The Use of Fog and Foam by Small Fire Departments
THERE has been much discussion among men whose business is that of fighting fires regarding the use of fog and foam streams and comparisons between the effect of their use and that of straight water streams. It is remarkable how individual opinions of men, who are good and expert firemen, vary from one extreme to the other. The writer has heard more than one man of long experience in a fine city fire department state that “foam is no good”; others express lack of confidence in fog as an extinguishing agent, and yet many others say that foam and fog have been of great value to them.
It would seem that the truth is at neither extreme; that no one extinguishing agent is the answer to all problems; that straight water streams must be employed for most ordinary fires, that in special cases fog and foam have their field of usefulness, and that in every fire of any kind the value of the extinguishing agent used will depend on how it is applied as well as its selection. Also, it is true that there are occasions where the employment of foam or fog may be of value to even the smallest village fire fighting organization, and sometimes in ways that were unforseen when the equipment was purchased.
Fires that are commonplace and routine affairs to a department in a large city may be serious affairs in a small town, and the choice of methods and ways of fighting them can, from the outset, determine the difference between success and disaster.
The following examples of fires, and points to be noted in connection with them, should be of interest, to small towm fire officers. They were taken from the experience of the writer and are given for whatever they may be worth.
Case One: A hose and chemical truck from an industrial plant department went four miles out into the country to a cross roads community in response to a phone call. It was found that a fire, starting at one end of a row of five small one-story, frame, shingle roofed dwellings, had involved two, and seemed certain to destroy all of them. There was no source of water, nor any apparent way to fight the fire.
There was, on this piece of apparatus, a forty gallon foam extinguisher. This was operated, and covered the exposed side and half of the roof of the third house with foam; these surfaces were scorching and smoking and about to “light off.” The blanket of foam remained in place and protected and saved this house and the other two dwellings beyond it, white the first two that were on fire burned to the ground. The point about this case that it was a peculiar and unusual one of the use of foam on a Class I fire.
Case Two: A large two-story frame residence, with a shingle roof, in a small town of just a little more than one thousand population had the entire roof and attic involved by a quick and hot fire.
The local volunteer fire department responded with a hose truck and laid and operated a single hydrant line of 2 1/2-inch hose. This was siamesed into short leader lines of 1 1/2-inch hose, with fog nozzles of the high velocity fog type, throwing circular cones of spray. These were taken into the front door and up the hall stairway to the second floor. They were carried up short ladders to the scuttle and through a hole were pulled in the second floor ceiling and they were operated into the attic. What happened after the fog streams had been operated for a few minutes astonished the men who were using them as well as most of the spectators, who had seen similar fires in similar houses fought with one hydrant line in that town. The flames, which were roaring twenty-five feet up above the roof, began to die down like a gas flame that is being turned off.
The writer, who was associated with this department as well as the one at an industrial plant five miles away, was called and made a quick run to this fire. Upon arriving within somewhat less than ten minutes he found that the fire was out. Those present said that the blaze had seemed to go down like magic. Their words were “The water looked like it ate up the fire and the fire ate up the water.” (There was very little water dripping down from the second floor ceiling, which was burned through in but a few places. The water used on the fire had seemed to evaporate.)
The small town firemen had fought other fires like this one before. Some of the time they had never been able to stop the fire. In others, they had finally fought their way up into the attic and “whipped out” the fire foot by foot and joist by joist. Several of them reported that steam had “boiled down” at them from the attic during the first few minutes the fog streams contacted the fire. The point of interest in this case is the successful application of fog on a Class I fire.
Fire in Coal Tar Plant
Case Three: A quick and fierce fire had involved a distillation room, 40 by 40 feet in area and 35 feet high, in a coal tar by-products plant. It contained several large stills and tanks of highly flammable liquids, had tile walls and a metal roof and tvas equipped with a sprinkler system. More than forty sprinkler heads fused and were operating at a working pressure of sixty pounds at the dry valve gauge.
