SPRAY BETTER THAN CARBONIC ACID GAS.
In THE JOURNAL of March 30, 1878, appeared a criticism on an essay on extinguishing fires, which was printed two weeks previous, in which I recommended applying water in the condition of spray instead of a solid stream in all cases where spray could reach the fire. The writer very sensibly conceals his name, and borrows that of “Bicarb.” As his letter is a very interesting compound of truth, prejudice and error, I shall dissect a few of his arguments, which I have no doubt will prove both amusing and instructive to the readers of the JOURNAL. He says: “lo throw spray on a hot fire is to convert it at once into steam, which will at once escape into’the air.” Thank you, ” Bicarb,” for this great and important truth. That is just what it ‘will do, and it is exactly what we want. To let me illustrate: Suppose you had the charge of unloading a boatload of corn, and that it had to be carried off in sacks on the backs of laborers. As soon as one had got as much as he could carry, you would want to make room for another. Just so with water ; as soon as one portion has taken up all the heat it can carry, the sooner it gets out of the way and makes room for another the better. If all the water that is thrown the first five minutes on a fire could be converted into steam we should have very few large fires. “ Bicarb ” says : “It is a well known fact that concussion or the force with which a stream is thrown against a burning object has nearly as much to do with extinguishing the fire as the quantity of water used.” Now. instead of this being a well-known fact, it is a popular fallacy—a natural result of unfamiliarity with the subject in qcstion. Weight and velocity are what produces the concussion. How will “ Bicarb” explain the action of carbonic acid gas, which he claims is so much superior to water, when the gas has less than one five-hundredth the weight of water. Some explanation is needed here. He further says : “A stream is not directrd against the flame, but against the material from which it originates.” This is a general practice, I admit; hut does that prove that it is right? I think not. As flame is the principal propagator of fire, our first business ought to be to kill the flame and then extinguish the solid carbon. It frequently happens that the flame matter originates where we cannot reach. This was the case, I understand, in the burning of Shaw’s crockery siore in New York some years ago. The fire originated in the cellar, and as it could not be got at, and as no means were at hand for extinguishing the flames, the building was destroyed. Had the Department been provided with a few spray nozzles, delivering two hundred thousand particles to the cubic inch, I have no doubt but that tin y would have conquered the fire at once.
Bicarb ” further says : “ Had he made the same study of carbonic add gas, and given your readers the benefit of it, his time would have been much better employed than advocating a false theory.” As to spray being a false theory, if “Bicarb,” or any other man, will examine a file of the Hartford newspapers for the latter part of the year 1865, he will find an account of a competitive trial that took place between spray and solid streams Two buildings were erec ed and filled with combustibles. A Steamer was brought out, connection made with the watr and two lines of hose were laid, one with spray and the other with solid stream nozzles attached ; steam was gotten up, the buildings were fired, and when the lire had made sufficient progress the order was given to play. The result was what every clear-headed, unprejudiced, intelligent man had anticipated -a complete victory for the spray, As to a study of carbonic acid gas, I think that if Bicard ” had studied the subject one half as much as I have, lie would never have written such a foolish letter. I have had quite a respectable acquaintance with carbonic acid gas as a fire and life extinguisher for over forty-six years ; I have generated by combustion, fermentation anddecomposition of various carbonates ; I have quaffed it in foaming bumpers of mellow ale, in modest ginger beer, as well as in that extreme temperance beverage improperly called soda water. I recognize its wonderful relationship between the animal and vegetable kingdom,in sustaining the balance of vitality between them, as well as when it slumbers in the embrace of lime under the name of marble, that adorns the splendid palatial structures so conspicuous in every beautiful city. 1 have more than once had my breathing operations interfered with by it, but I have never had carbonic acid gas on the brain. I well remember the time when the Philips’ Fire Annihilator was introduced into New York from England, about thirty years ago, and what great things were predicted for it. I said that it might assist water, but it would never supersede it. Thirty years have proved the truth of my predictions. Every Fireman in New York knows full well that water is the chief article depended on for extinguishing fires, and I predict that it always will be. but