Gas explosion

“ Mention has already been made of the slight noise caused by the explosion of the gas shell, and instructions were accordingly [143] issued that all shell that sounded like duds were to be regarded as gas shell, and the respirators adjusted accordingly. This got over one of the elements of surprise.
A great many men, especially those in battery positions, had been gassed in their dugouts before warning of the gas bombardment had been spread. Numbers of these men were actually gassed in their sleep and were awakened too late by the choking fumes themselves. ”

“ This danger proceeds from fire-damp, as one unlucky stroke of the pick may bring forth a stream of carbureted hydrogen gas, inexplosive of itself, but if mixed with eight times its bulk of air, more dangerous than gunpowder, and which, if by chance it comes in contact with the flame of a candle, is sure to explode, and certain death is the result—not always from the explosion itself, but from the after-damp or carbonic acid gas which follows it. ”

“ BURNT DISTRICT, SHOWING GAS HOUSE CHIMNEY AND SMOKING RUINS, TAKEN FROM LOWER COVE.
Photo by G. F. Simonson.
One hundred thousand feet of gas were in the holder's close, and the flames not a block away. The direst danger was imminent, and an explosion terrible in its character might occur at any minute. No one can say how many lives might have been lost, or how much valuable property destroyed. ”

“ The gas has the curious power of combining with the blood and refusing to let go, thus keeping out the oxygen necessary for life. It may be that that is what accounts for what we've seen—that it is actual poisoning to death of men not killed by the immediate explosion. ”

“ Sometimes in an unexpected moment there is a great dislodgement of coal, and a tremendous quantity of gas is set free, which may be sufficient to foul the passages for some distance around. The introduction or exposure of a naked light for even so much as a second is sufficient to cause explosion of the mass; doors are blown down, props and tubbing are charred up, and the volume of smoke, rushing up by the nearest shaft and overthrowing the engine-house and other structures at the mouth, conveys its own sad message to those at the surface, of the dreadful catastrophe that has happened below. ”

“ Explosive mixtures of marsh-gas and air may be fired by an unprotected light. But when coal-dust is present, and little or no marsh-gas, an initial explosion—such as is produced by a blown-out shot—is required. To guard against explosions from this cause it is necessary to use explosives in moderate quantities and to see that the blast-holes are properly placed, so that the danger of blown-out shots may be lessened. ”

“ Fire-damp, marsh-gas, or carburetted hydrogen, is colorless, almost scentless; it burns with a blue flame, and makes respiration impossible. The miner could not live in a place filled with this injurious gas, any more than one could live in a gasometer full of common gas. Moreover, fire-damp, as well as the latter, a mixture of inflammable gases, forms a detonating mixture as soon as the air unites with it in a proportion of eight, and perhaps even five to the hundred. When this mixture is lighted by any cause, there is an explosion, almost always followed by a frightful catastrophe. ”

“ The principles upon which this contrivance rests, are the modification of the explosive tendencies of fire-damp (the inflammable gas in mines) when mixed with carbonic acid and nitrogen; and the obstacle presented to the passage of an explosion, if it should occur, through a hole less than the seventh of an inch in diameter; and accordingly, while the small oil lamp in burning itself mixes the surrounding gas with carbonic acid and nitrogen, the cylinder of wire-gauze which surrounds it prevents the escape of any explosion. ”

“ Small particles and dust were thrown out to a much greater distance, and the man who was working in front had been thrown back and buried under the fragments. About seventy-six tons of coal appear to have been displaced by the explosion. Carbonic acid continued to escape from the coal after the accident, and even the pieces that had been thrown into the gallery gave it out when they were disturbed. No satisfactory explanation has been offered of the manner in which the gas could have accumulated, and have gained so high a pressure as to cause a detonating explosion. ”

