Ensure a comfortable indoor climate

Microclimate is artificially created climatic conditions in enclosed spaces to protect against adverse external influences and create a comfort zone.

Microclimatic conditions ( physical conditions) - pressure (not standardized), temperature, relative humidity, the speed of air movement - affect the well-being of a person and cause certain borderline conditions. A person responds to these conditions through:

The mechanism of thermoregulation, that is, the regulation of heat exchange with the environment.

Preservation of body temperature at a constant normal level of 36.6 ° C, regardless of external conditions and the severity of the work performed.

Thermoregulation can be:

physical;

chemical.

Chemical thermoregulation of the body is achieved by a weakening of metabolism in case of the threat of overheating or by an increase in metabolism during cooling. The role of chemical thermoregulation in the thermal balance of the body with the external environment is small compared to the physical one, which regulates the release of heat in environment, emitting infrared rays from the surface of the body in the direction of surrounding objects with a lower temperature. Convection, evaporation of sweat from the surface of the body, moisture from the lungs and mucous membranes of the upper respiratory tract also leads to cooling of the body. IN comfortable conditions the amount of heat generated is equal to the amount of heat given off per unit of time, this state is called the body's heat balance, and if it is disturbed, overheating or hypothermia occurs. Overheating occurs at high air temperature, accompanied by low air mobility, high relative humidity, and is characterized by an increase in heart rate, respiration, weakness, an increase in body temperature above 38 ° C, speech difficulty, etc. An increase in humidity W £ 75-80% at high temperatures prevents sweating and leads to overheating, heat stroke and cramps. Signs of this severe defeat - loss of consciousness, weak pulse, almost complete cessation of sweating.

Consequences of moisture loss:

1 - 2% of body weight - thirst.

5% - clouding of consciousness, hallucinations.

20 - 25% - death.

During the day, a person loses:

at rest - up to 1 liter;

with heavy physical work - up to 1.7 liters per hour, up to 12 liters per shift. At the same time, Na, Ca, K, P salts are excreted - up to 5-6 grams per liter, microelements Cu, Zn, I, vitamins, gastric secretion decreases.

Hypothermia occurs at low temperatures, high humidity, high winds. This is explained by wet air conducts heat better, and its mobility increases heat transfer by convection.

Signs of hypothermia:

a sharp decrease in body temperature;

narrowing of blood vessels;

dysfunction of the heart vascular system;

With hypothermia, colds are possible.

Dust. The presence of dust in the air is measured in mg/m3. Dust content:

on a dusty road - 150 mg/m3;

in a residential area - 5-6 mg / m3.

Dust can be toxic, organic, inorganic, mixed. The degree of exposure to dust on the human body depends on its physical and chemical properties, toxicity, dispersion, and concentration, in addition to its "usual" manifestations in the form of dermatitis, bronchitis, silicosis, etc. We must always remember that this is the strongest carcinogen.

Dust control methods:

1) Creation of conditions for its precipitation (gravitational method).

2) Creation in a mixture of forces, the action of which leads to the extraction of dust particles from the air - a decrease in the concentration of dust (dust concentration is the ability of dust to remain suspended for a long time). This regulation of the dust concentration is usually achieved by means of ventilation.

With an increase in concentration, the premises can be classified as explosive and fire hazardous (at a concentration of more than 65 mg/m3). There may be gaseous substances in the air of the RP, which are detected when such air is aspirated through an indicator tube, it changes color, and the concentration of a potent gas in the room is judged by the change in color.

PHYSICO-CHEMICAL BASES OF COMBUSTION AND EXPLOSION.

Systems for ensuring microclimate parameters

Optimal microclimate parameters in industrial premises provided with air conditioning systems, and valid parameters– conventional ventilation and heating systems. The most perfect type of industrial ventilation is air conditioning. Conditioning– artificial automatic air treatment in order to maintain optimal microclimatic conditions regardless of the nature of the technological process and environmental conditions. In some cases, during air conditioning, the air undergoes additional special treatment - dust removal, humidification, ozonation, etc. Air conditioning provides both life safety and technological process parameters, where fluctuations in temperature and humidity of the environment are not allowed. The use of shielding significantly reduces the effect of heat on the body. Screens can be heat-reflecting (aluminum foil, aluminum paint, aluminum sheet, tinplate), heat-absorbing (colorless and colored glass, glazing with an air or water layer), heat-conducting (hollow steel plates with water or air, metal meshes). Personal protective equipment is widely used: overalls made of cotton, linen, wool, air- or moisture-proof, helmets, felt helmets, goggles, masks with a screen, etc. Ventilation- organized and regulated air exchange, which ensures the removal of exhaust air from the room and the supply of fresh air in its place. Natural unorganized ventilation is carried out due to the difference in pressure outside and inside the room. For residential premises, air change (infiltration) can reach 0.5-0.75 volume per hour, for industrial premises 1.0-1.5 volume per hour. natural organized, duct ventilation designed for residential and public buildings. When the wind flows around the outlet of the exhaust shaft, which sometimes has a nozzle-deflector, a vacuum is created that depends on the wind speed and an air flow occurs in the ventilation system. mechanical ventilation- this is such ventilation in which air is supplied (supply) or removed (exhaust) using special devices - compressors, pumps, etc. There are public ventilation (for the entire room) and local ventilation (for certain workplaces). public ventilation designed to assimilate excess heat, moisture and harmful substances in the entire volume of the working area of ​​the premises. It is used in the event that harmful emissions enter directly into the air of the room, jobs are not fixed, but are located throughout the room. Usually, the volume of air supplied to the room during general ventilation is equal to the volume of air removed from the room. However, in some cases it becomes necessary to violate this equality. So, in especially clean shops of electrovacuum production, for which great importance has no dust. The volume of air inflow is greater than the volume of the exhaust, due to which some excess pressure is created in the production room, which eliminates the ingress of dust from neighboring rooms. By using local ventilation the necessary meteorological parameters are created at individual workplaces. For example, capturing harmful substances directly at the source of occurrence, ventilation of observation booths, etc. Localized exhaust ventilation is the most widely used. The main method of dealing with harmful secretions is to arrange suction from shelters. With mechanical ventilation, the air can first pass through the filter system, be cleaned, and harmful impurities can be trapped in the exhaust air. Mechanical ventilation has a number of advantages compared to natural ventilation: a large radius of action due to the significant pressure created by the fan, the ability to change or maintain the necessary air exchange, regardless of the outdoor temperature and wind speed; subject the air introduced into the room to preliminary purification, drying or humidification, heating or cooling; organize optimal air distribution with air supply directly to workplaces; capture harmful emissions directly at the places of their formation and prevent their spread throughout the room, as well as the ability to purify polluted air before releasing it into the atmosphere. The disadvantages of mechanical ventilation include the significant cost of the structure and its operation, the need to take measures to combat the noise it creates. . Aeration- organized natural ventilation premises through transoms, vents, windows. The air exchange in the room is regulated by varying degrees of opening of the transoms (depending on the outdoor temperature, wind speed and direction). As a method of ventilation, aeration has found wide application in industrial buildings, characterized by technological processes with large heat releases (rolling shops, foundries, forgings). The intake of outside air into the workshop during the cold period is organized so that cold air does not enter the working area. For this outside air they are fed into the room through openings located at least 4.5 m from the floor; in the warm season, the inflow of outside air is oriented through the lower tier of window openings (height 1.5-2 m). When calculating aeration, determine the required flow area of ​​openings and aeration lamps for supply and removal required amount air. The initial data are the structural dimensions of the premises, openings and lanterns. The values ​​of heat production in the room, the parameters of the outside air. The main advantage of aeration is the ability to carry out large air exchanges at no cost. mechanical energy. The disadvantages of aeration include the fact that during the warm period of the year, the efficiency of aeration can significantly decrease due to an increase in the temperature of the outside air, and, in addition, the air entering the room is not cleaned or cooled. Ventilation, by which air is supplied to or removed from industrial premises through ventilation duct systems using special mechanical stimulators, is called mechanical ventilation.