in a very different mode from what it is now generally used. I wish all to remember that the Philips’ Fire Annihilator was a dry gas machine, no water being used in either its composition or operation. “ Bicarb ’’ has kindly told us that in a “chemical extinguisher the water is discharged from the nozzle in the form of spray.” This is a very important piece of information, and I shall not forget it. I have shown that carbonic acid gas has very little capacity for absorbing heat, but if a sufficient quantity is thrown into a burning building it will speedily extinguish flame, but has very little power to extinguish red-hot carbon. Steam and nitrogen have the same property j that is, they arc flame-killers, but not heat-absorbers, consequently, we need a heat-absorber to make an efficient extinguisher. The reason why this, gas kills flame so readily js because flame has no solidity. A cubic foot of it will weigh less than half an ounce. I candidly admit that a five gallon chemical extinguisher will extinguish more fire than five gallons of water as ordinarily applied. It is evident that this must be due to the combination of the water and gas. We know that charcoal, sulphur and saltpetre are comparatively harmless things in their separate state, bufwhcn combined as gunpowder, then they become the most terrible exponent of human intellect and passion, as expressed by the cannon’s roar on the battle-field. This sustains the idea that the efficacy of carbonic acid gas is in some way due to its union with water.
We will next inquire whether that union is chemical or mechanical. In all chemical compounds the compound is different from the ingredients of which it is composed. Now, if we call for a glass of soda water and let it stand until the gas has escaped, we shall find that the water is about the same as ordinary water, but containing a little more gas. If this water is thrown on fire it will have about the same extinguishing power as water drawn from the hydrant. We see here that the combination of the gas and water is simply mechanical, due to pressure, and as every drop of water is charged with gas as soon as the water is permitted to escape, it is expelled by the force of the gas, the same as water in an ordinary Fire Engine. At the same time that the water reaches the open air, the compressed gas in the water expands and disintegrates the stream, or, in plain English, converts it into spray, precisely as “ Bicarb ” has told us. Now for the explanation of the fact that water in the form of spray will extinguish more fire than when in the condition of a solid stream. The functions which water performs in extinguishing fire is the absorption of heat, and as the amount of heat that a given amount of water will absorb in a given time will be in proportion to the amount of surface, up to certain limits, that the water covers, let us take an Extinguisher with a one-eighth inch nozzle. Suppose the stream expands until it covers a circle one inch in diameter, it will cover a surface sixty-four times greater than if it struck the fire in a solid stream ; if it expands so as to cover a circle one and a half inches in diameter, then the surface covered will be one hundred and forty-four times greater than the solid stream, and the result will be exactly as “ Bicarb” has told uf—that is, it’will be converted into steam, or, in other words, it will absorb its full complement of heat, and take its departure, if permitted. 1 do not say that the sulphate of soda and gas have nothing to do with it. In liquid hydro-carbons—especially the lighter kinds— the gas exerts a useful effect, but in solid hydro-carbons, such as the various kinds of wood that form fully three-fourths of all our fires, I think the water is entitled to fully three-fourths of the glory of extinguishing them. As the Chemical Extinguisher has been endorsed by the National Association of Fire Engineers, they have virtually endorsed the spray theory, unintentionally I admit. But the spray theory has been endorsed and practiced, without the intervention of gas, by a far higher authority than the National Association of Fire Engineers ; that authority the God of Nature, who, when He undertakes to extinguish a raging forest fire, practices the spray theory to the fullest extent. If you will examine the meteorological record you will see that the annual rainfall, where these fires are apt to occur, is between forty and fifty inches, or about four inches a month. I think it quite probable that a rainfall of four inches will extinguish a severe forest fire. Contrast this with the amount used by our solid-stream Firemen. What a pity it is that so many hundreds and thousands of brave Firemen, who are willing and desirous to save property from destruction, cannot subdue their prejudices sufficiently to permit them to take this one lesson and example from the God of Nature. Firemen, study the laws of nature and obey them. I ry all things, prove all things, hold fast that which is good.
LITTLE FALLS, N. Y., Aprilb, 1882.
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