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created in the mind of an observer that the spray is so dense and forcible that a man directly under the sprinkler would be strangled." The sprinkler may be used in all classes of risks, such as factories, hotels, elevators, mills, department stores, schools, and steamboats. In case the climate in some places is too cold at times to permit the use of water in the sprinkler pipes, compressed air can be kept in the pipes by means of a "dry valve," so arranged that in case

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O shows a sprinkler. © shows a riser.

the sprinkler opens because of the presence of fire, the compressed air escapes and automatically permits the water to enter the pipes. The sprinkler system also contains an automatic alarm valve, so constructed that a flow of water through the same will operate an electrical or mechanical gong, or both, according as the character of the property may require. The importance of this automatic alarm arrangement cannot be overemphasized, since a large water loss may result from a small fire, which is extinguished by the sprinklers, if there is not some method of notification with a view to checking the flow.

The automatic sprinkler, as just described, is the only device known which meets all the conditions enumerated as necessary to quench a fire in its incipiency, and which thus overcomes the old and defective method of trusting to human eyes to detect a fire in time, and to human hands in extinguishing a fire after discovered. Fire underwriters and fire engineers are quite generally agreed that the automatic sprinkler is by far the most reliable and most gener

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Fig. 11.—Best Method of Piping a Large Building.

O shows a sprinkler. 0 shows a riser.

ally known of fire-fighting agencies. As Mr. Everjtt U. Crosby stated in an address on the subject of '' Fire Prevention": "We have had for some twenty years the sensitive automatic sprinkler protection, and yet to-day its possibilities are not realized. This type of protection is destined within a short time to be regarded generally as the apparatus-in-chief for extinguishing fires. It will be generally found in buildings having combustible construction, or contents of from moderate to large values. This branch of fire protection, more than any other, has been the subject of the most careful search, test, and specialization." The importance, of automatic sprinklers as a factor in reducing the fire waste, and consequently the cost of insurance, is confirmed by all, and especially by the glowing accounts of the factory mutuals, which have been greatly benefited by their use. Mr. Frederick C. Moore, Superintendent of the Special Risk Department of the Hartford Fire Insurance Company, presents the benefits of sprinklers, as shown by the records of 8,942 fires in risks equipped with sprinklers, and extending over a period of twelve years. In 5,791 cases the sprinklers extinguished the fire unaided. In most of the remaining cases the sprinkler system proved of value, and in only 483 cases, or less than 6 per cent of the total, did it prove of no value. The value of the system in extinguishing fires with the least accompanying damage by water is shown by the fact that 7,239 fires out of the 8,942, or 88 per cent, were extinguished with not more than twelve sprinklers opening.

Tlie Installation of Automatic Sprinklers.—It is unnecessary to state in detail the rules for installing automatic sprinklers. Suffice it to say that this matter is properly regulated by the National Board of Underwriters, the New England Insurance Exchange, the New York Board of Underwriters, and other organizations. Property owners may, therefore, receive full specifications by consulting the bureau of underwriters in the particular jurisdiction in which the building to be rated is situated. A few general rules, however, are always specified in fire-prevention manuals. It is highly important that the distributing rising pipes should be of such capacity as to be proportionate to the number of orifices which are to be supplied with water. When installing a sprinkler system, it is also highly important to protect every portion of the building and to overlook none. A small room or closet not provided with sprinkler protection may easily enable a fire to gain such headway as to nullify the effect of the sprinklers situated in other parts of the building. Sprinklers can only be expected to extinguish fires when they first occur, and not when they have reached considerable proportions. • Every portion of the building, therefore—closets, basements, lofts, elevator wells, understairs, etc.—should be fully protected. The building should also be so constructed as to avoid the presence of concealed spaces. The sprinklers should be so situated that water discharged from them will reach every portion of the interior, and the construction of the building should be such as to enable the water to reach all portions of the woodwork.

It is also of primary importance that the sprinkler system should be provided with a water supply, amply sufficient and constant. It is advisable to have two sources of supply whenever possible, i.e., a large tank supply as well as a supply by a force pump or by direct connection with the city water supply. If one source fails the other may be utilized, or better still, the city supply can be used to supplement the tank supply when the latter becomes exhausted.

After a sprinkler system has been installed it is necessary to inspect the same periodically and prevent conditions which on the one hand may cause the sprinklers to fail in their work, or which may cause the opening of too many sprinklers in case of fire. There are certain conditions with which the sprinkler cannot cope, such as conflagrations, hollow spaces between ceiling and floor, and long exposure from outside fires which may reduce the water pressure. The sprinkler is also of less utility in industries where the stock consists of large quantities of inflammable liquids, or articles which shed water easily. Again, the system may be rendered defective or useless by the existence of corrosive vapors, coatings of paint, or incrustations from cement, plaster, and other articles. It follows, therefore, that a sprinkler system, even though properly installed, should be tested periodically by expert service, if absolute reliability is desired, and should receive the same care and inspection as any other machinery in the plant.

Tlie Importance of Automatic Sprinklers in Reducing Fire Rates.—Granting the effectiveness of automatic sprinklers in preventing the spread of fires, the question will naturally be asked, How may property owners, who are always viewing their business affairs from the standpoint of profit and loss, be induced to adopt this modern appliance? The answer again is, just as in the case of the other facilities discussed, that the surest way to bring about reform is to appeal to the selfish interests of property owners. If the owner of a large establishment can be convinced that the installation of an automatic sprinkler service will mean a large reduction in his fire rate, and that the saving in his fireinsurance bill will amount to more than a good investment return on the capital expended for such a service, it is only reasonable to expect that the improvement will be made.

That there is a decided saving in practically all cases cannot be questioned, although, owing to the numerous factors which enter into the installation of sprinkler systems, it is only possible to point out in a general way what the real saving is. Thus one building may be constructed in such a manner that a sprinkler may be installed with a tank supply at comparatively small expense. Another building may have been so poorly constructed as not to support a tank, and the installation of a sprinkler service in that building may necessitate much preliminary construction work at great expense. Again, the availability of a proper water supply may make the sprinkler service in one building much less expensive than in another. The representatives of the sprinkler installation companies state, that it frequently occurs because of the many varying factors which enter into the cost of such installations, that it costs as much to install a sprinkler service of a given type in a

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