TESTING AUTOMATIC SPRINKLERS.
IN view of the fact that the losses by fire are steadily increasing year by year, propertyowners and fire underwriters are devoting more attention to the methods of fire prevention that are proposed, and to the means offered for extinguishing fires in their incipiency. Various devices have been suggested for local apparatus to be placed in large buildings—factories, storehouses, etc.—to be ready for service at an instant’s notice, either to put out the fire before the arrival of the fire department or to supplement its apparatus when the flames have acquired great headway. Among the devices that have met with much favor are the automatic sprinklers. These are simply nozzles for the discharge of water, usually perforated or arranged so as to throw a multitude of small jets of water or spray; they are attached at frequent intervals to water-pipes fixed to the ceiling or walls of the rooms to be protected ; these pipes contain water under pressure, or the water may be turned into them when desired; the sprinkler-heads are constructed in parts, some of which are held together with fusible solder, which melts at a certain temperature, opens the sprinkler, and the water thus released rushes through the perforations, covering an area of greater or less extent, according to its construction and the degree of water pressure. The sprinkler-heads may be hung pendant from the feed-pipe, or placed upright so that the water discharged will strike the ceiling and thence fall to the floor. In the latter position there is less danger of freezing, as the pipes can be thoroughly drained.
The value of this meams of fire protection having been recognized by underwriters, who make a reduction in their rates where automatic sprinklers are employed, there sprang up a demand for them which resulted in the introduction of a great number of automatic sprinklers, each claimed to be the best, and all of them patented. It became a matter of considerable importance to propertyowners, as well as underwriters, to ascertain if all these were trustworthy, and which of them were such as they could recommend to their patrons. The mill mutual insurance companies of New England, which require some such appliance to be placed in all the mills they insure, recently determined to make an exhaustive test of the various kinds of automatic sprinklers; nineteen of these companies united with the Boston Underwriters Union to make this test, which was conducted under the supervision of C. J. H. Woodbury, who was aided by Professor John M. Ordway. Thirty-one different patterns of sprinklers were tested, some of which had been in use a number of years, and others were fresh from the factory. The report of the various tests has just been published, and is of great value to all interested in the subject of fire prevention and extinguishment. The tests were made upon the following points: Sensitiveness, bursting strength, opening temperature, melting of solder, distribution of water and volume of discharge. While the report does not indicate which sprinkler these experts regarded as the best, the comparative tables are sufficiently explicit to serve as a guide to propertyowners who desire to avail themselves of this valuable device for fire protection. The first proposition made to the sprinkler manufacturers was that two experts should be selected by the underwriters, two by the manufacturers, with Prof. Ordway as umpire, but the manufacturers interposed so many objections that the test was finally made without regard to them. The result of this work is thus summarized :
First. That time and pressure has not affected the strength and fusioa point of the solder during an experience of twelve years.
Second. That portions of sprinklers where corrosion might interfere with prompt action should be protected, preferably by heavy mineral oil.
Third. That the distribution of water between three and thirty-six pounds’ pressure is such that w.fter is directed upon a smooth ceiling and upon each square foot of floor, with all of the sprinklers used in these experiments.
Fourth. That the concentration of water at the beginning of a fire is greater than by any other form of inside apparatus.
Fifth. That where tanks are used for a first supply for sprinklers, the bottom of the tank ought not to be less than ten feet above the sprinklers.
Sixth. That as a matter of practical application, sprinklers have worked at 131 mill fires in seven years without any known instance of their failure.
Seventh. That the results of the experience in respect to automatic sprinklers demonstrate that their efficiency is not liable to beco.xe impaired by time, and prove the good judgment of those underwriters who advocated their introduction as a safeguard against loss.
Eighth. That it is essential that valves be so arranged that the proper persons can readily know that a full-water pressure is upon the sprinklers. Valves with traveling stems are preferable on this account. Valves with stationary stems can be fitted to show their position by winding around the valve stem a line with a weighted tag at the end. When the valve is open or shut, the tag will hang i a corresponding extreme position of the line. Left-hand valves should lot be used in sprinklers. It is well to secure the valves open with a riveted strap ; if it is necessary to shut the valve on account of mishap, anybody can cut it ; but do not use a lock and chain, as the key will, in the nature of things, be lost, and the valve spindle bent in the efforts to sunder the chain.
The temperature required to melt the solder and start the sprinklers varied from 163 degrees to 271 degrees, the latter being regarded as impracticable devices. Some of them required practically many degrees more heat to re lease them than the guarantee of the manufacturer specified. Herein apparently lies the main point to be considered in purchasing automatic sprinklers. They require to be adjusted with such a degree of sensitiveness that when the temperature rises to a point that threatens to become dangerous, they will release the water and reduce the temperature; or, in other words, put out the fire; at the same time it will not do to have them so sensitive that the rise in temperature caused by lighting half a dozen gas lamps will set them going and deluge the premises. Nor is it desirable that a fire should get too much headway before the sprinklers operate, as would be the case where so high a temperature is required to melt the solder as is indicated by some of the tests. The test showed that there is great diversity among sprinklers as to the extent of area covered by them and the volume of water discharged. These are important points to be taken into consideration, and must be largely governed by circumstances and conditions. Appended to the report is a list of 128 fires that have occurred in mills since 1877, that were equipped with automatic sprinklers. In sixty-eight of these instances no claims for damages were made, while in others the loss varied from $10 to $20,OCX). In concluding his introduction to the report, Edward Atkinson says :
It could not have been expected that, in such an examination as this, some minor faults should not have been found. Such minor faults have been found, and measures have been taken to present such faults to the makers of the sprinklers and to assure the remedy. They do not need to be named in this report, since none of them have been of such a nature as to cause distrust of the whole service of either kind. While all the sprinklers tested may be expected to operate under fire and to check or extinguish it, there are such variations in the quality of sprinklers in other respects as to warrant a choice being made among them. The underwriters have now given all the facts which can be determined by any method of experiment open to them, and it only remains to them to caution all their members that the proportions and sizes of supply pipes should be carefully adjusted to the quantity of water delivered by that particular sprinkler which each one may choose.
In calling attention recently to the fact that the tests referred to were being made, we said that the report would probably be non-committal, for if the committee gave preference to any particular sprinkler they would be accused of favoritism, while if they condemned any they would be sued for damages. The result justifies our conclusion ; the report is made and the would-be purchaser is permitted to make his choice from the thirty-one different kinds tested. To sum up, it seems to be settled that automatic sprinklers are valuable under certain conditions ; that some are good and some are bad, but that even the best require a certain degree of intelligence in their arrangement, and more or less care in their supervision after they are put up. There is no doubt but the best of them will do efficient work in extinguishing fire ; but whether the possibility of their deluging a building with water does not offset some of their advantages, seems still to be an open question. That they will furnish an abundance of water is fully established, but it requires human intelligence to shut off the supply when enough has been used.