【 Weak current College 】 firefighting basics---Power By 【 China power house network 】

A basic principle, fire fighting
By combustion must have some basic conditions that the fire was the destruction of combustion conditions in which the combustion reaction terminates the process. Its basic principle summarized into the following four aspects: cooling, chemistry asphyxiated, isolation and depression.
1. cooling fire: on General fuel, one of the conditions of continuous combustion is their flame or heat of the action has reached the respective ignition temperature. Therefore, the General fuel fires, will fuel cooling to their ignition or flash point below the combustion reaction will be aborted. Water fire extinguishing mechanism is primarily a cooling effect.
2. smothering: various fuel combustion must be at its minimum oxygen concentration above, otherwise you cannot sustain combustion. Therefore, by reducing combustion of oxygen concentration around the fire. Usually use carbon dioxide, nitrogen, water vapour and other fire-fighting mechanism mainly suffocation.
3. isolation of fire: the fuel and ignition or oxygen separation, combustion reaction is automatically aborted. Fire, close the valve, cut off the flow to the fire zone of combustible gases and liquids; open the valve so that the containers have been burning or affected by the fire threat liquids in containers of fuel through the pipeline to a security zone, are quarantined fire.
4. chemical suppression fire: is the use of extinguishing agent and chain reaction intermediate of radical reactions, allowing combustion chain reaction will not interrupt the combustion. Common powder extinguishing agent, halon fire extinguishing agent's main fighting mechanism is chemical restraint.

Second, several common extinguishing agent and fire extinguishers
(A) several commonly used fire extinguishing agent
1. water is the most widely distributed in nature, the cheapest fire extinguishing agent, because the water has a high specific heat (4.186J/g ° c) and the latent heat of (2260J/g), the fire in the cooling effect is very clear that its fire extinguishing mechanism relies mainly on the role of cooling and suffocation. The main disadvantage of water fire extinguishing agent is to produce water loss and pollution, cannot be used for live-fire fighting.
2. foam extinguishing agent: through water miscible, mechanical or chemical methods to produce foam fire extinguishing agent. By chemical substances, protein or surface active agents and other additives for aqueous solution. Usually there are chemical foam fire extinguishing agent, mechanical epigastric and base foam, foam detergent. Foam extinguishing mechanism is cooling and suffocation of the fire burning on the surface, forming a continuous foam layer, through the foam itself and precipitates mixture on combustion surface for cooling, as well as through the foam layer of coverage of the combustion of oxygen insulation and fire-fighting. Foam extinguishing agent's main disadvantage is that water loss and pollution, cannot be used for live-fire fighting.
At present, in fire-extinguishing system in the use of foam mainly air machinery epigastric base foam. By foaming ratio can be divided into three types: foaming multiples of 20 times the following referred to as low expansion foam; 21---200 times between called foam; 201-1000 times between as and high-expansion foam.
3. is used for fire extinguishing agent: fire drying, easy-to-mobile fine powder, consisting of a fire and a small amount of inorganic additives by drying, crushing, a mixture composed of fine powder. Mainly chemical fire suppression and suffocation. In addition to fight metal fire special powder extinguishing agent, the common powder extinguishing agent will generally be divided into BC powder extinguishing agent and ABC powder extinguishing agent, such as sodium bicarbonate powder, modified sodium salt powder, dry ammonium dihydrogen phosphate, phosphoric acid, diammonium phosphate powder, powder, etc.
Powder extinguishing agent mainly by the action of gases under pressure of powder spray and flame exposure, mixing occurs when the physical and chemical effects of fire. A by dry powder of inorganic salts of volatile decomposition and combustion in combustion produces free radicals or reactive chemically inhibiting and negative chemical catalyst so that the interruption of polymerase chain reaction; the second is by extinguishing the dry powder into fuel, chemical reaction on the surface, and in high-temperature formation under a layer of mulch layer, thereby cut off oxygen smothering. The main disadvantage of dry powder fire extinguishing agent is for precision fire polluting.