Topic 3. Sources of air pollution

The gas composition of the Earth's atmosphere provides conditions for life and protects all living things from harsh radiation. cosmic radiation. Human activity changes the balance in nature. Surrounding man atmospheric air is continuously polluted. The air in industrial premises is polluted by emissions technological equipment or when carrying out technological processes without localization of waste substances. Ventilation air removed from the room can cause pollution atmospheric air industrial sites and populated areas. In addition, the air of industrial sites and populated areas is polluted by technological emissions from workshops, emissions from thermal power plants, vehicles and other sources. Strong air pollution occurs in large cities: 90% of the substances polluting the atmosphere are gases and 10% are solid particles. The most dangerous result of pollution is smog. Smog appears when the air is still, when, on the one hand, there are no horizontal winds, and on the other hand, the temperature distribution over the height of the atmosphere is such that there is no vertical mixing of the atmospheric layers. Mixing, or convection, of air in the troposphere occurs due to the fact that as it moves up from the earth, every 100 meters the temperature decreases by 0.6ºC. At a height of 8-10 km, the change in temperature changes sign, that is, warming occurs. This phenomenon is called inversion. Under certain conditions, temperature inversion is already observed in the lower layers of the troposphere and leads to the cessation of air mixing above the inversion level. Sometimes during the winter months one can observe the location of the inversion between the polluted lower layer of air and the upper transparent layer. Smogs are of two types. Smog, called London smog, is observed in foggy calm weather. All the smoke is not carried away by the wind, but is retained by the fog and remains over the city, producing a severe effect on people's health. On days of such strong smgs, an increase in human mortality is noted. Replacement solid fuel gaseous significantly reduces smoke. The second type of smog - photochemical, appears in large southern cities in calm, clear weather, when nitrogen oxides contained in car exhaust gases accumulate. These compounds undergo a chain of chemical transformations under the action of solar radiation. The main components of photochemical smog are: ozone, nitrogen dioxide and nitrous oxide. Accumulating in large quantities, these substances and their decay products under the action of ultraviolet radiation enter into a chemical reaction with hydrocarbons in the atmosphere. As a result, chemically active organic substances peroxylacyl nitrates are formed, which have a harmful effect on the human body: they irritate the mucous membrane, tissues of the respiratory tract and lungs, these compounds discolor the greenery of plants. An excess of ozone in smog, which has a strong oxidizing property, has a harmful effect on the environment and the human body. The hydrocarbons in smog are partly of natural origin. Methane is released during the decomposition and decay of plants. Other hydrocarbons are emitted as a result of the operation of oil refineries, internal combustion engines. The share of motor transport accounts for more than 50% of the total atmospheric emissions of technogenic origin, the composition of automotive emissions includes more than 170 toxic components. There are more or less distinct impacts on soil, plants and animals near roads with high traffic. Diesels are a major source of hydrocarbon pollution, including carcinogenic cyclic hydrocarbons found in soot emitted from diesel engines. Air pollution during the operation of a car engine occurs due to the fact that the products of combustion of fuel are emitted from it directly into the air. Along with these components essential role impurity play, the effect of which is manifested at low concentrations. Such an impurity is tetraethyl lead, which is used as an additive to gasoline and serves to prevent fuel detonation in the engine. Its amount by weight is slightly less than 0.1%. Running car engines annually emit about two million tons of lead into the atmosphere. As a result, lead appears already in vegetables in amounts up to 2 mg/kg. It has been established that the fruits of trees growing in a strip of up to 50 meters near the freeway should not be eaten. An excess of lead in the body leads to lead poisoning, which manifests itself first in neurosis, insomnia, fatigue, then in depression, mental deterioration. An important hazardous component of the atmosphere is sulfur, which is part of sulfate aerosols, one of the most common types of aerosols in the atmosphere. Globally, sulfur aerosol emissions are 160-180 million tons per year. Of these, 90% comes from the combustion of mineral fuels and 10% from emissions from metallurgical and chemical enterprises. Under the action of ultraviolet radiation, sulfurous anhydrite is converted into sulfuric anhydride (SO 3), which forms sulfurous acid with atmospheric water vapor. Sulfurous acid spontaneously converts to sulfuric acid, which is very hygroscopic and can form a toxic mist. MPC SO 2 in the air is 100-150 mg/m³. Nitrogen oxides are very dangerous pollutants of the biosphere. Every year, about 150 million tons of nitrogen oxides enter the Earth's atmosphere, half of which is emitted by thermal power plants and cars, and the other half is formed as a result of oxidation processes occurring in the biosphere. Nitrogen peroxide, a yellow gas that gives a brownish tint to the air, greatly impairs visibility on city streets. This gas absorbs ultraviolet rays, producing photochemical pollution. Nitric oxide, when interacting with atmospheric oxygen, forms nitrogen dioxide, which, as a result of reaction with atmospheric water vapor (water hydroxyl radical), turns into nitric acid. Nitrogen dioxide irritates the respiratory system, causes coughing, at high concentrations - vomiting, headache. Nitric acid can remain in a gaseous state for a long time, as it is poorly condensed, and at high concentrations it can cause pulmonary edema. Cloud droplets condense on aerosol particles and molecules of sulfuric and nitric acid. When precipitation falls, the layer of atmosphere between the cloud and the ground is washed. This is how acid rain is formed. Their appearance is caused by a significant accumulation of sulfur and nitrogen oxides in the atmosphere. Acid rains suppress the biological productivity of soils and water bodies and cause significant economic damage. Acid rain leads to destruction various objects and buildings, interact with the calcium carbonate of sandstones and limestones, turning it into gypsum, which is washed out by rains. Acid rain causes active corrosion of metal objects and structures. Under the influence of acid rain, the biochemical properties of the soil change, which leads to disease and death of some plant species. Industrial emissions have led to an increase in the content of heavy metals in individual elements of the biosphere by tens and hundreds of times. Heavy metals enter the atmosphere and return back with precipitation and dry deposition. Acid rain, interacting with heavy metals in the soil, converts them into a form that is easily absorbed by plants. Further along the food chain, heavy metals enter the organisms of fish, animals and humans. Up to certain limits, living organisms are protected from the direct harmful effects of acidity, but the accumulation of heavy metals is dangerous. So, aluminum, soluble in an acidic environment, is toxic to microorganisms living in the soil, weakens the growth of plant roots. Acid rains, acidifying the waters of lakes, lead to the death of their inhabitants. Obviously, the content of zinc and cadmium in pork and beef often exceeds acceptable levels. Getting into the human body, heavy metals cause changes in it. Heavy metal ions easily bind to