Fire control knowledge
1, the fire extinguisher is a portable fire extinguisher that can be moved by manpower. It can put out the fire by spraying the filled extinguishing agent under the action of its internal pressure. Because of its simple structure, convenient operation and wide application, it has a certain effect on extinguishing the initial fire. Therefore, it can be seen almost everywhere in factories, enterprises, shops, warehouses, cars, ships, planes and other means of transportation, and has become a popular conventional fire-fighting weapon.
2. There are many kinds of fire extinguishers, which can be divided into portable and cart-type according to their moving modes; According to the power source of driving fire extinguishing agent, it can be divided into: gas cylinder type, pressure storage type and chemical reaction type; According to the fire extinguishing agent filled, it can be divided into foam, dry powder, carbon dioxide, acid and alkali, clear water and halon fire extinguishers.
3. At present, the air foam extinguisher developed in China is a new type of fire extinguisher with excellent performance. It can be filled with protein foam, fluoroprotein foam, light water (water film) foam and anti-solvent foam according to different needs, which can be used to put out the initial fires of various oils and polar solvents. Because of its low density, foam can cover the surface of flammable liquid. On the one hand, it can capture the liquid surface temperature (endothermic) and the coolant surface. On the other hand, after the liquid is completely covered with foam, an isolation layer is formed to block the air from contacting the liquid surface, and the fire is extinguished.
4. The primary condition of dust explosion is that the dust itself is combustible, that is, it can react with oxygen in the air. Such as coal powder, aluminum powder, flour, etc. Secondly, the dust should be suspended in the air to reach a certain concentration (exceeding its lower explosion limit), so that the dust surface can fully contact the air (oxygen) and the accumulated dust will not explode; Third, there should be enough initial energy to cause dust explosion. As long as the above three conditions are met at the same time, it will lead to dust explosion.
5. Call the fire alarm. It is necessary to find out the name of the fire unit, the town, the district, the street and the house number; Find out what's on fire. The size of the fire, whether anyone is besieged, whether there are explosive dangerous goods, etc. ; Make clear the name, unit and telephone number of the alarm person. And pay attention to listen to the fire brigade's inquiries and give accurate and concise answers. You can hang up when the other party makes it clear. Immediately after the alarm, send someone to the door of the unit to meet the fire truck at the street intersection, and lead the fire truck to the fire scene quickly.
6. Call the police around you.
1) In places where people are relatively concentrated, such as factory workshops, office buildings and residential areas. You can call the police by shouting and tapping the sound instrument.
2) When giving an alarm to the masses, try to let them know where the fire is, what it is, whether to inform them to put out the fire or to evacuate in an emergency. Indicate the location of the fire point to firefighters, and indicate the evacuation passage and direction to those who need to be evacuated.
7. All fire fighting measures are aimed at destroying the existing combustion conditions. According to the principle of material combustion and practical experience of fire extinguishing, there are four basic methods of fire extinguishing:
(1) isolation fire extinguishing method.
(2) asphyxiation fire extinguishing method.
(3) cooling fire extinguishing method.
(4) suppression fire extinguishing method.
8, common ignition energy can be divided into four categories:
9.( 1) Mechanical fire sources: such as friction, impact and adiabatic compression.
(2) Heat source: high temperature surface, thermal rays (including sunlight), etc.
(3) Electrical fire source: electric spark, electrostatic spark, lightning, etc.
(4) Chemical (or physical) fire sources: naked flame, chemical energy, spontaneous combustion due to heat, etc.
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1. The three conditions that cause fire are the coexistence and interaction of combustible, oxidant and ignition energy. The conditions leading to explosion are that explosives (including reductant and oxidant) or combustible substances (combustible gas, steam or dust) coexist and interact with air mixture and initiation energy. If measures are taken to avoid or eliminate one of the above situations, fire or explosion accidents can be prevented, which is the basic principle of fire prevention and explosion prevention. When formulating fire and explosion prevention measures, we can consider the following four aspects:
(1) Preventive measures. This is the most basic and important measure. We can divide the preventive measures into two categories: eliminating the material conditions (that is, the combination of combustible materials and oxygen ratio) and eliminating the energy conditions (that is, the ignition or detonation energy) that lead to the thermal disaster, thus fundamentally eliminating the possibility of ignition (detonation).
