Harmful chemicals

The rapid development of the chemical industry and the chemicalization of the entire national economy led to a significant expansion of production and application in the industry of various chemicals; The range of these substances was also significantly expanded: many new chemical compounds were obtained, such as monomers and polymers, dyes and solvents, fertilizers and pesticides, combustible substances, etc. Many of these substances are not indifferent to the body and, falling into the air. Work premises, directly on working or inside their organism, they may not affect health or normal life activity. Such chemicals are called harmful. The latter, depending on the nature of their action, are divided into irritating substances, toxic (or - poisons), sensitizing (or allergens), carcinogenic and others. Many of them have at the same time several harmful properties, and above all in one way or another toxic, so the concept of "harmful substances" is often identically identified with "toxic substances", "poisons", regardless of the presence of other properties in them.

Poisoning and diseases arising from the effects of harmful substances in the process of performing work in production are called professional poisoning and diseases.

Causes and sources of harmful substances

Made of harmfulness can be part of raw materials, ultimate, side or intermediate products of a particular production. They can be three species: solid, liquid and gaseous. The formation of dust of these substances, vapors and gases is possible.

Toxic dust is formed as a result of the same reasons as conventional dust described in the previous section (grinding, combustion, evaporation, followed by condensation), and are released into air through open opening, poorness of dusting equipment, or when crossing them in an open way.

Liquid harmful substances are most often seeping through looseness in the equipment, communications, are sprayed when they are discovered from a single container to another. At the same time, they can get directly on the skin of working and have an appropriate adverse effect, and in addition, to pollute the surrounding exterior surfaces of the equipment and fences that become open sources of their evaporation. With such contamination, large surfaces of evaporation of harmful substances are created, which leads to a rapid saturation of air in pairs and the formation of high concentrations. The most frequent causes of seeping of liquids from equipment and communications are the separation of gaskets in flange connections, loosely fitted cranes and valves, insufficiently compacted seals, metal corrosion, etc.

If liquid substances are in open containers, from their surface also evaporates and the establishment of the formed vapors in the air of work premises; The greater the open surface of the fluid, the more it evaporates.

In the event that the liquid partially fills the closed container, the formed pairs are saturated to the limit of the unfilled space of this container, creating very high concentrations in it. In the presence of strokes in this container, the concentrated pairs can penetrate the atmosphere of the workshop and pollute it. The output of vapors increases if the container is under pressure. Massive vapor allocations also occur at the time of filling with the tank with liquid when the fluid is filled. Copy concentrated pairs from the container, which through the open part or looseness go to the workshop (if the closed container is not equipped with a special air terminal out of the workshop). The selection of vapors from closed containers with harmful liquids occurs when the covers or hatches are opened to monitor the process, mixing or loading additional materials, sampling, etc.

If gaseous harmful substances are used as raw materials or are obtained as ready or intermediate products, they, as a rule, are allocated in the air of work rooms only through random loosening in communications and equipment (since if there are them in the devices, the latter cannot be held even on a short time).

As mentioned in the previous section, gases can settle on the surface of the dust and together with them for certain distances. In such cases, the places of dust-finding can be simultaneously both gas divisions.

The source of excretion of harmful substances of all three species (aerosol, vapor and gas) is often various heating devices: dried, heating, roasting and smelting furnaces, etc. Harmful substances are formed in them due to combustion and thermal decomposition of some products. The selection of them into the air occurs through the working openings of these furnaces and dried, loosening their masonry (proper) and from the heated material removed from them (molten slag or metal, dried products or burnt material, etc.).

The frequent cause of massive distinguishing distinguishes is the repair or cleaning of equipment and communications containing toxic substances with their opening and even more dismantling.

Some vapor and gaseous substances, standing out into the air and polluting it, are sorbed (absorbed) by separate building materials, such as wood, plaster, brick, etc. over time, such building materials are saturated with these substances and under certain conditions (temperature changes and others. ) themselves become sources of their separation in the air - desorption; Therefore, sometimes even with the full elimination of all other sources of distinguishing, elevated concentrations of them in the air can remain for a long time.

Ways of receipt and distribution of harmful substances in the body

The main ways of receipt of harmful substances in the body are airways, digestive tract And skin.

The greatest value is the flow of them. through respiratory organs. The toxic dust, couples and gases entered the air are inhaled and penetrated into the lungs. Through the branched surface of bronchiole and alveoli, they are absorbed into the blood. Inhaled poisons have an adverse effect on almost all over the time of operation in a polluted atmosphere, and sometimes even at the end of work, since their suction is still continuing. The poisons received through the respiration organs through the organs throughout the body, as a result of which their toxic action can affect the most varied organs and tissues.