proteins (including enzymes), inhibiting the synthesis of macromolecules and, in general, metabolism in cells. So, for example, cadmium accumulates in the kidneys, affects the kidneys and the human nervous system, and in large quantities leads to severe specific diseases. The combustion of fossil fuels and other fuels is accompanied by the release of carbon dioxide into the atmosphere. An increase in the amount of carbon dioxide as a result of anthropogenic impact leads to a change in the heat balance of the Earth. Carbon dioxide passes the solar radiation incident on the Earth, but absorbs long-wave infrared radiation reflected from the Earth. This leads to a warming of the atmosphere. Contaminants and dust in the atmosphere absorb some of the radiation incident on the Earth, which further increases the temperature of the atmosphere. The heated atmosphere sends an additional flow of heat to the earth, raising its temperature. This process is called greenhouse by analogy with a greenhouse, into which solar radiation freely passes in the optical part of the spectrum, and infrared radiation is delayed. As air pollution increases, the temperature of the earth's surface increases. The manifestation of the greenhouse effect is especially characteristic in cities with industrial production - the temperature in the center is several degrees higher than the temperature in the vicinity of the city, especially in calm weather. The main source of atmospheric dust is mining and the use of building materials, the metallurgical industry. The dust contains many different minerals (gypsum, asbestos, quartz, etc.), about 20% iron oxide, 15% silicates, 5% soot, oxides of various metalloids. The entry of technogenic particles into the Earth's atmosphere is annually 500 million tons. Dust creates a shield against solar radiation, due to pollution, large cities receive 15% less sunlight. Dust in the atmosphere leads to the appearance and exacerbation of respiratory and pulmonary diseases. Increase average temperature atmosphere by several degrees due to a decrease in its transparency can cause the melting of glaciers and a rise in sea level. This may be accompanied by flooding of fertile lands in river deltas, changes in water salinity, as well as global changes in the Earth's climate. Anthropogenic impact on atmospheric ozone has a destructive effect. Ozone in the stratosphere protects all life on Earth from the harmful effects of short waves of solar radiation. A decrease in the ozone content in the atmosphere by 1% leads to an increase by 2% in the intensity of hard ultraviolet radiation falling on the Earth's surface, which is detrimental to living cells. The strongest ozone depletion is associated with the production of freons. Freons are used as aerosol fillers, foam components and as a working substance of refrigerators. When using cans with aerosols, when leaking from refrigerating tanks, freon enters the atmosphere. Freons are harmless to humans, chemically passive. Falling into the atmosphere, at an altitude of several tens of kilometers, freons decompose into constituent components under the action of hard ultraviolet radiation from the Sun. One of the components formed - atomic chlorine - actively contributes to the destruction of ozone, moreover, the chlorine molecule acts as a catalyst, remaining unchanged in tens of thousands of acts of destruction of ozone molecules. The residence time of freons in the stratosphere is several decades. The problem of the influence of freons on stratospheric ozone has acquired international significance, especially in connection with the formation of "ozone holes". An international program has been adopted to reduce production using freons. Sometimes weather conditions contribute to the accumulation of harmful impurities near the ground surface. The wind can blow along a number of pollutant sources, with the pollutants cumulating. With a strong wind, harmful impurities move and disperse in layers closer to the ground. The composition of the air in industrial premises is determined primarily by the pollutants of those industries that are characteristic of the types of production activities themselves, as well as those pollutants that come from the outside air through the vents, open windows, doors, ventilation openings. Of no small importance for human health is what we breathe in our apartment. According to scientists, the air in apartments is 6 times dirtier than outdoor urban air and 10-12 times more toxic. What is the cause of air poisoning in our homes? First of all, these pollutants come with outdoor air along with dust from the street. Health hazards are products of incomplete combustion of gas entering the air from switched on gas stoves; carbon monoxide, sulfur compounds, as well as by-products formed during combustion. Artificial pollution air (up to 80%) is brought by modern furniture, in the manufacture of which wood-chip and wood-fiber boards containing many synthetic substances are used. Polymers, paints, varnishes used in the manufacture of this furniture emit formaldehyde, phenol and other toxic chemical compounds. In the manufacture of furniture, elastic polyurethane is used, which after a few years begins to turn into brown dust. Up to 60 mg of hydrogen cyanide is released from each gram of this material. Widely used in contemporary clothing, carpets, draperies, etc. nylon during decay releases the harmful substance caprolactam, which has a specific "mouse" smell and has a negative effect on human well-being. "Chemistry" is used all the time. A floor covered with synthetic lacquer releases extremely hazardous volatile substances into the air. Linoleum made of synthetic polymers with mineral additives and plasticizers is in use, as well as PVC tiles with special adhesives, which is another source of environmental pollution. In residential and industrial premises, experts found the presence of more than a hundred organic compounds. Harmful, toxic fumes have a detrimental effect on the human body, contribute to the occurrence of chronic diseases and even affect heredity. Carbon monoxide (carbon monoxide - CO) can accumulate in the room. This is a highly toxic compound. It has been established that one person emits up to 15 ml of CO2 per day. If there are many people in the room, if they smoke in it, if a gas stove burns, etc., then the concentration of carbon monoxide can be quite high. So, after an hour of burning a gas stove, the content of carbon monoxide and nitrogen dioxide becomes such that it significantly exceeds the norm permissible, for example, at chemical plants. In the air of residential and industrial premises, various solvents contained in paints, adhesives, plastics, as well as plasticizers - substances that give flexibility to plastics, microorganisms, various allergens, etc. are also determined. More than 100 compounds harmful to humans can be found in indoor air. All of them, emitted both by a person and the objects surrounding him, sometimes lead to painful changes in the respiratory organs, and also affect others. internal organs Their adverse effect on the nervous system manifests itself quite quickly: a feeling of lethargy, decreased performance, headache, irritability, sleep disturbance, etc. are noted. As a rule, we underestimate the harmful effects of such air on health. But, for example, American scientists believe that thousands of people die every year from diseases resulting from the influence of toxic substances in the air of residential and office industrial premises in the United States. Experts see a way out in fighting air pollution with the help of indoor plants. Where they are, the rooms are fresher and easier to breathe. Plants not only assimilate the accumulated in the air carbon dioxide and emit oxygen, but also absorb a number of harmful substances. So, indoor plant chlorophytum cleans the air better than some technical devices. This plant is proposed by scientists to purify the air in spacecraft.

