1. Accidental touching of live parts that are energized (touching unfenced, uninsulated live parts, erroneous actions, loss of orientation by the victim).
Touch voltage is the potential difference between two points in an electrical circuit that are simultaneously touched by a person.
If a person touches one phase with his hand, then the voltage of the touch will be the potential difference between the hand and leg.
2. The appearance of voltage on metal non-current-carrying parts of the installation due to damage to the electrical insulation of current-carrying parts (insulation damage, wire fall).
3. The appearance of voltage on disconnected current-carrying parts on which work is being performed as a result of erroneous activation of a disconnected installation or a lightning discharge.
4. The occurrence of step voltage on a piece of land where a person is located as a result of a short circuit of the phase wire of the network to the ground.
Step voltage is the voltage between two points on the earth's surface in the zone of a phase-to-ground fault, spaced from each other at a distance of one step of 0.8 m.
The step voltage is greatest near the fault point. At a distance of 8 m outdoors, 4 m indoors or more from the fault point, it poses virtually no danger
Conditions for damage under step voltage. At a step voltage of 100-150 V, intense cramps may occur. This will cause a person to fall to the ground, as a result of which the distance between points on the ground that he can touch with his hands and feet increases, therefore the current will flow along a more dangerous path (arm-leg). The combination of these factors can lead to injury to a person electric shock. If the step voltage is more than 250V, a person may lose consciousness and even respiratory paralysis may occur.
5. Accidental occurrence of an electric arc in the human work area.
Electric Shock Conditions
1. A person touching a faulty phase when one of the phases is shorted to ground is exposed to line voltage.
A single phase to ground fault can go undetected for a long time.
A short circuit of one of the phases to ground is equivalent to a short circuit with a current value that is insufficient to trip the fuse or trip the disconnecting devices.
2. Schemes for connecting a person to an electrical network:
Two-phase connection - between two phases;
Single-phase connection - between phase and ground.
Single-phase switching is observed more often:
A. work under voltage in the absence of protective equipment;
b. when using devices with poor insulation of live parts;
V. when voltage transfers to metal parts of equipment that is not properly protected.
3. The environment creates conditions for electric shock (dampness, the presence of conductive dust, caustic vapors and gases in the air), acts destructively on the insulation and reduces its resistance.
Statistics show that electric shocks are common in everyday life and at work. How to protect yourself and what to do if exposed to electric current?
What is electrical injury?
Electrical shocks are rare, but they are also among the most dangerous injuries. With such a lesion, death is possible - statistics show that it occurs in an average of 10% of injuries. This phenomenon is associated with the effect of electric current on the body. Therefore, the risk group includes representatives of professions related to electrical engineering, but it is not excluded among people who accidentally encountered the effects of current at home or on sections of electrical lines. As a rule, the cause of such damage is technical problems or failure to comply with safety regulations.
Types of electric shock
The nature of the effect on the body and its degree may vary. The classification of the lesion is based precisely on these features.
Electrical burn
Electrical burn is one of the most common injuries. There are several variants of this injury. The first thing to note is the contact form, when an electric current passes through the body upon contact with a source. There is also an arc injury, in which the current itself does not pass directly through the body. The pathological effect is associated with an electric arc. If there is a combination of the forms described above, such a lesion is called mixed.
Electroophthalmia
An electric arc leads not only to burns, but also to irradiation of the eyes (this is a source of UV rays). As a result of such exposure, inflammation of the conjunctiva occurs, the treatment of which may take long time. In order to avoid this phenomenon, special protection against electric shock and compliance with the rules for working with its sources are necessary.
Metallization
Among the types of skin lesions, metallization of the skin, which occurs due to the penetration of metal particles melted under the influence of an electric current, stands out for its clinical features. They are small in size and penetrate the surface layers of the epithelium of exposed areas. The pathology is not fatal. Clinical manifestations soon disappear, the skin acquires a physiological color, and pain stops.
Electrical signs
Thermal and chemical action leads to the formation of specific signs. They have sharp contours and a color ranging from gray to yellowish. The shape of the signs can be oval or round, and also resemble lines and dots. The skin in this area is characterized by the occurrence of necrosis. It becomes hardened due to the necrosis of the surface layers. Due to cell death in the post-traumatic period, pain is not among the complaints. The lesions go away after some time due to regeneration processes, and the skin acquires a natural color and elasticity. This injury is very common and is usually not fatal.
