An essay on the topic The profession of a Firefighter (a heroic profession). Essay on the topic "Why it is necessary to comply with fire safety rules Fire hazard assessment of industrial enterprises

1. Fire safety

Fires inflict enormous material damage and in some cases are accompanied by the death of people. Therefore, fire protection is the most important responsibility of every member of society and is carried out on a national scale.

Against fire protection aims to find the most effective, economically feasible and technically sound methods and means of preventing fires and eliminating them with minimal damage at the most rational use forces and technical means extinguishing.

Fire safety is the state of an object in which the possibility of a fire is excluded, and in the event of a fire, the necessary measures are taken to eliminate negative impact dangerous factors fire on people, structures and material values

Fire safety can be ensured by measures of fire prevention and active fire protection. Fire prevention includes a set of measures aimed at preventing a fire or reducing its consequences. Active fire protection - measures to ensure a successful fight against fires or an explosive situation.

1.1. Fire as a factor in a man-made disaster

A fire is combustion outside a special hearth, which is not controlled and can lead to mass destruction and death of people, as well as to environmental, material and other harm.

Combustion is a chemical oxidation reaction that produces heat and light. For combustion to occur, three factors are required: a combustible substance, an oxidizing agent, and a source of ignition. Oxidizing agents can be oxygen, chlorine, fluorine, bromine, iodine, nitrogen oxides and others. In addition, it is necessary that the combustible substance be heated to a certain temperature and be in a certain quantitative ratio with the oxidizer, and the source of ignition has a certain energy.

The highest burning rate is observed in pure oxygen. When the oxygen content in the air decreases, combustion stops. Combustion with a sufficient and above-dimensional concentration of the oxidizer is called complete, and with its shortage, it is called incomplete.

There are three main types of self-acceleration of a chemical reaction during combustion: thermal, chain and chain-thermal. The thermal mechanism is associated with the exothermicity of the oxidation process and an increase in the rate of the chemical reaction with increasing temperature. Chain acceleration of the reaction is associated with the catalysis of transformations, which is carried out intermediate products transformations. Real combustion processes are carried out, as a rule, according to a combined (chain-thermal) mechanism.

The combustion process is divided into several types:

Flash - rapid combustion of a combustible mixture, not accompanied by the formation of compressed gases.

Combustion is the occurrence of combustion under the influence of an ignition source.

Ignition - Combustion accompanied by the appearance of a flame.

Spontaneous combustion is a phenomenon of a sharp increase in the rate of exothermic reactions, leading to the occurrence of combustion of a substance in the absence of an ignition source. There are several types of spontaneous combustion:

Chemical - from exposure to combustible substances of oxygen, air, water or the interaction of substances;

Microbiological - occurs at a certain humidity and temperature in plant products (spontaneous combustion of grain);

Thermal - due to long-term exposure to insignificant heat sources (for example, at a temperature of 100 C thyrsa, fiberboard and other slopes to spontaneous combustion).

Self-ignition - spontaneous combustion, accompanied by the appearance of a flame.

An explosion is an extremely fast (explosive) transformation, accompanied by the release of energy with the formation of compressed gases.

The main indicators fire hazard are the autoignition temperature and the ignition concentration limits.

Autoignition temperature characterizes the minimum temperature of a substance at which there is a sharp increase in the rate of exothermic reactions, resulting in the appearance of flame combustion.

Flash point - the lowest (under special test conditions) temperature of a combustible substance at which vapors and gases are formed above the surface, which can flash in the air from an ignition source, but the rate of their formation is still insufficient for subsequent combustion.

According to this characteristic, flammable liquids are divided into 2 classes:
1) liquids with tvsp< 610 C (бензин, этиловый спирт, ацетон, нитроэмали и т.д.) - легковоспламеняющиеся жидкости (ЛВЖ); 2) жидкости с tвсп >610 C (oil, fuel oil, formalin, etc.) - flammable liquids (GZh).

Ignition temperature is the combustion temperature of a substance at which it emits flammable vapors and gases at such a rate that after they are ignited from the ignition source, stable combustion occurs.

Temperature limits of ignition - temperatures at which saturated vapors of a substance form in a given oxidizing environment concentrations equal to the lower and upper concentration limits of ignition of liquids, respectively.

Combustible substances are substances that can burn independently after removing the source of ignition.

According to the degree of flammability, substances are divided into: combustible (combustible), hardly combustible (hardly combustible) and non-combustible (non-combustible).

Fuels include those substances that, when ignited by an extraneous source, continue to burn even after it has been removed.

Non-combustible substances are those that are not able to spread the flame and burn only in the place where the ignition source is exposed.

Non-flammable substances are substances that are not flammable even when exposed to sufficiently powerful ignition sources (impulses).

Combustible substances can be in three states of aggregation: liquid, solid and gaseous. Most combustible substances, regardless of their state of aggregation, when heated, form gaseous products, which, when mixed with air containing a certain amount of oxygen, form a combustible medium. Combustible environment can be formed by fine atomization of solid and liquid substances.

Combustible gases and dust form combustible mixtures at any temperature, while solids and liquids can form combustible mixtures only at certain temperatures.

Under industrial conditions, the formation of mixtures of combustible gases or vapors in any quantitative ratio can take place. However, these mixtures can be explosive only when the concentration of flammable gas or vapor is between the flammable concentration limits.

The minimum concentration of flammable gases and vapors in the air at which they are capable of igniting and spreading a flame is called the lower flammable concentration limit.

The maximum concentration of flammable gases and vapors at which the flame can still spread is called the upper flammable concentration limit.

The indicated limits depend on the temperature of gases and vapors: with an increase in temperature by 100 ° C, the values of the lower ignition limits decrease by 8-10%, the upper ones increase by 12-15%.

The fire hazard of a substance is the greater, the lower the lower and higher upper ignition limits and the lower the autoignition temperature.

Dusts of flammable and some non-flammable substances (for example, aluminum, zinc) can form flammable concentrations when mixed with air.

Airborne dust poses the greatest explosion hazard. However, dust deposited on structures is dangerous not only from the point of view of a fire, but also a secondary explosion caused by the swirling of dust during the initial explosion.