Harmful substances come to the digestion organs during the swallowing of toxic dust, located on the mucous membranes of the oral cavity, or by bringing them there with contaminated hands.

The poisons entered into the digestive tract at all of its length absorbed through the mucous membranes into the blood. Basically, suction occurs in the stomach and intestines. The blood entered through the digestive bodies of the poison is directed to the liver, where some of them are delayed and partially neutralize, because the liver is a barrier for applicants through the digestive tract of substances. Just passing through this barrier, the poisons go into common bloodstream and they are spread throughout the body.

Toxic substances with the ability to dissolve or dissolve in fats and lipoids can penetrate the skin when contaminated by the latter with these substances, and sometimes in the presence of their cargo (to a lesser extent). Penetrated through the skin of the poisons immediately enter the overall bloodstream and they are dealt with the body.

We entered the body in one way or another, the poisons can be relatively uniformly distributed over all organs and tissues, having a toxic effect on them. Some of them accumulate mainly in some one tissues and organs: in the liver, bones, etc. Such places of the predominant accumulation of toxic substances are called the Depot of Ida in the body. For many substances, certain types of tissues and organs are characterized, where they are deposited. Delayed poisons in the depot can be both short-term and longer - up to several days and weeks. Gradually, leaving the depot to the overall bloodstream, they can also have a definite, as a rule, a weak toxic effect. Some unusual phenomena (alcohol intake, specific food, disease, injury, etc.) can cause a faster elimination of poisons from the depot, as a result of which their toxic effect is manifested more pronounced.

The selection of poisons from the body is mainly through the kidneys and intestines; The most volatile substances are also released through the lungs with exhaled air.

Introduction ................................................... .................................................. ........... 3.

1. Classification of harmful substances and ways of their admission to the human body .. ............................................................. ............................. five

2. The influence of harmful substances on the human body ... .. ............ ... ....... 9

3. Prevention of professional poisoning ...... ......................... 11

Conclusion ............................................................... .................................................. ..... 14

List of used literature ............................................................. ............... 16

Introduction

For a person, harmful (causing diseases) industrial factors can affect a person in the process of his work. Harmful production factors are divided into four groups: physical, chemical, biological and psychophysiological.

Harmful physical factors are: an increased or reduced air temperature of the working area; High humidity and speed of air; Increased levels of noise, vibration, ultrasound and various radiation - thermal, ionizing, electromagnetic, infrared, etc. To harmful physical factors also include dustiness and gas acquisition of the working area; insufficient illumination of jobs, passes and travel; Increased light brightness and luminous pulsation.

Chemical harmful production factors according to the nature of the human action are divided into the following subgroups: general-toxic, irritants, sensitizing (causing allergic diseases), carcinogenic (causing tumors' development), mutagenic (acting on genital cells). This group includes numerous pairs and gases: pairs of benzene and toluene, carbon monoxide, sulfuric anhydride, nitrogen oxides, lead aerosols, etc., toxic dust, formed, for example, when processing cutting beryllium, lead bronze and brass and some plastics with harmful fillers. This group includes aggressive liquids (acids, alkali) that can cause chemical skin burns when contacting them.

Biological harmful production factors include microorganisms (bacteria, viruses, etc.) and macroorganisms (plants and animals), the impact of which on working causes diseases.

Psychophysiological harmful production factors include physical overloads (static and dynamic) and neuropsychiatric overloads (mental overvoltage, overvoltage of hearing analyzers, vision, etc.).

Impact levels on working harmful production factors are normalized by extremely permissible levels, the values \u200b\u200bof which are indicated in the relevant standards of the system of labor safety standards and sanitary and hygienic rules.

The maximum permissible value of a harmful production factor is the limit value of the magnitude of a harmful production factor, the impact of which, with a daily regulated duration, during the whole work experience, does not lead to a decrease in performance and the disease both during the period of employment and the disease in the subsequent period of life, as well as It does not adversely affect the health of the offspring.

Section I: Classification of harmful substances and ways of their admission to the human body

The irrational use of chemicals, synthetic materials adversely affects the health of working.

Harmful substance (industrial poison), falling into the human body during his professional activity, causes pathological changes.

The main sources of air pollution of industrial premises with harmful substances may be raw materials, components and finished products. Diseases arising from the effects of these substances are called professional poisoning (intoxication).

According to the degree of impact on the body, harmful substances are divided into four classes of danger:

1st - substances are extremely dangerous;

2nd - highly hazard substances;

3rd - substances are moderately dangerous;

4th - fastening substances.