Plant fire department responded with several pieces of apparatus and laid five lines of hose. City department was also called and its personnel worked at fire but it was not necessary for them to lay hose. Of the five lines of hose, one was laid to steamer connection of sprinklers, straight streams were operated from two to cool and protect metal roof of building and two fed portable single-powder foam generators, with foam streams operated in building on fire. Sprinklers protected main structure of building and cooled down part of fire, but a quantity of flammable material in pans and on the floor was still burning under the shower of w’ater.
Foam Extinguished Fire
The foam streams advanced into the building, extinguished the fire involving this material, although the falling spray from the sprinklers was diluted and washing the foam partially away. The quality and quantity of the foam that actually reached the fire was considerably affected, but was enough to end the blaze, which was threatening a hundred thousand dollar building.
The point of interest about this case is that foam and water were used in an unusual conjunction with each other. Although water was falling in considerable quantity on the foam and reducing its quality and efficiency, yet enough of this remained to put out the fire that water alone could not finish. No fog nozzles were available at that time.
Case Four: A fast spreading fire had involved the oil storage yard of a steel plant. More than one thousand piled drums, containing oil, paint and paint thinner were involved. Fire over an area the size of a football field was going seventy five feet in the air. Drums were exploding everywhere, parts of them being projected several hundred feet. Streams of burning oil were flowing into the main plant area.
The fire was fought by apparatus and men from a small city department, an industrial plant a mile away from the fire and an ordnance plant. The plant involved had no apparatus beside small portable extinguishers, and the nearest hydrant was seven hundred feet away. The three organizations responding were accustomed to work with each other without rivalry or jealousy, and functioned together as one larger department would have done.
One pumper pumped through two long lines of hose to a deluge set, another through three lines to another deluge set and a third pumper supplied lines to a single-powder, portable foam generator and a fog nozzle. The storage yard was triangular in shape, about three hundred feet on each side. The deluge sets were operated into each of these two sides, and the foam stream advanced into the third.
The heavy and powerful deluge set streams began to have effect at once where they fell, seeming to drown out much of the burning oil or wash it into the area where the foam stream was piling foam over everything. Seventyseven buckets of foam powder were used. The fog nozzle was used on the edges of the fire, and later, for overhauling it. It was effective where used, but when directed somewhere else, the fire moved back in. Within an hour the fire was under control and was then overhauled by fog nozzles on one 2 1/2inch line and two 1 1/2-inch lines.
At least one third of the drums of oil exposed to the fire remained unbroken, with heads bulging and contents rumbling and boiling for several hours afterward. The point about this fire was that heavy water streams were operated on it without interfering with each other and so that their combined efficiency was attained.
The following conclusions are among those which may be drawn from consideration of the above cases:
That fog and foam apparatus may be of value to even a village fire department.
That once in a while fog or foam apparatus may be found useful in some manner that is a far departure from the way that it is generally supposed to be used. Cases I and II are examples of this.
- It should be present on the apparatus that goes to a first alarm assignment. It is too late to send back for it when a gasoline tank truck is upside down on Main Street in front of the bank, or when an oil tank car has split a switch down by the depot.
There are times when there may be combined, and yet effective, use of straight water, foam and fog streams. Every patch of foam on a fire, even though it be diluted and of poor quality, may help to keep it from reflashing.
- There are fires where fog may be of more use than foam, and others where the reverse of this is true. Sometimes fog may sweep away a running stream of burning liquid material on which foam will not remain in place, and in other cases, on a tank or pool surface, that one fog stream cannot cover, a foam stream will pile foam over it.
In conclusion, the writer would say that the methods of fire fighting described above are not given as being the best ones that exist, but as the best ones available, in each case, to a small fire department of limited facilities.
Also, the writer does not presume to indicate that these paragraphs may contribute to the guidance of fire officers of larger departments, but they are offered in the humble hope that some representatives of smaller organizations, where any good sized fire may be a major one and where methods and means are limited, may find something of interest in them.