(A) the definition of combustion
Combustion, commonly known as fire, refers to the exothermic reaction between combustible and oxidant, usually accompanied by flame, luminescence and/or smoke.
Combustion has three characteristics, namely, chemical reaction, exotherm and luminescence.
(2) Combustion conditions
Necessary conditions for combustion —— The occurrence and development of material combustion process must meet the following three necessary conditions, namely, combustible, oxidant and temperature (ignition source). Only when these three conditions are met at the same time can combustion occur, and no matter which condition is lacking, combustion cannot occur. However, the above three conditions do not necessarily exist at the same time, and the combustion phenomenon will certainly occur. These three factors also need to interact.
1. Combustible: Any substance that can react with oxygen or other oxidants in the air is called combustible. Combustible substances can be divided into gas combustible substances, liquid combustible substances and solid combustible substances according to their physical states. Combustible substances are mostly compounds containing carbon and hydrogen. Some metals such as magnesium, aluminum and calcium can also burn under certain conditions, and many substances such as hydrazine and ozone can release light and heat through their own explanation at high temperature.
2. Oxidant: A substance that helps and supports the combustion of combustible substances, that is, a substance that can undergo an oxidation reaction with combustible substances is called an oxidant. The oxidant in the combustion process is mainly free oxygen in the air, and other oxidants such as fluorine and chlorine can also be used as oxidants in the combustion reaction.
3. Temperature (ignition source): refers to the energy source of combustion reaction between combustible substances and oxygen or combustion improver. Common is heat energy, as well as other heat energy converted from chemical energy, electric energy and mechanical energy.
4. Chain reaction: There is a chain reaction in flame combustion. When the fuel is heated, it will not only vaporize, but also the molecules of the fuel will decompose to produce free radicals. Free radical is a very active chemical form, which can react with other free radicals and molecules to keep the combustion going. This is a chain reaction of burning.
Sufficient conditions for combustion-(1) a certain combustible concentration; (2) certain oxygen content: (3) certain ignition energy; (4) Unrestricted chain reaction. For example, the minimum ignition energy of gasoline is 0.2raj, that of ether is 0. 19mJ, and that of methanol is 0.2 15mJ. For flameless combustion, the first three conditions exist and interact at the same time, and combustion will occur. For flame combustion, in addition to the above three conditions, there are unrestrained free radicals (free radicals) in the combustion process, forming a chain reaction, which is also one of the sufficient conditions for combustion.
(3) the type of combustion
Combustion is generally divided into four types according to its formation conditions and instantaneous characteristics: flash, fire, spontaneous combustion and explosion.
Flash burning is a burning phenomenon in which a substance can flash when it meets fire.
Fire is a phenomenon that combustible substances contact with the fire source in the air, and when they reach a certain temperature, they start to burn with flames, and they can continue to burn after the fire source is removed.
Spontaneous combustion is the combustion of combustible materials caused by heating or self-heating and heat accumulation without external sparks, flames and other fire sources.
Explosion is a phenomenon that the temperature and pressure rise or both rise due to the rapid oxidation or decomposition reaction of substances. Explosion can be divided into physical explosion, chemical explosion and nuclear explosion.
Physical explosion is an explosion caused by the rapid expansion of liquid or gas, and the pressure increases rapidly, which greatly exceeds the limit pressure of the container. Such as steam boilers; Liquefied gas cylinder explosion, etc.
Chemical explosion is an explosion caused by the chemical reaction of the substance itself, which produces a lot of gas and high temperature. Such as explosive explosion, explosion of combustible gas, liquid vapor, dust and air mixture, etc. Chemical explosion is the key to prevent explosion in fire fighting.
In addition to the direct contact of flame, heat usually spreads outward in three ways: heat conduction, heat radiation and heat convection.
(d) definition of fire
Fire refers to the disaster caused by burning out of control in time or space. Fire is mostly a social phenomenon, and the main causes of fire can be summarized into three aspects. One is man-made unsafe behavior (including arson); The second is the unsafe state of matter; The third is the defect of technology. And people's unsafe behavior is the most important factor.
(5) Classification of fire
According to the combustion characteristics of substances, fires can be divided into five categories: A, B, C, D and E.
Class A fire: refers to solid material fire. This kind of substance often has the nature of organic matter, and generally produces glowing embers when burning. Such as wood, coal, cotton, wool, hemp, paper and other fires.