The minimum concentration of dust in the air at which it is ignited is called the lower ignition limit of the dust.

Since it is practically impossible to achieve very high concentrations of dust in suspension, the term "upper flammable limit" does not apply to dusts.

Ignition of a liquid can occur only if there is a mixture of vapors with air above its surface in a certain quantitative ratio corresponding to the lower temperature limit of ignition.

2. Causes of fires at enterprises

A fire at an enterprise causes great material damage to the national economy and is very often accompanied by accidents with people.

The main reasons contributing to the emergence and development of a fire are:

violation of the rules for the use and operation of devices and equipment with low fire protection;

use in construction in some cases of materials that do not meet the requirements fire safety;

absence at many sites National economy and in fire departments of effective means of fighting fire.

2.1. Road transport enterprises

Causes of materials ignition and fires in road transport enterprises:

incorrect arrangement of thermal furnaces and boiler furnaces;

malfunction of heating devices;

malfunction of electrical equipment and lighting and their improper operation;

spontaneous combustion from improper storage of lubricants and cleaning materials;

the presence of static electricity, the absence of lightning rods;

careless handling of fire, inadequate supervision of fire devices and production equipment.

2.2. Mechanical engineering enterprises

Machine-building enterprises are distinguished by an increased fire hazard, as they are characterized by the complexity production processes; the presence of significant quantities of flammable and combustible liquids, liquefied combustible gases, solid combustible materials; large equipment with electrical installations and more.

1) Violation of the technological regime - 33%.

2) Malfunction of electrical equipment - 16%.

3) Poor preparation for equipment repair - 13%.

4) Spontaneous combustion of oily rags and other materials - 10%

As well as violation of the rules and regulations of storage fire hazardous materials, careless handling of fire, use of open flames of torches, blowtorches, smoking in prohibited places, failure to comply firefighting measures firefighter equipment water supply, fire alarm, providing primary funds fire extinguishing, etc.

2.3. Laboratories

During the operation of the computer, the following occurrences are possible emergency situations:

short circuits;

overload;

increase. transition resistances in el. contacts;

overvoltage;

the occurrence of leakage currents.

In the event of emergency situations, a sharp release of thermal energy occurs, which can cause a fire.

The share of fires occurring in the email. installations account for 20%.

Fire statistics:

Main reasons: %

short circuit 43

overload of wires / cables 13

formation of transition resistances 5

Mode short circuit- the appearance as a result of a sharp increase in current strength, el. sparks, molten metal particles, el. arc, open fire, ignited insulation.

Short circuit reasons:

design errors;

aging of insulation;

moisture insulation;

mechanical overload.

Fire hazard during overloads - excessive heating of individual elements, which can occur due to design errors in the case of a prolonged passage of current exceeding the nominal value.

At 1.5 times the power, the resistors heat up to 200-300 ° C.

Fire hazard of transient resistance - the possibility of ignition of insulation or other nearby combustible materials from the heat generated in the place of the accident. resistance (in transition terminals, switches, etc.).

Overvoltage fire hazard - heating of live parts due to an increase in currents passing through them, due to an increase in overvoltage between separate elements electrical installations. It occurs when a failure or change in the parameters of individual elements.

Fire hazard of leakage currents - local heating of insulation between individual current-carrying elements and grounded structures.

3. Measures to fire prevention

The basics of fire protection of enterprises are defined by standards

GOST 12.1. 004 - 76 "Fire safety"

GOST 12.1.010 - 76 "Explosion safety. General requirements"

These GOSTs allow the possible frequency of fires and explosions so that the probability of their occurrence during the year does not exceed 10-6 or that the probability of exposure to hazardous factors on people during the year does not exceed 10-6 per person.

Fire prevention measures are divided into organizational, technical, regime, construction and planning and operational.

Organizational measures: provide for the correct operation of machines and intra-plant transport, the correct maintenance of buildings, territories, fire safety instructions, and the like.

Regime measures - the prohibition of smoking in unidentified places, the prohibition of welding and other hot work in fire-hazardous premises, and the like.

Operational measures - timely prophylaxis, inspections, repairs and testing of technological equipment.

Construction planning is determined by the fire resistance of buildings and structures (the choice of construction materials: combustible, non-combustible, hardly combustible) and the fire resistance limit is the amount of time during which the load-bearing capacity of building structures is not disturbed under the influence of fire until the first crack appears.

According to the fire resistance limit, all building structures are divided into 8 degrees from 1/7 hour to 2 hours.

Depending on the degree of fire resistance, the greatest additional distances from exits for evacuation in case of fire

Technical measures are compliance fire regulations during the evacuation of ventilation systems, heating, lighting, el. security, etc.

Using a variety of protective systems;

Compliance with the parameters of technological processes and operating modes of equipment.

3.1. Methods and means of extinguishing fires

In the practice of extinguishing fires, the following principles of stopping combustion are most widespread:

1) isolation of the combustion center from air or reduction of oxygen concentration by diluting the air with non-flammable gases (carbohydrates CO2< 12-14%).

2) cooling the combustion center below certain temperatures;

3) intensive inhibition (inhibition) of the rate of the chemical reaction in the flame;

4) mechanical stripping of the flame by a jet of gas or water;

5) the creation of fire protection conditions (conditions when the flame spreads through narrow channels).

Substances that create conditions under which combustion stops are called extinguishing agents. They should be cheap and safe to operate and not harm materials and objects.

Water is a good extinguishing agent with the following advantages: cooling effect, dilution of the combustible mixture with steam (when water evaporates, its volume increases 1700 times), mechanical effect on the flame, availability and low cost, chemical neutrality.

Disadvantages: oil products float up and continue to burn on the surface of the water; water has a high electrical conductivity, so it cannot be used to extinguish fires on energized electrical installations.

Fire extinguishing with water is carried out with water fire extinguishing installations, fire trucks and water shafts. To supply water to these installations, water pipes are used.

Water fire extinguishing installations include sprinkler and deluge installations.