4. carbon dioxide is a gas fire extinguishing agent, in the nature there is also a wider, low price, easy, its fire extinguishing acquired depend mainly on suffocation and some cooling effect. The main disadvantage is the high concentration of fire needed, making people affected by the poisoned asphyxia.
5. halon fire-extinguishing its mechanism is halon contact high temperature surface or flame, decomposition of activity of free radicals, bromine and fluorine and other halogen hydrides of negative chemical Catalysis and chemical cleaning effect, a large number of spring catch, combustion chain reaction of free radicals, destructive and suppressed combustion of rapid polymerase chain reaction, which will fire fight; rely on chemical fire suppression effect. In addition, there are some diluted oxygen and cooling effect. Halon fire extinguishing agent major drawback is the destruction of the ozone layer. Current common Halon 1211 fire-extinguishing agent and 1301. 1211 fire-extinguishing agent of molecular formula for CF2ClBr, is the most expensive a halon fire extinguishing agent. 1211 fire extinguishing agent is a low boiling point of liquefied gas, fire extinguishing effect high, low toxicity, corrosivity, long storage and eradicating corruption, track-fire fighting back, no pollution of the protected materials, electric insulation properties, etc., but its good chemical stability, damage to the ozone layer in the atmosphere, the more serious as this internationally advanced work States have begun to retire. After China in 2010 will also be eliminated. 1301 fire extinguishing agent for less toxic, halon fire extinguishing agent is low in toxicity, so you can use in some situations, but stability than 1301 1211 fire extinguishing agent, on the destruction of the ozone layer in the atmosphere, therefore it is necessary to substitute products.

(2) the introduction of several commonly used fire extinguishers
Fire extinguisher is determined by the cylinder, head, nozzles, etc, with driving pressure moves the filling out of the fire extinguishing agent, fire-fighting purposes. Is the beginning of fire fighting important fire equipment. Fire extinguishing agents by the filling can be divided into foam, dry powder, halon, Carbon dioxide, acid and alkali, clear water, etc.
1. foam fire extinguishers: means the extinguisher filling of the foam fire extinguishing agent, can be divided into chemical foam fire extinguishers and air-foam fire extinguishers.
Chemical foam fire extinguishers containing aluminum sulfate (acidic) and sodium bicarbonate (alkaline) two chemicals. When used, two solutions mixed reaction produces foam and pressure blasting out for fire-fighting. Air-foam fire extinguishers filling the air foam fire extinguishing agent, its performance is fine, save the validity period, fire, easy to use, is a chemical foam extinguisher replacement products. It can be applied according to different needs filling protein foam, f protein foam, polymer foams, light-water (water film) foam and foam, etc.
The scope of application of the foam fire extinguishers is class b, class a charged fire; fire is not applicable and c, class d fires. Anti-stripping foam fire extinguishers can fight water-soluble flammable, combustible liquid fire.
Chemical foam fire extinguishers for use: portable cylinder upper mentioned ring near fire ignition point, 10 meters, over the top to the cylinder, a hand hold references to the ring with one hand and hold the bottom circle, the cylinder will Jet at combustion. In case of fire extinguishing combustible liquids, such as combustion is flowing shape, the foam from far and near Jet, make foam covered entirely in combustion liquids; such as combustion within the container, the container wall foam, foam flowing along the inner wall of the container, gradually covering the burning surface. Do not spray liquid directly aligned to avoid impact due to Jet will be burning liquid out of the container to expand the range of combustion. In case of fire extinguishing solid, Jet at the burning fire at the fiercest. In the course of using, fire extinguishers should always be upside-down state, otherwise disrupt Jet.
Chemical foam fire extinguishers maintenance requirements:
(1) where in cool, dry and ventilated, and access to a convenient location. Not close to high temperatures or under sunlight exposure in case of sodium bicarbonate decomposition, winter to antifreeze, and regularly check the nozzle is blocked so that it remains open.
(2) each year to periodically check whether the failure of sodium bicarbonate solution. Inspection method is taken from the body in three sodium bicarbonate solution, remove the bottle tank a sulfate solution, two solutions quickly to look into the measuring cup, produces foam is greater than four solutions to more than double the volume of 6. If less than 6 times, you should replace the extinguishing agent.