Mechanical damage
They occur when exposed to current for a long time. Mechanical injuries are characterized by tears of muscles and ligaments that occur as a result of muscle tension. In addition, the neurovascular bundle is further damaged, and severe injuries such as fractures and complete dislocations are also possible. More serious and highly qualified assistance in case of electric shock is required with such a clinic. If assistance is not provided in a timely manner or exposure is too long, death may occur.
As a rule, the listed types do not occur separately, but are combined. This factor makes it difficult to provide first aid and further treatment.
What determines the degree of electric shock?
This indicator depends not only on the strength, duration of action and nature of the current, but also on the resistance of the body. Skin and bones have a high resistance index, while in the liver and spleen it is, on the contrary, low. Fatigue contributes to a decrease in resistance and therefore, in such cases, death is most likely. Moist skin also contributes to this. Clothing and shoes made of leather, silk, wool and rubber will help protect the body from harmful effects, as they will act as an insulator. These factors influence the risk of electric shock.
Consequences
Electric current causes multiple damages. First of all, it acts on the nervous system, due to which it worsens physical activity and sensitivity. In addition, for example, severe convulsions and loss of consciousness can cause death due to respiratory arrest. After rescuing the victim, deep lesions of the central nervous system are sometimes noted. The main ones lead to this.
Impact on the heart can also lead to death, since the current leads to impaired contractility and causes fibrillation. Cardiomyocytes begin to work uncoordinatedly, as a result of which the pumping function is lost, and the tissues do not receive required amount oxygen with blood. This leads to the development of hypoxia. Another dangerous complication is vascular ruptures, which can lead to death from blood loss.
Muscle contraction often reaches such force that a fracture of the spine is possible, and, consequently, damage to the spinal cord. On the part of the sensory organs, there is a violation of tactile sensitivity, tinnitus, hearing loss, damage to the eardrum and elements of the middle ear.
Complications do not always appear immediately. Even with short-term exposure, electrical trauma can make itself felt in the future. Long-term consequences - arrhythmias, endarteritis, atherosclerosis. From the nervous system, neuritis, autonomic pathologies and encephalopathy may occur. In addition, contractures are possible. This is why electrical shock protection is important.
Causes
The main etiological factor is the effect of current. Additional conditions are the condition of the body and the presence or absence of any protection. Electrical shock usually occurs due to non-compliance with the rules of use or lack of protection when working with wiring. The risk group includes professions associated with working with electricity. However, electrical injury can happen to anyone. There are frequent cases of defeat in everyday life, but they mostly end favorably. In addition, episodes of contact with such lesions are common. Attention and knowledge of safety precautions will protect against such phenomena.
Clinical manifestations of electrical injury
Symptoms depend on the type of injury, and their complex is based on a combination of manifestations of the described types of injuries. Also, the clinic depends on the severity. It should be noted that the most dangerous are functional deviations of the respiratory, nervous and cardiovascular systems. The victim experiences severe pain. A characteristic pained expression appears on the face, and skin become pale. Under the influence of current, muscle contraction occurs, the duration of which determines the preservation of their integrity. All this can cause loss of consciousness, and in more severe cases, death. Protection against electric shock will help prevent this condition from occurring.
The effect of current on the body
The changes that occur in the body under the influence of current are associated with the versatility of its effects. It produces a thermal effect by converting electrical energy in thermal due to tissue resistance. This explains the formation of burns and marks. Thermal effect has an adverse effect on the body, as it inevitably leads to tissue destruction.
The electrochemical effect mainly affects the circulatory system. This changes the charge of many molecules and also sticks blood cells together, thickening the blood and promoting the formation of blood clots.
The biological effect is associated with disruption of organs and systems - an effect on muscle tissue, respiratory system, nerve cells.
The multiple effects of current on the body aggravate the condition of the victim, increasing the risk of death. Combined factors of electrical shock can lead to different outcomes. Even the effect of 220 Volts on the body will cause irreversible damage.