The sprinkler system is a branched pipe system filled with water and equipped with sprinkler heads. The outlet openings of the sprinkler heads are closed with fusible locks, which are soldered when exposed to certain temperatures (345, 366, 414 and 455 K). Pressurized water from the system exits the head opening and irrigates room structures and equipment.

Deluge installations are a system of pipelines on which special drencher heads with open outlets with a diameter of 8, 10 and 12.7 mm of blade or rosette type are located, designed for irrigation of up to 12 m2 of floor area.

Deluge installations can be manual or automatic. Once activated, water fills the system and flows out through the holes in the deluge heads.

Steam is used in conditions of limited air exchange, as well as in closed rooms with the most dangerous technological processes. Steam fire extinguishing is carried out by isolating the combustion surface from environment... When extinguishing, it is necessary to create a vapor concentration of approximately 35%

Foams are used to extinguish solid and liquid substances that do not interact with water. The extinguishing effect is achieved by isolating the surface of the combustible substance from the surrounding air. Fire extinguishing properties foam is determined by its multiplicity - the ratio of the volume of the foam to the volume of its liquid phase, resistance to dispersion, viscosity. Depending on the method of obtaining foam, they are divided into chemical and air-mechanical.

Chemical foam is formed by the interaction of solutions of acids and alkalis in the presence of a foaming agent and is a concentrated emulsion of carbon dioxide in an aqueous reactor of mineral salts. The use of chemical salts is difficult and expensive, so their use is decreasing.

Air-mechanical foam of low (up to 20), medium (up to 200) and high (over 200) expansion rates is obtained using special equipment and foam concentrates PO-1, PO-1D, PO-6K, etc.

Inert gaseous diluents: carbon dioxide, nitrogen, smoke and exhaust gases, steam, argon and others.

Inhibitors - based on saturated hydrocarbons, in which one or more hydrogen atoms are replaced by halogen atoms (fluorine, chlorine, bromine). Halocarbons are poorly soluble in water, but mix well with many organic substances:

tetrafluorodibromoethane (freon 114B2);

methylene bromide;

trifluorobromomethane (freon 13B1);

3, 5, 7, 4НД, СЖБ, БФ (based on ethyl bromide);

Powder formulations despite their high cost, complexity in operation and storage, they are widely used to stop the combustion of solid, liquid and gaseous combustible materials. They are the only means of extinguishing fires. alkali metals and organometallic compounds. Sand, soil, fluxes are also used to extinguish fires. Powder compositions do not have electrical conductivity, do not corrode metals and are practically non-toxic.

Compositions based on sodium and potassium carbonates and bicarbonates are widely used.

Fire extinguishing devices: mobile (fire trucks), stationary installations, fire extinguishers.

Cars are designed for the manufacture of extinguishing agents, are used to extinguish fires at a considerable distance from their deployment and are subdivided into:

tank trucks (water, air-mechanical foam) AC-40 2.1 -5m3 of water;

special - AP-3, powder PS and PSB-3 3.2t .;

airfield;

water, freon.

Stationary installations are designed to extinguish fires in initial stage their occurrence without human intervention. They are subdivided into water, foam, gas, powder, steam. They can be automatic and manual with remote control.

Fire extinguishers are devices for extinguishing fires with a fire extinguishing agent, which he releases after activating it, is used to extinguish small fires. Chemical or mechanical air foam, carbon dioxide (liquid state), aerosols and powders, which include bromine, are used as fire extinguishing agents. Subdivided:

by mobility:

manual up to 10 liters;

mobile;

stationary;

fire extinguishing composition:

liquid;

carbon dioxide;

chemical foam;

air-foam;

freon;

powder;

combined.

Fire extinguishers are marked with letters (type of fire extinguisher by category) and digital (volume).

Handheld firefighting tool is a tool for opening and disassembling structures and carrying out rescue operations when extinguishing a fire. These include: hooks, crowbars, axes, buckets, shovels, scissors for cutting metal. The tool is placed in a visible and accessible place on stands and boards.

4. Assessment of fire hazard industrial enterprises

In accordance with SNiP 2-2-80, all industries are divided into fire, explosive and explosion hazard into 6 categories.

A - explosive: industries that use flammable gases with a lower flammability limit of 10% and below, liquids with twsp £ 280 C, provided that gases and liquids can form explosive mixtures in a volume exceeding 5% of the volume of the room, as well as substances that can explode and burn when interacting with water, air oxygen or with each other (painting shops, shops with the presence of flammable gases, etc.).

B - explosive and fire hazardous: industries in which flammable gases with a lower flammability limit are higher than 10% are used; liquids tvsp = 28 ... 610С inclusive; combustible dusts and fibers, the lower concentration limit of flammability of which is 65 g / m3 and below, provided that gases and liquids can form explosive mixtures in a volume exceeding 5% of the volume of the room (ammonia, wood dust).

B - fire hazardous: industries in which flammable liquids with twsp> 610C and combustible dust or fibers with a lower flammable limit of more than 65 G / m3 are used, solid combustible materials that can burn, but do not explode in contact with air, water or with each other ...

D - industries that use non-combustible substances and materials in a hot, incandescent or molten state, as well as solids, liquids or gases that are burned as fuel.

D - production in which non-combustible substances and materials are processed in a cold state (workshops for cold processing of materials, and so on).

E - explosive: industries in which explosive substances are used (flammable gases without a liquid phase and explosive dust) in such an amount in which explosive mixtures can form in a volume exceeding 5% of the volume of the room, and in which, according to the conditions technological process only an explosion is possible (without subsequent combustion); substances that can explode (without subsequent combustion) when interacting with water, atmospheric oxygen or with each other.

The Electrical Installation Rules PUE regulate the design of electrical equipment in industrial premises and for outdoor technological installations based on the classification of explosive zones and mixtures.

Class B-? Zone. Rooms in which explosive mixtures of vapors and gases with air can form under normal operating conditions (flammable liquids discharge into open vessels).

Class B-Ia zone. Explosive mixtures are not formed under normal operating conditions of the equipment, but can be formed during accidents and malfunctions.