The hazard class of harmful substances is set depending on the norms and indicators specified in the table.

The attribution of harmful substances to the hazard class is carried out by the indicator, the value of which corresponds to the highest hazard class.

Toxic substances are entered into the human body through the respiratory tract (inhalation penetration), the gastrointestinal tract and the skin. The degree of poisoning depends on their aggregate state (gaseous and vapor substances, liquid and solid aerosols) and on the nature of the technological process (the heating of the substance, grinding, etc.).

The predominant majority of professional poisoning is associated with inhalation penetration into the body of harmful substances, which are the most dangerous, as the large suction surface of the pulmonary alvetol, intensely washed by blood, determines the very rapid and almost unhindered penetration of poisons to the most important life centers.

The intake of toxic substances through the gastrointestinal tract in production conditions is quite rare. This happens due to violation of personal hygiene rules, partial ingestion of vapors and dust penetrating through the respiratory tract, and non-compliance with safety regulations when working in chemical laboratories. It should be noted that in this case the poison falls through the system golden Vienna In the liver, where turns into less toxic compounds.

Substances that are well soluble in fats and lipoids can penetrate the blood through intact skin. Strong poisoning causes substances with increased toxicity, low volatility, rapidly solubility in the blood. These substances include, for example, nitro and aminoproducts of aromatic hydrocarbons, tetraethylswin, methyl alcohol, etc. can be attributed.

Toxic substances in the body are distributed unequal, with some of them are capable of accumulating in certain tissues. It is particularly possible to select electrolytes, many of which are extremely quickly disappearing from blood and focus in separate organs. Lead accumulates mainly in the bones, manganese - in the liver, mercury - in the kidneys and a colon. Naturally, the peculiarity of the distribution of poisons can to some extent reflect on their further fate in the body.

When entering into a circle of complex and diverse life processes, toxic substances are subjected to various transformations in the course of oxidation reactions, restoration and hydrolytic splitting. The general direction of these transformations is characterized by most often the formation of less poisonous compounds, although more toxic products can be obtained in some cases (for example, formaldehyde when the methyl alcohol oxidation) can be obtained.

The release of toxic substances from the body often occurs in the same way as admission. Unreacting pairs and gases are partially or completely removed through the lungs. A significant amount of poisons and their conversion products are distinguished through the kidneys. A certain role for the allocation of poisons from the body is played skin Covers, moreover, this process is mainly committing hasty and sweat glands.

It should be borne in mind that the release of some toxic substances is possible in the composition of female milk (lead, mercury, alcohol). This creates the danger of inflation of infants. Therefore, pregnant women and nursing mothers should temporarily remove from production transactions separating toxic substances.

The toxic effect of individual harmful substances can manifest itself in the form of secondary lesions, for example, colitis with arsatitis and mercury poisoning, stomatitis with lead and mercury poisoning and so on.

The danger of harmful substances for a person is largely determined by their chemical structure and physicochemical properties. An important value for the toxic effect is the dispersion of a chemical penetrating agent, and the higher the dispersion, the toxic substance.

Conditions of the environment can either enhance or weaken its action. So, at high air temperature, the danger of poisoning increases; The poisoning of amido and nitrogenation of benzene, for example, in the summer there are more often than in winter. Heat It also affects the volatility of gas, the rate of evaporation, etc. It has been established that air humidity enhances the toxicity of some poisons (hydrochloric acid, hydrogen fluoride).

2.4.3. Ways of penetration of harmful substances in the human body

Toxic substances in the environment can penetrate the human body in three ways: inhalation,through the respiratory tract; oralthrough the gastrointestinal tract (gastrointestinal tract); percantialthrough intact skin.

Absorption through the respiratory tract

Absorption through the respiratory tract is the main way of receipt of harmful substances into the human body in production. Inhalation poisonings are characterized by the fastest flow of poison in blood.

The respiratory tracts are an ideal system for gas exchange with a surface up to 100 m 2 with deep breathing and a capillary network of about 2000 km long. They can be divided into two parts:

a) upper respiratory tract: nasopharynx and tracheobronchial tree;

b) the lower part consisting of bronchioles leading in air bags (alveoli) collected in lobes.

From the point of view of absorption in the lungs, Alveolas are the greatest interest. The alveolar wall is enjoyed by alveolar epithelium and consists of an intramanese frame consisting of basal membranes, connective tissue and capillary endothelium. Gas exchange is carried out through this system, having a thickness of 0.8 microns.

