To successfully extinguish a fire, it is necessary to use the most suitable extinguishing agent, the choice of which should be resolved almost instantly. Its correct choice will reduce damage to the vessel and the danger to the entire crew. This task is greatly facilitated by the introduction of the classification of fires and their division into four types, or classes, denoted by the Latin letters A, B, C, D. Each class includes fires associated with the ignition of materials that have the same properties during combustion and require the use of the same or fire extinguishing agents. Therefore, knowledge of these classes, as well as the combustibility characteristics of the materials available on board, is absolutely essential for successful firefighting.
Fire classification has several standards, for example: ISO 3941 (standard international organization standards) and NFPA10 (National Fire Protection Association). Here is the last one.
Class A fires are fires associated with the burning of solid (ash-forming) combustible materials that can be extinguished with water and aqueous solutions. These materials include: wood and wood-based materials, fabrics, paper, rubber and some plastics.
Class B fires are fires caused by the combustion of flammable or combustible liquids, flammable gases, fats and other similar substances. The extinguishing of these fires is carried out by stopping the supply of oxygen to the fire or preventing the release of combustible vapors.
Class C fires are fires that occur when energized electrical equipment, conductors or electrical devices ignite. To fight these fires, extinguishing agents that are not conductors of electricity.
Class D fires are fires associated with the ignition of combustible metals: sodium, potassium, magnesium, titanium or aluminum, etc. To extinguish such fires, heat-absorbing fire extinguishing agents are used, for example, some powders that do not react with burning metals. The main purpose of developing such a classification is to assist ship crews in choosing the appropriate extinguishing agent. However, it is not enough to know that water is the best extinguishing agent for class A fires because it provides cooling, or that powder is good for putting out flames when burning liquid, you need to be able to correctly apply the extinguishing agent, using accurate technique fire fighting. Three elements are needed for combustion: a combustible substance that will vaporize and burn, oxygen to combine with the combustible substance, and heat to raise the temperature of the combustible vapor until it ignites. The symbolic fire triangle illustrates this point and gives an idea of two important factors needed to prevent and extinguish fires:
1) if one of the sides of the triangle is missing, the fire cannot start;
2) if one of the sides of the triangle is excluded, the fire will go out.
The fire triangle is the simplest representation of the three factors necessary for the existence of a fire, but it does not explain the nature of the fire. In particular, it does not include the chain reaction that occurs between a combustible substance, oxygen, and heat as a result of a chemical reaction.
Topic: Fire safety vessel.
Objective: Learn the basics of counter fire safety on the ship and acquire practical skills in extinguishing fires in the conditions of the ship.
Exercise: Study what is stated in methodological guide material and prepare, using the same recommended literature and lecture material, a written report on the implementation of laboratory work.
Plan
Introduction.
combustion theory
1.2. Types of combustion.
1.3. Fire conditions.
1.3. The combustion triangle ("fire triangle").
1.4. Spread of fire.
1.5. Fire hazard.
1.6. constructive fire protection vessel.
1.7. Conditions for extinguishing a fire.
Combustible substances and their properties.
Features and causes of fires on ships, preventive measures.
3.1. Violation of the established smoking regime.
3.2. Spontaneous combustion.
3.3. Malfunction of electrical circuits and equipment.
3.4. Discharges of atmospheric and static electricity.
3.5. Charges of static electricity.
3.6. Ignition of flammable liquids and gases.
3.7. Violation of the rules for the production of work with the use of open fire.
3.8. Violation of the fire regime in the engine room.
fire classes.
Fire extinguishers.
5.1. Water extinguishing.
5.2. Steam extinguishing.
5.3. Foam extinguishing.
5.4. Gas extinguishing.
5.5. Fire extinguishing powders.
5.6. Sand and sawdust. Nightmare.
Fire extinguishing methods.
Fire equipment and systems.
7.1. Portable foam fire extinguishers and rules for their use.
7.2. Portable CO 2 fire extinguishers and rules for their use.
Portable powder fire extinguishers and rules for their use.
