Fire and Its Causes
THE first recorded act of the Creator of the universe after He had created the heavens and the earth had to do with fire—“And God said, Let there be light; and there was light.” (Genesis 1:3). Since the dawn of creation fire has therefore held the centre of interest for the world’s greatest scientists and philosophers, and many theories have been advanced to account for all the remarkable phenomona which accompany it.
So far as modern scientific research has been able to go, however, fire, or combustion, has been shown to be the result of violent chemical alterations in bodies of various kinds. The heat thus evolved is merely incidental phenomenon, or, in other words, the vehement combination of various elements; smoke is the product of imperfect combustion, due either to want of oxygen or want of temperature; and flame may be defined as aeriform or gaseous matter heated to such a degree as to be luminous.
The elements of all fire consist of hydro-carbons, which in turn consist of oxygen and nitrogen. In combustion, the carbon and oxygen have so great a chemical affinity for each other, that they rush violently together, and by the force of their combustion produce intense heat. The hydrogen and nitrogen in the meantime are set free.
The whole universe is composed of matter; anything that has weight is matter, such as iron, wood, air, etc. Matter is subject to two changes, physical and chemical. Take a piece of wood and saw it, the result is sawdust, take a piece of marble, grind it into dust, the result is marble dust. Both the marble dust and sawdust retain the same ingredients as before, only the shape, or form, is changed. This change is called the physical change. In other words; changing the form, or shape, of matter is called the physical change.
If we pour sulphuric acid on the marble dust it instantly begins to bubble, and soon there is neither marble dust or acid left; the gas or fumes forming a high explosive. If we apply sufficient heat to the wood or sawdust to burn it we will have only the residue of ash. This ash is certainly not wood, so we have changed both the wood and marble into entirely different matter. This change is called the chemical change. In other words, changing one substance into another entirely different substance is called the chemical change.
What, then, is fire? Ignite a piece of paper and record what takes place. We find that in the process of burning it gives off heat, light and smoke, and that there is nothing but ash left. This ash is certainly not paper, so it can readily be seen that fire is a chemical change.
What causes fire? Causes of fire may be enumerated as follows:
1st. “Direct ignition,” placing combustible material in direct contact with fire, such as applying a match.
2nd. “Faint, or prolonged, heat,” as an end of a beam in a chimney or against a furnace, etc. No matter how faint the heat, if continued long enough, it will start fire.
In a paper warehouse in New York City the piles of paper on the ground floor were mysteriously igniting and the owners could not find the cause. They sent for a Fire Prevention expert and he noticed that the fire always started at the bottom of the piles of paper, so he felt the floor with his hand and found it so hot that he could not keep his hand there very long.
On going below, he found two high power boilers just under the spot and he was still puzzled, as the tops of the boilers were 24 inches below the underside of the floor, which was composed of reinforced concrete six inches thick. But feeling above the boilers he found that the air had pocketed above the boilers and was very hot. lie ordered a window or opening cut in the wall back of the boilers and immediately the air began to circulate and no further trouble was experienced.
3rd. “Spontaneous heating”:
4th. “Spontaneous ignition”:
What firefighters commonly call “spontaneous combustion” is combustion produced in a substance by the evolution of heat through the chemical action of its elements. There is no such thing as “spontaneous combustion.”
All matter has three degrees of heat, flash point, ignition and burning point. First heated to the flash point and then if temperature is increased will reach the ignition point, and if increased again will reach the burning port, or, in other words, will take fire.
5th. “Explosions”: There are three kinds of explosions ; first, explosion by force or pressure such as takes place when a boiler explodes; second, explosives such as dynamite, etc., and third, such as combustion, or fire.
6th. “Electric sparks, flashes of lightning”:
There are two kinds of electric sparks, first; direct current, when wires are poorly insulated the electricity will set fire to combustible material; second; “Static Electricitv.” this is produced by rubbing, friction, etc. A case of this kind took place in New York City a short time ago. A man was rubbing down an automobile bodv with a piece of chamois and an explosion took pUce. On investigation, it was found that all the windows were closed and consequently the gasoline vapor soon filled the room. The rubbing of the chamois produced a spark which ignited the gasoline vapor and caused the explosion.