The behavior of gases and vapors inside the respiratory tract depends on their solubility and chemical reactivity. Water soluble gases are easily dissolved in the water contained in the mucous membrane of the upper respiratory tract. Less soluble gases and pairs (for example, nitrogen oxides) reach alveoli, in which they are absorbed and can react with the epithelium, causing local damage.

The fat-soluble gases and pairs diffuse through intact alveolar-capillary membranes. The absorption rate depends on their solubility in the blood, ventilation, blood flow and metabolic intensity. Gaseous substances having high blood solubility are easily absorbed, and those in which low solubility are easily released from the lungs with exhaled air.

The retention of particles in the respiratory tract depends on the physical and chemical properties of the particles, their size and shape, as well as from anatomical, physiological and pathological characteristics. Soluble particles in the respiratory tract dissolve in the deposition zone. Insoluble can be removed in three ways depending on the deposition zone:

a) with the help of mukiciliary cover both in the upper respiratory tract and at the bottom of the respiratory tract;

b) as a result of phagocytosis;

c) by passing directly through the alveolar epithelium.

It is possible to establish a well-defined pattern of sorption of poisons through the lungs for two large groups of chemicals. The first group is the so-called non-mentoringcouples and gases that include a pair of all hydrocarbons of aromatic and fat rows and their derivatives. Names are named nonreagating due to the fact that they do not change in the body (such little) or their transformation is slower than accumulation in the blood (such most). The second group is made reactcouples and gases. These include such poisons like ammonia, sulfur gas, nitrogen oxides. These gases, quickly dissolving in body fluids, easily enter into chemical reactions or undergo other changes. There are also poisons that, with respect to sorption, they are not subject to the laws established for these two groups of substances.

Non-mentoringcouples and gases enter blood based on the diffusion law, i.e., due to the difference in partial pressure of gases and vapors in the alveolar air and blood.

Initially, blood saturation with gases or couples due to a large partial pressure difference occurs quickly. It is then slowed down and finally, when the partial pressure of gases or vapors in the alveolar air and blood is terminated - stops (Fig. 35).

Fig. 35. Dynamics of blood saturation vapor benzene and gasoline

when inhaled

* -After removing the victim from a polluted atmosphere begins desorption of gases and vapors and removing them through the lungs. Desorption also occurs on the basis of diffusion laws.

The established pattern allows to make a practical conclusion: if at a constant concentration of vapors or gases in the air during a very short time, there was no sharp poisoning, in the future it will not come, because when inhalation, for example, drugs, the state of equilibrium of blood concentrations and the alveolar air is installed instantly. The removal of the victim from the contaminated atmosphere is dictated by the need to create the possibility of desorption of gases and vapors.

It can be seen from the figure that, despite the same concentration in the air of the vapor of gasoline and benzene, the level of blood saturation levels of benzene pairs are significantly higher, and the saturation rate is significantly less. It depends on solubility, or, otherwise, the distribution coefficient of benzene and gasoline in the blood. The distribution coefficient (K) is the relationship of the concentration of vapor in arterial blood to the concentration of them in the alveolar air:

K \u003d from blood / with ALV. Ware. .

The smaller the distribution coefficient, the faster, but at a lower level, the blood saturation occurs in pairs.

The distribution coefficient is for each of the reacting vapors (gases) of the magnitude of constant and characteristic. Knowing for any substance, it is possible to provide a danger of fast and even deadly poisoning. Gasoline pairs, for example (K \u003d 2,1), at high concentrations are able to cause instant acute or fatal poisoning, and pairs of acetone (K \u003d 400) cannot cause instantaneous, the more deadly, poisoning, since when inhaling acetone vapor by appear Symptoms can be prevented by acute poisoning, removing a person from a contaminated atmosphere.

The use of the distribution coefficient in the blood is facilitated by the fact that the solubility coefficient, i.e. distribution in water (coefficient of ostelald), has about the same order of magnitude. If substances are well soluble in water, they are well soluble and blood.

Other pattern of inherent sorption when inhalation reactgas: When inhaling these gases, saturation never occurs (Table 10).

Table 10.

Sorption of hydrogen chloride when inhaling his rabbit

Sorption, as can be seen from the table, proceeds at a constant speed, and the percentage of sorbed gas is directly dependent on the resistance volume. As a result, the danger of poisoning is the more significant than the longer a person is in a polluted atmosphere.

This pattern is inherent in all reacting gases; Differences can only be in the sorption site. Some of them, such as hydrogen chloride, ammonia, sulfur gas, are well soluble in water, are sorbed in the upper respiratory tract; Others, for example, chlorine, nitrogen oxides, are worse dissolved in water, penetrate the alveoli and are mainly sorbed there.