Class B fire: refers to liquid fire and meltable solid fire. Such as gasoline, kerosene, diesel oil, crude oil, methanol, ethanol, asphalt, paraffin and other fires.
Class C fire: refers to gas fire. Such as gas, natural gas, methane, ethane, propane, hydrogen and other fires.
Class d fire: refers to metal fire. Such as potassium, sodium, magnesium, aluminum-magnesium alloy, etc.
Class E fire: refers to the fire of charged objects, precision instruments and other substances.
(6) Fire level
According to the National Regulations on Fire Statistics Management, fires are divided into major fires, major fires and general fires.
Extraordinary fire: in any of the following circumstances, it is an extraordinary fire with death 10 or more (including this number, the same below); Seriously injured more than 20 people; More than 20 people were killed or seriously injured; More than 50 families were affected; The direct property loss was 6,543,800 yuan+0,000 yuan.
Major fire: in any of the following circumstances, it is a major fire: more than 3 people died (including this number, the same below): seriously injured 10 or more people: dead or seriously injured 10 or more people; More than 30 households were affected: the direct property loss was more than 300,000 yuan.
General fire: A fire without the first two situations is a general fire.
(1) Types of fire extinguishers
There are many types of fire extinguishers, which can be divided into: portable and cart-type; 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 filling fire extinguishing agent, it can be divided into: foam, dry powder, haloalkane, carbon dioxide, acid and alkali, clear water and so on.
(2) How to use a fire extinguisher
1. How to use a carbon dioxide fire extinguisher
When putting out the fire, just lift or carry the fire extinguisher to the fire site. Put down the fire extinguisher and pull out the safety pin when it is about 5 meters away from the combustibles. Hold the handle at the root of the horn with one hand and the pressure handle of the switch valve with the other hand. For carbon dioxide fire extinguishers without spray hose, the horn should be placed at 70 ~ 90 degrees from the upper plate. When using, you can't directly grasp the outer wall of the horn or the metal connecting pipe with your hands to prevent your hands from being frostbitten. When putting out fire, when combustible liquid burns in a flowing state, the user sprays the jet of carbon dioxide extinguishing agent from near and far to the flame. If combustible liquid burns in the container, the user should raise the horn. Spray into the combustion container from the upper part of one side of the container. However, the carbon dioxide jet can not directly impact the surface of combustible liquid, which prevents combustible liquid from being washed out of the container, expands the fire and brings difficulties to fire fighting.
When using a carbon dioxide fire extinguisher, it should be sprayed in the upwind direction when it is used outdoors. When used in a narrow indoor space, the operator should leave quickly after the fire is extinguished to prevent suffocation.
2. How to use the portable 12 1 1 fire extinguisher?
When using, you should carry a fire extinguisher or shoulder a fire extinguisher. Put down the fire extinguisher about 5 meters away from the burning place, first pull out the safety pin, hold the opening handle in one hand and the nozzle at the front end of the injection hose in the other. If the fire extinguisher has no spray hose, you can hold the opening handle with one hand and the bottom ring part at the bottom of the fire extinguisher with the other hand. Firstly, aim the nozzle at the burning place, and open the handle hard to make the fire extinguisher spray. When the rescued combustible liquid is flowing and burning, the user should aim at the root of the flame from near to far and from left to right and push it forward quickly until the flame is completely extinguished. If combustible liquid burns in a container, the quasi-flame should sweep from one side to the other. When the flame is driven out of the container, the jet should follow the flame until it is completely extinguished. However, it should be noted that the jet can not be directly sprayed on the surface of the burning liquid, so as to prevent the impulse of the extinguishing agent from rushing the flammable liquid out of the container, which will expand the fire and make it difficult to put out the fire. If the initial fire of combustible solid substances is put out, when the jet is aimed at the violent burning place, it should be put out with a flame machine, and measures should be taken in time to prevent re-ignition.
12 1 1 When using the fire extinguisher, it should not be inverted or placed horizontally, otherwise the fire extinguishing agent will not be sprayed out. In addition, when it is used outdoors, it should be sprayed in the upwind direction: when putting out a fire in a narrow room, the operators should evacuate quickly after putting out the fire, because the extinguishing agent 12ll is also toxic to prevent harm to human body.
