Extinguishing a domestic fire: through a keyhole
Fire –– the process of uncontrolled burning,
Household fire can try to put outindependently, first depriving it of fuel — gas or electricity, and then oxygen. A small hearth is overwhelmed, for example, with a cloth, and with a larger fire extinguisher cope with a special composition. It is worth remembering that solid fuel is poured with water –– wood, leaves, coal. If oily flammable substances burn, use a fire extinguisher.
The powder for the fire extinguisher includespotassium phosphate salts, alkali metals and their chlorides, silica gel saturated with freon. After using the powder fire extinguisher use the burning object will not work. A more expensive alternative is carbon dioxide OS, the gas from which evaporates after spraying.
All fire extinguishers, including water ones, haveOne drawback is the difficulty of disposal. This is an explosive scrap that requires cleaning and parsing. Ordinary consumers often do not know about these difficulties.
In calm conditions, firefighters usespraying water or an indirect jet that is directed to the ceiling. A direct jet hits right in the seat of fire, “choking” the flame. After two hoses, the fire can be extinguished with both a regular stream and a spray - this method is popular in conditions of rapid spread of fire.
Firefighters usually have one or two points, fromwhich they serve water. At the same time, a large area of a door or window opening becomes a minus rather than a plus –– extinguishing takes place in a small area, to which the jet is directly directed. The fire depends on the intensity of the flame, but to eliminate it instantly will not work in any case.
Smaller and faster: "water machines"
Paradoxical solution: to extinguish a fire you need only one hole with a diameter of several millimeters. The “water machine” technology was developed by PyroLance in 2006. At first, the technology was used by the US Navy and the US Navy, and after the military test, it was used by civilian firefighters. The installation cost ranges from $ 15 thousand to $ 80 thousand.
The principle of the "water machine" is basedon waterjet cutting. This is the technology of cutting materials with the help of a water jet produced under high pressure of 4 thousand at. On a hard surface –– concrete, steel or bulletproof glass –– direct a mixture of water and granite chips that punches a small hole.
The development came up with a pathetic slogan: “Water of fire power”, and this partly has the right to life. A jet of droplets of 1/64 in size from a normal under high pressure of 4 thousand atm is sent to the wall and makes a small three-millimeter “well” in it through which water is sprayed around the room. Additionally, “compressed” water picks up speed about three to four times the speed of sound. The results are impressive - the device copes with a fire of 700 ° C in a minute.
The area of the spray surface grows in16–20 times: the usual fire jet spends about 90% of the water in vain, falling into the zone of already extinguished fire. The "water machine" sprays so that 90% of the water absorbs heat, and the remaining 10% goes into steam. Such a transition from one state to another acts as an additional cooling factor, because the heat capacity of water vapor reaches 56,530 J / kg · ° C, while a similar indicator of water is 4,220 J / kg · ° C.
"Water machine" can be used to extinguishdomestic fires, and in cases of more serious fires, when you cannot get directly to the fire. A big plus of this technology is its safety. Firefighters do not need to go into a burning room to install equipment, and therefore the risk to life is seriously reduced.
In addition, "air machines" do not spraychemical elements that can gradually poison a person using the room in the future. The targeting of this development does not harm the environment. But the following method of alternative fire extinguishing strongly influences the ecological situation of the environment where it is used.
How to blow a fire: bombs and waves
Although fires differ in intensity andthe scale, the principle of their appearance is the same: the triad "heat - fuel - oxygen". By the same principle, industrial fires appear, which are more difficult and more dangerous to eliminate. The most effective way to get rid of a raging fire is to cut off the flow of fuel. The question is how to do it.
In the age of "peaceful atom" its use wasubiquitous and related, including industry. The use of nuclear charges for peaceful purposes began in 1965, at the Semipalatinsk test site. One of the first tests was the attempt to create a habitable lake. In a well at a depth of 178 m, a charge of 170 kt was laid. As a result of the explosion, a 400-meter lake Chagan appeared on the map, practically unsuitable for life of living organisms –– 90% of organisms submerged into the water died and the survivors mutated. It became clear that it is impossible to create life with the help of an atom. But you can save.
One of the most famous fires extinguishedthe explosion began on December 1, 1963 at the gas well Urta-Bulak in the territory of present-day Uzbekistan. Due to the abnormal underground pressure of 300 atm, the drilling rig entered the rock too sharply: the tower overturned, and the gas rose above the ground and ignited. The fire lasted for 1074 days, and every day 12 million cubic meters burned in Urta-Bulak. m of gas –– this is enough to provide for the millionaire city. The gas torch even tried to shoot down with the help of ballistic weapons, but attempts were unsuccessful.
Finally, in the fall of 1966, after the testtechnologies for drilling additional adit, a nuclear charge was placed near the well. An explosion with a capacity of 30 kt displaced rock strata that blocked the gas outlet, stopping burning. 22 seconds after the explosion - it took so much time to stop the fire that lasted three years.
The longest fires, because of which peopleI had to leave the city, started not on the ground, but under it. The bowels of the city of Centreilia in the state of Pennsylvania have been burning for 57 years: an underground fire began because of the negligence of firefighters. The Burning Mountain, a stone gorge in Sulzbach, burns even longer: the place became a landmark because of a 331-year-old fire. This is not the only mountain fire: in Canada there are Smoking Hills, a fire in which was discovered in 1826. How many actually lasts burning, nobody knows.
Nuclear explosions do not pass without a trace. If the well at Urta-Bulak was immediately sealed in order to stop the spread of radiation, then repeated attempts to use charges in the oil and gas industry were the cause of disastrous radioactive contamination.
In the summer of 1972, to shut off the gas columnfield in the Kharkiv region, oil and gas used a charge with a capacity of 3.8 kt. He released a gas fountain out of the ground, created a nuclear “mushroom” and caused radiation pollution of the environment. Unpolished gas torch was eliminated by instillation of a well. Residents of the nearest villages of Krestyshche and Pershotravnevoe, who subsequently sought medical assistance, were not recognized as victims directly by the explosion.
The underground explosion mechanism is based on the principledisplacement of rock layers. A powerful charge "shakes" and brings down the adjacent layers of the earth, changing its microstructure. New channels are open, and the old ones, which were required to “block”, are sealed. The explosion tamps the soil, making it impermeable both from the depth and from the surface.
It doesn't matter how people use nuclear warheads. It is important that they continue to be nuclear. This means that an explosion that occurs due to atomic fission and synthesis is fraught with radiation pollution. Although this method can help extinguish underground fires, its price is too high.
A safer method of extinguishing fires withThe explosions were invented by the Australian scientist Graeme Doig of the University of New South Wales. Its development is a four-meter steel pipe in which the projectile is exploded. The concentrated shock wave is squeezed out of the pipe in the direction of an open flame.
The flame is extinguished not because of the air itself, but becausewhich turns out to be cut off from the fuel source. In the demo experiment Doig he was propane burner. The scientist explains: "As soon as the flame loses its fuel, it stops burning."
The speed of spreading forest fire starts from 4,500 m / h. If the technology turns out to be mastered, then the fire will be blown off from the tops of burning trees, and then extinguish the lower layers of the forest.
While Doig technology does not look like somethingable to extinguish forest fires: the pipe allows you to blow off a small flame, while in the forest can burn more than 100 square meters. In addition, helicopters are not able to lift large amounts of fuel for an explosion at height. These factors encourage further research on the effects of waves on a fire.
Australian "explosive" gun - not the onlyfire installation using the power of the waves to extinguish the fire. Two American students from the University of Virginia, Viet Tran and Seth Robertson, developed a special manual column that allows you to extinguish the flames. The fire is affected by low frequencies from 30 to 60 Hz. Sound waves move oxygen, and the specific sound frequency separates the flame molecules from the environment.
Acoustic waves accelerate the rate of evaporationfuel, reducing the temperature of the fire. In addition, the waves shift the oxygen needed for combustion, reducing its concentration around the flame. Although the fire can flare up with a new force after turning off the column, the sound stops the burning process. Unlike classic fire extinguishers, this technology acts precisely and does not waste extra resources.
Today technologies allow making classicfire extinguishing devices are smaller and more efficient, but they all work according to the same principle of chemical or water spraying. Radically alternative methods of extinguishing the flame are highly specialized. Some, as eco-friendly wave devices, are still at the design stage. Others, like nuclear explosions, are too dangerous for humans and the environment. Firefighting is an area that constantly needs new and more effective methods.