First aid
All types of electric shock require otherwise death may occur. First of all, it is necessary to stop the impact of the current on the victim, that is, turn it off from the circuit. To do this, the rescuer should be sure to protect himself with insulating materials and only then pull the victim away from the source. Then you need to call an ambulance and begin providing first aid. These activities are carried out before the arrival of specialists. The person exposed to the current cannot tolerate cold, so they must be transferred to a warm, dry surface. First aid is aimed at restoring life important functions- breathing and blood circulation. This requires cardiopulmonary resuscitation. Every person should be trained in it or have at least the slightest idea. Resuscitation is carried out on a hard surface. The rescuer combines artificial respiration and cardiac massage. The ratio required is 2 breaths and 30 presses. Rescue begins with a massage, since restoration of blood circulation is a priority. It is performed with straight arms, placing palms on top of each other (pressure is applied from the wrist area to the lower part of the sternum). The recommended frequency is 100 compressions per minute (the chest should move 5 cm). Afterwards, the oral cavity is cleared of secretions and artificial respiration is performed. To protect the rescuer, it is recommended to carry out the manipulation through a scarf. Resuscitation can be carried out by two rescuers, while maintaining the ratio of 2 breaths and 15 presses. When one person inhales, the second is contraindicated from touching chest. When inhaling, the victim’s chest must rise - this indicates that the procedure was performed correctly.
Treatment
Electric shock requires prompt resuscitation and subsequent treatment. Therapy is carried out in a hospital. Even if the victim feels well and the damage is minor, preventive monitoring is required to help avoid complications.
Treatment is aimed at speedy healing of skin lesions, as well as at eliminating other disorders associated with the harmful effects of current. Observation in the hospital is carried out until complete recovery.
Prevention
Following safety precautions will help prevent all types of electric shock. You should not use electrical appliances that are faulty. It is also contraindicated to touch them wet hands, as this will improve current conduction. Working with electrical appliances and wiring requires the use of protective equipment against electric shock. These include gloves and special pads. Tools must have an insulated handle. Also, for prevention, the public should be informed about the possibility of such an injury. A special role is played by informing in the media, as well as conducting conversations with schoolchildren. This will reduce the risk of electric shock.
Electrical injuries are very dangerous, and their outcome depends on many factors. It is influenced not only by current indicators (voltage, duration), but also protective forces body. For example, a current of 220 volts, depending on the conditions of exposure, can lead to both non-fatal injuries and death. It is very important to follow safety precautions - this will help avoid such injuries.
safety vital activity injury electric current fire
The most widely used at the moment are three-phase three-wire networks with a solidly grounded neutral and three-phase four-wire networks with an isolated neutral of a transformer or generator.
Solidly grounded neutral - the neutral of a transformer or generator connected directly to the grounding device.
Isolated neutral - the neutral of a transformer or generator that is not connected to a grounding device.
To ensure safety, there is a division of the operation of electrical installations (electrical networks) into two modes:
- - normal mode, when the specified values of its operating parameters are ensured (there are no ground faults);
- - emergency mode in case of single-phase ground fault.
In normal operation, the least dangerous network for humans is a network with an isolated neutral, but it becomes the most dangerous in emergency mode. Therefore, from the point of view of electrical safety, a network with an isolated neutral is preferable, provided that a high level of phase insulation is maintained and operation in emergency mode is prevented.
In a network with a solidly grounded neutral, it is not necessary to maintain a high level of phase insulation. In emergency mode, such a network is less dangerous than a network with an isolated neutral. A network with a solidly grounded neutral is preferable from a technological point of view, since it allows you to simultaneously receive two voltages: phase, for example, 220 V, and linear, for example, 380 V. In a network with an isolated neutral, you can only get one voltage - linear. In this regard, at voltages up to 1000 V, networks with a solidly grounded neutral are more often used.
There are a number of main causes of accidents resulting from exposure to electric current:
- - accidental touching or approaching at a dangerous distance to live parts that are energized;
- - the appearance of voltage on metal structural parts of electrical equipment (cases, casings, etc.), including as a result of damage to the insulation;
- - the appearance of voltage on disconnected live parts where people work due to the installation being turned on by mistake;
- - the occurrence of step voltage on the surface of the earth as a result of a wire short to ground.
The main measures to protect against electric shock are the following:
- - ensuring the inaccessibility of live parts under voltage;
- - electrical separation of the network;
- - eliminating the risk of injury when voltage appears on housings, casings and other parts of electrical equipment, which is achieved by using low voltages, using double insulation, potential equalization, protective grounding, grounding, protective shutdown, etc.;
- - use of special electrical protective equipment - portable devices and devices;
- - organization of safe operation of electrical installations.