Sorbiation of chemicals in the form of dust different dispersion occurs just as the sorption of any non-toxic dust. The danger of poisoning when inhalation of dust depends on the degree of solubility. Dust, well soluble in water or fats, is already absorbed in the upper respiratory tract and even in the nasal cavity.

With an increase in the volume of pulmonary respiration and blood flow rate, sorption occurs faster, therefore, when performing physical work or stay under high temperature, when the volume of breathing and the speed of blood flow increases sharply, poisoning may occur faster.

Toxic substances are entered into the human body through the respiratory tract (inhalation penetration), the gastrointestinal tract and the skin. The degree of poisoning depends on their aggregate state (gaseous and vapor substances, liquid and solid aerosols) and on the nature of the technological process (the heating of the substance, grinding, etc.).

The predominant majority of professional poisoning is associated with inhalation penetration into the body of harmful substances, which are the most dangerous, as the large suction surface of the pulmonary alvetol, intensely washed by blood, determines the very rapid and almost unhindered penetration of poisons to the most important life centers.

The intake of toxic substances through the gastrointestinal tract in production conditions is quite rare. This happens because of the violation of the rules of personal hygiene, partial ingestion of vapors and dust,

penetrating through the respiratory tract, and non-compliance with the rules of techniques of non-safety during operation in chemical laboratories. It should be noted that in this case the poison enters through the system of the portal vein into the liver, where it turns into less toxic compounds.

Substances that are well soluble in fats and lipoids can penetrate the blood through intact skin. Strong poisoning causes substances with increased toxicity, low volatility, rapidly solubility in the blood. These substances include, for example, nitro and aminoproducts of aromatic hydrocarbons, tetraethylswin, methyl alcohol, etc. can be attributed.

Toxic substances in the body are distributed unequal, with some of them are capable of accumulating in certain tissues.

It is particularly possible to select electrolytes, many of which are extremely quickly disappearing from blood and focus in separate organs.

Lead accumulates mainly in the bones, manganese - in the liver, mercury - in the kidneys and a colon. Naturally, the peculiarity of the distribution of poisons can to some extent reflect on their further fate in the body.

When entering into a circle of complex and diverse life processes, toxic substances are subjected to a variety of transformations in the course of oxidation reactions, restoration and hydrolytic splitting. The general direction of these transformations is characterized by most often the formation of less poisonous compounds, although more toxic products can be obtained in some cases (for example, formaldehyde when the methyl alcohol oxidation) can be obtained.

The release of toxic substances from the body often occurs in the same way as admission. Unreacting pairs and gases are partially or completely removed through the lungs. A significant amount of poisons and their conversion products are distinguished through the kidneys. A certain role for the isolation of poisons from the body is played by skin cover, and this process is mainly performing salted and sweat glands.

It should be borne in mind that the release of some toxic substances is possible in the composition of female milk (lead, mercury, alcohol). This creates the danger of inflation of infants. Therefore, pregnant women and nursing mothers should temporarily remove from production transactions separating toxic substances.

The toxic effect of individual harmful substances can manifest itself in the form of secondary lesions, for example, colitis with arsatitis and mercury poisoning, stomatitis with lead and mercury poisoning and so on.

The seriousness of harmful substances for a person is largely determined by their chemical structure and physicochemical properties. An important value for the toxic effect is the dispersion of a chemical penetrating agent, and the higher the dispersion, the toxic substance.

Conditions of the environment can either enhance or weaken its action. So, at high air temperature, the danger of poisoning increases; The poisoning of amino and nitrogenation of benzene, for example, in the summer there are more often than in winter. High temperature affects the volatility of gas, the rate of evaporation, etc. It is established that air humidity enhances the toxicity of some poisons (hydrochloric acid, hydrogen fluoride).

inhalation

10. The level of air pollution of the working area toxic substance is determined by the multiplicity of exceeding the measured concentration relative to:

11. The parameter characterizing the level of natural light is a coefficient:

natural lighting

12. The blinding effect of the light source is estimated:

blindfold

What is the indicator not taken into account when normalizing natural and combined lighting?

the color of the background, on which the object of difference is considered, and the contrast