3. How to use the cart type 12 1 1 fire extinguisher?
When putting out a fire, it is usually operated by two people. First push or pull the fire extinguisher to the fire, and stop at a distance of about 10 meters from the burning place. One person quickly loosens the spray hose, grabs the spray gun and aims at the burning place; The other man quickly opened the fire extinguisher valve. The fire extinguishing method is the same as the portable 12 1 1 fire extinguisher.
4. How to use portable dry powder fire extinguisher
When putting out a fire, you can quickly walk to the fire with a fire extinguisher in your hand or a fire extinguisher on your shoulder, and put down the fire extinguisher about 5 meters away from the burning place. If you are outdoors, you should choose to spray against the wind.
If the dry powder fire extinguisher used is cylinder type, the operator should hold the spray gun with one hand and lift the opening bail on the cylinder with the other hand. If the cylinder is opened by handwheel, loosen it counterclockwise, turn it to the highest position, and then lift the fire extinguisher. Dry powder is sprayed on the mountain and quickly aimed at the root of the flame to extinguish the fire. If the dry powder fire extinguisher used is pressure storage type, the operator should first unplug the safety pin on the opening handle, then hold the nozzle at the front end of the injection hose, press the opening handle with the other hand, and open the fire extinguisher to extinguish the fire. When the fire extinguisher is in use, be sure to hold the handle with one hand and don't let go, otherwise the spraying will be interrupted.
When using dry powder fire extinguisher to put out flammable and combustible liquid fires, the root of the flame should be sprayed accurately. If the extinguished liquid fire is burning, it should be sprayed to the root of the quasi-flame from near to far, left and right, until all the flames are extinguished. If combustible liquid burns in the container, the user should shake the root of quasi-flame left and right to make the sprayed dry powder flow cover the whole opening surface of the container; When the flame is driven out of the container, the user should continue to spray until the flame is completely extinguished. When extinguishing the flammable liquid fire in the container, it is necessary to pay attention to the fact that the nozzle is not directly aimed at the liquid level to prevent the impact of the jet from splashing flammable liquid, which will expand the fire and bring difficulties to the fire extinguishing. If the flammable liquid burns in a metal container for a long time, the wall temperature of the container is higher than the self-ignition point of the flammable liquid, and it is easy to re-ignite after fire extinguishing. If we cooperate with foam extinguisher, the fire fighting effect will be better.
When using ammonium phosphate dry powder fire extinguisher to put out solid combustible fire, it should be sprayed in the place where quasi-combustion is the fiercest, up and down, left and right. If conditions permit, the user can spray the fire extinguisher along the periphery of the combustion object, so that the dry powder extinguishing agent can be evenly sprayed on the surface of the combustion object until the flame is completely extinguished.
5. How to use the cart type dry powder fire extinguisher?
The use method of cart dry powder fire extinguisher is the same as that of portable dry powder fire extinguisher.
The initial fire range is small and the fire is weak, so it is the best time to put out the fire with a fire extinguisher. Therefore, it is very important to configure the fire extinguisher correctly and reasonably.
(3) the scope of application of fire extinguishers
Water-based fire extinguishers, foam extinguisher, ammonium phosphate dry powder fire extinguishers and halon fire extinguishers can be selected for class A fire fighting.
Foam extinguisher (chemical foam extinguisher is limited to extinguishing nonpolar solvents), dry powder fire extinguishers, halon fire extinguishers and carbon dioxide fire extinguishers can be used for Class B fires.
Dry powder fire extinguishers, halon fire extinguishers and carbon dioxide fire extinguishers can be selected to put out Class C fires.
To put out Class D fires, powdered graphite fire extinguishers and special dry powder fire extinguishers can be used, or dry sand or cast iron chips can be used instead.
Dry powder fire extinguishers, halon fire extinguishers and carbon dioxide fire extinguishers can be selected to put out the fire on site. Electrified fires include fires of household appliances, electronic components and electrical equipment (computers, copiers, printers, fax machines, generators, motors, transformers, etc.). ) and the wires and cables are still charged when burning, and the fire in the ceiling, wall-hung daily lighting lamps and equipment that can automatically cut off the power supply after fire should not be included in the scope of charged fire.
(4) Extinguishing efficiency of fire extinguishers
Compared with putting out the same fire, the effects of different fire extinguishers are very different; The amount of carbon dioxide and foam extinguishing agent is large, and the fire extinguishing time is long; The amount of dry powder fire extinguishing agent is small, and the fire extinguishing time is short: the amount of haloalkane fire extinguishing agent is moderate, and the time is slightly longer than that of dry powder. Configuration can be comprehensively considered according to the importance of the site and the requirements of fire extinguishing speed.