Class B-Ib zone:

a) rooms containing flammable gases and vapors with a high lower flammable limit (15% or more) with a pungent odor (ammonia);

b) rooms in which explosive mixtures can form in a volume exceeding 5% of the volume of the room.

Class B-Ic zone. Outdoor installations containing explosive gases, vapors and flammable liquids.

Zone class B-II... Handling combustible dusts and fibers that can form explosive mixtures during normal operation.

Class B-IIa zone. B-II in case of accidents or malfunctions.

Premises and installations containing combustible liquids and combustible dusts with a lower concentration limit above 65 G / m3 are classified as fire hazardous and classified.

Zone of class P - I. Premises containing GZh.

Zone class P - II. Rooms containing combustible dusts with a lower concentration limit higher than 65 g / m3.

Zone class P - IIa. Rooms that contain solid combustible substances that are not capable of being suspended.

Plants of class P - III. Outdoor installations, which contain combustible liquids (tsp> 610C) and solid combustible substances.

Bibliography

GOST 12.0.003-74 SSBT. Dangerous and harmful production factors... Classification. M., 1980.

GOST 12.1.004-91 Fire safety. General requirements, M., 1992.

SNiP 2.09.02-85 Industrial buildings... M., 1985.

SNiP 21-01-97 Fire safety of buildings and structures. M. 1997.

A.I.Salov "Labor protection at enterprises road transport", Moscow," Transport ", 1985.

"Collection of guidance documents of the State Fire Service", GUGPS, M., 1997.

Dolin P.A. "Safety Handbook", Moscow, "Energoizdat", 1982.

Yudin E. Ya. "Labor protection in mechanical engineering", Moscow, "Mechanical engineering", 1976.

Essay
"Fire is a friend and enemy to man"
We cannot do without a good fire. He is reliably friends with us: Chases the cold, drives the darkness. He raises a friendly flame like a flag. We need a good fire. And for that he is honored, That the children are warming dinner, Cuts the steel And bakes bread. Ilyich
4724401270 In ancient times, people were still practically animals, huddled in caves, died in hundreds, did not know fire, and did not know how to stand up for themselves. And the gods lived at the top of Olympus, they were strong and beautiful. They had unbreakable power over the world and over people. People who lived on earth did not know fire, but on Olympus it was already with the god-blacksmith Hephaestus and Athena, his wife. The titan Prometheus also lived there on Olympus. And then Prometheus saw that the gods on Olympus are only having fun, and below, on Earth, people suffer from cold and hunger. And Prometheus decides to help people.
Each time Prometheus came to Olympus with a rod, and then one day he brought with him instead of a rod a hollow reed stalk. Arriving at the forge of his friend Hephaestus, Prometheus, imperceptibly, distracting the owners with a conversation, took a coal from the fire of the forge, and put it in his kind of hollow staff.
No one suspected anything, and Prometheus managed to quietly carry the fire to the ground and transfer it to people.
4196715616585Once Zeus looked at the Earth and saw that people were no longer the same people in skins, angry, almost beasts, that they already knew how to heat their homes, cook food, make tools of labor and hunting, trim skins, in general, they received knowledge and began their journey evolution.
Zeus became angry, the deception was revealed, and they learned about Prometheus. And for his deed he was overthrown from Olympus and chained forever and ever to a rock on Earth, doomed to suffer.
Today, both on holidays and on weekdays, the fire is always with us. Fire is our helper in everything and always. Fire can be a good friend to people. He gives us light, warmth, joy. At the monument to the heroes, people bow their heads before the Eternal Flame, athletes carry the Olympic flame in the torchlight -13335413385 relay.
But fire can also be the worst enemy of people, a raging fire that sweeps away everything in its path. A big fire or fire is a huge monster that devours everything around with its fiery tongue. But the main thing is that people can die in a fire. Forest fires are also very terrible, in which a lot of forest burns down, animals die. And it can be impossible to stop it! There is no life without fire, and trouble can come from fire. How to understand when fire turns from a friend into a bitter enemy?
V modern world, in which we live, everything changes and develops rapidly. Unfortunately, even today problems and troubles from careless handling of fire do not disappear. For example, forest fires can start by accident. A forest can be set on fire by an accidental lightning, but much more often the forest burns through the fault of a person. The reason for this may be an unextinguished fire, as a result - trees with charred trunks, the bird cannot make a nest, the animal leaves. Therefore, it is no coincidence that during the hot period of summer it is forbidden to visit the forest, and even more so to make fires. People, remember: one tree can make a million matches, and one match can burn a million trees. 35775901841500
A person spends most of his life at home, in an apartment, at an enterprise. Here and there it is surrounded by dozens of devices: electric heating and lighting devices - kettles, irons, table lamps, televisions, computers, which, if used ineptly or carelessly, pose a great danger. And how many different furniture around people, which not only burns easily, but also emits poisonous gases when burning. And stoves, gas stoves ... Children left unattended by adults, playing with matches, lighting candles, kindling fires are no less dangerous.
Dear adults and children, do not leave the iron, tiles and other appliances unattended, keep an eye on your family and friends and remind them of this.
Say what you like, but in most cases of fires, people themselves are to blame, who do not follow fire safety rules. As one of the proverbs says: "Do not joke with fire, you will burn yourself."
Well, if all the same trouble came, what should we all do then? In the old days, houses were mostly wooden, with a stove, so fires happened very often. If the house caught fire, then the residents were going to ring the bell, everyone ran together with buckets and shovels, stood up like a snake and passed buckets of water along a chain, poured fire, men rolled out logs, threw earth into the fire, someone threw things from the house into the street through the windows. , someone saved the cattle, drove it out into the street. Everything was working like ants, no one stood aside and watched, and everyone was busy with something.
In the modern world, very brave and courageous people - firefighters - are sent to fight fires. Throwing themselves into fire and smoke, they save people, sometimes even at the cost of their own lives. Firefighters now have modern technology at their disposal. Since fires break out in different places, on different objects that are completely different from each other, then fire fighting equipment very versatile and mobile: mobile pumping stations, smoke exhausters, auto-mechanical ladders, communication means, all this allows firefighters to quickly cope with fire. The profession of a firefighter is dangerous, and people who work as firefighters are brave and smart. They have the courage physical strength, dexterity and professionalism. 35013902048510
Not only firefighters, but also ordinary people are distinguished by their courage in fires. History keeps many feats committed in days of peace. The most expensive medal is considered by firefighters "For courage in a fire", and the gratitude of people saved from the fire is also called a high award.
-228601021080 Fire is blind and deaf, he recognizes only the power of knowledge and retreats before them. Fire safety rules are just such rules that are needed "more than once" and you must always refer to them. And strict adherence to the rules of conduct in the event of a fire is the alphabet of safety for every person!
People, do not forget the simple truth that has become a safety commandment: "It is easier to prevent and avoid a fire than to liquidate and fight it!" After all, fire is a terrible element of fire, and fire is the judge of people's carelessness. And so that no trouble happens, so that there are as few fires as possible in our world, and fire always remains a friend of man, study and observe the fire safety rules.