14. Pressure difference arising in an indignant and unperturbed elastic medium is called:

sound pressure

15. With sanitary and hygienic rationing of noise, the following indicator is taken into account:

the severity and tension of the labor process

16. Reducing the level of aerodynamic noise is achieved by using:

silencers

17. The rationalization of vibration rate levels is carried out at the following frequencies of octave bands:

medium meterometric

18. AC current with a frequency of 50 Hz and the value of 810 mA when passing through the human body is:

holding

19. When carrying out repair work on electrical installation, except for turning off the chop, to prevent lesions electric shock Electricians should additionally be provided:

warning posters

20. The principle of protective grounding is based on:

reducing the voltage between the case, which turned out to be energized, and the earth to a safe value

21. Easily flammable liquids (s) having a flash point of less than 18 ° C refer to:

particularly dangerous

22. Introduction of inert gas into an explosive mixture of combustible gas with air:

sushing the ignition range

23. The zone in which the explosive concentration of the aerosol constantly exists with normal modes of the technological process, in accordance with Pue, is indicated as:

24. A boiler room operating on natural gas according to the degree of explosion and fire danger refers to the category:

25. For the automatic extinguishing of the emergence of the fire focus in enterprises include:

drencher Installations

Ticket number 17.

1. Games of children in careers, near the roads, on the territory of the facility under construction, on ice and TP are associated with risk:

on conscious

2. Risk level after implementation protective Mer called:

minimal

3. Ensuring the rights of an employee on labor protection and guarantees of these rights are enshrined in the documents:

4. Workplace With dangerous working conditions:

subject to liquidation

5. The normalization of microclimate parameters is carried out by the set of indicators:

temperature, relative humidity and air velocity in the working area

6. The "hot workshop" includes a room in which the minimum value of the specific excess of explicit heat is equal to:

7. Combined actions of microclum parameters on the human body is estimated by parameter:

thermal load environment

8. In the direction of the air flow, the ventilation is divided into:

support and exhaust

9. With long-term admission of harmful substances in the human body in relatively small quantities May develop:

chronic poisoning

10. Systematic work in the conditions of an increased level of air dusting can lead to:

pneumoconios

11. Quio is a coefficient:

possible inhalation poisoning

12. The gravimetric method of analysis allows you to determine the concentration in the air of the working area:

aerosol

13. The level of air pollution of the working area and the risk of worsening the state of health when working with harmful substances is established on the basis of:

multiplicities of exceeding the actual concentration of harmful substance over the PDKR

14. Unit of measurement of the coefficient of natural lighting is:

15. Lighting of industrial premises with two and more fluorescent lamps is primarily due to:

reduce pulsation of light flux

What type of benefits is not characteristic of luminescent lamps?

independence of the light rate of temperature

17. Sound intensity is:

the amount of energy carried by the sound wave per unit of time through the unit area

18. With sanitary and hygienic rationing of noise at workplaces, it is taken into account:

subjective perception of noise man

19. Porolan, foam, fiberglass - these are materials related to:

sound absorbing

20. The main normalized parameter that takes into account the degree of danger of vibration is:

level of vibration

21. A variable current of 50 Hz is fatal for humans:

22. The touch of a person to one phase during normal operation of electrical equipment is less dangerous online with a neutral type:

does not depend on the type of neutral

23. The protective grounding of the equipment is preferably used in the networks of voltage up to 1000 V:

in the network with zero wire with an isolated neutral

24. Easily flammable liquids (LVZ), having a flash point of more than 18 ° C to 23 ° C, in the degree of explosive danger refer to liquids:

constantly dangerous

Section 1. Question 5

Harmful substances, the paths of their penetration into the human body. Classification of harmful substances. The principle of defining MPC. Tools of collective and individual protection against damage to harmful substances of various types.

Harmful substances - Substances adversely affecting the human body and causing violation of normal life processes. The result of the impact of harmful substances can be sharp or chronic poisoning of working. Harmful substances can penetrate the human body through the respiratory organs, the gastrointestinal tract, the skin, and also through the mucous membranes of the eyes. The elimination of harmful substances from the body occurs through light, kidneys, gastrointestinal tract and skin. The toxic effect of harmful substances depends on a number of factors: sex and ages of working, individual sensitivity of the body, the nature and severity of the work performed, the meteorological conditions of production, etc. Some harmful substances can have bad influence The human body is not at the moment of their impact, but after many years and even decades (distant consequences). The manifestation of these influences may affect the offspring. Such negative effects are gonadotropic, embryotoxic, carcinogenic, mutagenic action, as well as accelerating the aging of the cardiovascular system. All harmful substances are divided into four-class dangers: 1st - extremely dangerous (MPC 0.1 mg / m 3); 2nd - highly hazardous (0.1 MPC 1 mg / m 3); 3rd - moderately dangerous (1 MPC 10 mg / m 3; 4th - low hazard (MPC 10 mg / m 3).