Fire hoses, barrels and nozzles.
Respiratory protection for a firefighter.
Organization of extinguishing fires on ships.
Vessel fire safety
Introduction. Fire- a sudden and terrible incident on a ship, often developing into a tragedy. It always occurs unexpectedly and for the most incredible reason. Fires on ships are a relatively rare occurrence. ( about 5-6% of all accidents), but this is a disaster with usually severe consequences. From experience it has been established that the critical period for fighting a fire on a ship is 15 minutes. If during this time the fire could not be localized and brought under control, the ship dies. Fires are especially dangerous in engine rooms, where there is a lot of combustible materials. A fire in the Moscow Region disables the main power supply systems, the ship loses the ability to move, and fire extinguishing equipment is often damaged.
Main damaging factor for people during fires, it is not thermal radiation, but suffocation caused by the formation of thick smoke during the combustion of various materials. Maritime history knows a lot of fires on ships.
The tragedy that happened in Hoboken, in the suburbs of New York at the beginning of the last century, when 4 large modern ocean-going ships were almost completely destroyed by a fire - the Kaiser Wilhelm passenger liner, the Bremen ship with a displacement of 10,000 tons, the Mine (6400 tons ) and "Zel" (5267 tons), shocked the whole world. And only the death of the Titanic after 12 years, and then the 1st World War overshadowed by the aftermath of the Haboken tragedy. The fire in Haboken began with the ignition of a single bale of cotton and, if it were not for the complacent behavior of port workers who extinguished the fire with several hand-held fire extinguishers, but for the vigorous and timely use of suppressive fire extinguishing agents, the fire could have been immediately contained. And the reasons for the tragedy that broke out in Haboken, which claimed the lives of 326 people, have not yet been clarified.
To successfully extinguish fires, it is necessary to quickly, almost instantly decide on the use of the most effective fire extinguishing agent. Mistakes made in the choice of fire extinguishing agents lead to the loss of time, which is counted in minutes, and the spread of the fire. A very recent example is the sinking of the SALAM-98 ferry in the Red Sea in 2006. As a result of untimely measures taken by the ship's crew, the resulting fire was not localized in a timely manner. As a result, more than 1,000 passengers and crew members and the ship itself died during the tragedy.
combustion theory
1.1. Types of combustion. Combustion is a physical and chemical process accompanied by the release of heat and the emission of light. The essence of combustion lies in the fast-flowing process of oxidation of the chemical elements of a combustible substance with atmospheric oxygen.
Any substance is a complex compound, the molecules of which can consist of many chemical elements linked to each other. A chemical element, in turn, consists of atoms of the same type. Each element in chemistry is assigned a specific letter symbol. To the main chemical elements involved in the combustion process are oxygen O, carbon C, hydrogen H.
During a combustion reaction, atoms of different elements combine to form new substances. The main combustion products are:
Carbon monoxide CO is a colorless, odorless gas with high toxicity, the content of which in the air is more than 1% dangerous to human life (Fig. 1., a);
Carbon dioxide CO 2 refers to inert gases, but when the content in the air is 8-10%, a person loses consciousness and can die from suffocation (Fig. 1.,6);
water vapor H 2 O, giving the flue gases a white color (Fig. 1., c);
Soot and ash, giving the flue gases a black color.
Rice. 1. Elements of the combustion reaction: a - carbon monoxide; 6 - carbon dioxide; in - water vapor.
Depending on the rate of the oxidation reaction, there are:
smoldering - slow burning, caused by a lack of oxygen in the air (less than 10%) or the special properties of a combustible substance. During smoldering, light and heat radiation are negligible;
combustion - accompanied by a pronounced flame and significant thermal and light radiation; by the color of the flame, you can determine the temperature in the combustion zone (Table 1.); during the flame combustion of a substance, the oxygen content in the air should not be lower than 16-18%;
Table 1 Flame color versus temperature
explosion - instantaneous oxidation reaction with the release of a huge amount of heat and light; the resulting gases, rapidly expanding, create a spherical shock wave moving at high speed.
