feet by 100 feet or more), the fire floor formula is adjusted to compensate for the larger apartments, longer hallways, and enclosed stairways. The fire floor is still the key, but another length is immediately added to the hose estimate. This might be called the "fire floor plus one" formula. A fourth floor fire in a large multiple dwelling would warrant at least five lengths of hose within the fire building in order to avoid a "short stretch." If the building has a large lobby, a sixth length would be added in order to reach the base of the stairs from the entrance door.

Some large apartment buildings are divided into wings. Each wing may resemble a small multiple dwelling with its own entrance door and stairway. If this is the case, the "fire floor formula" may be appropriate. Large multiple dwellings may also feature deep exterior courtyards that will necessitate additional lengths. The best way to determine how much hose will be required is to calculate it in advance during drills or a trip to the building specifically for pre-fire planning purposes.

Handline stretches can also be modified based on the presence of a well hole. A well hole is an opening in the center of a stairway that allows a single length of hose to reach from the base of the stairs to the fifth floor. In addition, lines can be stretched utilizing hooks (pike poles) or utility ropes on the outside of the building. Utilizing a utility rope is a particularly effective tactic when the stairway wraps around a dumbwaiter or elevator shaft. Knowledge of your response area is vital.

For private dwellings, between one and three lengths of hose should be sufficient. In the case of both private dwellings and attached "town homes" (sometimes called "row frames"), always ensure sufficient hose is stretched to cover the entire building. Fires in these buildings travel quickly through void spaces and interior shafts, as well as on the outside of the building, which is often covered by wood or asphalt siding.

Hose estimates for commercial buildings can vary widely, but two or three lengths will cover most small retail stores. A rule of thumb is to add the street frontage and the depth of the occupancy in order to obtain a hose estimate. In the case of a hardware store that is 50 feet wide and 80 feet deep, 50 + 80 = 130 feet. This is almost 150 feet, so three lengths of hose should be available for the store. This will account for the necessary bends and turns as the line is advanced.

Like all firefighting operations, planning and training are essential for accurate handline estimation. For years, engine companies in New York City have operated under the credo: "take the time to make the time." A few moments taken before placing a handline in service to ensure the proper amount of hose has been unloaded will pay huge dividends in terms of fire attack safety and efficiency.

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