According to the degree of impact on the human body Harmful substances in accordance with GOST 12.1.007 SSBT " Harmful substances. Classification and general safety requirements"divided into four classes of danger:
1 - substances are extremely dangerous (vanadium and its compounds, cadmium oxide, nickel carbonyl, ozone, mercury, lead and its compounds, terephthalic acid, tetraethylswin, phosphorus yellow, etc.);
2 - substances are highly dangerous (nitrogen oxides, dichloroethane, carbofos, manganese, copper, arsenic hydrogen, pyridine, sulfuric and hydrochloride, hydrogen sulfide, carbon black, tiuram, formaldehyde, hydrogen fluoride, chlorine, solutions of caustic alkalis, etc.);
3 - substances are moderately dangerous (camphor, caprolactam, xylene, nitroposk, low pressure polyethylene, sulfurian anhydride, methyl alcohol, toluene, phenol, furfurol, etc.);
4 - Low-haired substances (ammonia, acetone, gasoline, kerosene, naphthalene, turpentine, alcohol ethyl, carbon oxide, White spirit, dolomite, limestone, magnesite, etc.).
The degree of danger of harmful substances It can be characterized by two toxicity parameters: upper and lower.
Upper toxicity parameter It is characterized by the magnitude of the fatal concentrations for animals of various types.
Lower - minimal concentrations affecting the highest nervous activity (conditional and unconditional reflexes) and muscle performance.
Almost unbelievable substances Usually called those that can become poisonous in completely exceptional cases, with such a combination of various conditions that are not found in practice.

Tools of collective protection - means of protection, constructively and functionally related to the production process, industrial equipment, room, building, building, production platform.

Depending on the destination come:

• means of normalization of the air environment of industrial premises and jobs, localization of harmful factors, heating, ventilation;
• means of normalizing the illumination of premises and jobs (light sources, lighting equipment, etc.);
• means of protection against ionizing radiation (fender, sealing devices, safety signs, etc.);
• means of protection against infrared radiation (fender; sealing, heat insulating devices, etc.);
• means of protection against ultraviolet and electromagnetic radiation (fender, for air ventilation, remote control, etc.);
• protection against laser radiation (fence, safety signs);
• means of protection against noise and ultrasound (fence, silencers of noise);
• vibration protection tools (vibration insulating, vibration, vibrating absorbing devices, etc.);
• means of protection against electric shock (fencing, alarm, insulating devices, grounding, zeroing, etc.);
• high and low temperature protection (fencing, thermally insulating devices, heating and cooling);
• means of protection against the effects of mechanical factors (fencing, safety and brake devices, safety signs);
• remedies for impact chemical factors (devices for sealing, ventilation and air purification, remote control, etc.);
• funds of protection against the impact of biological factors (fence, ventilation, safety signs, etc.)

Collective remedies are divided into: fender, safety, brake devices, automatic control and signaling devices, remote control, safety signs.

1) Fitting devices Designed to prevent accidental people in the danger zone. These devices are used to insulate the moving parts of machines, machine processing zones, presses, shock elements of machines from the working area. Devices are divided into stationary, movable and portable. They can be made in the form of protective housings, visors, barriers, screens; both solid and mesh. They are made of metal, plastics, wood.

Stationary fences must be strong enough and withstand any loads that arise from the destructive actions of objects and breakdowns of the processed parts, etc. Portable fences in most cases are used as temporary.

2) Safety devices. They are intended for automatic shutdown of machinery and equipment at any deviation from the norms of operation mode or with a random person in the danger zone. These devices are divided into blocking and restrictive devices.

Blocking Devices on the principle of operation are: electromechanical, photovoltaic, electromagnetic, radiation, mechanical.

Restrictive devices are composite parts of machines and mechanisms that are destroyed or fail during overloads.

3) Brake devices. According to constructive execution, such devices are divided by types of booms, disc, conical, wedge brakes. They can be a manual (foot) drive, semi-automatic and fully automatic drive. These devices on the principle of destination are divided into workers, backup, parking brakes and emergency braking devices.

4) Automatic Control and Alarm Devices Very important to ensure proper safety and reliable equipment. Control devices are a different kind of measuring sensors of pressure, temperature, static and dynamic hardware for equipment. The efficiency of their use is significantly increased by combining with alarm systems. According to the method of operation, the alarm is automatic and semi-automatic. Also alarm can be an informational, preventive and emergency. Forms of information alarm are different kind of schemes, pointers, inscriptions on equipment or scoreboard, directly in the service area.