The main ways to combat air pollution

These methods include: 1. Air quality control. In Russia, such control is carried out in more than 450 cities and industrial centers, mainly in terms of the content of dust, sulfur dioxide, sulfur oxides, and carbon monoxide. 2. Implementation of non-waste and low-waste industries. 3. Implementation of gas-cleaning and dust-collecting installations at industrial enterprises. 4. Reducing harmful emissions of vehicles into the atmosphere. 5. Application of automated control systems (ACS) for urban transport. 6. Organization of pedestrian zones with a complete ban on the entry of vehicles. Thus, the solution to the problem of air pollution is difficult task, requiring large funds, a number of complex activities.

The conditions of human production activity largely depend on the quality of the air environment in which this activity is carried out. The air environment is characterized by physical parameters, chemical composition, ionic composition and other indicators.

The physical parameters of air include temperature, relative humidity, speed, barometric pressure. The first three parameters determine the process of thermoregulation of the body, that is, maintaining the body temperature within 36–37С, which ensures a balance between the amount of heat continuously generated in the body during metabolism and excess heat continuously released into the environment, that is, it maintains heat balance of the human body.

The physical parameters of the air must be taken into account when organizing all types of activities. Of particular importance are the parameters of the microclimate of the premises, i.e. temperature, relative humidity and air mobility. In addition, it should be borne in mind that the air speed at a certain value poses a serious danger to structures, technical devices, structures, as it can create large wind loads that can produce destructive effects. The parameters of the microclimate have a direct impact on the thermal well-being of a person and his performance. For example, a decrease in temperature and an increase in wind speed contribute to an increase in convective heat transfer and the process of heat transfer during the evaporation of sweat, which can lead to hypothermia of the human body and, thereby, to a deterioration in well-being. As the temperature rises, the opposite occurs. Researchers have found that at an air temperature of more than 30С, a person's performance begins to decline. For a person, maximum temperatures are determined depending on the duration of their exposure and the means of protection used. The limiting temperature of inhaled air, at which a person is able to breathe for several minutes without special protective equipment, is about 116°C.

Air environment - necessary condition the existence of life. It plays an important role in the respiration of humans, animals, plants, in providing them with oxygen, removing metabolic products, heat exchange, and has a decisive influence on the formation of working conditions in the workplace.

Meteorological conditions are the physical state of the air environment, which is determined by the combination of temperature, humidity, air velocity, atmospheric pressure and radiation of heated surfaces (infrared or thermal radiation) acting on the human body.

The microclimate is characterized by meteorological conditions in some limited area (settlement, workshop, etc.) and significantly. affects the course of internal processes in the human body, its performance.

Air temperature is a parameter that reflects the thermal state of the air. Air temperature is characterized by the kinetic energy of the movement of air gas molecules, it is measured in degrees Celsius (°C).

Air humidity is a parameter that reflects the content of water vapor in the air. Distinguish between absolute, maximum and relative air humidity. Absolute humidity is the density of water vapor in the air, expressed in grams per cubic meter. Maximum humidity is the maximum possible density of water vapor at a given temperature. Relative humidity,

expressed as a percentage (\%), is the ratio of absolute humidity to maximum at the same temperature and pressure. Air movement in working area can be caused by uneven heating of air masses, the action ventilation systems or process equipment and is measured in meters per second (m/s).

Atmospheric pressure is characterized by the intensity of the force of gravity of the superior column per unit area measured in Pascals (Pa) or millimeters of mercury (mmHg)

Infrared radiation (IR) occurs in the wavelength range 1-780 nm (nm nanometer, 1 nm = 10 −9 m). Its sources are the sun, heated surfaces of equipment, an open flame, an electric arc, etc. They measure the intensity of infrared radiation in watts per square meter. Infrared radiation is also called thermal radiation. An unfavorable combination of microclimate parameters can cause an overstrain of thermoregulation mechanisms, overheating of the body ( heat with increased values ​​of speed, air humidity and infrared radiation) or hypothermia of the body (low temperature combined with high humidity and air velocity).

The chemical composition of the air. Clean air has the following chemical composition: nitrogen ≈78.08%; oxygen ≈20.94\%; argon, neon and other inert gases ≈0.94%; carbon dioxide ≈0.03\%; other gases - ≈0.01\%. The air may also contain harmful substances of various origins in the form of gases, vapors, aerosols, including radioactive ones.