(3) each time you replace fire extinguishing agents or use a full two years, the annual water pressure test, the test pressure for the fire test pressure 1.5 times test before continuing to use, and a fire extinguisher pressure test date indicated on your test.
Air-foam fire extinguishers, fire extinguisher with method: will be referred to the distance from the burning of 6 meters, pull out the insurance sold in one hand holding the opening pressure, another hand grip spray gun, pinch the opening pressure to open the sealed or Pierce gas cylinder gasket, the air bubble can be exhaled from the Lance. Fire-fighting methods and the same chemical extinguisher. But unlike chemical foam fire extinguishers, air-foam fire extinguishers, fire extinguisher in use, should be upright, not upside down, or lying, otherwise disrupt Jet; nor can they release the opening pressure, otherwise also breaks Jet.
Air-foam fire extinguishers maintenance
(1) fire extinguishers should be placed in a cool, dry and ventilated, and access to a convenient location. Environment temperature should be 4 ~ 40 ° c, winter should be aware of antifreeze.
(2) to regularly check the nozzle is blocked so that it remains open. Half-yearly check fire extinguishers are there working pressure. On the reservoir pressure type air-foam fire extinguishers simply check pressure display tables, such as a table-pin point to red areas that should be repaired in a timely manner; on the gas cylinder air foam fire extinguishers, you want to open the device cover check CO2 gas cylinder, check weighing whether the weight of the cylinder, cylinder as less than 25 grams weight shall be inspected for repair.
(3) each time you replace the extinguishing agent or factory is three years, to deal with fire extinguishers, water pressure and water pressure strength test of strength to continue using the competency.
(4) fire extinguisher inspection should be performed by a trained professional staff, maintenance should be made maintenance license of professional units.
2. carbon dioxide fire extinguisher, carbon-dioxide fire extinguishers: using its internal filling of liquid carbon dioxide vapor pressure of carbon dioxide fire extinguishing spray out. Because carbon dioxide with track-fire fighting, and have some electric insulation properties, and other characteristics, and therefore more suitable for extinguishing 600 volts of electric appliances, valuable equipment, books, instruments, and other places of the beginning of the fire, and General fire flammable liquids. That is, its scope is A, class b fire of fire and low voltage electrification.
When using carbon dioxide extinguisher, a fire extinguisher referred or carry the fire burning in the distance of 5 meters above sea level, put down the fire extinguisher, pull out the insurance sold in one hand hold souba barrel root handle with one hand and hold the on-off valve, the pressure put on no spray hose extinguisher should push on megaphone to 70-90 degrees, use, and not directly by hand to seize megaphone wall or metal connection pipe to prevent hands were frostbitten. Fire, when the combustible liquid is flowing like Burns, users should be carbon dioxide of Jet from near and far to flame Jet; if combustible liquids in containers Burns, users should lift the megaphone, from one side of the upper part of the container to the combustion of container injection, but cannot be a direct impact on carbon dioxide Jet combustible liquids to prevent combustible liquid out of the container and the expansion of the fire, the fire caused difficulties.
Trolley carbon dioxide fire extinguishers General consists of two individual operations, when used by two people together will push or pull to fire extinguishers, fire department, a burning from 10 meters to stop a person quickly remove the megaphone and expand the Jet hose, hold megaphone root handle, another rapid clockwise rotation handwheel, and drove up to the maximum position. Fire-fighting methods and portable way.
Carbon dioxide fire extinguishers, outdoor use, you should select the poop Jet, indoor narrow space use, fire after the operator should leave promptly to prevent suffocation.
Carbon dioxide fire extinguisher maintenance:
(1) fire extinguishers deposited in theA cool, dry and ventilated places, not close to the fire, environment temperature should be-5 + 45 degrees.
(2) fire extinguishers should be checked every six months once weight check weighing method. Called out of weight and a fire extinguisher cylinder bottom play compared to the total weight of stamp, if lower than the amount shown on the stamp of 50 grams, maintenance and repair units should be sent.
