Basic Theory of Line Placement at Fires
DAY-TO-DAY fire fighting involves a large number of fires which are relatively easy to extinguish and a few fires which are difficult to handle. Difficult fires may involve large buildings or areas or those regardless of size which involve hazardous processes, materials or both. To back up this statement, the National Board of Fire Underwriters Bulletin 148 reports that in fewer than one out of 200 fires are conditions such that powerful streams have to be used, and on even fewer occasions are ladder pipes, water towers, etc., used. Fire departments generally have no difficulty in handling simple fires but they may be weak in handling complex ones. Unfortunately, it is the relatively few which cause the greatest loss of life and property damage. The National Board also reinforces this with figures showing that less than 2 per cent of fires cause most of the loss of life and 70 per cent of the damage.
The rareness of difficult fires rules out the possibility of fire fighters learning how to handle them by experience alone. Regular training in the manipulative skills necessary for the quick assembling of multiple lines and heavy appliances, plus study of the theory of placing such lines provides the only answer to this problem.
The basic purpose of a hose line is to protect lives, confine and extinguish fire. Protection of life takes priority at all times. At small fires fulfilling this purpose is comparatively easy. It is the big fires, those requiring four or more lines, which give commanding officers the most trouble and it is to such fires that this article is directed.
of Line Placement at Fires
Importance of size-up
Is there a reason for placing lines in a certain position, or is it a matter of just guessing? Sometimes commanding officers guess simply because they are not sure of the fire situation or of themselves. They may become confused by the arrival of a large number of fire companies asking for positions. To relieve the tension of the mounting pressure inside themselves they shout an order for a company to take some position or other at the fire.
Such a decision may be a serious blunder. It is often difficult to recall a company from a previously assigned position and that company may be needed desperately at another location just a few minutes later. A commanding officer, who is not sure of the position he wants a company to take, should order it to stand fast while he quickly reviews the fire situation. A logical decision can then be arrived at and the proper orders passed along.
Fire fighting has been described as a science, but this is not exactly true. Science deals in measurable qauntities, immutable laws and principles. Since no two fires are ever alike, fire fighting involves constantly changing problems that can only be met by experience, training and judgment, plus the knowledge of some basic principles.
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It thus becomes an art as well as a science.
The main function of a hose line is to extinguish fire or to protect someone or something from fire (Sketches 1 and 2). This purpose is so academic that fire fighters sometimes lose track of it. There is also a logical pattern to fire fighting which is: (1) Locate the fire. This is not always an easy job and too often men deluge smoke with water. (2) Confine the fire. In simple terms this means to head it off and surround it. (3) Extinguish the fire.
Notice that extinguishment comes after the confinement phase. The parent fire already exists and it is the fire fighter’s duty to see that it doesn’t propagate. Unless life is in jeopardy, the first line or lines should be stretched to head off the fire (Sketches 3 and 4); to protect exposures that are not as yet on fire.
There are two types of exposures. Internal exposure being that which a building offers to itself—from room to room, floor to floor, or inside to outside. External exposure is that which a building offers to another structure. In the great majority of cases confining and extinguishing are almost simultaneous. But in the large fire, confinement presents a serious problem that must be dealt with first.
Here, the fire fighter runs into problems. Planned fire tactics to be used on target hazards within a department’s jurisdiction is one method of reducing the problems, but often two different fires within the same building will present different problems, and require different techniques. It is difficult to draw up set rules in the matter of line placement. The fire officer must therefore be able to think fast and alter any prearranged plan to fit the situation.
In general, where the body of fire is so large as to constitute a difficult extinguishing problem for one line, then stretch another to this same area.
Where the fire may extend because of vertical arteries, then stretch another line to cover the fire from above.
Where the fire is of such intensity that men may be endangered or in serious difficulty because of sudden loss of water, then stretch another line behind them.
Where the fire is threatening to extend laterally (as in a row of stores with common hanging ceilings) stretch additional lines so that extension in either direction is covered (Sketch 5).
Where fire involves hazardous chemicals or volatiles with explosive potential, do not rely on one line. Stretch an additional line or lines to cover firemen and exposures.
Inside lines offer definite advantages over outside lines in most instances, and should be employed wherever possible.
- The nozzle man can see the direction of his stream and whether or not he is on target. He hits fire and not smoke, and as a result there is less water damage.
- If using a fog nozzle, the nozzleman can vary the pattern of his stream as required by changing conditions.
- Nozzleman is in a good position to judge path of fire and extension.
- Rescue is facilitated. In the event this is not complete due to exceptional circumstances, nozzleman may come across unconscious or trapped victims while operating inside the building.
At the same time it must be remembered that outside lines are generally a must for large, fast-spreading fires.
Generally these require a blind operation. Firemen can only guess how much, if any, of a stream is doing a proper job. A large runoff at fires indicates that most of the water is being wasted.
Streams may be entering shaftway windows and water falling into cellar without striking any fire.
- Streams may be hitting partitions and not the center of fire.
- If men are operating inside buildings, outside lines operating simultaneously may injure them or at least drive them from their positions.
- Tremendous water damage may occur if outside lines are not used properly, with the possibility of building collapse if the water does not run off or is absorbed by stock such as paper or rags.
It must be remembered, however, that there are times when outside streams of large caliber should be used. Some may argue that an outside stream does not necessarily have to be of large capacity. If this were so, why resort to an outside stream in the first place?
The purpose of an outside stream is to try to contain and drive back a large, spreading body of fire. In general, if the fire is small, don’t use outside streams—advance the lines inside the building instead. Normally, one should use the smallest nozzle tip on a hose line that will do the job properly. By the same token, don’t send a boy on a man’s errand. There is no point in stretching booster lines or 1 ½-inch lines to a lumber yard or a supermarket that is fully involved unless no other kind is available.
Large fast-spreading fires require large streams, the big guns of the fire department. Bear in mind, however, that heavy water flow produces high friction losses and it is at such times that advantage must be taken of proper layouts, large-diameter lines, siamesing of lines, large mains or large-scale drafting operations.
Often at major fires in an attempt to surround the fire, lines are operated at opposing points and are in effect aimed at other operating units, causing unnecessary punishment to the men (Sketch 6). This may sometimes be unavoidable when protecting exposures, but it should never be permitted within a structure. In such cases it is far better to have two lines work abreast and advance together driving the fire ahead.
A most important decision that has to be made at some fires is at what point to call for help. The answer is quite simple. When a commanding officer had decided to commit his last unit at a fire that is not darkening down, he should call for more companies. This decision may have to be made at the instant of his arrival or an hour later, but it should be made without hesitation. To do otherwise is to gamble. Companies not needed can always be returned, but if they are never summoned the consequence can be disastrous. A ready reserve is just as important to a fire department as it is to an army.
As an over-all picture, line placement should follow the classic pattern wherever possible: The first hose lines are positioned to head off the extension of fire, as well as supply both sprinkler and standpipe systems. Additional hose lines should then be stretched to surround the fire area. The commanding officer must realize that every structural fire has six sides with which he has to contend: The top, bottom, and north, east, south and west sides. If all sides are not properly covered the fire may extend. Once the fire is surrounded, additional lines are placed to back up the originals (Sketch 7).
The accompanying illustrations are self explanatory and indicate to a greater or lesser degree the theories behind the placement of lines at fires. Remember that life comes first, confinement second, and extinguishment last. This is the basic theory behind the placement of all hose lines.