1. Fire safety

Fires cause tremendous material damage and, in a number of cases, are accompanied by the death of people. Therefore, fire protection is the most important duty of every member of society and is carried out on a national scale.

Fire protection is aimed at finding the most effective, economically feasible and technically sound methods and means of preventing fires and eliminating them with minimal damage with the most rational use of forces and technical means of extinguishing.

Fire safety is the state of an object, in which the possibility of a fire is excluded, and in case of its occurrence, the necessary measures are taken to eliminate the negative impact of hazardous fire factors on people, structures and material values.

Fire safety can be ensured by measures of fire prevention and active fire protection. Fire prevention includes a set of measures aimed at preventing a fire or reducing its consequences. Active fire protection - measures to ensure successful fight against fires or explosive situations.

1.1. Fire as a factor in a man-made disaster

A fire is combustion outside a special hearth, which is uncontrolled and can lead to mass destruction and death of people, as well as the infliction of environmental, material and other harm.

Combustion is a chemical oxidation reaction accompanied by the release of heat and light. For combustion to occur, three factors are required: a combustible substance, an oxidizer, and a source of ignition. Oxidizing agents can be oxygen, chlorine, fluorine, bromine, iodine, nitrogen oxides and others. In addition, it is necessary that the combustible substance be heated to a certain temperature and be in a certain quantitative ratio with the oxidizer, and the source of ignition has a certain energy.

The highest burning rate is observed in pure oxygen. When the oxygen content in the air decreases, combustion stops. Combustion with a sufficient and above the measured concentration of the oxidizer is called complete, and with a lack of it, incomplete.

There are three main types of self-acceleration of a chemical reaction during combustion: thermal, chain and chain-thermal. The thermal mechanism is associated with the exothermicity of the oxidation process and an increase in the rate of the chemical reaction with increasing temperature. The chain acceleration of the reaction is associated with the catalysis of transformations, which is carried out by the intermediate products of the transformations. Real combustion processes are carried out, as a rule, by a combined (chain-thermal) mechanism.

The combustion process is divided into several types:

Flash - rapid combustion of a combustible mixture, not accompanied by the formation of compressed gases.

Ignition is the occurrence of combustion caused by an ignition source.

Ignition - Combustion accompanied by the appearance of a flame.

Chemical - from exposure to combustible substances, oxygen, air, water or the interaction of substances;

Microbiological - occurs at a certain humidity and temperature in plant products (spontaneous combustion of grain);

Thermal - due to long-term exposure to insignificant heat sources (for example, at a temperature of 100 C thyrsa, fiberboard and other slopes to spontaneous combustion).

Self-ignition - spontaneous combustion, accompanied by the appearance of a flame.

Explosion - an extremely fast (explosive) transformation, accompanied by the release of energy with the formation of compressed gases.

The main indicators of fire hazard are self-ignition temperature and concentration limits of ignition.

Autoignition temperature characterizes the minimum temperature of a substance at which there is a sharp increase in the rate of exothermic reactions, resulting in the occurrence of flame combustion.

Flash point - the lowest (under special test conditions) temperature of a combustible substance at which vapors and gases are formed above the surface, which can flash in the air from the ignition source, but the rate of their formation is still insufficient for subsequent combustion.

According to this characteristic, flammable liquids are divided into 2 classes:
1) liquids with tvsp< 610 C (бензин, этиловый спирт, ацетон, нитроэмали ит.д.) - легковоспламеняющиеся жидкости (ЛВЖ); 2) жидкости сtвсп >610 C (oil, fuel oil, formalin, etc.) - flammable liquids (GZh).

Ignition temperature limits are the temperatures at which saturated vapors of a substance form in a given oxidizing environment concentrations equal to the lower and upper concentration limits of ignition of liquids, respectively.

Combustible substances are substances that can self-burn after the removal of the ignition source.

According to the degree of flammability, substances are divided into: combustible (combustible), hardly combustible (hardly combustible) and non-combustible (non-combustible).

Fuels include those substances that, if ignited by an extraneous source, continue to burn even after it has been removed.

Non-combustible substances are those that are incapable of spreading the flame and burn only in the place where the ignition source is exposed.

Non-flammable substances are substances that are not flammable even when exposed to sufficiently powerful ignition sources (impulses).

Combustible substances can be in three states of aggregation: liquid, solid and gaseous. Most combustible substances, regardless of their state of aggregation, when heated, form gaseous products, which, when mixed with air containing a certain amount of oxygen, form a combustible medium. A combustible medium can be formed by finely dispersed spraying of solid and liquid substances.

Combustible gases and dust form combustible mixtures at all temperatures, while solids and liquids can form combustible mixtures only at certain temperatures.

In industrial conditions, the formation of mixtures of combustible gases or vapors in any quantitative proportions. However, these mixtures can be explosive only when the concentration of combustible gas or vapor is between the flammable concentration limits.

The minimum concentration of flammable gases and vapors in the air at which they are capable of igniting and spreading a flame is called the lower flammable concentration limit.

The maximum concentration of flammable gases and vapors at which flame propagation is still possible is called the upper concentration limit for ignition.

The fire hazard of a substance is the greater, the lower and higher the upper ignition limits and the lower the autoignition temperature.