(5) The ambient temperature of the fire extinguisher installation site.
The ambient temperature of the fire extinguisher installation site has obvious influence on the spraying performance and safety performance of the fire extinguisher. To. If the ambient temperature is too low, the spraying performance of the fire extinguisher will be obviously reduced, which will affect the fire extinguishing efficiency; If the ambient temperature is too high, the internal pressure of the fire extinguisher will increase, and the fire extinguisher is in danger of explosion and personal injury. Therefore, the ambient temperature of the set point of the fire extinguisher should be within the service temperature range of the fire extinguisher.
(six) the degree of pollution of fire extinguishers to protected items
Water stains, foam pollution and dust pollution may occur in different degrees after spraying water, foam and dry powder fire extinguishers. For expensive equipment, precision instruments, precious cultural relics and high-grade electrical equipment, efficient and clean fire extinguishers such as carbon dioxide and halon should be selected, and inefficient fire extinguishers with obvious fouling effect should not be configured. For items with low value, there is no need to consider the influence of fire extinguishing agent pollution too much.
(seven) the physical quality of the fire extinguisher users
The weight of fire extinguishers varies from 0.5 kg to dozens of kg. When configuring a fire extinguisher, the age, sex and physical strength of the user should be considered. Places where users are mainly young and middle-aged, can be equipped with large fire extinguishers, which will help to put out the fire quickly. In garment factories (mainly female workers), hospitals, primary schools and nursing homes, welfare factories (workers with physical defects) and other places, smaller fire extinguishers should be equipped to facilitate fire fighting.
(eight) the fire risk level of the place where the fire extinguisher is installed.
The higher the fire risk level, the smaller the protection area of unit dose fire extinguisher. In order to put out the initial fire conveniently and effectively, we should choose fire extinguishers with higher fire extinguishing level, such as large cart fire extinguishers in yards and garages. For places with low fire risk, such as office buildings and teaching buildings, you can choose small fire extinguishers to avoid unnecessary waste.
(9) Configure fire extinguishers at the same place.
Various fire extinguishers operate in different ways. In order to use multiple fire extinguishers with the same operation method to extinguish the fire smoothly, it is best to use the same type of fire extinguisher or use the same operation method in the same place.
(10) Compatibility between different types of fire extinguishers
Different types of fire extinguishers are equipped with different extinguishing agents, and different extinguishing agents may react during fire extinguishing, resulting in adverse reactions that are not conducive to fire extinguishing. Therefore, when two or more types of fire extinguishers are selected, fire extinguishers compatible with fire extinguishing agents should be adopted.
(1 1) Maintenance of fire extinguishers
First, the fire extinguisher should be placed in a ventilated, dry and convenient place, and the ambient temperature is -5℃ ~ 45℃.
Second, the fire extinguisher should avoid high temperature, humidity and serious corrosion, which can prevent the dry powder extinguishing agent from caking and decomposing.
The third is to check whether the dry powder is caked and whether the carbon dioxide gas in the gas cylinder leaks. Check the carbon dioxide cylinder. Remove the gas cylinder and weigh it. Whether the weight is the same as the value marked on the steel seal on the gas cylinder. If it is less than 7 grams of the marked value, it should be sent to the maintenance department for repair. If there is a pressure gauge, check whether its pointer points to the green area. If the pointer is already in the red area, it means that the internal pressure has leaked and cannot be used, and it should be sent to the maintenance department for repair.
(twelve) other issues that should be considered.
Compared with several kinds of fire extinguishers, halon 12 1 1 fire extinguisher has the highest price, followed by ammonium phosphate dry powder, and the rest are relatively cheap; Carbon dioxide fire extinguishers have the largest volume in each fire extinguishing level. In order to protect the atmospheric ozone layer, halon fire extinguishers are not allowed in non-essential places, and cart fire extinguishers are not allowed in places with anti-vibration requirements such as computer rooms.
(a) Common fire hazards
1. classroom fire hazard
(1) The door is blocked or only one door is opened;
(2) Use high-power lighting or electric heating appliances to keep warm near flammable materials;
(three) the use of electronic teaching AIDS in violation of operating rules;
(4) line aging or overload;
(five) failing to store flammable items in accordance with safety regulations;
(6) Smoking and littering cigarette butts in the classroom.