A substance is considered harmful if, in contact with the human body, it can cause diseases or abnormalities in the state of health, detectable modern methods both in the process of contact with them, and in separate periods of life of the present and subsequent generations.

To prevent the negative consequences of the impact of harmful chemicals on individual components of the natural environment, it is necessary to know their limiting levels, at which normal life and functioning of the body is possible. The main value of ecological regulation of the content of harmful chemical compounds in the components of the natural environment is the maximum allowable concentration of MPC.

Air is characterized by ionic composition.

Air ionization is the process of converting neutral atoms and molecules of the air into electrically charged particles (ions). Ions in the air can be formed due to natural, technological and artificial ionization.

Natural ionization occurs as a result of the impact on the air environment of cosmic radiation and particles emitted by radioactive substances during their decay. Natural ion formation occurs everywhere and constantly.

Technological ionization occurs when the air environment is exposed to electromagnetic, radioactive, X-ray and ultraviolet radiation and other ionizing factors caused by technological processes. The ions formed in this process spread mainly in the immediate vicinity of the process unit.

Artificial ionization is carried out by special ionizer devices. Ionizers provide a given concentration of ions of a certain polarity in a limited volume of air.

Р-агрузка...

Lecture #7

Subject:Physiology of labor and comfortable living conditions.

Lecture plan:

Influence of the microclimate on labor productivity and health status, occupational diseases.

Systems for ensuring microclimate parameters and air composition: heating, ventilation, air conditioning; their structure and requirements for them.

Control of microclimate parameters.

Lighting. requirements for lighting systems. Natural and artificial lighting. Lamps and light sources. Illumination calculation. Light control

Alekseev S.V., Usenko V.R. Labor hygiene. - M.: Medicine, 1998. - 244 p.

Life safety: A textbook for students of secondary special. Proc. institutions / S.V. Belov, V.A. Devisilov, A.F. Koziakov and others / ed. ed. S.V. Belova. - M .: Higher. school, 2003. - 357p.

Life safety. Ed. prof. E. A. Arustamova. M.: "Dashkov and Co", 2003. -258 p.

Belyakov G.I. Workshop on labor protection. – M.: Kolos, 1999. – 192p.

Hwang T.A., Hwang P.A. Life safety. Series "Textbooks and teaching aids". Rostov n / a: "Phoenix", 2001. - 352 p.

Chusov Yu.N. Human physiology. – M.: Enlightenment, 1981. – 193 p.

1. Influence of the microclimate on labor productivity and health status, occupational diseases.

Microclimate of industrial premises or weather conditions, are made up of the air temperature in the room, infrared and ultraviolet radiation from heated equipment, hot metal and other heated surfaces, air humidity and its mobility.

All these factors, or meteorological conditions in general, are determined by two main reasons: internal (heat and moisture release) and external (weather conditions). First of them depend on the nature of the technological process, equipment and sanitary devices used and, as a rule, are relatively constant for each workshop or individual production site; second - Seasonal character, change dramatically depending on the time of year. The degree of influence of external causes largely depends on the nature and condition of the external fences of industrial buildings (walls, roofs, windows, entrance openings, etc.), and the internal ones - on the capacity and degree of isolation of sources of heat, moisture and the efficiency of sanitary devices.

Thermal regime of industrial premises is determined by the amount of heat released into the workshop from hot equipment, products and semi-finished products, as well as from solar radiation penetrating into the workshop through open and glazed openings or heating the roof and walls of the building, and in cold season- on the degree of heat transfer outside the premises and from heating. A certain role is played by heat generation from various types of electric motors, which heat up during operation and give off heat to the surrounding space. Part of the heat entering the shop is given out through the fences, and the rest, the so-called sensible heat, heats the air in the working rooms.

According to the sanitary standards for the design of industrial enterprises (SN 245 - 71), production facilities are divided into two groups according to specific heat release: cold shops , where the apparent heat release in the room does not exceed 20 kcal / m 3 h, and hot shops where they are above this value.

The air of the workshop, gradually coming into contact with the hot surfaces of heat sources, heats up and rises up , and its place displaces heavier cold air , which, in turn, also heats up and rises. As a result of constant air movement in the workshop it is heated not only at the location of heat sources, but also in more remote areas. This way of heat transfer to the surrounding space called convection . The degree of air heating is measured in degrees. Particularly high temperatures are observed in the workplace , which do not have sufficient inflow of outside air or are located in close proximity to heat sources.

The opposite picture observed in the same workshops during the cold season. The air heated by hot surfaces rises and partially leaves the workshop through openings and leaks in the upper part of the building (lanterns, windows, shafts); in its place, cold outside air is sucked in, which heats up very little before it comes into contact with hot surfaces, which is why often workplaces bathed in cold air .

All heated bodies radiate a stream from their surface radiant energy . The nature of this radiation depends on the degree of heating of the radiating body. At temperatures above 500 o WITH the emission spectrum contains as visible - light rays , and invisible - infrared rays ; at lower temperatures this spectrum consists only of infrared rays.

Hygienic value has a mostly invisible part of the spectrum, i.e. infrared, or, as it is sometimes incorrectly called, thermal radiation . The lower the temperature of the emitted surface, the lower the radiation intensity and the longer the wavelength; as the temperature increases, the intensity increases, but the wavelength decreases, approaching the visible part of the spectrum.

Heat sources having a temperature 2500 - 3000 o WITH and more, begin to radiate also ultra-violet rays (voltaic arc of electric welding or electric arc furnaces). In industry, for special purposes, so-called mercury-quartz lamps which emit predominantly ultraviolet rays.

Ultra-violet rays also have different wavelengths, but unlike infrared, as the wavelength increases, they approach the visible part of the spectrum. Therefore, visible rays are between infrared and ultraviolet in wavelength.

infrared rays , falling on any body, heat it, which was the reason for calling them thermal. This phenomenon is explained by the ability of various bodies to absorb infrared rays to one degree or another, if the temperature of the irradiated bodies is lower than the temperature of the emitting ones; in this case, radiant energy is converted into thermal energy, as a result of which one or another amount of heat is transferred to the irradiated surface. This way of heat transfer called radiation .