Double insulation is electrical insulation consisting of working and additional insulation. Working insulation is designed to isolate live parts of an electrical installation and ensure its normal operation and protection from electric shock. Additional insulation is provided in addition to the working one to protect against electric shock in case of damage to the working insulation. Double insulation is widely used when creating manual electric machines. In this case, grounding or grounding of the housings is not required.
Protective grounding- this is a deliberate electrical connection to the ground or its equivalent of exposed conductive parts (touchable conductive parts of an electrical installation that are not energized during normal operation, but may become energized if the insulation is damaged) for protection from indirect contact, from static electricity accumulating due to friction of dielectrics, from electromagnetic radiation, etc. The equivalent of land can be river or sea water, coal in a quarry, etc.
With protective grounding, the grounding conductor connects the exposed conductive part of the electrical installation, for example, the housing, to the ground electrode. The ground electrode is a conductive part that is in electrical contact with the ground.
Since the current follows the path of least resistance, it is necessary to ensure that the resistance of the grounding device (grounding electrode and grounding conductors) is low compared to the resistance of the human body (1000 Ohms). In networks with voltages up to 1000 V, it should not exceed 4 Ohms. Thus, in the event of a breakdown, the potential of the grounded equipment is reduced. The potentials of the base on which the person stands and the grounded equipment are also equalized (by raising the potential of the base on which the person stands to a value close to the potential of the open conductive part). Due to this, the values of human touch and step voltages are reduced to an acceptable level.
As the main means of protection, grounding is used at voltages up to 1000 V in networks with an isolated neutral; at voltages above 1000 V - in networks with any neutral mode.
Zeroing- intentional electrical connection to the neutral protective conductor of metal non-current-carrying parts that may be energized, for example, due to a short circuit to the housing. It is necessary to provide protection against electric shock during indirect contact by reducing the housing voltage relative to the ground and limiting the time the current passes through the human body by quickly disconnecting the electrical installation from the network.
The operating principle of grounding is that when a phase wire is closed to the grounded housing of an electrical consumer (electrical installation), a single-phase current circuit is formed short circuit(that is, a short circuit between the phase and neutral protective conductors). Single-phase short circuit current causes overcurrent protection to trip. For this purpose, fuses and circuit breakers can be used. As a result, the damaged electrical installation is disconnected from the supply network. In addition, before the maximum current protection is triggered, the voltage of the damaged housing relative to the ground decreases due to the action of re-grounding the neutral protective conductor and the redistribution of voltage in the network when a short circuit current flows.
Grounding is used in electrical installations with voltages up to 1000 V. three-phase networks alternating current with grounded neutral.
Safety shutdown- this is a fast-acting protection that ensures automatic shutdown of an electrical installation when there is a danger of electric shock to a person. Such a danger can arise, in particular, when a phase is shorted to the housing, the insulation resistance decreases below a certain limit, as well as in the event of a person touching directly live parts that are energized.
The main elements of the device protective shutdown(RCD) are a protective shutdown device and an executive body.
A residual current device is a set of individual elements that perceive an input value, react to its changes and, at a given value, give a signal to open the circuit breaker.
The executive body is an automatic switch that ensures the disconnection of the corresponding section of the electrical installation (electrical network) upon receipt of a signal from the residual current device.
The operation of protective shutdown as an electrical protective device is based on the principle of limiting (due to quick shutdown) the duration of current flow through the human body when it unintentionally touches energized elements of an electrical installation.
Of all the known electrical protective equipment, the RCD is the only one that provides protection to a person from electric shock when directly touching one of the live parts.
Another important property of an RCD is its ability to provide protection against fires and fires that occur at facilities due to possible damage to insulation, faulty wiring and electrical equipment.
The scope of application of the RCD is networks of any voltage with any neutral mode. But they are most widespread in networks with voltages up to 1000 V.
Electrical protective equipment - These are portable and transportable products that serve to protect people working with electrical installations from electric shock, from the effects of an electric arc and an electromagnetic field.
According to their purpose, electrical protective equipment (EPD) is conventionally divided into insulating, fencing and auxiliary.
Insulating EZS are used to isolate a person from live parts of electrical equipment, as well as from the ground. For example, insulating handles of assembly tools, dielectric gloves, boots and galoshes, rubber mats, walkways; stands; insulating caps and linings; insulating stairs; insulating supports.
Fencing EZS are designed for temporary fencing of live parts of electrical installations under voltage. These include portable fences (screens, barriers, shields and cages), as well as temporary portable grounding. Conventionally, warning posters can also be classified as such.