2. Fire hazard in the laboratory
(1) The inflammable and explosive articles in the laboratory are improperly preserved or broken and scattered;
(2) violation of operating procedures during the experiment;
(3) Lack of expert guidance during the experiment;
(4) The experimental project lacks fire prevention measures;
(5) mixing storage reagents.
3. The fire danger in the library
(1) wires and electrical equipment are short-circuited;
(2) accidental lighting such as matches and lighters;
(3) Smoking and littering cigarette butts;
(4) The evacuation passage is not smooth.
4. Fire hazards in dormitories
(1) Using inferior electrical appliances:
(2) illegal use of high-power electrical equipment, making the line overloaded;
C3) Connect wires separately;
(4) Smoking in bed:
(5) light candles and read in mosquito nets;
(six) unauthorized use of kerosene stoves, liquefied gas stoves, alcohol stoves and other appliances that may cause fire;
(7) Burning sundries:
(8) The desk lamp is close to pillows and bedding;
(9) The mobile phone charger charges on the bed.
5. Fire hazard in auditorium and lecture hall
(1) wire aging:
(2) throwing cigarette butts;
(3) High-power lighting is close to curtains or flammable decorations;
(four) the illegal use of open flames;
(5) The emergency doors and evacuation passages are blocked;
(6) The number of people in the venue seriously exceeds the rated number.
(2) Fire prevention
1. Fire prevention in student dormitory
The fire safety of student dormitories should be absolutely forbidden.
(1) Don't pull the wire without permission.
(2) It is forbidden to smoke and throw cigarette butts in bed.
(3) It is forbidden to occupy or block the evacuation passage.
(4) It is forbidden to burn sundries in the building.
(5) Flammable and explosive articles are not allowed to be brought indoors.
(6) Electric heating equipment such as "quick heating" is not allowed.
(7) It is forbidden to use open flame appliances such as alcohol stoves.
(8) It is forbidden to change the power supply equipment without authorization.
(9) Don't leave the dormitory without turning off the power.
(10) Don't damage fire extinguishers and fire-fighting facilities.
2. Fire prevention of common electrical appliances
(1) Causes of fire caused by hair dryer and fire safety measures
1) the cause of the fire caused by the hair dryer
First, when the hair dryer is in use, I have to go away because of other things (such as answering the phone, someone knocking at the door, etc.). ) I put the hair dryer on the wooden table for a while and completely forgot the purpose of the hair dryer. As a result, it was put on hold for a long time, so the high temperature of the hair dryer shell ignited the combustible.
Second, when using the hair dryer, if you encounter power failure, you should handle other things or go out without cutting off the power supply. After the power supply is restored, the heating wire of the hair dryer heats up for a long time, and the temperature rises, causing a fire.
2) hair dryer fire safety measures:
First, power sockets and wires should meet fire safety requirements, and the connection should be tight and firm.
2. Beware of knocking, bumping and disassembling the hair dryer, so as not to damage the heating elements and insulation devices, causing leakage or even short circuit and fire.
Third, people can't leave when using the hair dryer, and can't put it on flammable materials such as benches, sofas and mattresses at will.
Fourth, be sure to cut off the power supply in time after use.
(2) The causes of fire caused by incandescent lamps and fire safety measures.
1) incandescent lamp causes fire:
First, the surface temperature of incandescent bulbs is very high, which can bake combustible materials in contact or close to them. Under general heat dissipation conditions, the surface temperature of incandescent bulbs increases with the increase of their power. For example, for incandescent lamps with power of 40 watts, 100 watts and 200 watts, the bulb surface temperature can reach 50-60 degrees Celsius, 170-200 degrees Celsius and 160-300 degrees Celsius respectively. Such as wood, paper, cotton cloth, firewood, etc. , are low ignition point, if close to the light bulb is energized, it is easy to bake and catch fire. The test shows that the 200-watt incandescent lamp clings to the wooden box and can bake the wooden box in less than 1 hour. If you hold the cotton-padded coat tightly, it will catch fire in only 5 minutes. The greater the power of the bulb, the longer the turn-on time, the higher the surface temperature of the bulb, the lower the ignition point of combustible materials, and the closer the distance between them, the easier it is to cause combustion.