“ It was monstrous, and yet—
"People say they 've got a new kind of poison-gas," continued Merritt. "Some think that they dig underground places and make the gas there, and lead it by secret pipes into the shops; others say that they throw gas bombs into the factories. It must be worse than anything they 've used in France, from what the authorities say."
"The authorities? Do they admit that there are Germans in hiding about Midlingham?"
"No. They call it 'explosions.' But we know it is n't explosions. We know in the Midlands what an explosion sounds like and looks like. ”

“ When we read the account of some fatal gas explosion, we are always prepared to find the oft repeated tale of the foolish one who goes to look for the leak with a lighted candle. A recent explosion of this kind in Paris has led to the appointment of a Commission to determine the best manner of searching for gas-escapes. ”

“ The noise accompanying an explosion is due to an air wave, and is markedly different in the case of a detonator from a real propellant. Some cases of ordinary combustion can be accelerated into explosions by increasing the area of contact between the combustible and the oxygen supplier, for instance, ordinary gas or dust explosions. Neither temperature nor quantity of heat energy necessarily gives an explosive action. ”

“ Well built, such plant will stand much heat and fire without failure; if it is non-automatic, and of combustible materials contains nothing but gas in the holder, the worst that could happen in times of fire would be the unsealing of the bell or its fracture, and this would be followed, not at all by any explosion, but by a fairly quiet burning of the escaping gas, which would be over in a very short time, and would not add to the severity of the conflagration unless the generator-house were so close to the residence that the large flame of burning gas could ignite part of the main building. ”

“ More or less danger, however, attends the operation of a two-cycle engine, principally from the fact that an explosive mixture in a partially compressed condition is forced into the space which the instant before was occupied by a flame, and it is only because the expansion of the burst gases at the previous charge has its temperature decreased so far below the explosion point, that the fresh gas is not ignited, although there have been occasions when explosions have taken place during the upstroke. ”

“ If these are properly made and tamped, the force of the explosion will tear down the coal properly; but if the man has been careless in his work, the tamps will blow out like shot from a gun-barrel, and igniting such gas or coal-dust as may be present, kill or badly burn the shot-firers. The proper tamping is wet clay, but it is impossible to convince the men of it, and nine out of ten will tamp their holes with dummies filled with coal-dust (itself a dangerous explosive) scooped up from the side of the track. ”

“ When marsh-gas, which is often set free in large quantities from coal-seams, is mixed with ten times its volume of air, it becomes highly explosive. Moreover, this gas, the fire-damp of mines, in exploding, renders ten times its bulk of air unfit for breathing, and the choke-damp thus produced is often as fatal to miners as the first explosion. To do away with these dangers, Sir Humphry Davy began his experiments on flame, which resulted in his invention of the safety-lamp. ”

“ It is evident that not only hydrogen, but every other combustible gas, will give an explosive mixture with oxygen. For this reason coal-gas mixed with air explodes when the mixture is ignited. The pressure obtained in the explosions serves as the motive power of gas engines. In this case advantage is taken, not only of the pressure produced by the explosion, but also of that contraction which takes place after the explosion. ”

“ According to the researches of Sir Humphrey Davy, seven or eight parts of air, to one of gas, produce the greatest explosive effect; while larger proportions of gas are less dangerous. A mixture of equal parts of gas and air will burn, but it will not explode. The same is the case with a mixture of two of air, or three of air, and one of gas; but four of air and one of gas begin to be explosive, and the explosive tendency increases up to seven or eight of air and one of gas, after which the increased proportion of gas diminishes the force of the explosion. ”

“ If carburetted hydrogen be mixed with a sufficient quantity of oxygen gas or common air and fired by the electric spark, or by any other method, an explosion takes place more or less violent according to the quantity of carbonaceous matter condensed in the hydrocarbonat; and the remaining gas consists of carbonic acid, together with any unconsumed gas, or excess of oxygen, whilst the water condenses in drops on the sides of the vessel. A few cubic inches of the mixed airs is as much as can be conveniently managed at a single explosion ”

