Page images
PDF
EPUB

especially by the factory mutuals. The latter, we have seen, emphasize fire prevention above everything else, and the remarkably low premium rates or large dividends of these companies, as the case may be, are .the result of the rigid enforcement of stringent rules relating to fire prevention. It has also been the practice for fire-insurance engineers, usually acting in cooperation, to visit the large cities of the country, and carefully inspect and report on the water supply, the fire department, the conflagration hazard, and all other important local conditions.

"Fire prevention" involves two lines of effort, namely: the prevention of the origin of fires, and the prevention of the spread of fires when once under way. It thus becomes necessary to study, first, the use of fire-extinguishing and fire-notification facilities, and second, the planning, construction, and occupancy of buildings with a view to reducing the fire loss to the minimum.

FIRE-EXTINGUISHING FACILITIES

Standpipes and Water Pails.—Every building should be supplied with fire-extinguishing facilities in proportion to its area and height. Standpipes should exist, with siamese or double connections, for the use of fire engines in the street; and at the windows there should be hose outlets, so as to make unnecessary the carrying of hose upstairs. In high buildings internal standpipes should exist, supplied from roof tanks supported on iron beams. According to the Universal Mercantile Schedule, the presence of an internal standpipe with tank supply will mean a reduction of 2 per cent in the occupied building rate, while the presence of an external standpipe with siamese connection for the use of the fire department will mean another reduction of 1 per cent.

Of fundamental importance in mercantile risks is the presence of a proper supply of fire pails filled with water. "The best fire appliances, strange as it may seem," writes Mr. F. C. Moore, "are the cheapest pails filled with water ready at every staircase, and for the reason that every one knows how to use a pail of water, while the average person, especially in the hour of excitement and danger, does not understand 'patent fire-extinguishing appliances, and might not know how to turn on the valve of the standpipe and bring the hose into action. Even in manufactories, where cool-headed mechanics might be supposed competent to handle fire apparatus, more than 65 per cent of all the fires are extinguished by pails of water.''

How highly underwriters regard these simple but effective appliances may be judged from the reduction in the fire rate, which their presence secures. If six filled pails of water exist for every 2,500 square feet of floor area, a 5 per cent reduction in the occupied building rate is allowed. Since fire pails cost about $4 per dozen, the saving in the rate constitutes a very material return on the capital invested. Thus, in the case of a manufacturing risk which the writer has in mind, the value aggregated $300,000, the area 50,000 square feet, the rate 1 per cent, and the total premium for full insurance $3,000. To secure the reduction of 5 per cent in the occupied building rate, or $150, requires the provision of six fire pails per 2,500 square feet, or 120 pails for the 50,000 square feet of area in the building, at a cost of about $40. In addition to this saving, amounting to several times the capital invested in the fire-extinguishing appliance, there is also the added protection against the important risk of loss in time and business, which would result from a fire on the premises.

Fire-Notification Facilities.—Among the remaining types of fire-extinguishing apparatus may be mentioned public and private water-works systems, post hydrants, a public and private fire department, three-gallon carbonic-acid chemical extinguishers of approved type, playpipes, spanners, stationary steam fire pumps, and pressure and gravity tanks. But in order to make these various types of fireextinguishing apparatus as quickly available as possible in cases of fire, certain notification facilities must also be installed. Consequently, there are frequently used automatic fire-alarm systems, which extend to all portions of the building. In connection with the sprinkler service, to be described later, an electrical notification system is also coming into use, which will give immediate notice to a central station in case there is too high or too low a temperature or water level in a gravity or pressure tank, or in case the water in the pipes of the system is set in motion.

The importance of such appliances to the property owner, who is always viewing his business from the profit standpoint, and who is, therefore, reluctant to introduce the same unless he can see a personal profit, regardless of the demands which the community may justly make upon him in the interests of the common safety of all against the conflagration hazard, may be seen by observing the Universal Mercantile Schedule. If there is one hydrant, supplied by an eight-inch water main, within 300 feet of the building, a reduction of 5 per cent in the occupied building rate is allowed; and if two or more hydrants, supplied with eightinch water mains, exist within 300 feet, the reduction is raised to 10 per cent. The installation of an automatic firealarm signal to a central fire station or fire department enables a property owner to secure another reduction of 5 per cent in the occupied building rate, while the presence of an auxiliary private fire plant and force pump means a reduction of another 10 per cent. In addition to these appliances, it is still customary to employ the old-fashioned watchman, but no longer under the happy-go-lucky methods of former years. To make the watchman honest and efficient, he is in turn watched by a central station, or by a stationary or portable clock system. If there is a watchman on the premises, the Universal Schedule grants a reduction in the occupied building rate of 5 per cent; if, however, there is a watchman with watch clock or electric director, the reduction is increased to 10 per cent.

Automatic Sprinklers.—But the best by far among the automatic devices for extinguishing fires in their incipiency is the automatic sprinkler. It must be apparent that the checking of a fire in its earliest stage is of transcendent importance. In fact, it is a maxim among fire underwriters that practically every fire can be prevented with a cup of water, if available in time. A few minutes' start in a building with unprotected vertical openings through the floors, and filled with large quantities of highly combustible materials, may suffice to spread the flames from top to bottom of the structure. Within a few minutes so much material may be set on fire as to thwart the efforts of any fire department to cool off the mass faster than the fire spreads to new stocks of combustible goods.

Considerations like these show the supreme importance of having some automatic device which, without the assistance of human effort, will discharge water almost simultaneously with the outbreak of the fire, will apply the water locally in the very spot where combustion is taking place, will distribute the discharge of water in such a manner as to accomplish the greatest good with the least amount of water, and will also give immediate notice of the existence of a fire. Such a device, it may seem at first thought, is quite impossible of realization. Yet years of experimenting have resulted in the modern sprinkler system, which operates automatically, applies water almost simultaneously with the outbreak and in the precise location of the fire, and which, through the sprinkler pipe-alarm valve, gives immediate notice at any desired point.

The automatic sprinkler may be described as an arrangement of pipes regularly spaced under all ceilings for distributing water, supplied automatically from elevated tanks, pressure tanks, pumps, or city connections, to all portions of a building, and having valves so arranged as to open when any undue rise of temperature occurs. In other words, for about every 75 to 80 square feet of floor area, there exists a sprinkler, arranged with valves and fed by water through a system of main and distributing pipes. The arrangement of the valves, so as to open with a rise of temperature, is

[graphic]

Fig. 9.—Center Central Feed to Automatic Sprinklers.

O shows a sprinkler. 0 shows a riser.

brought about by having the joints soldered with fusible metal, which will melt with increasing temperature, and release them as soon as heated. The fusible solder used is, for the sake of convenience, adjusted for different temperatures, varying from 165 to 360 degrees, according to the nature of the risk to be protected.

As explained by Mr. Frederick C. Moore, "A single sprinkler at 30 pounds pressure per square inch will discharge as a fine spray about thirty gallons a minute. Under most conditions the operation of one or two sprinklers would have 30 pounds pressure. At 100 pounds the impression is

« PreviousContinue »