Second, because the power supply voltage is too high, the bulb power is too large, the load capacity of the conductor is small, and the insulation is aging, which leads to overheating, short circuit and fire.
Thirdly, because the power supply voltage is too high and the filament calorific value is too high, the inert gas inside the bulb expands violently, or the bulb with high power and high surface temperature is quenched and heated, splashed with water and vibrated. , causing the bulb to explode, and the high-temperature glass sheet and high-temperature filament splashed on the combustible, causing a fire.
Fourth, because of the poor contact of the contact part of the lamp holder, it causes fever and fire; When the glass shell of the lamp holder is loose, the lamp holder is twisted, which leads to short circuit and fire.
2) incandescent lamp fire safety measures:
A, the light bulb should be set in a safe and appropriate place, and keep a certain fire distance with combustible materials. Where collision may occur, the light bulb should have a metal protective net or a glass cover.
Second, it is forbidden to cover lamps with paper, cloth or other combustible materials, and it is forbidden to use light bulbs to keep warm and bake clothes under quilts.
Third, light bulbs should not be attached to wooden furniture, doors, frames or cardboard, nor embedded in the ceiling or ceiling. When moving the desk lamp, the light bulb should keep a certain distance from flammable materials such as curtain cloth and mosquito net.
Fourth, the power supply voltage of incandescent lamp can't exceed its rated voltage. Don't touch the working light bulb with wet hands or wet cloth to prevent the light bulb from exploding. If the connection between the lamp holder and the glass bulb is loose, don't twist the bulb hard. If you use a light bulb above 150 watt, don't use a bakelite lamp holder to avoid heating and fire.
Fifth, the wires used for incandescent lamps should have excellent insulation performance. The conductor shall not be close to the bulb to prevent the insulation layer of the conductor from aging, melting and burning due to long-term baking. Safety devices should be installed on the lines to protect them. The switch shall not be installed on the ground wire.
Sixth, when using incandescent lamps, especially high-power incandescent lamps, the continuous power-on time should not be too long, and the "ever-burning lamp" should not be lit. Remember to turn off the lights when you go out to class.
(3) Causes of fire caused by fluorescent lamps and fire safety measures.
1) Causes of fire caused by fluorescent lamp ballast:
First, the quality of ballast is poor. Some ballasts have not been strictly inspected or wound by themselves before leaving the factory, which are shoddy and have poor quality, such as insufficient coil turns, insufficient insulation capacity, too small wire diameter, too small wire core area, too large space gap, and too tight insertion of silicon steel sheets. These are easy to make ballast heat up, produce high temperature, damage insulation, melt asphalt, overflow from the box and so on. , forming a short circuit, causing a fire.
Second, the ballast is improperly installed. For example, the power of ballast and fluorescent lamp is not matched, the contact is not firm, the ballast is installed near the ceiling and other flammable materials, and the ventilation and heat dissipation conditions at the installation site are very poor. In this way, on the one hand, the ballast is easy to heat, on the other hand, the heat is not easy to dissipate, so a large number of sudden heat, forming a high temperature, baking flammable substances, causing fires.
Third, improper use. Excessive power supply voltage and overload of fluorescent lamps will lead to excessive ballast temperature, too long continuous use of fluorescent lamps or too frequent switching of fluorescent lamps will also lead to excessive ballast temperature, and even lead to fire.
Fourth, poor maintenance. A lot of combustible dust, sawdust, etc. Accumulated on the ballast of fluorescent lamp, if the ballast produces high temperature, it will be burnt and caught fire; When ballast is wet or flooded, it will reduce the insulation capacity of the coil and even short circuit and fire. These are caused by poor maintenance at ordinary times.
2) Fire safety measures for fluorescent lamp ballast:
First, we should choose high-quality and qualified products. The power of fluorescent lamps and ballasts should be matched, and ballasts without certificates cannot be used or wound by themselves. If the ballast hums after being electrified, it means that the quality is poor and it is easy to generate heat; if the ballast generates heat after being electrified for half an hour, it means that the ballast quality is not good.
Second, when installing fluorescent lamps, ballasts cannot be directly installed on combustible materials. Attention should be paid to ventilation, rain and dust prevention. The bottom of ballast should be upward, not downward and not vertically installed to prevent asphalt from melting and overflowing.