Different materials have different degree of absorption of infrared rays , and therefore, when irradiated, they heat up differently. Air does not absorb infrared rays at all and therefore does not heat up, or, as they say, it is heat-transparent . Shiny, light-colored surfaces (e.g. aluminum foil, polished tin sheets) reflect up to 94 - 95% infrared rays , but absorb all 5 - 6%. Matte black surfaces (e.g. carbon black) absorb almost 95 - 96% these rays, so they heat up more intensely.

At complete absorption of infrared rays as a result of the complete conversion of radiant energy into thermal energy, the irradiated object receives a certain amount of heat, which is usually measured in small calories per 1 cm 2 of the irradiated surface per minute (g.cal / cm 2 .min). This value is taken as a unit of irradiation intensity. Intensity infrared irradiation increases as the temperature of the radiation source increases and its surface area increases, and decreases in a square proportion as the distance from the radiation source increases. Infrared radiation usually comes from the same sources as the emission convection heat .

Hot shop workers are constantly or periodically exposed to infrared radiation, as a result of which they receive one or another amount of heat from the outside. The intensity of irradiation at workplaces, depending on the size and temperature of radiation sources and the distance from it to workplaces, varies widely: from a few tenths to 8 - 10 g.cal / cm 2 .min. When performing individual short-term operations, the intensity of irradiation reaches 13 - 15 g.cal/cm 2 .min. For comparison, it should be pointed out that the intensity of solar radiation on a cloudless summer day reaches only 1.3 - 1.5 g.cal/cm 2 .min.

Infrared radiation does not provide direct action into the air, but indirectly contributes to its heating. Various objects, equipment, structures and even walls exposed to radiation heat up and themselves become sources of heat release as radiation , and convection way. From them, the air of the workshop is heated.

When working with a voltaic arc or mercury-quartz lamps emitting ultraviolet rays, workers may be exposed to radiation if they are not protected from direct exposure to these rays in the eyes or on the skin. Ultra-violet rays pass well through the air, but almost do not pass through any dense tissue; even ordinary glass almost does not let them through.

In every room, and even more so in production workshops, the air is always in a state of motion , which is created due to the temperature difference in different parts of the building both in area and in height. The temperature difference is formed as a result of infiltration and suction of colder outside air through windows, lanterns, transoms, gates.

A stronger movement is observed in cases where there are heat sources in the workshop that heat the air and make it rise quickly. Travel speed or air mobility , measured in m/s.

Powerful heat sources in workshops cause significant air flows, the speed of which sometimes reaches 4-5 m/s. Especially high speeds of movement are created near open openings (gates, windows, etc.), where it is possible to suck in colder outside air. Due to the high speeds, cold jets travel considerable distances without sufficient dilution with the warm air of the workshop, blowing the workers and creating sharp fluctuations in temperature , which in everyday life is called drafts.

In some areas, unfavorable conditions for natural convection flow . Most often, this situation is observed in areas remote from openings, limited by walls and where any deaf ceilings (ceilings) prevent the rise of heated air upwards. Air mobility is reduced to minimum values ​​(0.05 - 0.1 m / s), which leads to its stagnation and overheating , especially if the sites are located close to heat sources.

Both the outdoor and the air of industrial premises contain a certain amount of water vapor, creating a certain humidity. The amount of water vapor , expressed in grams contained in a kilogram or in a cubic meter of air, is called absolute humidity.

An increase in the amount of water vapor at the same temperature can occur only up to a certain limit, after which the vapors begin to condense . Such a state, when the amount of water vapor (in grams) is able to saturate 1 kg or 1 m 3 of air at a given temperature to the limit, is called maximum humidity . The higher the air temperature, the more water vapor is needed to bring this air to maximum humidity. Therefore, the maximum air humidity at different temperatures , and for this value is constant at every temperature .

The most commonly used indicator for measuring air humidity is relative humidity , that is, the ratio of absolute humidity to the maximum saturated air to the limit at a given temperature, expressed as a percentage. So the relative humidity shows air saturation percentage water vapor at a given temperature.

In addition to the moisture content of the incoming outdoor air, inside the workshop there may be additional sources of moisture . These are mainly open technological processes, accompanied by the use of water or aqueous solutions, especially if these processes are heated. A certain part of the moisture is also released from the workers themselves during breathing and perspiration, but in practice this does not play a big role.

IN working conditions very different air humidity is observed - from 5-10 to 70-80%, in the presence of abundant moisture emissions (dye-bleaching shops of textile factories, washing departments of various industries, laundries) - sometimes up to 90-95%, and in the cold season - up to 100%, i.e. before fogging.

Microclimate the working environment affects the heat transfer process and the nature of the work. Prolonged exposure of a person to unfavorable meteorological conditions sharply worsens his state of health, reduces labor productivity and leads to diseases.

High temperature air contributes to rapid fatigue of the worker, can lead to overheating of the body, heat stroke or occupational disease. Low air temperature can cause local or general cooling of the body, cause colds or frostbite. High air temperature has an adverse effect on the vital organs and systems of a person (cardiovascular, central nervous system, digestive), causing disturbances in their normal activity, and under the most unfavorable conditions can cause serious diseases in the form of overheating of the body, called heat strokes in everyday life. .

Unlike high temperature infrared irradiation characterized primarily by local action, but also has a general effect on the body, which is in many ways similar to the effect of high temperature; in particular, when irradiated with infrared rays, an increase in body temperature, increased sweating, increased heart rate and increased gas exchange are observed; sometimes there is a decrease in blood pressure, increased respiration.

Ultra-violet rays different wavelengths have different effects on the human body. According to their biological activity, they can be divided into three sections:

with wavelengths over 315 µm that is, located on the border with visible rays, having little activity;

with wavelength from 280 to 315 µm that have a strong effect on the skin, causing dermatitis, swelling, burning, itching;

with a wavelength less than 280 µm - the most active, acting on tissue proteins and lipoids.

With direct contact with ultraviolet rays, especially small and medium wavelengths, they have an acute effect on the organ of vision, expressed in significant pain, burning, a feeling of sand in the eyes, photophobia, redness and swelling of the mucous membranes. All these phenomena are so-called electrophthalmia appear through 6-8 hours after exposure to ultraviolet rays and sometimes continue until two days .