Dusts of flammable and some non-flammable substances (for example, aluminum, zinc) can form flammable concentrations when mixed with air.

Airborne dust poses the greatest explosion hazard. However, dust deposited on structures is not only dangerous from the point of view of a fire, but also a secondary explosion caused by the swirling of dust during the initial explosion.

The minimum concentration of dust in the air at which it is ignited is called the dust ignition limit.

Since it is practically impossible to achieve very high concentrations in dusty suspension, the term “upper flammable limit” does not apply to dusts.

Ignition of a liquid can occur only if there is a mixture of vapors with air above its surface in a certain quantitative ratio corresponding to the lower temperature limit of ignition.

2. Causes of fires at enterprises

A fire at an enterprise causes great material damage to the national economy and is very often accompanied by accidents with people.

The main reasons contributing to the occurrence and development of a fire are:

violation of the rules for the use and operation of devices and equipment with low fire protection;

use in construction in some cases of materials that do not meet fire safety requirements;

the absence of effective means of fighting fire at many objects of the national economy and in fire-fighting units.

2.1. Road transport enterprises

The reasons for the ignition of materials and the occurrence of firefighting in road transport enterprises:

incorrect arrangement of thermal furnaces and boiler furnaces;

malfunction of heating devices;

malfunction of electrical equipment and lighting and their improper operation;

spontaneous combustion from improper storage of lubricants and cleaning materials;

the presence of static electricity, the absence of lightning rods;

careless handling of fire, unsatisfactory supervision of fire-fighting devices and production equipment.

2.2. Mechanical engineering enterprises

Machine-building enterprises are distinguished by an increased fire hazard, as they are characterized by the complexity of production processes; the presence of significant quantities of flammable and combustible liquids, liquefied combustible gases, solid combustible materials; large equipment with electrical installations and others.

1) Violation of the technological regime - 33%.

2) Malfunction of electrical equipment - 16%.

3) Poor preparation for equipment repair - 13%.

4) Spontaneous combustion of oily rags and other materials - 10%

As well as violation of the rules and regulations for the storage of fire hazardous materials, careless handling of fire, use of open flames, blowtorches, smoking in prohibited places, failure to comply with fire-fighting equipment, water supply, fire alarm systems, provision of primary fire extinguishing equipment, etc.

2.3. Laboratories

During the operation of the computer, the following emergency situations are possible:

short circuits;

overload;

increase. transition resistances in el. contacts;

overvoltage;

the occurrence of leakage currents.

In the event of emergency situations, a sharp release of thermal energy occurs, which can cause a fire.

The share of fires occurring in the email. installations account for 20%.

Fire statistics:

Main reasons: %

short circuit 43

overload of wires / cables 13

formation of transition resistances 5

Short circuit mode - the appearance as a result of a sharp increase in current strength, el. sparks, molten metal particles, electric arcs, open flames, ignited insulation.

Short circuit reasons:

design errors;

aging of insulation;

moisture insulation;

mechanical overload.

Fire hazard during overloads - excessive heating of individual elements, which can occur during design errors in the event of a prolonged passage of current exceeding the nominal value.

At 1.5 times the power, the resistors heat up to 200-300 ° C.

Fire hazard of transient resistance - the possibility of ignition of insulation or other nearby combustible materials of the thaw that occurs in the place of the emergency. resistance (in transition terminals, switches, etc.).

Fire hazard of overvoltage - heating of live parts due to an increase in currents passing through them, due to an increase in overvoltage between individual elements of electrical installations. It occurs when the parameters of individual elements fail or change.

Fire hazard of leakage currents - local heating of insulation between individual current-carrying elements and grounded structures.

3. Fire prevention measures

The basics of fire protection of enterprises are defined by standards

GOST 12.1. 004 - 76 "Fire safety"

GOST 12.1.010 - 76 “Explosion safety. General requirements"

Fire prevention measures are divided into organizational, technical, regime, construction and planning and operational.

Organizational measures: provide for the correct operation of machines and intra-plant transport, the correct maintenance of buildings, territories, fire safety instructions, and the like.

Regime measures - the prohibition of smoking in unidentified places, the prohibition of welding and other hot work in fire-hazardous premises, and the like.

Operational measures - timely prophylaxis, inspections, repairs and testing of technological equipment.

All building structures on the limit of fire resistance are divided into 8 degrees from 1/7 hour to 2 hours.

Depending on the degree of fire resistance, the greatest additional distances from exits for evacuation in case of fire

Technical measures are the observance of fire safety standards during the evacuation of ventilation systems, heating, lighting, electrical supply, etc.

Using a variety of protective systems;

Compliance with the parameters of technological processes and operating modes of equipment.

3.1. Methods and means of extinguishing fires

In the practice of extinguishing fires, the following principles of stopping combustion are most widespread:

1) isolation of the combustion center from air or reduction of oxygen concentration by diluting the air with non-flammable gases (carbohydrates CO2< 12-14%).

2) cooling the combustion center below certain temperatures;

3) intensive inhibition (inhibition) of the rate of the chemical reaction in the flame;

4) mechanical stripping of the flame by a jet of gas or water;

5) the creation of conditions for fire protection (conditions when the flame spreads through narrow channels).

Substances that create conditions under which combustion stops are called extinguishing agents. They must be cheap and safe to operate and not harm materials and objects.

Disadvantages: oil products float up and continue to burn on the surface of the water; water has a high electrical conductivity, therefore it cannot be used to extinguish fires on electrical installations under voltage.

Fire extinguishing with water is carried out with water fire extinguishing installations, fire trucks and water shafts. These installations use plumbing to supply water.

Water fire extinguishing installations include sprinkler and deluge installations.

The sprinkler system is a branched pipe system filled with water and equipped with sprinkler heads. The outlet openings of the sprinkler heads are closed with fusible locks, which are soldered when exposed to certain temperatures (345.366, 414 and 455 K). Pressurized water from the system exits the head opening and irrigates room structures and equipment.

Deluge installations are a system of pipelines on which there are special deluge heads with open outlets with a diameter of 8, 10 and 12.7 mm of blade or rosette type, designed for irrigation of up to 12 m2 of floor area.