(3) each time you use or after every five years, should be sent to the hydraulic test maintenance unit. Hydrostatic test pressure shall be stamped on the bottom of the cylinders of the same numerical value, hydrostatic test and also deal with the cylinder of residual deformation rate determination, only the water pressure test qualified and residual deformation rate is less than 6 cylinders in order to continue using it.
3. a halon fire extinguishers: where internal filling halon fire extinguishers are collectively referred to as halon fire extinguishers. Commonly used 1211 and 1301 fire extinguishers.
1211 fire extinguishers uses racked in the nitrogen pressure in the cylinder will 1211 fire-extinguishing spray out. Since 1211 fire-extinguishing agent is chemical suppression, its fire extinguishing efficiency is very high, with no pollution, insulation, etc., can be applied to all metal fire fire, especially suitable for fighting precision instruments, computer, relics and precious materials warehouse, the beginning of the fire. 1
1211 fire extinguishers when used, should be a reference to the portable fire extinguishers or shoulder fire extinguishers, fire extinguisher into the scene will be. From combustion of 5 meters above sea level, put down the fire extinguishers, first pull out the insurance sold in one hand holding the opening pressure, another hand in front of the Jet hose nozzles, such as fire extinguishers without blast hose, hand holding the opening pressure, another hand live fire extinguishers at the bottom of the base circle. Burning the nozzle alignment, firmly hold the opening pressure, so that the fire extinguisher Jet. When fighting combustible liquid is flowing like Burns, users should access the fire point from near and far and fast forward about fire, until the flame all fight. If combustible liquids in containers of combustion, flame fire, when around shaking flame was driven out of the container, the Jet stream with flame fire until the fire extinguished, but all should be careful not to spray the Jet direct combustion liquids to prevent fire extinguishing agent will cushion the impact of combustible liquid out of the container and the expansion of the fire, the fire caused difficulties. If you fight combustible solid surface material of the beginning of the fire, the Jet at spray combustion is the most violent, when the flame is extinguished, shall promptly take measures to prevent its recurrence. 1211 fire extinguishers to use couldn't upside down, or lying, otherwise the agent is spraying out. In addition to outdoor use, you should select the poop Jet, in the narrow space of indoor fire extinguishing, fire after the operator should rapidly spread out, because of the 1211 fire-extinguishing agent also has some toxic, to prevent harm to the human body.
1211 fire extinguisher maintenance:
(1) should be stored in ventilated, dry, cool and convenience, environment temperature should be between-10-+ 45 degrees as well.
(2) do not store near the heating equipment or direct sunlight should be placed in the Sun's position and a strong corrosive.
(3) every six months or so check fire extinguishers on internal pressure monitor, if it is discovered that the pointer has been reduced to the Red areas, the maintenance department should be promptly taken.
(4) each time you use a surplus after regardless of whether it should send the maintenance Department for refillable, each time you refill or out-of-three years, the hydraulic pressure test should be carried out, test pressure and label on the label of the same value, the test may continue to use.
(5) If a fire extinguisher on the internal pressure display tables, use the weighing method, when called by weight is less than the indicated weight of 90%, you should send the maintenance Department for repair. In the actual purchase should buy pressure display is an internal table of the 1211 fire extinguishers as well.
1301 fire extinguishers: 1301 fire extinguisher internal filling of extinguishing agent for a third of fluoride, methyl bromide, the molecular formula for CF2Br fire extinguishers, agent is colorless transparent liquid, but its low boiling point, vapour pressure higher, 1301 fire extinguisher cylinder compression, its wall thickness are thicker, with particular attention to could not be 1301 fire extinguishing agent filling the 1211 fire extinguisher cylinders, otherwise very prone to the risk of explosion.
1301 the use and maintenance of fire extinguishers
1301 fire extinguishers for use, and the same scope and 1211 fire extinguisher, but because 1301 fire extinguishing agent emit gas mist, outdoor wind conditions, the fire-fighting capability no 1211 fire extinguishers should be high, therefore the poop Jet.