Third, inspection and maintenance should be strengthened in use to prevent the power supply voltage from being too high or overloaded. Fluorescent lamps should not be switched on and off frequently, nor should they be used continuously for a long time to prevent the ballast from overheating. If it is found that the contact point is loose, the ballast makes noise, and it is hot or has a burning smell when it is in contact, measures should be taken to deal with it. People should cut off the power when they leave.
3. Causes and precautions of cigarette butts causing fire
(1) Causes of fire caused by cigarette butts
Although cigarette butts are not a big fire source, they can cause many substances to catch fire. The surface temperature of cigarette butts is 200~C-300~C, and the center temperature is 700 ~ C-800 ~ C The ignition point of general combustibles is mostly lower than the surface temperature of cigarette butts, such as 130~C for paper, 200~C for cloth and 250~C for loose. The burning time of a cigarette is 4 ~ 15 minutes. During this period, ordinary combustible materials can be ignited, and after a period of smoldering, they will catch fire and burn. According to the experiment under the condition of natural ventilation, cigarette butts will start to burn after 75 ~ 90 minutes when they are thrown into sawdust 5 cm deep. When they are thrown into sawdust with a depth of 5 ~ 10 cm, there is a 75% chance that they will start burning after 60 ~ 100 minutes. For dangerous chemicals, the open flame of cigarettes will immediately cause them to burn and explode.
(2) Fire prevention measures that should be paid attention to when smoking:
1) Don't smoke on the bed or sofa;
2) When smoking, if you have other things to go out temporarily, you should put out your cigarette butts before you leave.
3) Cross matchsticks and cigarette butts must be extinguished. Unburned matchsticks and cigarette butts should be put into ashtrays or spittoons: matchboxes and cigarette cases should not be used as ashtrays, cigarette butts and cigarette butts should not be thrown into wastepaper baskets, and they should not be thrown around.
4) When repairing cars and cleaning machine parts with oil, smoking is strictly prohibited. If you need to smoke, you should stay away from the oil basin (barrel); If you have oil on your hands, you should clean them before smoking. After smoking, put out the cigarette butt before you start your homework.
4. Fire prevention matters that should be paid attention to when setting off fireworks and firecrackers
Setting off fireworks is a festive event, but it is very easy to cause fire accidents. Therefore, the following matters should be paid attention to when setting off fireworks and firecrackers:
(1) It is forbidden to set off firecrackers, monkeys, voles and other fireworks that are easy to cause fire. When buying fireworks and firecrackers, you should go to the designated store to buy them, and indicate the name, trademark and. Various unloading instructions. Don't buy inferior varieties sold privately.
(2) Don't set off fireworks on windowsills, balconies, corridors and indoors. Before discharge, be sure to read the discharge instructions on fireworks and firecrackers carefully and discharge them according to the instructions. Setting off Goldman Sachs (two-way firecrackers) should stand upright on the ground and avoid it after lighting.
(3) Attention should be paid to prevent the rising fireworks from falling on combustible materials. When there is still residual fire, measures should be taken immediately to put out the residual fire or remove debris.
(4) Don't set off fireworks on buses, trains, ships and planes.
(5) Buy fireworks and firecrackers in a safe place, away from fire sources, heat sources and power sources, to prevent rats from biting and spontaneous combustion and explosion.
(6) Fireworks and firecrackers should be set off in a civilized manner, and should not be set off against pedestrians, windows or other people's balconies.
(7) When setting off fireworks and firecrackers, be sideways, not facing your face; Don't hold the gun in one hand (single tone) and ignite it with the other hand. Be sure to put it on the ground and ignite it; If you encounter a squib after ignition, don't rush to get it, wait a while, and then kick it to a safe place when it is confirmed that it can't ring again; Never pick it up and peel it with your hands, in case of explosion and injury.
5. Fire prevention measures that mosquito repellent should pay attention to.
In summer, especially at night, people often drive away mosquitoes, but when using open flames to drive away mosquitoes, a little carelessness will cause a fire. Therefore, special attention should be paid to fire prevention when repelling mosquitoes.
(1) The lit mosquito-repellent incense should be placed on a metal bracket, away from flammable materials such as curtains and door curtains, and never placed directly on wooden boards or other flammable materials.
(2) After the homemade mosquito-repellent incense is lit, it should be placed in a basin with a brick pad at the bottom.
(3) When lighting the fire to repel mosquitoes, someone should take care of it, so that people will go out.
(4) For safety, it is best to use "mosquito killer" or electronic mosquito repellent.