Auxiliary protective equipment is used to protect personnel from falling from a height (safety belts and safety ropes), for safe ascent to heights (ladders, claws), as well as to protect against light, thermal, mechanical and chemical influences (safety glasses, gas masks, mittens , workwear, etc.).
In the late 70s of the century before last, the first human death from electricity was recorded. A lot of time has passed since then, but the number of people affected by the same cause is only increasing. In connection with these events, people were forced to create a list of rules for how to behave with electricity. For many years, future electricians have been training in specialized educational institutions and immediately after completion of which they undergo an “internship” in production and, of course, pass the final test exam, after which they receive a license and can independently work with electric current. What is most surprising is that no one in this world is immune from mistakes. Even a highly qualified specialist can easily get injured due to carelessness. Can you say with confidence that with any problem related to electricity, you will solve it with ease and accuracy? If not, then this article is just for you! Next, we will talk about what are the causes of electric shock and the basic protective measures in everyday life.
What is electric current?
Concentrated movement of charged particles in space under the influence of an electric field. This is how the term electric current is explained. What about particles? So they can be absolutely anything, for example: electrons, ions, etc. Everything depends only on the object in which this very particle is located (electrodes/cathodes/anodes, etc.). If we explain it according to the theory of electrical circuits, then the reason for the occurrence of electric current is the “purposeful” movement of charge holders in a conducting environment when exposed to an electric field.
How does electricity affect the human body?
A strong electric current that is passed through a living organism (human, animal) may cause a burn, or may cause electric shock through fibrillation (when the ventricles of the heart do not contract synchronously, but each “on its own”) and ultimately this will lead to to death.
But if you look at the other side of the coin, electric current is used in therapy, for resuscitation of patients (during ventricular fibrillation, a defibrillator is used, a device that simultaneously contracts the muscles of the heart through electricity, thereby forcing the heart to beat in its “usual” rhythm), etc. etc., but that’s not all. Every day, starting from our birth, electricity “flows” into us. It is used by our body in nervous system to transmit impulses from one neuron to another.
Rules for handling electrical appliances
In essence, we will offer you a list of rules about what is not allowed and what must be done when interacting with children electrical appliances, BUT this does not mean that as an adult you can neglect these rules! So, let's begin!
When interacting with electrical devices IT IS FORBIDDEN:
- Touch exposed wires.
- Activate broken electrical appliances, because if something happens they can cause a fire or shock you.
- Touch the wires with wet hands (especially if they are bare).
NECESSARY:
- Remember that under no circumstances should you pull the wire in order to pull it out of the outlet.
- When leaving home, check to see if any electrical appliance has been left on.
- If you are a child, be sure to call an adult if, while plugging in an electrical appliance, you see that the wire or the electrical appliance itself begins to smoke.
The main causes of electric shock
An electric shock can occur when a person is near the place where live parts connected to the network are located. It can be described as the irritation or interaction of body tissues with electricity. Ultimately, this will lead to completely involuntary (convulsive) contractions of the human muscles.
There are a number of reasons for human injury from electricity, such as: the possibility of injury when replacing a light bulb in a lamp connected to the network, the interaction of the human body with equipment that is connected to the network, long (continuous) operation of electrical appliances, and of course people who do not fix everything themselves depending on whether it is successful or not (in other words, “Homemade”). Let's start by listing the main causes of electrical damage, and then we will figure out in order what the essence of these problems is.
The main causes of electric shock are:
- Human interaction with faulty household electrical appliances.
- Touching exposed parts of an electrical installation.
- Incorrect voltage supply to the work site. That is why in production you need to hang a special one, as in the picture below:
- The appearance of voltage on the body of equipment, which under normal conditions should not be energized.
- Electric shock due to a faulty power line.
- Replacing a light bulb in a lamp connected to the network. People can be injured due to the fact that during a banal light bulb change they simply forget to turn off the light. You need to remember that before you change a light bulb, you first need to turn off the light.
- Interaction of the human body with equipment that is connected to the network. There have been cases where people were injured from this option. Everything is simple here. When interacting with an electrical appliance (for example, a washing machine), you hold on to a part of the house that is grounded (for example, a pipe) with your other hand. Thus, a current will pass through your body, which will cause damage. To prevent this from happening, it is recommended.