5) Remote Control Devices Most reliably solve the problem of ensuring security, as it allows you to manage the necessary work of equipment from sites that are outside the danger zone.

6) Safety Signs We carry the necessary information to avoid accidents. They are divided according to GOST R 12.4.026-2001 SSBT. They
May be the main, additional, combined and group:

• Maintenance - contain an unambiguous semantic expression of requirements for
  Security. Major signs are used independently or as part of combined and group safety signs.
• Additional - contain an explanatory inscription, they are used in
  Combining with basic signs.
• Combined and group - consist of major and additional signs and are carriers of comprehensive safety requirements.

Safety signs by type of materials used may be unreasonable, retroreflecting and photoluminescent. Safety marks with external or internal lighting should be connected to an emergency or autonomous source of power supply.

Signs with external or internal electrical lighting for fire hazardous and explosive rooms must be made in fireproof and explosion-proof design, respectively, and for explosion-proof premises - in explosion-proof design.

Safety marks intended for accommodation in production conditions containing aggressive chemical media should withstand the effects of gaseous, vapor and aerosol chemical environments.

Individual Protection Means (PPE) - Designed to protect against entering the body, on the skin and clothing of radioactive and poisoning substances, bacterial agents. They are divided into SIZ respiratory and leather organs. These include an individual anti-chemical package and an individual first aid kit.

The respiratory facilities include:

• Gasy
• Respirators
• Antique fabric mask
• Tanning-gauze

The main means of protection is a gas mask, designed to protect the respiratory organs, face and human eye from the effects of poisoning substances in the form of steam, radioactive substances, pathogenic microbes and toxins. According to the principle of action, the gas mask is divided into filtering and insulating. The antique respirator is used to protect the respiratory organs from dust. It can be used under action in a focus of bacteriological infection to protect against bacterial aerosols. The respirator is a filter mixer, equipped with two inhaple and one exhaling valves. Difficult tissue masks consist of a housing and fastening. The case is made of 4-5 layers of fabric. For the top layer, hazard, staple facilities, knitwear are suitable; For internal layers - flannel, cotton or woolen fabric with puff. For a marble bandage Use a piece of gauze with a size of 100 by 50 cm. On its middle, the wool layer is 100 per 50 cm layer. In the absence of a mask and a dressing, you can use a folded fabric, towel, scarf, scarf, etc. According to the principle of protective action, sizod and SIZK are divided into filtering and insulating. The filtering is fed into the breathing zone purified by impurities of the air of the working area, insulating air from special containers or from a clean space located outside the working area.

Insulating remedies should be applied in the following cases:

• in the context of the lack of oxygen in the inhaled air;
• under conditions of air pollution in large concentrations or in the case when the concentration of contamination is unknown;
• under conditions when there is no filter that can protect against contamination;
• if hard work is performed when breathing through filtering sizod is difficult due to the filter resistance.

If there is no need for insulating remedies, you need to use filtering agents. The advantages of filter funds are easy, freedom of movements for the employee; ease of solution when changing the workplace.

The disadvantages of filter funds are as follows:

• filters have a limited shelf life;
• difficulty breathing due to filter resistance;
• the limitations of work using the time filter, if it comes to the filter mask, which is equipped with a subdomin.

Do not work using Filtering Sizod for more than 3 hours during the working day. Insulating skin protection products are made of airtight, elastic frost-resistant materials in the form of a kit (jumpsuit or cloak, gloves and stockings or boots). They are used during work under conditions of strong infection of PB, OV and BS when conducting special processing. Overalls it serves to protect the body working from the adverse effects of mechanical, physical and chemical factors of the production environment. Overalls should be reliably protected from a harmful production factor, not to disturb the normal thermoregulation of the body, to ensure freedom of movements, the convenience of wearing and is well cleaned from pollution, without changing its properties. Special shoes Must protect the feet of workers from the effects of dangerous and harmful production factors. Special footwear are made of leather and leatherette, dense cotton fabrics with a full-chill coated coating, rubber. Instead of leather soles, leatherette, rubber, etc. in chemical industries are often used, which use acids, alkalis and other aggressive substances, use rubber shoes. Plastic boots from a mixture of wildlif chloride resins and synthetic rubbers are also widely used. To protect the foot from damage due to falling on the feet of castings and For forgings, shoes are supplied with steel toe withsting a blow to 20 kilograms. Protective dermatological means Serve to prevent skin diseases when exposed to certain harmful production factors. These protective agents produce the form of ointments or pastes that are divided into: