Fire prevention. Fire prevention in an educational institution
The safety of PNI must also be ensured by measures fire prevention and active fire protection. The concept of fire prevention includes a set of measures necessary to prevent a fire or reduce its consequences.
Active fire protection refers to measures that ensure a successful fight against emerging fires or an explosive situation. Analysis of registered major fires in PNI showed that in case of fires in these buildings, a difficult situation is created for fire extinguishing, therefore, the development of a set of measures for fire protection... This complex includes preventive measures and the device of systems fire protection(fire extinguishing, alarm and warning systems).
Fire prevention measures are divided into:
Organizational measures that provide for the correct maintenance of buildings, territory, firefighting briefing employees, the organization of voluntary fire brigades, fire-technical commissions, the issuance of orders on strengthening fire safety etc.;
Technical Measures - Compliance fire regulations, norms for the design of buildings, for the installation of electrical wires and equipment, heating, ventilation, lighting, the correct placement of equipment;
Regime measures are the prohibition of smoking in unidentified places, the production of welding and other hot work in fire-hazardous premises, etc.;
Operational activities are timely preventive examinations, repairs and testing of equipment.
It should be remembered that a fire that has begun can develop rapidly and have catastrophic proportions if the conditions are right. Therefore, this issue should be paid special attention already at the design stage. technological systems, as well as during their construction and operation.
Operational practice different technologies testifies that in some cases the fire that has begun is self-localized, while in others it can develop and spread rapidly.
The fire can take big sizes, cause significant material damage and loss of life. In most cases, people in fires, especially children, do not die from high temperature, but from smoke saturated with poisonous combustion products of familiar and useful things in everyday life. Fires produce a lot of smoke, which contains carbon dioxide. This gas, mixed with air, reduces the concentration of oxygen in it. When the oxygen concentration in the ambient air decreases from 21% to 14%, the so-called oxygen starvation occurs, and at 8-11%, a person may die. Typically, the air contains no more than 0.04% carbon dioxide. If during a fire its concentration in the air increases to 4-5%, the respiratory rate increases, tinnitus and dizziness occur. At 8-9%, a person loses consciousness, at 12%, paralysis of the vital centers occurs, and death occurs. The smoke released during a fire is highly irritating to the respiratory system and mucous membranes of the eyes. Particularly great danger to the human body is carbon monoxide (CO) released during incomplete combustion. When burning, substances can be released that have a toxic effect on the human body.
The space covered by fires is conventionally divided into 3 zones - active combustion (fire source), heat exposure and smoke. Outward signs active combustion zones are the presence of flames, as well as smoldering or incandescent materials. The main characteristic destructive action fire is the temperature that develops during combustion. A fire can spread quickly if there are appropriate causes and conditions for the spread of a fire that has begun.
fire terrorism explosion evacuation
According to GOST, fire safety must be ensured by: a fire prevention system (SPP), a fire protection system (SPZ), organizational and technical measures (OTM).
A fire can be represented by the following diagram:
combustible substance + oxygen + ignition source = combustion.
The fire prevention system, based on the scheme, is aimed at reducing the likelihood of the appearance of components of the combustion process: a combustible medium (combustible substance + oxygen) and an ignition source.
V fire prevention system includes:
Maximum use of non-flammable materials, limiting the mass of flammable materials, their isolation, maintaining a safe concentration of flammable gases and vapors (the maximum permissible explosive concentration should not exceed 10% LEL;
Exclusion of the ignition source;
The use of machines (assemblies) without sparking, the elimination of electrical equipment in an explosive design, the elimination of spontaneously combustible substances, the maintenance of the surface temperature of machines and materials below the maximum permissible (less than 80% of the ignition temperature), compliance with the established rules for hot work, etc.;
Correct device and operation ventilation units and air conditioning systems.
Fire protection system includes:
1) methods and means of extinguishing fires;
2) fire barriers;
3) systems of automatic notification and extinguishing of fires;
4) the use of individual and collective protection equipment (anti-smoke - smoke hatches, explosion hatches);
5) evacuation of people.
Extinguishing methods fires:
Reducing the temperature of the burning substance;
Reducing the concentration of the oxidant (isolating the combustion site from air or reducing the percentage of oxygen by diluting the air with non-combustible gases);
Chemical inhibition of the combustion reaction (inhibition);
Mechanical knocking down of the flame (separation of the flame as a result of exposure to a strong jet of gas or water).
Extinguishing agents fires: water, foams (mechanical and chemical), water emulsions of various chemicals, water vapor, inert extinguishing agents (carbon dioxide, nitrogen, flue gases), freons and powders.
The most commonly used water. In this case, its cooling effect, mechanical action on the flame, dilution of air and gases with steam are used (the volume of steam is 1750 times greater than the volume of evaporated water). Water should not be used to extinguish live electrical installations and light oil products, because they float on its surface.
Foam is used to extinguish solid and liquid substances that do not interact with water. Depending on the ratio of the volume of the foam to the volume of the liquid that formed it, the foam can be low expansion (up to 10), medium expansion (up to 200) and high expansion.
Inert extinguishing agents are used to extinguish substances that interact with water, valuable items and electrical installations under voltage. Carbon dioxide is not used to extinguish alkali metals, oxygen-containing substances, and smoldering materials. Nitrogen and argon are used to extinguish these substances. The use of halogenated hydrocarbons (freons) is based on the effect of inhibition of the rate of a chemical reaction in the combustion zone. The most widespread are freon 114B2, methylene bromide, freon 13B1, ethyl bromide.
Powder formulations are the only extinguishing agent for alkali metals and organometallic compounds. For these purposes, powders based on sodium and potassium carbonates and bicarbonates, phosphorus-ammonium salts, sodium and potassium chlorides are used.
Fire extinguishers are used as the primary means of extinguishing fires, which, depending on the substances used, are divided into carbon dioxide, chemical foam, air-foam, freon, powder and combined. The primary means also include internal fire hydrants, hand pumps, water tanks, felts, boxes of sand, firefighting tools and equipment.
To extinguish fires with water, special fire water pipes of high and low pressure... From the water pipes high pressure water is used directly to extinguish a fire, from a low-pressure water supply system - through the pumps of fire engines. The choice of the type of water supply system, the required water flow rate, the procedure for placing fire hydrants and the place of installation of taps in buildings depend on the nature of the production, the protected area and the degree of fire resistance of the buildings.
Fire barriers create conditions for fire barriers, i.e. conditions under which the flame spreads through narrow channels. Obstacles are common and local. Common fire barriers dividing a building vertically or horizontally into separate compartments are fire walls or ceilings made of non-combustible materials (brick, reinforced concrete), with minimum limit fire resistance 2.5 hours. Local barriers are intended to limit the spread of flame in the initial stage of fire development. These include sides, thresholds, ditches, embankments.
Consider automatic warning and extinguishing systems fires. Fire extinguishing with water can be carried out using special automatic water fire extinguishing installations - sprinkler and deluge. Automatic fire detectors, depending on what sign of fire they react to, are divided into heat, smoke, light, ultrasonic, ultraviolet. By the nature of the reaction to the appearance of a fire source, they are divided into maximum and differential. The maximum ones are triggered when a predetermined maximum value of the monitored parameter is reached, for example, the room temperature, and the differential ones are triggered by the rate of change of this parameter. As heat detectors, bimetallic plates or fusible inserts can be used for a given temperature, for a change in linear dimensions, etc. As smoke - optical, based on the registration of light scattering by smoke particles, or ionization, triggered by a change in the current of the ionization chamber caused by the absorption of ions by smoke particles. Ultrasonic detectors can be used simultaneously for burglar alarms. They have a source and receiver of ultrasonic vibrations and allow detecting open flame as well as ultraviolet.
When designing a building, it should be possible to quickly evacuating people out of the building. The evacuation time is determined by the distance from the most distant workplace to the exit to the outside. The maximum distance is standardized depending on the category of production, the degree of fire resistance of the building and should not exceed 100 m. The standardized evacuation time in case of fires is given in Table 8.1.
Organizational and technical measures include:
1) Creation regulatory framework(documents) - Law of Ukraine on fire safety, GOSTs, instructions, regulations.
2) Division of production according to fire hazard and zones for explosion and fire hazard.
3) Organization of fire protection.
4) Training, instruction.
Table 8.1 - Standardized evacuation time in case of fires
Fire prevention - a set of measures aimed at preventing fires and creating conditions for preventing damage from them, and their successful extinguishing.
Fire prevention is part of technological processes of production, urban planning, planning and development of rural settlements. The organization of prevention is the responsibility of the fire authorities.
Fire prevention is achieved:
development, implementation and control over compliance with fire regulations and rules;
conducting design and planning, taking into account the fire safety of the objects being created;
improvement and content in readiness fire-fighting equipment;
regular fire-technical inspections of industrial and agricultural enterprises, organizations, residential and public buildings;
propaganda of fire-technical knowledge among the population.
Fire prevention is carried out by types of objects - in civil buildings, in warehouses, bases and shops, at industrial facilities and transport, in forests and in peat mines.
For fire prevention in civilian buildings, firefighting measures connected with heating systems, power supply, gas and other devices.
Fire prevention in warehouses, bases and shops includes the observance of fire-prevention gaps between buildings during their construction, the creation of an internal fire-fighting water supply, the equipment of fire and fire-security alarms, the separation of large storage room fire walls, separate storage of flammable and combustible substances, a ban on stove and gas heating.
Fire prevention at industrial facilities is organized on the basis of general requirements for all facilities, as well as in accordance with the fire hazard category of technological processes at each of them. It includes the execution of buildings and structures according to the degree of fire resistance, the corresponding category of fire hazard of the object, the device of fire breaks between buildings, the separation of warehouses with flammable and combustible materials from the main territory, and other measures. In fire hazardous industries, internal fire-fighting water supply, sprinkler and drainage installations, fire alarms, combustible ceilings are replaced with non-combustible ones, electrical equipment is installed in a dust-and-moisture-proof design, storage of combustible materials is systematized, buffer warehouses are organized to exclude the accumulation of combustible materials and waste at workplaces, especially hazardous technological areas are separated from the main production by fire walls, evacuation routes are maintained in cleanliness and serviceability, a strict fire-fighting mode.
Fire prevention at agricultural enterprises is carried out in the planning and development of rural areas and in the production process. In industrial buildings of a rural type, combustible structures are processed fire retardants, stocks of fire extinguishers, water in barrels and sand, other fire extinguishing means are being created. Grain warehouses are divided into compartments by fire walls and are equipped with reliable lightning protection.
Electricity of the net are laid in steel pipes or on insulators at intervals.
On farms, overloading of premises with fodder is prohibited, the premises for livestock and feed kitchens must be separate.
Explosion prevention measures are aimed at excluding their initiation due to fire, sparks, heating, impact, excess of the normal pressure in the container, etc.
In all explosive industries, the exclusion of sparking is ensured, it is prohibited to carry out flammable work, to use electric heating devices, employees are prohibited from having matches and lighters. All equipment is grounded. Work on electrical equipment is carried out with the network disconnected. In the premises, using gas analyzers, the air environment is monitored in order to detect explosive concentrations of gas-air mixtures. Work is carried out with ventilation on.
In transport, prevention of explosions is carried out in accordance with the "Rules for the transportation of explosive explosions", which determine the procedure for loading and transporting explosives.
Recommendations to the population on the prevention of fires and explosions, actions during these emergencies
Compliance with fire safety measures and the ability to act during a fire helps to reduce the fire hazard, save people and property.
To prevent fires and explosions, the personnel of enterprises and organizations act in accordance with the established fire safety rules, safety and labor standards, technological instructions.
When preventing fires and explosions in everyday life, saving people and property, a number of prohibitions and simple rules should be observed.