- Long (continuous) operation of electrical appliances. In fact, cases of damage in this way are minimal. The problem is this: devices such as a washing machine can break down from long-term operation and, in the case of a washing machine, at least leak. To avoid such incidents, simply check that the devices are working properly more often. We talked about this in the corresponding article.
- People who fix everything themselves. This is considered the most common problem of all, because today, using the Internet, you can find a lot of instructions like “How to do...”, even on our website in the section. However, the majority of people who start constructing something do not have the proper knowledge and, due to ordinary carelessness, are injured or even maimed.
- can be very dangerous for you or your equipment; in the end, voltage surges can cause a fire or worse - an electrical shock. So how to deal with this? Today, there are three main ways to reduce the consequences of power surges, namely: , and . These three things in everyday life will serve you and your equipment as protection from power surges.
The causes of electrical accidents are many and varied. The main ones are:
1) accidental contact with exposed live parts. This can happen, for example, when performing any work near or directly on live parts: in the event of a malfunction of protective equipment through which the victim touched live parts; when carrying long items on the shoulder metal objects, which can accidentally touch uninsulated electrical wires located within accessible in this case height;
2) the appearance of voltage on metal parts of electrical equipment (cases, casings, fences, etc.), which normal conditions are not under voltage. Most often, this can occur due to damage to the insulation of cables, wires or windings of electrical machines and devices, leading, as a rule, to a short circuit to the housing;
3) an electric arc that can form in electrical installations with a voltage of over 1000 V between a live part and a person, provided that the person is in close proximity to live parts;
4) the occurrence of a step voltage on the surface of the earth when a wire is shorted to the ground or when current flows from the ground electrode into the ground (in the event of a breakdown on the body of grounded electrical equipment);
5) other reasons, which include such as: uncoordinated and erroneous actions of personnel, leaving electrical installations energized without supervision, admission to repair work on disconnected equipment without first checking the absence of voltage and faulty grounding device, etc.
The main measures to eliminate the causes of electric shock discussed above and provide protection service personnel are:
* ensuring that live parts under voltage are inadmissible for accidental contact. For this purpose, live parts must be located at an inaccessible height; fencing and insulation of live parts are widely used;
*application protective grounding and zeroing electrical installations;
* automatic shutdown, use of reduced voltage, double insulation, etc.;
* use of special protective equipment - portable devices and devices, means personal protection;
* clear organization of safe operation of electrical installations.
End of work -
This topic belongs to the section:
Life safety
Ministry of Education and Science of the Russian Federation.. Federal State Budgetary educational institution higher vocational education Samara State Aerospace..
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Sound waves are characterized by wavelength, frequency, wave speed, intensity, sound pressure and a number of other parameters. Sound waves include elastic waves
Noise normalization
To protect people from the adverse effects of noise, it is necessary to regulate its intensity, spectral composition, and exposure time. This goal is pursued by sanitary and hygienic standards
Any noise source is characterized by: sound power P, i.e. the total amount of sound energy emitted by it per unit time [W]. where Jn is normal to bend
Main causes of fires and measures to prevent them
Burning is chemical reaction oxidation, accompanied by the release of a large amount of heat and usually glow. Fire - uncontrollable mountains
Organization of fire protection at enterprises
Legislation Russian Federation O fire safety is based on the Constitution of the Russian Federation and includes the Federal Law "On Fire Safety" No. 69-FZ, and when
Electrical heating devices left unattended
For the reasons given above, the largest number of fires and fires is observed in gravure printing shops, photomechanical shops and bookbinding shops. In addition, the cause of the fire at the printing press
Categories of production by fire hazard
Depending on the nature of the technological processes and the materials used, production as a whole and even their individual technological processes vary significantly in the degree of their explosion and fire
Fire hazard indicators of substances and materials
The main indicators for the assessment fire danger liquids are: flammability group; flash point; ignition temperature and concentration limits ignition. Main display
Combustibility and fire resistance of building materials and structures
All Construction Materials and structures according to flammability in accordance with SNiP 21-01-97 are divided into three groups: Non-flammable - all inorganic mats
Selecting the degree of fire resistance of buildings and structures
The degree of fire resistance of buildings and structures, the permissible number of floors and the permissible floor area between fire walls are established depending on the production category in accordance with SNiP 2.09
Fire barriers in buildings
Fire barriers include fire walls (firewalls), partitions, ceilings, doors, gates, hatches, airlocks, and automatic valves. Fire walls should
To an adjacent room on the same floor, provided with emergency exits
It is not allowed to provide evacuation passages through premises of categories A and B and airlocks attached to them, as well as through industrial premises
Fire safety requirements for the enterprise master plan
To localize a fire great importance It has correct location buildings and structures on the territory of the enterprise, taking into account the fire and explosion hazard of the production facilities located in them, directions of government
Ventilation
Ventilation ducts can contribute to the spread of fire through individual parts of the building, and due to the accumulation of flammable gases, vapors and dust in them when an ignition source appears (for example,
Electrical installations
Non-compliance of electrical installations with explosion and fire hazard requirements, their malfunction, and overload lead to fires, fires and explosions. IN last years number of fires caused by it
Lightning protection
Lightning protection is a set of protective devices designed to ensure the safety of people, the safety of buildings and structures, equipment and materials from possible explosions, fires and damage.
