Preconnected Hose Lines
departments
Gene Carlson’s Volunteers Corner
Preconnected hose lines are the most commonly used tool in initial fire suppression. These range in size from 3/4-inch booster line to the 3-inch blitz line. There is great controversy over the use of booster lines, however. In order to assure success and speed extinguishment, it is necessary to attack structural fires, even if confined to one room, with no less than a I 1 1/2-inch line. A major reason for this is to provide an adequate defense for the remainder of the building. Too many fire departments forget to consider the potential fire area of the entire structure. If the fire spreads, these departments then find themselves with a line much too small to deliver the required water.
This is espec ially common in commercial buildings where a small preconnect is pulled when, based on the building size, 2 1/8-inch or larger line is necessary to provide an insurance” delivery and assure a quick knockdown. In many cases although the small line may put out the fire, the time involved, the beating the fire fighters are subjected to, and the additional damage (from the longer water application and longer burning time) indicate a larger line is much more effective.
Rule of thumb: As a general rule of thumb the following line sizes are recommended.
Booster lines: Outside fires, mop-up and possibly on fires of less than one room if the potential of the building is small.
1 1/2 and 1 3/4-inch: One to three rooms in residential and small commercial buildings.
2 and 1/2-inch: One floor in residential and small commercial buildings, several rooms in large commercial buildings, and large open areas.
Remember, however, when determining the size of line to use, always consider the potential fire area in the structure and take a line large enough to handle the fire if it gets away
Most fire companies carry their preconnects in transverse or rear hosebeds loaded in a manner that permits removing the entire load quickly. The problem encountered here is that many of these loads must then be dragged to the fire area. Often a fire fighter is seen running with the nozzle toward the fire building from a pile of “spaghetti” beside the pumper. Someone must hurriedly straighten out the hose and drag additional working line to the entrance.
More efficient: A much more efficient (and energy conserving) method of advancing a preconnected line is to bed it in a shoulder carry so that it can be carried rather than dragged. Several loads can be used depending upon the size and arrangement of the available hosebed. For longer preconnects a combination of shoulder load and drag may be desirable in order to maintain a one-person operation. The method of loading the hose should provide a simple yet expeditious means of removing the hose from the apparatus. The amount of time to bed the hose is not important – the time to remove it, stretch it, get water through it and on’ the fire is important.
In a previous issue this column discussed positioning lines to cut off fire spread and protect interior exposures, another reason for being able to shoulder-load and carry the preconnect. It is essential that the preconnect be used to meet the fire head on and cut it off, not get behind it, chase it or, worse yet, push it.
Proper attack: Once in position the attack should be properly made. This means applying the water for rapid efficient extinguishment. A combination attack should be used with a 30-degree fog pattern. Application should start at the ceiling level in an O, I, T or Z motion. This initiates steam buildup and brings the stream to the base of the fire to complete extinguishment by cooling the burning materials with a direct attack. The O pattern should begin in the upper left corner and continue in a clockwise pattern until the fire darkens. In smaller areas the outside edge of the fog pattern should strike the ceiling, walls and floor.
The I and Z patterns sweep the heated ceiling area and then drop to the base of the flames to sweep and cool the burning materials. An additional reason for dropping down is to extinguish embers and burning material on the floor in the path of the fire fighters as they proceed.
The T pattern is more for a small localized fire It crosses the superheated ceiling area and drops to the fire below, such as in an overstuffed chair or sofa. Remember the nozzle must be shut down immediately when the flames darken. Wait briefly and then perform final extinguishment of any spot fires by a direct attack with short bursts from a partially opened nozzle. A good pattern requires adequate nozzle pressure. Determine by testing the engine pressure your department wants for each different length preconnect and train all pump operators to use that discharge pressure.
For ventilation: Once the fire has been blackened the preconnect can be used for ventilation. This is done by creating a venturi for ejection of the smoke by discharging the line out a window. The nozzle should be placed about 2 feet inside the window on a 60-degree fog pattern so that it covers approximately 85 percent of the window area. Ventilation will be rapid and a 2 1/2-inch preconnect can be used for larger areas.
There are three considerations before preconnect can be used in ventilation. First, the water supply must be ample so that water that may be needed in overhaul is not used for ventilation. Second, there must not be anything outside the window that would be damaged by the water. Third, the weather conditions must be such that the water will not cause a traffic or safety hazard.
Preconnected lines can also be used for special applications. Some departments have an in-line foam eductor in the piping to the preconnect so that the line is ready for flammable liquid fires or spills. Others carry a short preconnect on the back step or front bumper for trash baskets, dumpsters or washing down the pavement after an accident. These lines can be equipped with a variable-gallonage nozzle and used on a number of different situations.
Units equipped for pump-and-roll can use a preconnect for a mobile ground cover fire attack. A short preconnected 2 1/2 or 3-inch line can be used to pump off units with large tanks to an initial attack vehicle or to a water supply reservoir.
Extending: Each department should have a procedure for extending a preconnect if this becomes necessary. An extra section or donut roll of hose should be on the apparatus that can be easily carried to the end of the line. The nozzle can be removed, the extra line attached, and the preconnect extended. A hose clamp or field clamp (folding the line back on itself) may be used to clamp the line rather than shutting it down, if preferred. Adequate length problems can be overcome by surveying in advance lot sizes, building lengths and heights, and other access problems before determining the minimum length preconnect necessary.