Deluge installations can be manual or automatic. Once activated, water fills the system and is discharged through the holes in the deluge heads.

Steam is used in conditions of limited air exchange, as well as in closed rooms with the most dangerous technological processes. Steam extinguishing is carried out by isolating the combustion surface of the environment. When extinguishing, it is necessary to create a para concentration of about 35%

Foams are used to extinguish solid and liquid substances that do not interact with water. The extinguishing effect is achieved by isolating the surface of the combustible substance from the surrounding air. The fire-extinguishing properties of foam are determined by its multiplicity - the ratio of the volume of the foam to the volume of its liquid phase, resistance to dispersion, and viscosity. Depending on the method of obtaining foam, chemical and air-mechanical ones are divided.

Chemical foam is formed by the interaction of solutions of acids and alkalis in the presence of a foaming agent and is a concentrated emulsion of carbon dioxide in a water reactor of mineral salts. The use of chemical salts is difficult and expensive, so their use is decreasing.

Air-mechanical foam of low (up to 20), medium (up to 200) and high (over 200) expansion rates is obtained using special equipment and foam concentrates PO-1, PO-1D, PO-6K, etc.

Inert gaseous diluents: carbon dioxide, nitrogen, smoke and exhaust gases, steam, argon and others.

Inhibitors - based on unsaturated hydrocarbons, in which one or more hydrogen atoms are replaced by halogen atoms (fluorine, chlorine, bromine). Halocarbons are poorly soluble in the input, but mix well with many organic substances:

tetrafluorodibromoethane (freon 114B2);

methylene bromide;

trifluorobromomethane (freon 13B1);

3, 5, 7, 4НД, СЖБ, БФ (based on ethyl bromide);

Powder compositions, despite their high cost, complexity in operation and storage, are widely used to stop the combustion of solid, liquid and gaseous combustible materials. They are the only means of extinguishing fires of alkali metals and organometallic compounds. Sand, soil, fluxes are also used to extinguish fires. Powder compositions do not have electrical conductivity, do not corrode metals and are practically non-toxic.

Compositions based on sodium and potassium carbonates and bicarbonates are widely used.

Fire extinguishing devices: mobile (fire-fighting vehicles), stationary installations, fire extinguishers.

Cars are intended for the manufacture of extinguishing agents, are used to extinguish fires at a considerable distance from their deployment and are subdivided into:

tank trucks (water, air-mechanical foam) AC-40 2.1 -5m3 of water;

special - AP-3, powder PS and PSB-3 3.2t .;

airfield;

water, freon.

Stationary installations are designed to extinguish fires at the initial stage of their occurrence without human intervention. Subdivided into water, foam, gas, powder, steam. They can be automatic and manual with remote control.

Fire extinguishers are devices for extinguishing a fire extinguishing agent, which it releases after being activated, is used to extinguish small fires. As fire extinguishing agents they use chemical or air-mechanical foam, carbon dioxide (liquid state), aerosols and powders, which include bromine. Subdivided:

by mobility:

manual up to 10 liters;

mobile;

stationary;

fire extinguishing composition:

liquid;

carbon dioxide;

chemical foam;

air-foam;

freon;

powder;

combined.

Fire extinguishers are labeled with letters (type of fire extinguisher by discharge) and digital (volume).

A handheld fire-fighting tool is a tool for opening and disassembling structures and conducting rescue operations when extinguishing a fire. These include: hooks, crowbars, axes, buckets, shovels, scissors for cutting metal. The tool is placed in a visible and accessible place on stands and boards.

4. Assessment of fire hazard of industrial enterprises

In accordance with SNiP 2-2-80, all production facilities are divided into 6 categories according to fire, explosive and explosion hazard.

A - explosive: industries that use flammable gases with a lower flammable limit of 10% and below, liquids with twp £ 280 C, provided that gases and liquids can form explosive mixtures in a volume exceeding 5% of the volume of the room, as well as substances that are capable of explode and burn when interacting with water, oxygen in the air or with each other (painting shops, shops with the presence of flammable gases, etc.).

B - explosive: production, which uses flammable gases with a lower ignition limit of more than 10%; liquids tvsp = 28 ... 610С inclusive; flammable dusts of fibers, the lower concentration limit of flammability of which is 65 g / m3 and below, provided that gases and liquids can form explosive mixtures in a volume exceeding 5% of the volume of the room (ammonia, wood dust).

D - production in which non-combustible substances and materials are used in a hot, incandescent or molten state, as well as solids, liquids or gases that are burned as fuel.

D - production in which non-combustible substances and materials are processed in a cold state (workshop for cold processing of materials, and so on).

E - explosive: industries in which explosive substances are used (flammable gases without a liquid phase and explosive dust) in such an amount in which explosive mixtures can form in a volume exceeding 5% of the volume of the room, and in which, according to the conditions of the technological process, only an explosion is possible (without subsequent combustion); substances that can explode (without subsequent combustion) when interacting with water, atmospheric oxygen or with each other.

The Electrical Installation Rules PUE regulate the arrangement of electrical equipment in industrial premises and for outdoor technological installations based on the classification of explosive zones and mixtures.

Class B zone -? .. Premises in which explosive mixtures of vapors and gases with air can form under normal operating conditions (flammable liquid discharge into open vessels).

Class B-Ia zone. Explosive mixtures are not formed under normal operating conditions of the equipment, but can be formed during accidents and malfunctions.

Class B-Ib zone:

a) rooms containing flammable gases and vapors with a high lower flammability limit (15% or more) with a pungent odor (ammonia);

b) rooms in which explosive mixtures can form in a volume exceeding 5% of the volume of the room.

Class B-Ic zone. Outdoor installations containing explosive gases, vapors and flammable liquids.

Class B-II zone. Handling combustible dusts and fibers that can form explosive mixtures during normal operation.

Class B-IIa zone. B-II in case of accidents or malfunctions.

Rooms and installations containing combustible gases and flammable dusts with a lower concentration limit above 65 G / m3 are classified as fire hazardous and classified.