In the combustion process, not only oxygen, but also other elements can be used as an oxidizing agent. For example, copper burns in sulfur vapor, iron filings in chlorine, alkali metal carbides in carbon dioxide, etc.
Combustion is accompanied by thermal and light radiation and the formation of carbon monoxide CO, carbon dioxide CO 2 , water vapor H 2 O, soot and ash.
1 .2. Conditions for the occurrence of a fire. Each substance can exist in three states of aggregation: solid, liquid and gaseous. In the solid and liquid states, the molecules of a substance are closely related to each other, and it is almost impossible for oxygen molecules to react with them. In the gaseous (vaporous) state, the molecules of a substance move at a great distance from each other and can be easily surrounded by oxygen molecules, which creates conditions for combustion.
Combustion is the beginning of a fire. In this case, millions of vapor molecules are oxidized, which break down into atoms and, in combination with oxygen, form new molecules. During the decay of some and the formation of other molecules, heat and light energy are released. Part of the released heat returns to the fire, which contributes to more intense vaporization, activation of combustion and, consequently, the release of even more heat.
A kind of chain reaction occurs, leading to the growth of the flame and the development of a fire (Fig. 2.).
A fire chain reaction occurs with the simultaneous action of three factors: the presence of a combustible substance that will evaporate and burn; a sufficient amount of oxygen to oxidize the elements of the substance; heat source that raises the temperature to the ignition limit. In the absence of one of the factors, the fire cannot start. If during a fire one of the factors can be eliminated, the fire stops.
Fig.2. Chain reaction of combustion: 1 - combustible substance; 2 - oxygen; 3 pairs; 4, 5 - molecules in the combustion process
A fire occurs only with the simultaneous action of three factors: the presence of a combustible substance, a sufficient amount of oxygen, high temperature.
1.3. The combustion triangle ("fire triangle" For the combustion process, the following conditions are necessary: combustible substance capable of self-igniting after the source of ignition is removed. Air (oxygen), as well as ignition source, which must have a certain temperature and a sufficient supply of heat . If one of these conditions is absent, there will be no combustion process. So-called fire triangle (air oxygen, heat, combustible substance) can give a simple idea of the three fire factors necessary for the existence of a fire. The symbolic fire triangle shown in (Fig. 3.) clearly illustrates this situation and gives an idea of the important factors necessary to prevent and extinguish fires:
If one side of the triangle is missing, the fire cannot start;
If one side of the triangle is excluded, the fire will go out.
However, the fire triangle - the simplest representation of the three factors necessary for the existence of a fire - does not sufficiently explain the nature of the fire. In particular, it does not include chain reaction, which occurs between a combustible substance, oxygen and heat as a result of a chain reaction. Fire tetrahedron(Fig. 4.) - more clearly illustrates the combustion process (a tetrahedron is a polygon with four triangular faces). It allows you to more fully understand the combustion process, due to the fact that there is a place for a chain reaction in it and each face is in contact with the other three.
The main difference between the fire triangle and the fire tetrahedron is that the tetrahedron shows how the chain reaction keeps the fire burning - the side of the chain reaction keeps the other three sides from falling.
This important factor is used in many modern fire extinguishers, automatic systems extinguishing fires and preventing explosions - fire extinguishing agents act on a chain reaction and interrupt the process of its development. The fire tetrahedron gives a visual representation of how a fire can be put out. If you remove the combustible substance, or oxygen, or the source of heat, the fire will stop.
If the chain reaction is interrupted, then as a result of the gradual decrease in the formation of vapors and the release of heat, the fire will also be extinguished. However, in case of smoldering or possible secondary ignition, further cooling must be provided.
1.4. fire spread. If the fire cannot be localized at an early stage, then the intensity of its spread increases, which is facilitated by the following factors.
Thermal conductivity (Fig. 5, a): most ship structures are made of metal with high thermal conductivity, which contributes to the transfer of a large amount of heat and the spread of fire from one deck to another, from one compartment to another. Under the influence of heat from the fire, the paint on the bulkheads begins to turn yellow, and then swell, the temperature rises in the compartment adjacent to the fire, and if there are combustible substances in it, an additional fire occurs.