7th. “Chemical reaction”: Firemen have often noticed at fires when a pile of lumber was afire, that when they turned the stream of water on the burning pile it turned black and the fire was apparently ex tinguished, so they turned the stream in another direction. If they observe closely they will see little blue flames jump up from the burned wood and soon the whole pile starts afire again. This is caused by the chemical reaction of the burned wood which again absorbs the oxygen from the air and fire again takes place. Another case of chemical reaction occurs when a barrel containing powdered colors or paint gets wet on the bottom of the barrel, the contents generate heat which increases first to the flash point, then the igni tion point and finally the burning point and fire ensues.
8th. “Pressure, friction, falls and jarring”: Fire from pressure often occurs in haled paper that has been pressed too much when baling, also if baled paper is wet the paper will swell and it binding is strong enough, the paper is pressed and it will take fire in the center of the bale; lire from triction such as shafting out of line arid belts rubbing woodwork. Fire from falling material can occur in several ways. If we take a bag of flour and apply a torch to it we w ill find that it won’t take fire, but take the same bag of flour and dump it out of the sack down a shaft or chute with an open flame at the bottom and a terrific explosion results. I he reason for this is that the particles of flour in falling absorb the oxygen from the air on the way down and by the time they reach the light at the bottom are highly combustible. A ood many fires in factories and store houses that the re department have reported “cause unknown” have occured in just this way. Have you ever noticed at a fire that had started in the cellar or basement of an apartment or tenement house that before the firemen arrived the flames were bursting out the roof although the floors below were not on fire? This was caused by a dust explosion in the hanging ceiling, the superheated air or gases from the fire below’ found their way up by either airshaft, elevator shaft, pipe holes, hollow partitions, recesses, etc., and when they came in contact with the highly inflammable dust, an explosion took place. Particles of dust flying through the air act like absorbent sponges and collect gases and vapor from the air. This dust finds its way into hanging ceilings and spreads over the rafters and ignites with great rapidity, forming an atmosphere of hydrocarbons and carbon monoxide that furnishes, with the remaining air, a highly explosive mixture.
9th. “Focus Kays” : Fire caused by the rays of the sun focused through glass, etc.
Some Notes on Combustion
Spontaneous ignition point expresses the temperature at which a body takes fire.
Combustion point expresses the temperature at which burning starts.
Calorie expresses the unit measure of heat.
Extinguishing fires with water has a cooling action, reducing the temperature below the burning point.
Steam, when used in a confined space, excludes oxygen from the air and smothers the flame.
The three kinds of spontaneous ignition are:
Chemical, electrical and static electricity, and biological.
Substances causing spontaneous ignition:
By chemical action; acids, etc.
By electrical action; static electricity and lightning.
By biological; growth in hay and mildew.
Coal series of spontaneous ignition : Coal, coke, peat, carbon and lampblack.
Color and varnish series: Colors, varnish, resin and matches containing phosphorous.
Carbides and carries of oxygen: Nitrate acid and nitro compounds.
Artificial manure, dry manure, hay, clover, grass, moss, fodder, wool, cotton, silk, flax, hemp, tow, rope, oily rags, greasy clothing, polishing rags and buffing wheels.
Causes of spontaneous ignition:
4th. Storage in large heaps.
The above are four combined causes of spontaneous ignition in agriculture fodder and manure products.
5th. Spontaneous containing sulphur: In coal and lampblack series.
6th. Protractive drying: In wood series.
7th. Substances containing fat and oils: In paint series.
8th. Substances that absorb moisture: Quicklime, sodium and potassium.
9th. Exposure to the sun: Mixtures of chlorides and chorophus.
10th. Concentration of sun’s rays: Curtains, draperies, and empty volatile oil barrels.
11th. Electric sparks: Rubbing together of clothing in cleaning and dyeing establishments, causing static electricity setting fire to vapors.