“ When a bank of coal is brought down by an artificial explosion, by dynamite, by lime cartridges, or by some other agency, large quantities of gas are sometimes disengaged, and not only is this highly detrimental to the health of the miners, if not carried away by proper ventilation, but it constitutes a constant danger which may at any time cause an explosion when a naked light is brought into contact with it. Fire-damp may be sometimes heard issuing from fiery seams with a peculiar hissing sound. ”

“ If the air-current is good, this is blown away before it can do any harm. If the ventilation is bad, the gas collects gradually at the top of a room. Pretty soon it will get low enough to touch the flame in one of the lamps, and then usually there is a big explosion which wrecks all that part of the mine. If there isn’t enough of it to explode, it catches fire and rolls back and forth across the roof, and if the miners aren’t burnt to death, they’re pretty likely to be suffocated by the after-damp. ”

“ The poisonous gases which occur in mines, and which are formed in large quantities when high explosive goes off in an enclosed space, e.g., from a direct hit in a shelter, or on the explosion of a charge in a mine, are not protected against by the ordinary anti-gas appliances. ”

“ Owing to the small explosion which occurs with these shells, they are liable to be mistaken for blinds, and even when the gas is smelt men may not realize its possibly dangerous character at once and so may delay putting on respirators or helmets until too late. Men sleeping in dug-outs may be seriously affected unless they are roused. Men in the open air are unlikely to be seriously affected by poison gas shells, provided they put on respirators or helmets on first experiencing the gas. ”

“ When the oil is nearly consumed, a slight jar will inflame the gas, and an explosion is sure to follow. A bombshell is no more to be dreaded. Now, if the lamp is not allowed to burn more than half-way down, such accidents are almost impossible. ”

“ When the fire-damp comes off suddenly in any case, rendering the air foul and explosive at the foreheads, if no other remedy be found effectual, the working of the coal must be suspended, and a current of air sent directly from the fresh in-going stream, in order to dilute the explosive mixture, before it reaches the furnace. This is termed skailing the air; for otherwise the gas would kindle at the furnace, and flame backwards, like a train of gunpowder, through all the windings of the work, carrying devastation and death in its track. ”

“ There are numerous instances of men waking up and getting excited, who not only gassed themselves, but in their mad efforts to find their masks, or to escape from the gas, knocked others down, disarranging their masks and causing the gassing of from one to three or four additional men. The confusion inherent in any gas attack was heightened in the latter stages of the war by heavy shrapnel and high explosive bombardments that accompanied nearly all projector and cloud gas attacks for that very purpose. ”

“ The result is that when the cloud does come along the vacuum bulbs are often conspicuous only by their absence. Even if they are kept whole it is asking rather a lot of a man to take an accurate scientific sample during the excitement of a gas attack which is accompanied by a bombardment by explosive shells and gas shells. ”

“ They actually inhibit the outbreak of fire. We agree with the majority's conclusion that the use of CS tear gas prior was not a direct, proximate cause or contributing factor to the rapid ignition and expansion of the blaze. The audiotape and forensic evidence clearly indicate that the rapid ignition and spread of the blaze was due to the use of chemical accelerants (including gasoline, kerosene and camp fuel oil) distributed throughout the compound by individuals within the compound. ”

“ Sometimes also the tanks of crude oil take fire, and these conflagrations are said to present a splendid spectacle,—the resinous parts of the oil burning with a fierce deep-red flame and sending up volumes of smoke, through which are emitted lightning-like flashes exploding the ignited gas. ”

“ When the same explosive is ignited under water, the heated gas presses outward in all directions, forcing the surrounding molecules of water against their neighbors, which are, in turn, propelled forward with great violence. This effect continues until the back pressure of the liquid medium equals the now reduced pressure of the gas due to its expansion in the space vacated by the displaced water, which is likewise to some extent compressed by the action of the gas. ”