Its maintenance is also the same with the 1211 fire extinguishers, fire extinguisher can see 1211.
4. dry-powder fire extinguisher: dry powder fire extinguishers to liquid carbon dioxide or nitrogen as dynamic and the will of the extinguisher powder extinguishing agent is spraying out the fire. It applies to fight petroleum and its products, flammable liquids, flammable gases, flammable solids such as of the beginning of the fire. Due to the dry powder has more than 5 million Volt electric insulation properties, can also fire extinguishing live equipment. This fire is widely used in factories, mines, oil and transport etc.
Dry powder extinguisher scope: sodium bicarbonate dry chemical fire extinguisher suitable for flammable and combustible liquids, gases and the beginning of the line equipment; fire extinguishers in addition to the ammonium salt can be used for these types of fire, fighting solid substances in the beginning of a fire. But none can fire extinguishing light metal combustion.
Use dry chemical extinguisher, mobile or shoulder fire quickly rushed to the scene, the combustion of 5 meters above sea level, put down the fire extinguisher. If outdoors, you should select the poop Jet. Use dry chemical fire extinguisher if plug-in-gas cylinder, the operator should hand grip spray gun, the other hand lift the gas cylinder opens mentioned on. If the opening of the gas cylinder is hand wheel, then press the reverse time direction of swing and swing to the highest position, then lift the fire extinguisher. When the dry powder spray, quick alignment fire flame roots. Use dry chemical fire extinguisher if built-in air tank or reservoir pressure, the operator should be open to the insurance on the PIN Dial, and then hold the nozzle spray hose front-end, other roots will open the pressure put pressure, open fire extinguishers for injection. Have a blast hose, fire extinguisher or reservoir pressure type fire extinguishers, in use, one should always put the pressure down, can't let go, otherwise disrupt Jet。
Dry powder fire extinguishing combustible, flammable liquid fires, fire flame root should prevail. Who is fighting for flowed liquid fires are burning, you should access the flame root from near and far, and around the fire until the fire all the fight. If combustible liquids in containers, the consumer should prevail fire flame root to enable around shaking out of dry powder spray flow covers the entire surface of the container openings; when the flame is out of the container, the user should continue to spray until all the flame extinguished. In extinguishing the fire of flammable liquids in containers and should be can't direct the nozzle at the surface of the liquid spray to prevent Jet impact the combustible liquid Jet and the expansion of the fire, the fire caused difficulties. If combustible liquid in metal containers burning time, container wall temperature is higher than was fighting the ignition of flammable liquids, at this point, it is easy to result when fighting fire, can be combined with the bubble class fire extinguishers, fire extinguishing effect is better.
Dry powder fire extinguisher maintenance
(1) fire extinguishers should be placed in well-ventilated and dry place and have access to convenient place, environment temperature:-5-+ 45 degrees as well
(2) fire extinguishers should avoid high temperature, humidity and have serious corrosion occasions to prevent caking, decomposition powder extinguishing agent.
(3) half-yearly check whether dry powder caking, gas cylinder in carbon dioxide gas is leaking. Check for carbon dioxide gas cylinders, gas cylinder should be removed weighing, calling out the weight and gas cylinder on the stamp of the target value are the same, if less than the standard value 7 grams, should send the maintenance Department for repair. In the case of reservoir pressure type then check its internal pressure display table pointer is in the green zone. If the pointer is in the red zone, the internal pressure leak is not available, the maintenance department should be sent as soon as possible.
(4) fire extinguishers shall be open to refill, refillable, cannot transform the kinds of dry powder fire extinguishing agent, i.e. sodium bicarbonate dry chemical fire extinguisher cannot be switched to ammonium phosphate powder extinguishing agent.
(5) each time you refill or fire extinguishers factory after three years, hydrostatic test should be carried out, the hydraulic test on the extinguisher and gas cylinder should be conducted separately. Its hydrostatic test pressure shall be labelled with the fire extinguishers or stamp shows the same pressure. Hydraulic test qualified before filling using again.
(6) maintenance must be determined by a trained person in charge, repair, refillable should send professional maintenance unit.