(2) restrictive measures. That is, when there is a fire and explosion accident. Measures to limit its spread and reduce its losses. For example, install fire prevention and pressure relief equipment, and set up firewalls and explosion-proof walls.
(3) Fire control measures. Equipped with necessary fire control measures, once an accidental fire occurs, it can be put out in time. Especially if the fire can be put out at the early stage of the fire, a big fire or explosion can be avoided. Broadly speaking, this is also a part of fire and explosion prevention measures.
(4) Evacuation measures. Take necessary measures in advance, such as setting safety doors or evacuation stairs and evacuation passages on buildings, planes and vehicles. In the event of a big fire, people or important materials can be quickly evacuated to a safe area to reduce losses.
10, in order to eliminate the material conditions that lead to fire and explosion disasters, we mainly consider the following three aspects:
(1) Try not to use or use less combustible materials in production. By improving the production process, developing new materials, replacing flammable and combustible materials with non-combustible or flame-retardant materials, and replacing dangerous materials with substances with low explosion risk, it is the fundamental measure for industrial fire prevention and explosion prevention, which should be considered first. Such as replacing flammable materials with flame retardant materials: replacing flammable solvents (such as gasoline, benzene, etc. ) Use nonflammable or nonflammable solvents; It is such a measure to replace wood support with metal and cement support under the mine.
(2) Take measures in explosive dangerous places to keep the concentration of combustible substances (combustible gas, steam and dust) in the air below the safety limit (the lower explosion limit is 10 safety margin).
(3) Strengthen the management of explosion hazards. In production, use, storage and transportation, targeted preventive measures should be taken according to their characteristics.
1 1. At present, the industries found to be in danger of dust explosion mainly include:
(1) metal industry (magnesium, titanium, aluminum powder, etc. )
(2) Coal industry (activated carbon, pulverized coal, etc. )
(3) Synthetic material industry (plastics, dye dust, etc. )
(4) Textile industry (cotton dust, hemp dust, paper dust, wood dust, etc. )
(5) Chemical fiber industry (polyester dust, polypropylene dust, etc. )
(6) Military industry and fireworks industry (gunpowder, explosive dust, etc. )
(7) Grain industry (flour, starch, etc. )
(8) Agricultural and sideline products processing industry (cotton dust, smoke dust, sugar dust, etc.). )
(9) Feed industry (blood meal, fish meal, etc. )
12, dry powder fire extinguisher is a kind of fire extinguisher with good efficiency. This is a combination device of fine powder and carbon dioxide. Using carbon dioxide gas as the power, the powder powder is sprayed and burned, and a chemical reaction occurs to inhibit the development of the fire, thus extinguishing the fire.
13. When using the dry powder fire extinguisher to extinguish the fire, first unplug the safety pin, hold the nozzle (or spray gun) with one hand, and lift the bail (or handle) with the other hand. Aim the nozzle at the root of the flame, and dry powder will be sprayed from the nozzle to the flame, forming a thick cloud-like powder mist. When putting out the oil fire on the ground, we should take a flat posture, swing the hose from left to right, and advance quickly from far to near. If the cylinder is turned upside down several times before use, the dry powder will be loosened, and the effect will be better.
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14, which can effectively destroy the combustion conditions in the combustion zone, inhibit combustion or stop combustion, is called fire extinguishing agent.
15, the basic requirements for fire extinguishing agent are: high efficiency, convenient access, basically harmless to human body and objects, and low cost.
16, dry powder fire extinguishing agent is mainly used to put out fires of various water-insoluble and water-soluble flammable flammable liquids, as well as fires of flammable gases such as natural gas and petroleum gas and fires of general live equipment. When extinguishing water-insoluble flammable and combustible liquid fires, fluoroprotein foam can be used to achieve better fire extinguishing effect and effectively prevent re-ignition.
17, dry powder is a dry, flowable solid powder with good moisture resistance and anti-caking, also known as powder fire extinguishing agent. At present, there are two types:
(1) Ordinary dry powder fire extinguishing agent (also known as BC dry powder fire extinguishing agent) consists of sodium bicarbonate (92%), activated clay (4%), mica powder and anti-caking additive (4%).