Fire extinguishing methods and means
Extinguishing a fire involves stopping the combustion process; to do this, it is enough to eliminate at least one factor necessary to maintain combustion. Exist various ways achieving this goal.
Extinguishing fire with water
Water is the most common and cheapest extinguishing agent. Once in the combustion zone, it intensively evaporates, absorbing a large amount of heat (1 liter of water absorbs 2260 kJ of heat during evaporation)
Fire water supply
Fire water supply called a water supply system that provides successful fight with fire at any time of the day. Water for fire extinguishing can be supplied directly from the city
Automatic installations for extinguishing fires with water
Sprinkler and deluge systems are used to automatically extinguish fires with water. The sprinkler installation consists of devices supplying water, main and
Extinguishing with foam
Currently, chemical and air-mechanical foam are widely used to extinguish flammable and combustible liquids. Chemical foam is formed as a result of a chemical reaction
Extinguishing fires with chemical foam
To extinguish small fires, hand-held chemical agents are widely used. foam fire extinguishers type OHP-10 (Figure 2). The fire extinguisher body contains the alkaline part of the charge - an aqueous solution
Extinguishing fires with air-mechanical foam
Air-mechanical foam, unlike chemical foam, is formed as a result of intensive mixing of air with an aqueous solution of a foaming agent in special devices - foam mixers in air
Extinguishing fire with carbon dioxide
Carbon dioxide is used to extinguish flammable and combustible liquids, solids, and electrical installations under voltage. Carbon dioxide does not spoil substances in contact with it,
Extinguishing fires with halogenated hydrocarbons
Currently, highly effective compounds based on halogenated hydrocarbons, such as tetrafluorodibromomethane (freon 13B and 114B2), these bromide, are increasingly being used to extinguish fires.
Extinguishing fires with powder compounds
Powder formulations are intended for extinguishing fires of flammable liquids and gases, alkali and alkaline earth metals and their carbides, electrical installations under voltage, and valuable items (archives, museum
Fire communications and alarm
The fastest and most reliable way to notify about a fire is electrical fire alarm(EPS). EPS consists of the following main parts: detectors installed
Labor protection legislation
The main legislative documents in this industry to date are the “Basic Legislation on Labor Protection” and the Labor Code of the Russian Federation. Laws for this industry
Principles, methods and means of ensuring safety
In structure general theory security, a certain hierarchy of principles, methods and means of ensuring security has developed. A principle is an idea, a thought, a basic position.
Analysis of industrial injuries
When analyzing the causes that led to an accident, the following methods are used: Statistical method, which processes statistical data on
Standardization in the field of safety
A special place among regulatory documents In the field of occupational safety, the system of occupational safety standards - SSBT, the structure of which is presented in Fig. 2, occupies a position. A special role belongs
Construction norms and rules (SNiPs)
For example: - SNiP 11-4-79 (part 2. Design standards. Chapter 4. Natural and artificial lighting); - SNiP 2.09.02-85 - Industrial buildings; - SNiP 2.01.02-85 - Against
Safety briefing
Instructions and standards of the enterprise on labor protection The employer is obliged to provide workers with instructions on labor protection. this work must implement
The effectiveness of measures to ensure safety at work
Measures to improve working conditions include all types of activities aimed at preventing, eliminating or reducing negative impact harmful and dangerous production fact
Economic results
· Savings by reducing funds for temporary disability benefits. · Annual savings due to reduced injury rates · Fund savings wages V