In order to prevent fires, it is necessary to avoid storing in the house a significant amount of flammable and combustible liquids, as well as substances prone to spontaneous combustion and explosive substances (gasoline, kerosene, technical oils, acetone, liquefied gases etc). Small amounts of these substances present in the house should be kept in tightly closed vessels, away from heating devices, not subject to shock, shock, or spillage. Be careful when using household chemicals. Do not heat mastics, varnishes, aerosol cans over an open fire. Do not wash in gasoline. Do not store furniture, combustible materials, clutter basements and attics on staircases. It is not recommended to install electric heaters near combustible objects. Keep switches, plugs, power supply sockets, heating and other devices in good condition. It is forbidden to repair the electrical network, especially where there are no circuit breakers (switches), to leave electric heating appliances and TVs unattended. Be careful when smoking. Do not dry laundry over burning gas stove or oven.
Particular attention should be paid to the possibility of fire due to children's pranks. Do not allow children to play with matches, turn on gas, and electrical appliances, leave children unattended.
In order to create favorable conditions for extinguishing a fire, it is prohibited to: block access roads to buildings, approaches to fire hydrants, force balcony hatches with heavy objects.
In the event of a fire, one must be afraid of: high temperature, smoke and gas pollution of premises, collapse of structures, explosions of technological equipment, falling burnt trees, sinkholes into the ground (burning peat bogs).
In the event of a fire and during it, it is necessary to maintain calmness and quickly assess the situation for acceptance. correct decision... Do not panic and keep others from it.
It is dangerous to enter the smoke zone if the visibility is less than 10 m.
When rescuing victims and extinguishing a fire, it is necessary to follow some rules:
before entering a burning room, cover your head with a wet cloth, raincoat, jacket;
open the door to a smoky room with caution, slowly and standing to the side of the door in order to avoid a flash of flame and explosion from a sudden influx of air;
in a heavily smoky room, move crouching or crawling;
To avoid carbon monoxide poisoning, use a wet breathing cloth.
When carrying out rescue operations, remember that small children from fear often hide under beds, in closets, huddled in a corner.
At the beginning of a fire, an attempt should be made to extinguish it. To do this, use fire extinguishers, an internal fire water supply, sand, water, a dense blanket for extinguishing small fires and other means.
Burning clothing is extinguished with a blanket, throwing it off, or pouring water over it.
Direct the extinguishing agents to the places of the most intense burning, not to the flame. When burning vertical surface start to extinguish the fire from above.
In a smoky environment, use a spray jet to help deposit smoke and lower temperatures.
Combustible liquids are extinguished with foaming compounds, sand, earth or a blanket with a small fire source.
Fire on the elements of the power supply system must not be extinguished with water. You must first de-energize (turn off the switch or cut off the wiring with an ax with a dry wooden handle).
If it is impossible to extinguish the fire, it is necessary to evacuate. If it is impossible to leave the apartment, with strong smoke in the corridors, close the door tightly and plug the cracks, preferably with a wet cloth, go to the balcony or stand in the window opening, and then evacuate using improvised means or with the help of firefighters.
You need to leave the fire zone from the windward side.
GOST 12.1.033-81 * SSBT. Fire safety. Terms and definitions GOST 12.1.044-89 * SSBT. Fire and explosion hazard of substances and materials. Nomenclature of indicators and methods for their determination GOST 13449-82 Ceramic sanitary ware. Test methods GOST 25772-83 * Steel railings for stairs, balconies and roofs. General technical conditions GOST 30244-94 Building materials. Flammability test methods GOST 30247.0-94 Building structures. Fire resistance test methods. General requirements GOST 30247.1-94 Building structures. Fire resistance test methods. Bearing and enclosing structures GOST 30247.2-97 Building structures. Fire resistance test methods. Doors and gates GOST 30402-96 Building materials. Flammability test methods GOST 30403-96 Building structures. Method for determining fire hazard GOST 30444-97 Building materials. Test method for flame propagation NPB 101-95 Design standards for fire protection facilities NPB 104-95 Design of systems for warning people about a fire in buildings and structures NPB 105-95 Determination of categories of premises and buildings for explosion and fire hazard NPB 110-96 List of buildings, structures , premises and equipment to be protected automatic installations extinguishing and fire detection NPB 110-99 List of buildings, structures, premises and equipment subject to protection by automatic fire extinguishing installations and automatic fire alarms NPB 233-96 Buildings and fragments of buildings. The method of full-scale fire tests. General requirements. NPB 239-97 Air ducts. Fire resistance test method. NPB 241-97 Fire dampers ventilation systems... Fire resistance test method. NPB 250-97 Elevators for transportation of fire departments in buildings and structures. General technical requirements PPB 01-93 * Fire safety rules in Russian Federation SNiP 10-01-94 System of regulatory documents in construction. Basic provisions of SNiP 2.01.02-85 * Fire protection standards SNiP 2.04.05-91 * Heating, ventilation and air conditioning SNiP 2.07.01-89 * Urban planning. Planning and development of urban and rural settlements SNiP 23-05-95 * Natural and artificial lighting SNiP II-89-80 * Master plans industrial enterprises SNiP II-97-76 Master plans of agricultural enterprises ST SEV 383-87 Fire safety in construction. Terms and definitions This document is referred to: Technical solutions for the insulation of external fences of houses of the first mass series About individual provisions SNiP 21-01-97 * "Fire safety of buildings and structures" "Intelligent" multifunctional high-rise building: problems of terminology Features of the calculation of the actual redistribution of fire resistance of steel-reinforced concrete building structures
FIRE PREVENTION AND FIRE PROTECTION
Fire prevention means training fire engineering safety and a set of measures aimed at preventing fires. Fire protection is measures aimed at reducing damage in the event of a fire. It is not always possible to draw a clear line between these two main objectives of fire safety, as, for example, in the case of actions aimed at limiting the spread of fire when ignited. Since most people spend most of their time in buildings, the focus is on building fire safety. Specialized fire prevention and protection measures are required for the fire safety of forests, vehicles, rail, air and sea transport, as well as underground tunnels and mines.
The main elements of the fire. In order for a fire to start, three elements must be present in one place: combustible material, heat and oxygen. The combination of these three elements in a fire causes an uncontrollable chain reaction. Since all three elements are required for combustion, removing one of them can prevent a fire or extinguish a fire.
The class of fire depends on the type of combustible material, which determines the methods and means of extinguishing. V regulatory documents In a number of countries, fires are divided into four classes: A - ignition of common combustible materials such as wood, paper and plastics; B - ignition of flammable or combustible liquids, gases and lubricants; C - electrical wiring fire; D - ignition of combustible metals. The degree of fire hazard depends on the type and amount of combustible material in the considered fire hazardous area.
FIRE PREVENTION
Responsible authorities and their responsibilities. Fire prevention has traditionally been limited to safety training and fire prevention measures and has always been the responsibility of municipal fire departments. Today, the range of fire prevention activities has been expanded, and it includes the verification and approval of construction projects, control over the implementation of fire safety standards, the fight against arson (including with fire hazardous games for adolescents), data collection, as well as briefing and training the public and special contingents. The tasks of fire prevention can be divided into three broad, but closely related sets of measures: 1) training, incl. dissemination of knowledge about fire safety behavior (about the need to install home smoke indicators and store lighters and matches in places inaccessible to children); 2) fire supervision, which provides for the development of state fire safety and building codes, as well as verification of their implementation; 3) provision of equipment and technical development (installation of portable fire extinguishers and manufacture of lighters for safe use). Of the three listed complexes of measures, fire supervision seems to be the most difficult of all. The scope of supervision includes fire prevention standards, building fire codes and regulations, manufacturing and installation standards. fire fighting equipment and fire safety standards for consumer goods.
FIRE PROTECTION
Fire protection measures include: 1) control of materials, products and equipment; 2) active limitation of the spread of fire using fire alarms, systems automatic fire extinguishing and portable fire extinguishers; 3) the device of passive systems that limit the spread of fire, smoke, heat and gases by sectioning the premises; 4) evacuation of people from a burning building to a safe place.
Fire alarm systems. In the event of a fire, the fire alarm system must be triggered immediately, followed by a regulated system of measures.
Special connection. The special communication system ensures the transmission of fire messages to the fire department personnel. The message can come from the public telephone network, from an alarm button provided outside the building, from a speakerphone, from a duplex portable radio, from a municipal fire alarm system or from a commercial system. automatic alarm... All messages are automatically logged along with all radio and voice messages from the fire department. Fire department must receive and process the signal, promptly send firefighters to the scene of the fire and begin the operation to fight the fire. No matter how fast firefighters work, early detection of fires is critical to saving lives and property.
Protective alarm. The security alarm system transmits a fire signal, a telltale signal and a fault signal (in speech or digital form) from the installation site of the alarm button to other parts of the building or to a remote monitoring station, usually serviced by a unit of the relevant specialization. Household smoke indicators and alarm systems. The most common are single and multipoint smoke detectors (each with its own power supply and alarm). Smoke indicators are of three types: ionization, photoelectric and combined (ionization-photoelectric). Ionization smoke detectors contain a small amount of a radioactive isotope (americium-231) that ionizes the air in the sensor, making it electrically conductive. Smoke particles reduce air conductivity, as a result of which it turns on sound signal... A small light source is provided in the photocell chamber of the photoelectric smoke indicator. In the presence of smoke in the chamber, the amount of light falling on the photocell changes, which causes a sound signal. Smoke indicators different types about the same. All of them can operate on battery or mains supply, or on mains with a backup battery. Some regulations prescribe this electrical connection multi-position smoke indicators, in which they all give a sound signal if at least one indicator is triggered. Regardless of the principle of operation, the smoke indicator must provide a signal with an audible signal level of at least 85 dB at a distance of 3 m. In order for the smoke indicators to function properly, the maintenance, service and inspection procedures prescribed by the manufacturer's instructions must be regularly followed. Domestic fire alarm systems are usually a series of smoke detectors connected to a common mains powered control unit. alternating current and a separate battery capable of powering the system for 24 hours. Such systems are often also equipped with heat detectors, manual (push-button) alarms, bells and sirens. Combined systems provide for both fire and burglar alarm, and the signal of the second is canceled by the signal of the first.
Automatic fire alarm. In non-residential buildings, automatic fire alarm systems are used with smoke, heat, gas analyzers or flame detectors. Heat detectors are inexpensive and reliable, but they respond later than smoke detectors. Thermal sensors can operate in different modes. Some are triggered when a certain temperature is reached (usually FIRE PREVENTION AND FIRE PROTECTION 60 ° C); others - upon reaching a certain rate of temperature rise, say, 7-8 ° C / min. The pneumatic sensor is triggered when, due to the heating of the air in the room, the gas pressure in the sealed tube rises. The thermistor sensor generates a signal when the set resistance value is exceeded due to a rise in the room temperature. In a gas detector, a semiconductor element or catalyst is used to detect combustion products in air. An alarm with such sensors is triggered when the conductivity of the semiconductor element or the temperature of the catalyst changes. Semiconductor-based carbon monoxide (CO) detectors are not very suitable for fire safety systems (as CO is formed at a fairly late stage in a fire), but they are extremely effective as detectors of hazardous CO concentrations from faulty stoves and heaters. The technical regulations of various industries prescribe the mandatory installation of CO detectors in fire-hazardous areas. Flame detectors, usually used only in areas of increased fire risk, react to infrared or ultraviolet radiation from a flame.
Other systems. If necessary, three other alarm systems are also provided: a control system for the operation of the fire extinguishing system, signaling the inclusion of the latter; alarm system for the accumulation of high concentrations of flammable and flammable gases (in special industries); control system for the work of security and fire alarm systems.
Automatic fire extinguishing systems. Liquid, carbon dioxide, powder and foam automatic fire extinguishing systems are used. The most common water system is just a system water pipes, terminated with sprinkler heads with thermosensitive valves. The heat opens the valve of the sprinkler head, and a stream of water flows out of it, widely sprayed by mechanical deflectors. Each head is individually triggered according to the temperature at its location. (Otherwise, the filling systems work, which will be discussed below.) For the system to work properly, the sprinkler heads should not be filled with paint, foreign objects should not hang on them, and the space around them should not be obstructed. In "wet" water-based fire extinguishing systems, the pipelines are always filled with pressurized water. In "dry" systems, the pipelines are filled with compressed air or nitrogen until the sprinkler head opens, after which the pressure in the pipe drops and water begins to flow from the pressure side. In pre-action systems, the fire detector opens the valve and fills the pipes with water before the sprinkler head opens. Sometimes the principles of dry system and pre-action are combined in one system. In flood systems, the sprinkler heads are always open, and the fire alarm controls the common water valve, so that in the event of a fire, water flows into all sprinkler heads at once. Special water systems are also envisaged to protect the outer walls of the building and for other special tasks. Water automatic fire extinguishing systems household use end of the century releases require such small amounts of water that one sprinkler head is sufficient for an area of almost 40 m2. The distribution of the sprayed water is such that when the sprinkler head operates, it protects furniture in the corners of rooms and even the ceiling.
Portable fire extinguishers. Portable fire extinguishers are divided into four classes according to the fire classes (see above). Some of them are suitable for extinguishing fires of two or three different classes, but not all four.
Types of fire extinguishers. Fire extinguishers of different types differ in extinguishing agent. Class A liquid fire extinguishers use water with the addition of antifreeze (antifreeze salt solution alkali metal) or other wetting agent. Alkaline acid and foam (on water based) fire extinguishers fell out of use in the late 1960s. Liquid extinguishers are available with a propellant gas supply or with a booster pump. The mass of a fire extinguisher with a supply of expelling gas is 14 kg. Pump knapsack fire extinguishers are often used to extinguish forest fires. Carbon dioxide fire extinguishers are charged with liquefied carbon dioxide. When the valve is opened, they give a jet of carbon dioxide snow up to 2 m long. Such extinguishers are mainly used to extinguish class B and C fires, but can also be used to extinguish class A fires before water is delivered. They leave no residue (and are therefore called clean), but they should not be used in small enclosed spaces. V powder fire extinguishers compressed gas throws out the extinguishing agent. They are especially suitable for Class B and C fires, but can also be used to extinguish Class A fires prior to delivery of liquid extinguishers.
Special powders are used to extinguish class D fires.
Fire protection barriers. Arrangement of fire barriers preventing the spread of fire from one part of the building to adjacent rooms, is an extremely important fire safety measure. The wide spread of fire entails an increase in human losses and material damage, and also sharply complicates the fight against a fire. Although only 20% of home fires fire outside the floor where the fire occurred, these 20% account for almost 70% of deaths, more than 30% of injuries and about 70% of property losses. Smoke and gases can travel much farther than flames, posing a hazard to people far from the fire zone. Smoke and combustion gases from even a small fire can damage or interrupt the operation of computers and other sensitive electronic equipment. Fire barriers are special fire walls (firewalls) and non-combustible ceilings designed to prevent the spread of fire, smoke and heat horizontally (from room to room on the same floor) or vertically (from floor to floor) inside a building, and also from one building to another. Fire zones are also envisaged - sections of the building made of fire-resistant materials and dividing it into isolated sections. These fire and smoke free areas can provide shelter for people caught in a building by fire.
Building construction. The enclosing and supporting structures of the building (its walls and floors), with the right approach, are important elements fire safety, as they keep the fire within one room, one section, one floor. The fire and building codes and regulations establish the necessary fire resistance limits for such structures. The fire resistance limit is the time in hours or minutes during which a building structure resists the effects of fire or the high temperature of a fire. However, the guideline values quoted are for standard test conditions and are for guidance only, especially since unprotected openings for doors, windows, ventilation and cabling reduce the ability of the building envelope to contain the spread of fire, smoke, heat and gases.
see also
BUILDING ;
CONSTRUCTION AND BUILDING MATERIALS.
Fire doors, windows and sashes. Such devices are used to protect openings in fire walls. They also require an appropriate level of fire resistance, and they provide protection only when closed.
Separation of buildings. Radiated heat and local fire sparks pose a threat of its transfer to neighboring buildings. Protection is provided by a standardized "fire" distance between buildings. If, according to the construction conditions, such a distance cannot be maintained, then this must be compensated for by an increase in the fire resistance of the enclosing structure.
Passages and boxes. Horizontal and vertical passages and ducts for heating, ventilation and air conditioning systems are pathways for easy fire propagation in buildings. At the same time, they can be used to limit the spread of fire by providing fire and smoke alarms actuated by protective flaps that block the path of fire and fans that draw smoke outside.
Evacuation of people. In case of fires in buildings, first of all, the task of protecting people by evacuating them to a safe zone should be solved. In some cases, instead of immediate evacuation, the "protection in place" method is used - people temporarily take refuge in the internal fire zone. Such areas (lobbies in front of elevators, extended staircases) protected by automatic systems fire extinguishing, are separated from adjacent zones by free gaps or smoke-tight and fire-resistant enclosing structures.
The evacuation system should enable people to enter a safe area during a fire. It should provide a continuous, unobstructed path of exit from anywhere in the building to the street and provide for special easy-to-open door locks, horizontal exits, interfloor stairs, smoke-tight shafts, fire escapes, escalators, horizontal passenger conveyors, elevators, windows, emergency lighting and exit signs. Building owners and residents often clutter up corridors, doors and stairwells with various stored items, which can lead to tragic consequences in the event of a fire. Therefore, it is in the interest public safety Blocked or covered exits should always be reported to the building administration or fire department. Much attention is paid to evacuation systems in the safety regulations and building codes and regulations. In particular, the minimum width of doors and corridors is regulated, maximum length dead-end corridors, width and slope of flights of stairs. To facilitate and speed up the evacuation, it is necessary that the doors open towards the exit. Special door locks should open when pressed lightly. Evacuation lighting should help expedite evacuation. The standards regulate the illumination at the doors and the location of the lamps. In some cases, emergency lighting should be provided with power from an autonomous electric generator or battery. In addition, in some cases it is obligatory to install luminous inscriptions "EXIT". Buildings regulations require managers of high-rise public, commercial and industrial buildings conducted periodic fire drills, during which building personnel and fire brigades would become better acquainted with their tasks and responsibilities in the event of a fire. In addition, these exercises provide an opportunity for other workers, visitors and residents to know who is included in the fire brigade their buildings, learn the safety rules, remember the evacuation scheme, the location of the alarm buttons, portable fire extinguishers and fire escapes. Many standards recommend that residents of individual houses also periodically conduct fire drills so that all family members know the exit routes and meeting points, and the functionality of the home smoke indicators is checked.
MODERN FIRE MANAGEMENT
Equipment and outfit. Fire departments are usually made up of specialized units called teams. In one fire station, several teams of different specializations are usually based with their own equipment and equipment. Most of the pumping teams are responsible for the supply of water through the sleeves to the place of extinguishing the fire. The main type of equipment of the pumping team is fire engine with a tank for 2.5 tons of water and a pump (also equipped with fire hoses and water cannons). The staircase team performs search and rescue operations, breaks into entrances, provides ventilation (by, for example, opening the roof to release heat, smoke and gases), take measures to save property and conduct a checkup to ensure that the fire is completely extinguished and the building protected. A staircase fire truck is often equipped with a car ladder, as well as ladders, tools, hand (saws, axes) and mechanical, and large sheets of waterproof tarpaulin. In addition to the pumping and staircase teams, many fire departments have rescue teams (specializing in providing first aid, releasing victims from vehicles, dismantling debris, etc.) and special units for different situations from forest fire before accidents involving flammable and explosive materials.
Protective overalls. Firefighters work in an environment of nearby flames, smoke, heat, toxic gases, falling objects, broken glass, when you can stumble and fall at every step. In addition, they are required to work even in extreme weather conditions, and in the course of fighting a fire, they can be caught in streams of water. Therefore, they are provided with fire-retardant and waterproof workwear, consisting of a helmet, jacket, trousers, shoes and gloves, and auxiliary equipment- autonomous breathing apparatus and a personal alarm system. The personal alarm system is the latest component; with its help, the firefighter can, if necessary, give a sound signal, and it automatically gives a sound signal if its owner does not move for more than 30 seconds. There is also a uniform for firefighters working with hazardous materials.
FIRE SAFETY AS A PROFESSION
Fire departments need not only firefighters, but other specialists as well. Fire department personnel include chemists, computer specialists, analysts, dispatchers, fire safety and first aid educators, fire investigators, fire protection engineers, mechanics, drivers, inspectors and public information specialists. Fire safety specialists are needed not only in fire departments. The scientific and technical knowledge of fire protection engineers is needed when analyzing dangerous factors fire protection, design of active and passive fire protection systems, approval of construction drawings and conduct of fire investigations. Fire protection engineers most often work not in fire departments, but in consulting engineering, insurance companies, large corporations, government agencies, manufacturing enterprises. Technical training also receive fire protection technicians and technologists, although their level of training is somewhat lower than that of engineers. Technicians and technologists often inspect fire protection equipment (such as fire alarm systems and automatic fire suppression systems in high-rise buildings). Technicians and technologists usually hold an engineer license without a diploma or a government-certified fire protection technician diploma.
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The fire safety of an object is understood as its state in which, with a specified probability, the possibility of the occurrence and development of a fire and exposure of people to dangerous fire factors is excluded, and the protection of material values is provided.
Analysis of fires that took place on industrial enterprises, shows that 50% of them occur due to ignorance and non-observance of fire safety rules by service personnel.
By fire is a combustion process that has arisen involuntarily (or by malicious intent), which will develop and continue until all combustible substances and materials are burned out, or conditions leading to self-extinction do not arise, or special active measures are not taken to localize it and extinguishing.
Combustion - a chemical reaction of oxidation, accompanied by the release of heat and light.
Flash point - this is the temperature at which rapid combustion of the combustible mixture occurs, not accompanied by the formation of compressed gases.
Ignition temperature - the temperature is 1-5 ° C higher than the flash point, at this temperature a fire occurs, accompanied by a flame.
Lower concentration limit ignition gases is the minimum concentration of flammable gases and vapors in percent in the mixture, at which the mixture ignites and burns throughout the entire volume.
Upper flammable concentration limit is the maximum concentration of flammable vapors in percent in the mixture, at which the mixture ignites and burns throughout the entire volume.
Under hearth fire understand the place (area) of the most intense combustion. The initial fire site can be a small area or object, and as the fire progresses, the entire area engulfed in fire can become.
When a fire occurs:
combustion with the release of heat, light and combustion product;
gas exchange (mass transfer) under the influence of conventional flows of hot and cold gases, providing delivery of the oxidizer to the combustion zone and removal of combustion products from it;
transfer of heat from the combustion zone to the surrounding space (danger of ignition of nearby objects).
The fire develops in a certain area or in volume and can be conditionally divided into three zones:
Combustion zone- occupies a part of the space in which the processes of thermal decomposition of combustible materials take place in the volume of the diffusion flame;
Heat affected zone- the part of the space adjacent to the combustion zone, within which the processes of heat exchange take place between the flame surface and the surrounding building structures and combustible materials;
Smoke zone- the zone where the combustion products rise above the combustion zone in the form of a heat jet and form a layer of smoke in the upper zone under the overlap.
Fire dynamics- the process of fire development in time and space, accompanied by the impact of its dangerous factors on the environment. Knowing the laws of fire dynamics, it is possible to predict the situation and predict its change in the course of the fire development.
The first phase of the fire characterized by the fact that when the average volumetric temperature rises to 200 ° C, the supply air flow increases, and then constantly decreases (closed rooms). Depending on the conditions of gas exchange of the composition and the method of distributing the fire load in a room or in an open space, the development time of the first phase varies. By the end of the first phase, the temperature in the combustion zone rises sharply, the flame spreads to most of the combustible materials and structures, the flame height rapidly increases, the oxygen concentration decreases significantly and, accordingly, the concentration of carbon oxide and dioxide and other combustion products increases, the temperature reaches a maximum.
During second phase of fire due to an increase in temperature, the limits of fire resistance of some structures come (heating, the formation of through cracks, collapse), from thermal radiation there is a threat of fire spreading to neighboring buildings and structures. The most dangerous conditions are created for people in a burning building due to the rapid spread of fire to adjacent rooms and overlying floors, as well as the accumulation of toxic combustion products.
Firefighters arriving before the end of the first phase of the fire immediately begin to rescue people and at the same time serve fire extinguishing agents to the fire site and to protect neighboring objects and adjacent premises.
At third phase of fire the rate of burnout of materials drops sharply, and the process of afterburning and smoldering begins wooden structures, household items, fabric and upholstery materials. The temperature of the medium remains high for a long time. During the cooling period, individual building structures, such as curtain panels, can collapse.
For a comprehensive solution to the issues of fire protection of newly designed, reconstructed and operating facilities paramount importance has their objective assessment of the fire hazard of technological processes of production, equipment, units and installations and their classification by explosive, explosion and fire hazard.
2. Classification of industries for explosive, explosion and fire safety
The regulatory classification of industries for explosive, explosion and fire safety is based on comparative data that determine the likelihood of a fire or explosion depending on the properties and condition of substances and materials circulating in production.
All production facilities are divided into six categories according to the degree of explosion and fire hazard:
Category A - especially explosive and fire hazardous category. It includes industries associated with the use of substances capable of exploding and burning when interacting with water, air oxygen or with each other; combustible gases, the lower flammability limit of which is 10% or less, liquids with a flash point of vapors up to 28 ° C inclusive, provided that these gases and liquids can form explosive mixtures exceeding 5% of the volume of the room (acetone - 18 ° C, toluene - 4 ° С, solvent No. 646 - 9 ° С, solvent No. 648 - 13 ° С). This category includes oil refineries, chemical plants, pipelines, oil storage facilities.
TO Category B include production related to the circulation of combustible gases, the lower limit of ignition of which is more than 10% of the total volume; liquids with a flash point from 28 ° to 61 ° C inclusive; liquids heated under industrial conditions to a flash point and above; combustible dusts and fibers, the lower explosive limit of which is 65g / m3 or less, provided that these gases, dusts and liquids can form explosive volumes exceeding 5% of the volume of the room. This category includes workshops for the preparation of coal dust, wood flour, powdered sugar, potting and grinding departments of mills.
TO Category B include industries associated with the use of liquids with a flash point of vapors above 61 ° C, combustible dusts and fibers, the lower explosive limit of which is more than 65 g / m3; substances that can burn on contact with water, atmospheric oxygen or with each other; solid combustible materials. This category includes sawmills, woodworking, model, carpentry shops, warehouses for wood materials.
Category D includes production related to the use of non-combustible substances and materials in a hot, incandescent or molten state, the processing of which is accompanied by the release of radiant heat, sparks and flame; solid, liquid and gaseous substances combusted or used as fuel. These are foundries, forging, assembly and welding shops, liquid and gaseous fuel boilers.
Category D includes industries associated with the use of non-combustible substances and materials in a cold state: locksmiths, machine shops, warehouses of non-combustible materials (without the presence of combustible materials) - pig iron, fittings, etc.
Category E - explosive category. It includes industries associated with the use of flammable gases without a liquid phase and explosive dust in such an amount that it can form explosive mixtures in an amount exceeding 5% of the volume of premises in which technical specifications the technological process may explode (without subsequent combustion); substances that can explode when interacting with water, atmospheric oxygen or with each other (for example, charging stations for acid and alkaline batteries).
Depending on the category of production facilities, various fire safety requirements are imposed on the facilities. Industrial buildings and structures in accordance with the standards of technological design are divided into five categories of fire resistance, they must meet the requirements of fire resistance, i.e. the actual degree of fire resistance of the building must be greater than the required one.
Depending on the degree of flammability, substances are divided into combustible, hardly combustible and non-combustible.
The most fire hazardous and fire and explosion hazardous types of raw materials and finished products are:
Liquids- oil, gasoline, kerosene, oils, alcohols (methyl, ethyl, butyl), varnishes, paints;
Gases- ammonia, acetylene, butane, hydrogen, methane, hydrogen sulfide;
Solids- wood and wood products, rubber, rubber, cotton, flax, hemp, coal, peat and other substances.
3. Causes of fires and fire prevention measures
The causes of fires are:
Careless handling of fire (smoking in the wrong places, breaking the rules during hot work);
Violation of the rules for the operation of electrical equipment (overloads, short circuits, insulation violations when using electric heating devices in rooms with the presence of vapors of flammable liquids and gases, etc.);
Violation technological process production and fire safety rules (in coal production - violation of the tightness of equipment - breakthrough of gaskets, oil seals, rupture of pipelines; overstatement of pressure temperatures);
Spontaneous combustion of raw materials, semi-finished products, finished products, tow, rags, overalls impregnated vegetable oils, coal.
Fire protection measures are regulated by the Law of the Republic of Belarus "On Fire Safety", standards, building codes and regulations, fire safety rules.
The fire safety system in the Republic of Belarus consists of a complex of social, organizational, scientific, technical and legal measures, forces and means fire service aimed at preventing and extinguishing fires.
Fire prevention measures are subdivided into organizational, technical, regime, operational.
Organizational measures provide for the correct operation of the equipment of buildings, territories, timely briefing of workers on fire hazards, conducting classes on the fire-technical minimum, creating voluntary fire brigades, checking their readiness for firefighting, training, creating fire-technical commissions, etc. Enterprises must be provided with general facility fire-fighting instructions, regulating the features of the maintenance of roads, fire breaks, entrances to buildings and water sources, storage of substances and materials, smoking regime, keeping fire extinguishing equipment in good working order, calling the fire department.
TO technical activities includes compliance with fire regulations and rules in the design and design of buildings, equipment, maintenance of equipment in good condition, strict control over the observance of the rules for the operation of equipment and compliance with the rules and instructions for fire safety, the use of automatic devices for detecting, warning and extinguishing fires.
Fire prevention measures during design and construction include: increasing the fire resistance of buildings and structures; territory zoning (planning taking into account signs of fire hazard); fire breaks; fire barriers; provision of safe evacuation routes (at least two exits); removal of smoke from the premises in case of fire (use of aeration lanterns, smoke hatches, easy-to-discharge structures); observance fire safety requirements to heating and air conditioning systems.
Regime measures regulate the mode and rules of work. Smoking is allowed only in specially designated areas equipped with waste bins and containers with water. In these areas, the signs "Smoking area" should be posted.
Operational activities are timely repairs, inspection, equipment testing.
4. Use of fire extinguishing agents
Depending on the combustion process, the most common methods of extinguishing fires are:
Cooling methods - cooling the condensed phase below the ignition temperature with continuous and sprayed jets of water (water is the most common, but electrically conductive); cooling by stirring (bulldozer on a stack of coal);
Dilution methods - dilution of gas and condensate phases (solid and liquid) jets water mist, non-flammable gases and water vapor (carbon dioxide, nitrogen, water vapor, bromine-containing compounds); intensive deceleration chemical reactions in flames; mechanical breakdown of the flame as a result of exposure to a strong jet of gas and water;
The method of isolating the hearth of combustion - isolation from the air with a layer of foam, fire-extinguishing powder, felt mat, sand; with the help of fire extinguishing powders or halogenated hydrocarbons (sodium or potassium carbons, metal chlorates).
Fire-fighting water supply at enterprises is determined by building design standards. In accordance with these standards, a fire-fighting water supply system is installed at the facilities, combined with an industrial or drinking water supply system. Fire-fighting water pipelines are made, as a rule, circular, in some cases - in the form of dead-end lines.
Hydrants are installed along roads and driveways at a distance of 100 - 150 m from each other, no closer than 5 m from the walls of the building and no more than 2 m from the road. If it is impossible to have a fire-fighting water supply system at the facility, then special reservoirs are created, from which water is supplied by motor pumps through hoses to the place of extinguishing the fire.
One of the promising areas for ensuring the fire safety of facilities is the installation of fire-prevention automation - sprinkler and deluge installations.
Sprinkler installations are designed for quick automatic extinguishing and localization of a fire source using water or air-mechanical foam as a fire extinguishing agent. Simultaneously with the supply of sprayed water to the fire, the system automatically drops a fire signal.
Deluge installations are designed for automatic and remote fire extinguishing with water. In deluge installations, water sprays (drenchers) are constantly open. Water is supplied to the network from the main pipeline when the valve is opened in a manual installation, automatically in case of fire - in automatic deluge installations.
Liquid and foam fire extinguishers are metal cylinders filled with an alkaline liquid, inside which a glass or polyethylene tube (glass) filled with sulfuric acid is inserted. A drummer is connected to the glass tube from the outside. From the blow, the drummer breaks the pipe. The acid combines with alkali to form a foam. The pressure inside the cylinder reaches up to 4 atm, due to which a jet of foam 8 to 12 m long is thrown out of the fire extinguisher. The duration of the fire extinguisher is approximately 60 seconds. Advantage foam fire extinguishers(OPH-5) is that the foam extinguishes most burning substances, including burning liquids (oils, kerosene, gasoline, oil).
To extinguish electrical installations and devices under electric current, as well as many solid and liquid combustible substances, carbon dioxide fire extinguishers such as OU-2, OU-5, OU-8 are used. A manual carbon dioxide fire extinguisher is a metal cylinder in which liquid carbon dioxide is located under a pressure of 170 kg / cm2. The cylinder is equipped with a valve with a safety diaphragm and a bell. The membrane ruptures at a temperature of 50 ° C and when the pressure rises to 200 kg / cm2. To activate the fire extinguisher, the bell is directed to the burning object and the valve is opened. Due to the instant expansion, liquid carbon dioxide is ejected through the funnel in the form of snow. The duration of the action of carbon dioxide fire extinguishers is 25-60 seconds, the irrigation length of the jet is from 1.5 to 3.5 m. According to the rules of operation, fire extinguishers must be recharged (once every three months).
In case of fires, buildings and premises must be provided with primary funds fire extinguishing:
Fire extinguishers;
Barrels of water and buckets (in the absence of an internal water supply);
Sand boxes and shovels;
Felt, felt.
The types, number and procedure for the placement of primary fire extinguishing means are regulated by the Standards for the provision of primary fire extinguishing means. For the placement of primary fire extinguishing means in production and other premises on the territory of the enterprise, special fire posts (shields) are installed. The use of the equipment on them for purposes other than firefighting is prohibited. Control over their content should be carried out by specially appointed persons.
Electrical and automatic alarm systems are used to report a fire. A telephone and radio communication are used as a means of fire alarm.
The main elements of electrical and automatic fire alarm are detectors installed at facilities, receiving stations that register a fire that has begun, and linear structures connecting the detectors with receiving stations. The reception stations located in special rooms of the fire department should be on duty around the clock.
Enterprises should be well equipped with fire extinguishing equipment, fire communication and signaling equipment. In addition, in order to preserve material values from possible fires, the employees of the enterprise must comply with the requirements of fire prevention.
The territory of the enterprise must be kept clean and systematically cleaned of production waste. All manufacturing wipes and used lubricants should be stored in metal sealed containers.
All buildings and structures of enterprises must be provided with free access. Driveways and entrances to buildings and fire water sources, as well as access to fire fighting equipment and equipment must always be free. Fire-prevention gaps between buildings are prohibited to be used for storage of materials, equipment and for parking vehicles.
The responsibilities of managers and other officials are set out in the Fire Safety Law. Responsibility for compliance with the required fire safety regime and timely implementation fire prevention measures assigned to the head of the enterprise and heads of departments.
1. Dadyshko V.I. Labor protection: Pract. allowance. / IN AND. Dydyshko, A. Ya. Mikhalyuk. - Minsk: 1998
2. Vashko I.M. Organization and labor protection: A course of lectures / I.M. Vashko - Minsk, 2004
3. SNiP2.01.02.85 - Fire safety standards
4. Safonov M.N. Labor protection in the organization: Reference manual/ M.N. Safonov. - Minsk: 1997.