(2) Multipurpose dry powder fire extinguishing agent (also known as ABC dry powder fire extinguishing agent) consists of sodium dihydrogen phosphate (75%) and ammonium sulfate (20%), catalyst, anti-caking agent (3%), activated clay (1.85%) and iron oxide yellow (0. 15%).
18, dry powder fire extinguishing agent is usually stored in dry powder fire extinguishers or fire extinguishing equipment. When extinguishing the fire, dry powder is sprayed from the nozzle by pressurized gas (carbon dioxide or nitrogen) to form a mist powder flow, which is emitted to the combustion zone. When dry powder extinguishing agent comes into contact with flame, a series of physical and chemical reactions will occur to extinguish the fire.
19, dry powder fire extinguisher: (1) Dry powder stored pressure fire extinguisher (portable) uses nitrogen as power to squeeze dry powder out of the cylinder. Suitable for fighting fires of petroleum products, paints and organic solvents. Can inhibit the chain reaction of combustion and put out the fire. It is also suitable for extinguishing liquid, gas and electrical fires (dry powder has electrical insulation performance above 50 kV). Some can also put out solid fires. (2) Dry powder fire extinguisher can't put out the light metal burning fire. (3) When using, unplug the safety pin (have a plenty of pull rings) first, and then press the handle to spray dry powder. (4) When putting out the fire, be close to the flame nozzle; The injection time of dry powder is short, so it is necessary to choose the injection target before injection. Because dry powder is easy to drift, it is not suitable for upwind spraying. (5) Pay attention to the maintenance of the fire extinguisher, and put it in a place that is easy to access, dry and ventilated. Check whether the dry powder is caked twice a year, and replace it if there is a joint; Check the weight of medicine once a year. If it is less than the specified weight or the pressure drops as follows, it should be filled in time. (6) When the dry powder cart is used, first push the cart fire extinguisher to the vicinity of the fire source quickly, pull out the spray hose and straighten it, pull out the safety pin, open the handle of the straightening door, and aim at the root of the flame to make the powder mist sweep the key flame. Pay attention to cut off the fire source, control the flame to retreat, and push the fire from near to far. (7) The effective range of dry powder fire extinguisher (MFZ) is 2.5m for 2-3kg, 4m for 4-5kg, and the time is 8-9seconds. 8kg range 5m, time 12 seconds. (MFTZ) The effective range of 35-50kg cart is 8m, and the time is 20 seconds. A 70 kg cart with a range of 9 meters and a time of 25 seconds. 20. Carbon dioxide fire extinguisher: (1) Carbon dioxide fire extinguishers all use carbon dioxide gas stored in high-pressure gas cylinders as fire extinguishing agent, leaving no trace after fire extinguishing, and are suitable for fire extinguishing in places such as valuable instruments and equipment, archives and computer rooms. It is also suitable for extinguishing live low-voltage electrical equipment and oil fires, but it cannot be used to extinguish fires of potassium, sodium, magnesium, aluminum and other substances. (2) When in use, unplug the duckbill safety pin first, and then press the handle; Secondly, remove the handwheel-type lead seal, and then rotate the handwheel counterclockwise to spray the medicine. Be careful not to touch the loudspeaker with your fingers to prevent frostbite. (3) The carbon dioxide fire extinguisher has a short range and should be close to the fire point and sprayed in the upwind direction. (4) Check the carbon dioxide fire extinguisher regularly. When the weight is less than 5%, it should be inflated and replaced in time.