Fig.5. Fire spread: a - thermal conductivity; b - radiant heat transfer; c - convective heat transfer; 1 - oxygen; 2 - warmth
Radiant heat transfer (Fig. 5., b): high temperature in the seat of fire contributes to the formation of radiant heat fluxes that propagate rectilinearly in all directions. The ship structures encountered on the path of the heat flow partially absorb the heat of the flow, which leads to an increase in their temperature. Due to radiant heat exchange combustible materials can ignite. It is especially active inside the ship's premises. In addition to the spread of fire, radiant heat transfer creates significant difficulties in the operation of extinguishing a fire and requires the use of special protective equipment for people.
Convective heat transfer(Fig. 5., c): when hot air and heated gases spread through the ship's spaces, a significant amount of heat is transferred from the fire source. Heated gases and air rise, their place is taken by cold air - a natural convective heat exchange is created, which can cause additional fires.
The following factors contribute to the spread of fire: thermal conductivity of the ship's metal structures; radiant heat exchange caused by high temperature; convective heat transfer arising from the movement of streams of heated gases and air.
1.5. Fire hazard. During a fire, a serious danger to the health and life of people is created. Fire hazards include the following.
Flame: when exposed directly to people, it can cause local and general burns and damage to the respiratory tract. When extinguishing a fire without special protective equipment, you should be at a safe distance from the source of fire.
Heat: Temperatures above 50°C are dangerous for humans. In the fire area in open space, the temperature rises to 90 ° C, and in enclosed spaces - 400 ° C. Direct exposure to heat fluxes can lead to dehydration of the body, burns, and damage to the respiratory tract. Under the influence of high temperature, a strong heartbeat and nervous excitement can begin in a person with damage to the nerve centers.
Gases: The chemical composition of the gases produced during a fire depends on the combustible substance. All gases contain carbon dioxide CO 2 (carbon dioxide) and carbon monoxide CO. The most dangerous for humans is carbon monoxide. Two or three breaths of air containing 1.3% CO lead to loss of consciousness, and a few minutes of breathing - to the death of a person. Excessive content of carbon dioxide in the air reduces the supply of oxygen to the lungs, which adversely affects human life (Table 2.).
Table 2. Human condition depending on the percentage of oxygen in the air
When exposed to high temperatures on synthetic materials, gases saturated with highly toxic substances are released, the content of which in the air, even in small concentrations, poses a serious threat to human life.
Smoke: particles of unburned carbon and other substances suspended in the air form smoke that irritates the eyes, nose, and lungs. Smoke is mixed with gases, and it contains all the toxic substances inherent in gases.
Explosion: fire may be accompanied by explosions. At a certain concentration of vapors of combustible substances in the air, which changes under the influence of heat, an explosive mixture is created. Explosions can be caused by excess heat flow, static electricity discharges or detonating shocks, or excessive pressure buildup in pressurized vessels. An explosive mixture can form when the air contains vapors of petroleum products and other flammable liquids, coal dust, dust from dry products. The consequences of the explosion can be serious destruction of the ship's metal structures and death of people.
Fire poses a serious danger to the vessel, health and life of people. The main hazards are: flame, heat, gases and smoke. An especially serious danger is the possibility of an explosion.
For any combustion, three are necessary and sufficient. mandatory conditions- the presence of a combustible substance, oxygen and an ignition source. These three conditions form the combustion triangle.
Combustible substance is the basis of combustion. It can be solid (wood, fabrics, rubber, coal), liquid (petroleum products, alcohols) and gaseous (methane, acetylene, hydrogen, ammonia). At concentrations below the lower concentration explosive limit, the combustion of the vapor/gas-air mixture does not occur due to insufficient combustible substance.
This area is considered safe. Within the limits between the lower and upper concentration limits, the zone is explosive. Concentrations above the upper limit are considered flammable. Explosions do not occur here due to insufficient oxidizing agent. Flame combustion is possible at the boundary of the volume with an open medium.