Ultra-violet rays in certain, relatively small doses, they also have a positive effect on the body: they stimulate the hematopoietic functions of the body; the formation of vitamin D, improve metabolism, have bactericidal, immunizing properties. Due to these properties, ultraviolet radiation is widely used in medicine as a prophylactic and therapeutic agent, as well as a means of neutralizing the air environment and objects contaminated with microbes.

Humidity and air movement in combination with other factors, they have a significant impact on the human body, playing an important role in the thermoregulation of the body.

Air humidity has a significant effect on the thermoregulation of the human body. High relative humidity (the ratio of the content of water vapor in 1 m 3 of air to their maximum possible content in the same volume) at high air temperatures contributes to overheating of the body, with low At the same temperature, it enhances heat transfer from the surface of the skin, which leads to hypothermia of the body. Low humidity causes drying of the mucous membranes of the respiratory tract of the worker.

Air mobility effectively contributes to the heat transfer of the human body and is positively manifested at high temperatures, but negatively at low temperatures.

In Fig.1. the classification of industrial microclimate is given.

				Industrial microclimate
comfortable											with high humidity													variable
assembly shop operator rooms										at normal and low temperature						at elevated temperature								outdoor work
										electroplating shops						paint shops
		heating																cooling
	with a predominance of radiative heat								dominated by convection heat							with subisometric air temperature									with low air temperature
	rolling mills foundry workshops								turbine shops chemical shops							from +10°С to –10°С									below -10°С

Fig.1. Types of industrial microclimate

The subjective sensations of a person change depending on the change in the parameters of the microclimate (Table 1).

Table 1. Dependence of subjective feelings of a person on the parameters of the working environment

Air temperature, °С	Relative air humidity, %	Subjective sensations
		The most pleasant state. Good, calm condition. Fatigue, depression.
		No discomfort. Unpleasant sensations. Need for rest.
		Unpleasant sensations. Normal performance. Inability to do hard work. Increase in body temperature. Health hazard.

2. Systems for providing microclimate parameters and air composition: heating, ventilation, air conditioning; their structure and requirements for them.

Microclimate parameters in working rooms are normalized according to three main indicators: temperature, relative humidity and air mobility. These indicators are different for the warm and cold periods of the year, for different types of work performed in these premises (light, moderate and heavy). In addition, they are standardized upper And lower limits these indicators, which must be observed in any workroom, as well as optimal indicators that provide best conditions work.

Measures to ensure normal meteorological conditions in production, like many others, are complex. An important role in this complex is played by:

architectural and planning solutions for an industrial building,

rational construction of the technological process

proper use of technological equipment

the use of a number of sanitary devices and fixtures;

personal protection and personal hygiene measures

An effective means of ensuring proper cleanliness and acceptable parameters of the microclimate of the air in the working area is industrial ventilation .

ventilation called organized and regulated air exchange, which ensures the removal of polluted air from the room and the supply of fresh air in its place. According to the method of air movement, natural and mechanical ventilation systems are distinguished.

natural ventilation is called a ventilation system, the movement of air masses in which is carried out due to the resulting pressure difference outside and inside the building. Natural ventilation can be unorganized and organized.

Unorganized natural ventilation (infiltration, or natural ventilation) is carried out by changing the air in the premises through leaks in the fences and elements of building structures due to the difference in pressure outside and inside the premises.

Organized natural general exchange ventilation(aeration) is carried out as a result of the intake and removal of air through the opening transoms of windows and lanterns. As a method of ventilation, aeration has found wide application in industrial buildings characterized by technological processes with large heat releases (rolling shops, foundries, forges). The main advantage of aeration is the ability to carry out large air exchanges without the expenditure of mechanical energy. The disadvantages of aeration include the fact that during the warm period of the year, the efficiency of aeration can significantly decrease due to an increase in the temperature of the outside air and the fact that the air entering the room is not cleaned and cooled.

mechanical ventilation ventilation is called ventilation, with the help of which air is supplied to the production premises or removed from them through the systems of ventilation ducts using special mechanical stimulators for this.

Mechanical ventilation has a number of advantages compared to natural ventilation: a large radius of action due to the significant pressure created by the fan; the ability to change or maintain the necessary air exchange, regardless of the outdoor temperature and wind speed; subject the air introduced into the room to preliminary purification, drying or humidification, heating or cooling; organize optimal air distribution with air supply directly to workplaces; capture harmful emissions directly at the places of their formation and prevent their spread throughout the room, as well as the ability to purify polluted air before releasing it into the atmosphere. The disadvantages of mechanical ventilation include the significant cost of the structure and its operation and the need for measures to combat noise.

Mechanical ventilation systems are divided into general exchange, local, mixed, emergency and air conditioning systems.

General ventilation designed to assimilate excess heat, moisture and harmful substances in the entire volume of the working area of ​​the premises.

The serving temperature of cold sweet dishes should be 12-15°C, hot - 55, ice cream - 4-6°C.

The most common defects: taste and smell are weakly expressed (weak aroma of vanillin in milk jelly, taste and smell of berries, fruits, wine are not sufficiently pronounced). In compotes, fruits and berries should be whole, unboiled, the syrup should be transparent, the taste should be sweet or sweet and sour, the jelly should keep its shape well. The duration of storage of cold sweet dishes at a temperature of 2-6ºС compotes - 12 hours, jelly - 24 hours, creams, curds - 24 hours, whipped cream - 6 hours. Hot sweet dishes are stored chilled for 12 hours, hot for 2-3 hours.

Control questions:

1. The importance of sweet foods in nutrition and their classification.

2. Fresh and quick-frozen fruits and berries.

3. Compotes and fruits in syrup.

4. Jellied sweet dishes.

5. Characteristics of gelling agents.

6. Frozen sweet foods.

7. Requirements for the quality of sweet dishes.

Literature:

1. Hygiene requirements to expiration dates and storage conditions of foodstuffs. SanPiN 2.3.2.1324-03 - M., 2003.

2. Technology of catering products. In 2-ht. T.2. Technology of dishes, snacks, drinks, flour culinary confectionery and bakery products / A.S. Ratushny, B.A. Baranov, N.I. Kovalev and others; Ed. doctor of technical sciences, prof. A.S. Town Hall. - M.: Mir, 2004. - 416 pp.: ill. (Textbooks and teaching aids for students of higher educational institutions).