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2 1, halon fire extinguisher (commonly known as "121"fire extinguisher and "130 1" fire extinguisher): (1) "/kloc-0. When putting out the fire, it does not pollute the goods and leave no trace, and is especially suitable for putting out fires such as precision instruments, electronic equipment and cultural relics. Its fire extinguishing principle is also to inhibit the chain reaction of continuous combustion, which is also suitable for fighting oil fires. (2) When in use, unplug the safety pin first, then hold the knob switch tightly, and the medicine will pop up. When in use, the fire extinguisher cylinder should be vertical, and horizontal or inverted use is not allowed. It has a short range, so when spraying, you should stand on the upper hand, close to the fire point, shoot at the root of the fire source, and push forward, paying attention to prevent re-ignition. (3) The nitrogen pressure of "1211"fire extinguisher should be checked every three months, and the weight and pressure of drugs should be checked every six months. If the weight of the medicine is reduced by 10%, it should be re-inflated and filled with medicine. (4) "1211"fire extinguisher. The effective range of 1kg is 2.5m, that of 2-3kg is 3.5m, and that of 4 seconds is 4.5m.. "12 1 1" cart effective range: 25kg range 8m, 20s, 40kg range 8m, 25s. (5) Halogenated fire extinguishers are not advocated because of their impact on environmental protection. 22. foam extinguisher: (1) At present, it is mainly chemical foam. It is necessary to develop air foam in the future, which can cover the surface of combustible materials and prevent air from entering. It is most suitable for putting out liquid fires, but it cannot put out water-soluble flammable flammable liquid fires (such as alcohol, ester, ether, ketone and other substances) and electrical appliances fires. (2) When using, first block the nozzle with your fingers, and turn the cylinder upside down twice, and the foam will be sprayed out. For oil fires, it is not allowed to spray in the center of the oil surface to prevent the burning oil from spraying out and spraying upward along the periphery of the root of the fire, gradually covering the oil surface and extinguishing the fire. When using, do not point the cylinder head at the bottom of the cylinder at the human body to avoid danger. (3) Chemicals in gas cylinders are generally replaced once every six months, at the latest once a year. In winter and summer, we should do a good job in antifreeze and sun protection. (4) Use of the foam cart: First, push the cart near the fire source, straighten the spray hose, move the cart cylinder slightly upward, turn the handwheel, straighten the valve handle, immediately touch the ground with the handle and the cylinder, and cover the key fire sources around the root of the fire source with the spray gun head. (5) The spraying distance of foam MP6m fire extinguisher (10L) is 5m, the range of time 35s65L is 9m, and the time is about150s. 23. Clear water fire extinguisher: the main spray is water, which is the same as the function of acid-base fire extinguisher. When in use, there is no need to pour the bucket. Take off the helmet first, and then hit the convex head hard, so that water will spray out of the nozzle. Mainly used for cooling, can only put out general solid fires (such as bamboo and wood, textiles, etc. ), but does not include liquid and electrical fires. 24. Selection of different types of fire extinguishers: (1) Water-type, foam, ammonium phosphate dry powder and halon fire extinguishers should be selected to put out Class A fires, that is, solid burning fires. (2) Dry powder, foam, halon and carbon dioxide fire extinguishers should be selected to put out Class B fires, that is, liquid fires and fusible solid fires (it is worth noting here that chemical foam extinguisher can't put out Class B polar solvent fires, because chemical foam will be quickly absorbed when it comes into contact with organic solvents, making the foam disappear quickly, thus failing to put out the fire. Alcohol, aldehyde, ketone, ether, ester, etc. Are polar solvents). (3) To put out Class C fire, that is, gas burning fire, dry powder, haloalkane and carbon dioxide fire extinguishers should be used. (4) Haloalkane, carbon dioxide and dry powder fire extinguishers should be selected for fire extinguishing. (5) As far as the current situation in China is concerned, there is no finalized fire extinguisher product for Class D fires, that is, metal burning fires. At present, there are mainly powder graphite fire extinguishers and special dry powder fire extinguishers to put out metal fires abroad. Dry sand or cast iron foam can be used to extinguish the fire when the domestic fire extinguisher and extinguishing agent beads have not been finalized. 25. How to use common fire extinguishers and identification of their signs There are only three common portable fire extinguishers: portable dry powder fire extinguishers, portable carbon dioxide fire extinguishers and portable halogenated fire extinguishers. Among them, most ammonium phosphate dry powder fire extinguishers (commonly known as ABC dry powder fire extinguishers) and carbon dioxide fire extinguishers are used in hotels, restaurants, theaters, hospitals, schools and other public gathering places, and sodium bicarbonate dry powder fire extinguishers (commonly known as BC dry powder fire extinguishers) are used for refueling and filling stations.