The oxidizer is the second side of the combustion triangle. Usually, air oxygen acts as an oxidizing agent during combustion, but there may be other oxidizing agents - nitrogen oxides.
The critical indicator for atmospheric oxygen, as an oxidizing agent, is its concentration in air environment closed ship premises in volume limits above 12 ... 14%. Below this concentration, the combustion of the vast majority of combustible substances does not occur (oil and oil products, wood and wood products, paper, fabrics, and others). However, some combustible substances are able to burn even at lower oxygen concentrations in the surrounding gas-air environment.
Ignition source - is the third component of the combustion triangle. It also has its critical indicators. For example, vapors of petroleum products are not capable of igniting the so-called friction sparks (a spark that occurs when metal collides with metal), although it can easily ignite ethers. Ammonia ignites when the match head burns (600-700), but, as a rule, the combustion temperature of the match straw is not enough for this.
Solid, liquid and gaseous combustible substances, along with other physical and chemical properties inherent in each of them, have the ability to ignite without direct exposure to an ignition source - they spontaneously ignite.
Self-ignition is the rapid self-acceleration of an exothermic chemical reaction, leading to the appearance of a bright glow - a flame.
Self-ignition occurs as a result of the fact that, during oxidation, it is carried out of the reacting system. For liquid and gaseous combustible substances, this occurs at critical temperature and pressure parameters.
The organization and conduct of fire and preventive work aimed at preventing the occurrence of a fire is based on the fact that the indicator of at least one of the sides of the combustion triangle is below the minimum required value.
If a fire breaks out (the triangle is closed), the actions of the participants in the fire extinguishing should be aimed at bringing these indicators (at least one) beyond the critical values (breaking the triangle) - this is theoretical basis combustion and extinguishing.
1. CAUSES OF FIRE, PREVENTION MEASURES
The main causes of fires during hot work are:
- violation of fire safety rules;
- violation of the rules of work;
- violation of the rules for the construction and operation of electrical equipment;
- careless handling of fire;
- violation of labor safety during hot work;
- lack of control over the places of work after their completion.
The necessary and sufficient condition for combustion in a fire is usually presented in the form "classic fire triangle"(Fig. 1): fuel - oxidizer - source of ignition. Eliminating one of the terms of the triangle reduces the likelihood of a fire.
In order to prevent the ingress of hot metal particles into adjacent rooms, adjacent floors, etc., all inspection, technological and other hatches (hatches), ventilation, mounting and other openings (openings) in ceilings, walls and partitions of rooms where hot work is carried out must be covered with non-combustible materials.
Fig.1 Classic fire triangle
The place of hot work must be cleared of combustible substances and materials within the radius indicated in Table. one
Table 1
Located within the specified radii building construction, flooring, trim and cladding, as well as insulation and parts of equipment made of combustible materials, must be protected from sparks by metal screens, asbestos sheets or other non-combustible materials and, if necessary, sprinkled with water.
In rooms where hot work is carried out, all doors connecting these rooms with other rooms, including the doors of vestibule locks, must be tightly closed. Windows, depending on the time of year, room temperature, duration, volume and degree of danger of hot work, should be, if possible, open.
Premises where vapors of flammable liquids, flammable liquids and flammable gases can accumulate must be ventilated before hot work.
The place for welding and cutting works in buildings and premises, in the constructions of which combustible materials are used, must be fenced with a solid partition made of non-combustible material. In this case, the height of the partition must be at least 1.8 m, and the gap between the partition and the floor - no more than 5 cm. 0 mm.
Before starting and during hot work, control over the state of the vapor-gas-air environment in the process equipment, which is carried out, should be carried out. said works, and in danger zone.
Fire mode on the object. Fire safety requirements for escape routes.
Evacuation of people- the forced process of movement of people from the zone where there is a possibility of influencing them dangerous factors fire.
Emergency exit- an exit leading to a safe area in case of fire.
escape route- a safe way for evacuation of people leading to the evacuation exit.
Escape routes must ensure the safe evacuation of all people in the premises of buildings through evacuation exits.
EXITS are evacuation if they lead from the premises:
- 1st floor outside directly or through the corridor, vestibule, stairwell;
- any floor, except for the 1st: to the corridor leading to the stairwell, or directly to the stairwell (including through the hall). At the same time, staircases should have access to the outside directly or through the vestibule, separated from the adjacent corridors by partitions with doors;
- to the next room on the same floor.
When arranging evacuation exits from two stairwells through a common vestibule, one of the stairwells, in addition to the entrance to the lobby, must have an exit directly to the outside.
It is allowed to provide exits to the outside through vestibules.
From buildings, from each floor and from the premises, at least two evacuation exits should be provided, with the exception of cases specified in SNiP Part 2.
From a room with an area of up to 300 m 3, located in the basement or basement floor, it is allowed to provide one emergency exit, if the number of permanent residents in it does not exceed 5 people. With the number of people from 6 to 15, it is allowed to provide a second exit through a hatch with dimensions of at least 0.6 * 0.8 m with a vertical ladder or through a window with dimensions of at least 0.75 * 1.5 m with an exit device.
The clear width of escape routes must be at least 1 m, doors - at least 0.8 m.
With doors opening from rooms to common corridors, the width of the evacuation route along the corridor should be taken as the width of the corridor, reduced:
- half the width of the door leaf - with a one-sided arrangement of doors,
- to the width of the door leaf "- with a double-sided arrangement of doors.
The height of the passage on the escape routes must be at least 2 m. In the floor on the escape routes, height differences of less than 45 cm and protrusions are not allowed, with the exception of thresholds in doorways. In places of height difference, stairs with at least three steps or ramps with a slope of no more should be provided.
In common corridors, it is not allowed to provide built-in cabinets, with the exception of cabinets for communications and fire hydrants.
The installation of spiral staircases, winder steps, sliding and lifting doors and gates, as well as revolving doors and turnstiles on escape routes is not allowed.
It is allowed to place security rooms, an open wardrobe and trade stalls in the lobbies.
In staircases, it is not allowed to provide premises for any purpose, industrial gas pipelines and steam pipelines, pipelines with flammable liquids, electrical cables and wires (with the exception of electrical wiring for lighting corridors and staircases), exits from elevators and freight elevators, garbage chutes, as well as equipment protruding from wall planes at a height of up to 2.28 m from the surface of treads and stair landings.
Doors on escape routes should open in the direction of exit from the building.
ALLOWED to design doors opening INSIDE of the room:
- to balconies, loggias (with the exception of doors leading to the air zone of non-smokeable stairwells of the 1st type),
- on the platforms of external evacuation stairs,
- no more than 15 people. in room,
- in storerooms with an area of \u200b\u200bno more than 200 m 2,
- to the bathrooms.
The clear height of doors on escape routes must be at least 2 m.
The arrangement of openings (with the exception of doorways) in the internal walls of stairwells is not allowed.
In the light openings of staircases filled with glass blocks, opening transoms with an area of at least 1.2 m 2 on each floor should be provided.
In buildings with smoke-free staircases, elevator shafts should be provided with air overpressure in case of fire in accordance with SNiP 2.04.05. The exits to these shafts should be provided through elevator halls, separated from adjacent rooms by type 1 fire barriers. In this case, the installation of fire doors in elevator shafts is not required.
Escape routes. Fire safety measures to prevent smoke escape routes
Evacuation is a process of organized independent movement of people out of the premises in which there is a possibility of exposure to dangerous fire factors. Evacuation should also be considered the independent movement of people belonging to low-mobility groups of the population, carried out by service personnel. Evacuation is carried out along the evacuation routes through evacuation exits.
Rescue is the forced movement of people outside when they are exposed to dangerous fire factors or when there is an immediate threat of this impact. Rescue is carried out independently, with the help of fire departments or specially trained personnel, including the use of rescue equipment, through evacuation and emergency exits
Protection of people on evacuation routes is provided by a complex of space-planning, ergonomic, constructive, engineering and technical and organizational measures.
Escape routes within the premises must ensure the safe evacuation of people through the evacuation exits from the given premises, without taking into account the fire extinguishing and smoke protection equipment used in it.
Outside the premises, the protection of escape routes should be provided from the condition of ensuring the safe evacuation of people, taking into account the functional fire hazard rooms facing the evacuation route, the number of evacuees, the degree of fire resistance and the class of constructive fire hazard of the building, the number of evacuation exits from the floor and from the building as a whole.
The fire hazard of building materials of the surface layers of structures (finishes and claddings) in rooms and on escape routes outside the premises should be limited depending on the functional fire hazard of the room and building, taking into account other measures to protect escape routes.
It is not allowed to place premises of class F5 of categories A and B under premises intended for the simultaneous stay of more than 50 people, as well as in the basement and basement floors.
It is not allowed to place premises of classes F1.1, F1.2 and F1.3 in the basement and basement floors.
Smoke protection must be carried out in accordance with SNiP 2.04.05-91 "Heating, ventilation and air conditioning".
The fire warning system must be carried out in accordance with NPB 104-95 "Design of fire warning systems for people in buildings and structures."
Evacuation and emergency exits
Exits are evacuation if they lead:
- from the premises of the first floor to the outside:
- directly;
- through the corridor
- through the lobby (foyer);
- through the stairwell;
- through the corridor and lobby (foyer);
- through the corridor and stairwell;
- from the premises of any floor, except for the first:
- directly to the stairwell or to the stairs of the 3rd type;
- to the corridor leading directly to the stairwell or to the stairs of the 3rd type;
- in the hall (foyer), which has access directly to the stairwell or to the stairs of the 3rd type;
- to an adjacent room (except for a class F5 room of category A and B) on the same floor, provided with exits indicated in "a" and "b";
- an exit to a room of category A or B can be considered an evacuation one if it leads from technical room without permanent jobs, intended to serve the above premises of category A or B.
exits from the basement ground floors, which are evacuation, as a rule, should be provided directly outside, isolated from the common staircases of the building.
At least two emergency exits must have:
- premises of class F1.1, intended for the simultaneous stay of more than 10 people;
- premises of the basement and basement floors, intended for the simultaneous stay of more than 15 people. in the premises of the basement and basement floors, intended for the simultaneous stay of 6 to 15 people;
- premises intended for the simultaneous stay of more than 50 people;
- premises of class F5 of categories A and B with the number of employees in the most numerous shift of more than 5 people, category C - more than 25 people. or an area of more than 1000 m 2 ;
- open shelves and platforms in class F5 rooms intended for maintenance, with a floor area of a tier of more than 100 m 2 - for rooms of categories A and B and more than 400 m 2 - for rooms of other categories.
Premises of class F1.3 (apartments) located on two floors (levels), with an upper floor height of more than 18 m, must have emergency exits from each floor.
Doors of evacuation exits and other doors on evacuation routes must open in the direction of exit from the building.
- premises of classes F1.3 and F1.4;
- premises with a simultaneous stay of no more than 15 people, except for premises of categories A and B;
- pantries with an area of not more than 200 m 2 without permanent jobs;
- sanitary facilities;
- access to the platforms of stairs of the 3rd type;
- exterior doors of buildings located in the northern building climate zone.
During the operation of evacuation routes and exits, it is prohibited:
- clutter up evacuation routes and exits (including passages, corridors, vestibules, galleries, elevator lobbies, landings, flights of stairs, doors, evacuation hatches) with various materials, products, equipment, industrial waste, garbage and other items, as well as clog doors emergency exits;
- arrange in vestibules of exits (with the exception of apartments and individual residential buildings) dryers and hangers for clothes, wardrobes, as well as store (including temporarily) inventory and materials;
- arrange thresholds on evacuation routes (with the exception of thresholds in doorways), sliding and lifting-lowering doors and gates, revolving doors and turnstiles, as well as other devices that prevent the free evacuation of people;
- use combustible materials for finishing, cladding and painting walls and ceilings, as well as steps and landings on escape routes (except for buildings of the V degree of fire resistance);
- fix self-closing doors of staircases, corridors, halls and vestibules in the open position (if not used for this purpose automatic devices, triggered in case of fire), as well as remove them;
- glaze or close the blinds of air zones in non-smoky stairwells;
- replace reinforced glass with conventional glass in glazing of doors and transoms.
When arranging technological, exhibition and other equipment in the premises, evacuation passages to stairwells and other escape routes should be provided in accordance with design standards.
In buildings with a massive stay of people in case of a power outage at service personnel must have electric lights. The number of lanterns is determined by the head, based on the characteristics of the facility, the availability of staff on duty, the number of people in the building, but not less than one for each employee on duty.
Carpets, rugs and other floor coverings in rooms with mass stay of people must be securely fastened to the floor.
Fire warning systems
Notification of people about a fire should be carried out:
- the supply of sound and (or) light signals to all premises of the building with permanent or temporary stay of people;
- broadcasting speech information about the need for evacuation.
The combustion process is a chemical reaction in which a large amount of heat and light energy is released. Three main elements are needed to start and sustain a reaction: oxygen, fuel, and heat. The union of the three elements is called the Triangle of Fire. In this article, we will get acquainted and consider in detail the components of this triangle.
What is the Triangle of Fire
Which of the sides of the triangle is removed when extinguishing in different ways:
- Putting out the fire with sand or covering it with a blanket will deprive the fire of oxygen.
- The water will bring the temperature down
- Forest clearings deprive fires of fuel.
Three mandatory components necessary for the combustion process to proceed are usually graphically depicted in the form of a "triangle of fire" or as it is also called the "Fire Triangle". When these components are combined, a reaction begins, and if at least one of the elements is removed, the triangle will be destroyed and the combustion will stop.
Triangle elements
Heat (temperature)
Temperature, under certain conditions, can lead to the ignition of substances and materials. Raising the temperature by rubbing one plank against another, our ancestors made fire. Later, people learned to raise the temperature of the material pointwise, using lighters, matches or flint. The spark flying off the flint reaches a temperature of 1100C and this is enough to ignite the prepared tinder. The fire that has ignited itself maintains the temperature necessary for the continuation of the combustion reaction.
Lowering the temperature is easy. It is known that if you fill the fire with water, the fire will go out, because water sharply reduces the temperature of the flame. So simply lowering the temperature removes the side of the triangle and stops the combustion.
Fuel
The third side of the triangle, fuel, is another component of the combustion process. Fuels are any kind of combustible materials, including paper, oils, wood, gases, textiles, liquids, plastics and rubber. These materials and substances release energy under the influence of high temperature and the influx of oxygen. By removing the "food" of the fire, you will definitely destroy the triangle. For example, turn off the gas on the stove and the combustion will stop. This property is used by firefighters, dismantling burning structures. According to this principle, fire protection of forest areas is arranged - fire clearings separate areas with "fuel".
Oxygen
Oxygen acts as an oxidizing agent in the combustion process. The more oxygen, the more intense the reaction will take place and the higher the temperature will be. An example of the effect of oxygen on a reaction is how coals are blown in a barbecue, turbines in car engines, or oxy-argon burners. When the oxygen supply to the source of ignition is cut off, the fire will go out, and the triangle will remain without one of its sides.
Some fire extinguishing agents are based on this principle: aerosol and powder fire extinguishers. That is why it is impossible to extinguish with water the oil that has caught fire on the stove - the evaporation of water will sharply add oxygen to the hearth. Just cover the pan with a lid and the reaction will remain without air.
Fire Fighting Basics
Understanding how fire is built and can spread is essential to learning how to put out fires. All primary fire extinguishers operate on the principles of removing one or more sides of a triangle. For example, carbon dioxide and water fire extinguishers reduce the temperature, while powder and aerosol ones block the flow of oxygen, as does the fire blanket with sand included in the fire shields.