3. Technology of catering products: a teaching aid for students of the specialty 260501 "Technology of catering products" / Comp. Ph.D. O.V. Pasko-Omsk: Ed. Omsk Economic Institute, 2005. - 120 p.

Microclimate. Rationing, control and systems for ensuring microclimate parameters.

1. Classification of the main forms of human activity.

Human activity is of the most diverse nature, but three main groups of forms of activity can be distinguished: physical labor, intellectual activity (mental labor), operator activity.

A. Physical work- this is the fulfillment by a person of energy functions in the system "Man - an instrument of labor."

Physical work requires significant muscle activity and is divided into two types: dynamic and static.

In dynamic activity, three types of physical work are distinguished: general- when more than 2/3 of the human muscles are involved; regional- from 2/3 to 1/3 of the muscles (only the muscles of the body, legs, arms) and local- less than 1/3 of the muscles are involved (more precisely, mechanical engineering, instrumentation, working with a computer, etc.).

Physical work is determined by energy costs in the process labor activity and is divided into the following three categories: light, moderate and heavy physical work.

Ia - work performed while sitting and accompanied by minor physical effort. Level of energy costs- up to 139 W.

I b - work performed while sitting, standing, or associated with walking, accompanied by minor physical effort.

II a - work associated with walking, moving heavy loads or applying efforts up to 1 kg. Energy costs- 140-174 watts.

II b - work associated with walking, moving heavy objects or applying efforts up to 10 kg. Energy costs- 175-290 W.

B. Mechanized forms of physical labor in the "Man-machine" system refer to operator activities. In this case, a person performs both mental and physical work. These activities include the following activities:

Operator-technologist- is included directly in the technological process, performs mainly performing actions) regulated by technological instructions, containing, as a rule, a fairly complete set of situations and decisions.

manipulator operator) - among the functions performed by him are J control of individual machines and mechanisms "])

Operator-observer (manager of a production line, transport system, etc.).

The operator in this case works both in the mode of immediate and deferred maintenance in real time.

This activity largely uses the thinking and experience embedded in figurative-conceptual models. Physical work plays an insignificant role here.

IN. Mental labor (intellectual activity).

This work is related with the reception and processing of information that requires a predominant tension of attention, sensory (sensory) apparatus, memory, as well as the activation of thinking processes, the emotional sphere (Management, creativity, teaching, science, study, etc.).

Operator labor- is characterized by great responsibility and high neuro-emotional stress.

managerial labor- is determined by an excessive increase in the volume of information, an increase in the lack of time for its processing, increased personal responsibility for decision-making, the emergence of conflict situations.

creative work- requires a significant amount of memory, tension of attention, neuro-emotional stress.

Teacher's work- constant contact with people, increased responsibility, lack of time and information for decision-making, neuro-emotional stress.

Work of a student (student)- memory, attention, perception, lack of time, stressful situations.

With intensive intellectual activity, the energy consumption of the brain rises to 15-20% of the total energy consumption in the body.

Daily energy consumption during mental work is 10.5-12.5 MJ. When reading a lecture, it increases by 94%.

At the end of mental work, fatigue remains longer than during physical work.

2. Normalization of microclimate parameters.

A necessary condition for effective human production is to ensure normal meteorological conditions in the premises (microclimate).

Microclimate- a complex of physical factors that affect the heat exchange of a person with the environment, his thermal state and determining well-being, working capacity, health and labor productivity. The formation of the microclimate is influenced by the technological process, the climate of the area, the season of the year, the conditions of heating and ventilation.

Indicators characterizing the microclimate in industrial premises are:

— air temperature, °C;

— temperature of enclosing surfaces (walls, floor, ceiling, equipment), °С;

- relative humidity, %;

— speed of air movement, m/s;

- intensity of thermal radiation, W / m 2.

If the work is done outdoors, then the meteorological conditions are determined by the climatic zone and the season of the year.

2.1 Physiological effects of weather conditions on a person

All life processes in the human body are accompanied by a continuous release of heat into the environment, the amount of which varies from 85 W (at rest) to 500 W (during hard work).

The heat balance equation "Man - environment" was first proposed prof. I. I. Flavitsky in 1884.

Q people \u003d Q conv. + Q temp. + Q izd. + Q isp. + Q resp.

where: Q people - heat emitted by a person (heat production);

Q conv. — heat transfer by convection;

Q temp. -heat transfer due to heat conduction through clothing;

Q izd. — heat transfer by radiation;

Q isp. - heat transfer through the evaporation of moisture (sweat);

Q breath. - heat transfer through heating of the exhaled air.

At a temperature of about 20 ° C, when a person does not experience any unpleasant sensations associated with the microclimate, heat transfer is: radiation - 50-65%, evaporation - 20-25%, convection - 15-20 (25)%.

Heat transfer by radiation in production conditions is one of the main ways of heat exchange between a person and the environment. However, this heat transfer path operates only under conditions when the temperature of the surrounding surfaces (walls, ceiling, floor, equipment surfaces) is lower than the temperature of the human body surface (31-32 ° C). In cases where the temperature of the surrounding surfaces is higher than the surface temperature of the human body, heat is perceived, i.e. body heating.

With an increase in the temperature of the air and surrounding surfaces over 31 ° C, the main way of heat transfer by the body is evaporation. Evaporation occurs from the surface of the skin, and evaporation through the respiratory tract is only 10-20%.

Under normal conditions, a person loses up to 1 liter of fluid (water). When 1 g of water evaporates, the body releases 2.5 kJ of heat. With heavy physical work and air temperature above 30 ° C, the amount of fluid lost by the body is 10-12 liters.

The torrential flow of sweat stops the release of heat from the body through the evaporation of sweat and there is a possibility of overheating of the body and heat stroke.

Neutral microclimate- such a combination of microclimate parameters, which, when exposed to work shift ensures the heat balance of the human body, when the difference between the value of heat production and total heat transfer is within ± 2 W (J/s), and the proportion of heat transfer by moisture evaporation does not exceed 30%.

Cooling microclimate- this is a combination of microclimate parameters that cause an excess of total heat transfer to the environment by more than 2 W.

Heating microclimate- a combination of microclimate parameters, which
leads to the accumulation of heat in the body with an intensity of more than 2 W (more than 2 J / s)
or to an increase in heat loss by evaporation of moisture (more than 30%).

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