Zone of class P - I. Premises containing GZh.

Zone class P - II. Premises containing combustible dust with a lower concentration limit higher than 65g / m3.

Zone class P - IIa. Rooms that contain solid combustible substances that are not capable of passing into a suspended state.

Plants of class P - III. Outdoor installations containing GF (tsp> 610C) and solid flammable substances.

Bibliography

GOST 12.0.003-74 SSBT. Dangerous and harmful production factors. Classification. M., 1980.

GOST 12.1.004-91 Fire safety. General requirements, M., 1992.

SNiP 2.09.02-85 Industrial buildings. M., 1985.

SNiP 21-01-97 Fire safety of buildings and structures. M. 1997.

A.I.Salov "Labor protection at the enterprises of automobile transport", Moscow, "Transport", 1985.

"Collection of guidance documents of the State Fire Service", GUGPS, M., 1997.

Dolin P.A. "Safety Handbook", Moscow, "Energoizdat", 1982.

Yudin E. Ya. "Labor protection in mechanical engineering", Moscow, "Mechanical engineering", 1976.

The subject of the essay is:

"What do I know about fire safety."

Prepared by: student of grade 8 V. V. Shcherbakova Kozlovskaya main comprehensive school Fire is the most common disaster in the world. And every hour dozens of people die in the fire, and many others suffer from harm to their health and property. Most fires take place in apartments. The reason for many of them is our childish prank with fire. From this we must conclude: "Never play with matches, do not let other guys play with them!" If there is a fire, remember that you can help yourself or others to stay alive. Having felt the smell of smoke in the house, you need to find its source as soon as possible. All doors, windows and vents must be tightly closed. If you can no longer smell the smoke, it may have entered your home through a window or door. Look for smoke on the landing. Just in case, check your apartment, including the balcony - it's better to play it safe than to overlook the beginning of a fire. If something catches fire in the apartment, turn off the gas and help your elderly neighbors and children get out. Remember that smoke is more dangerous than fire. Even breathing through a damp cloth, you cannot get rid of the thick smoke, because some building or finishing materials can be poisoned during combustion. Leave the house and call fire brigade... It is best to do this from neighbors or mobile phone by dialing the number "01". All citizens of our country are required to comply with fire safety rules. For violation of the requirements, as well as for other offenses with fire, a person can be brought to disciplinary, administrative or criminal liability... Firefighters are life savers. The earliest mentions of professional brigades date back to Ancient Egypt. On the territory of our country, the first fire service created in Moscow in 1504. But the day of the employee of the Ministry of Emergencies of Russia is celebrated on April 30, since on this day in 1649 Tsar Alexei Mikhailovich issued a decree determining the composition and responsibilities of fire brigades. Fire is a powerful element, capable of turning a huge territory into a black desert covered with ash in dry weather. Task fire service save people first, and then material values, buildings, forests, agricultural land, etc. these brave people extinguish multi-storey buildings and even entire factories, when man-made fires and also prevent the fire from spreading further. Without their exploits, the number of victims and material damage would have been catastrophic on the scale of our country. The profession of firefighters can be safely classified as one of the most dangerous in the world. Often these people themselves become victims of the fire, with which they came to fight. This is a noble profession, because not everyone will agree to run around a burning building, which is about to collapse, in an attempt to save people who have not yet managed to get out of it. But the gratitude of those who owe their lives to rescuers has no boundaries.

The composition "Fire is our worst enemy"

Fire is our worst enemy. A fire is a terrible phenomenon, it is flames that destroy everything around.

Anything can be the cause of the fire. This is a lighted candle or match, carelessly thrown and forgotten by someone, and a shard of glass reflecting sunlight, unbearable summer heat, careless handling of equipment, a lightning strike and much more. Man, despite his intelligence, has not learned how to properly handle fire and most often is the cause of the fire himself. The main cause of fires is the ugly attitude of people who do not exercise due caution when using fire: a cigarette butt, a burning match, refueling the tanks of cars with the engine running, making fires.

During fires, the greatest danger is fire, high air temperature, poisonous gases. Vast smoke zones are formed, which are dangerous for people.

Firefighters' work is difficult and dangerous. Only a brave and courageous person can become a firefighter. A person who is not afraid to sacrifice his life for the sake of saving other people. It is very difficult to extinguish a fire, since smoke and high temperatures have an adverse effect on humans. He can be in the immediate vicinity of the fire for no more than half an hour, after which he needs to rest for 20-30 minutes outside the smoke zone. Each fire extinguishing group must have a supervisor who is responsible for monitoring the direction of the spread of the fire.

If it is necessary to pass through the combustion zone, you should hold your breath or use special masks so that you do not burn the airways when inhaling, and do not swallow smoke.

Firefighters must work quickly and in a cohesive manner. Discipline in a group and mutual assistance, honor and courage, perseverance and self-sacrifice can reduce the threat to human life and health, and defeat the fire.

Qualities such as psychological readiness for decisive action are of no small importance. Success in extinguishing a fire largely depends on the courageous, proactive actions of citizens who find themselves in the fire zone, their prudence and caution, solid knowledge and compliance with safety requirements.

Fire is nature's worst enemy. Forest fires are destroying huge areas of forests. Fires with strong winds pose a great danger, then it becomes uncontrollable, all-consuming. Take care of nature, remember about animals for which the forest is a natural habitat. Don't take them away from your home.

If you find yourself in a fire zone, then, firstly, keep your cool, call fire department 01, close all doors to avoid air influx and fire spread. Cover your nose and mouth with a damp handkerchief, stand by the window so that the firefighters know about your stay in the apartment. Wait for firemen, do not try to fight the fire yourself.

Remember that with the least losses in this situation comes out the one who owns the fire safety rules and without panic, skillfully acts in the event of a fire, having the necessary fire extinguishing equipment at hand. And know that simple neatness and everyday culture of each of us can protect any object from fires better than a hundred fire brigades.

All about tuning cars

An essay on the topic The profession of a Firefighter (a heroic profession). Essay on the topic "Why it is necessary to comply with fire safety rules Fire hazard assessment of industrial enterprises