See what the "microclimate of industrial premises" is in other dictionaries. b) stability of clear vision. a) pale skin and mucous membranes
No matter how high breed and breeding qualities animals possess, bad hygiene conditions prevent them from realizing their genetic potential. The unsatisfactory state of the air environment leads to high morbidity. Therefore, the creation of an optimal microclimate in livestock buildings is a very important task.
Under the microclimate of the room is understood the climate of a limited space, which is a combination of the following environmental parameters: temperature, humidity, air velocity, illumination, noise, air ions, ammonia, carbon dioxide, hydrogen sulfide, other gases, as well as suspended dust particles and microorganisms in the air . These parameters have a significant impact on the physiological processes in the body of animals, on their health and productivity.
The first important factor after feeding, which has a significant impact on the body of animals, is the ambient temperature. Air temperature is the main physical irritant of the body, affecting its heat transfer. Any decrease in air temperature below the critical one leads to an increase in metabolism and heat production in the body of animals, to overspending of feed. If compensation for losses is impossible or untimely, then there will be a decrease in productivity. When keeping livestock in rooms with an air temperature below 5 degrees Celsius, milk yield decreases by 1 - 2 liters from each cow, weight gain of calves decreases by 15 - 20%, egg production of chickens decreases by 12 - 19%. Young animals are most sensitive to low temperatures. So, in newborn piglets, subcutaneous fat is almost absent and physical thermoregulation is poorly developed. Therefore, they are practically unable to retain the heat generated in the body as a result of the metabolic process. In addition, they have large surface per unit mass of heat, and their heat transfer is much higher than that of adult animals. The mechanism of physical thermoregulation in piglets and calves begins to function from 6-10 days after birth, and is actively included in the process only after 10-12 days in calves and after 30 days in piglets. Therefore, in the first 10 days of life, up to 80% of sick young animals die, and about 26% of pathologies are due to non-contagious colds.
Optimum temperature for cows 8 - 12 degrees of heat, for calves up to 20 days of age 16 - 20 degrees.
The hygienic value of air humidity is exceptionally high. Humidity largely determines the climate and microclimate of the environment. The heat capacity of moist air is 10 times greater than that of dry air. With an increase in air humidity in barns from 85% to 95%, milk yield decreases by 9 - 12%. The cost of feed in buildings for fattening livestock and pigs under such conditions increases by 20–25% with a decrease in the average daily weight gain of animals by 12–28%, and the mortality of young animals increases by 2–3 times.
Optimal Humidity in rooms for animals 50 - 75%.
Air temperature is closely related to such a factor as air movement, as it has a significant impact on the heat transfer of the animal organism, ventilation and heat preservation in the premises. The most insignificant speeds of air movement can have a noticeable cooling effect on the skin of animals. An increase in air velocity from 0.1 to 0.4 m/s is equivalent to a decrease in temperature by 5 degrees.
Zoohygienic standards provide for the maintenance of minimum air velocities for young animals in the premises of 0.02 - 0.03 m / s.
Light, as an active physiological stimulus of the body, by its intensity, duration of exposure and spectral composition, changes the metabolism of proteins, fats, carbohydrates, minerals and energy in general, which is reflected in the physiological state and productivity of animals. Keeping animals for a long time in conditions of low light and short daylight hours inhibits protein synthesis, as a result, its deposition in tissues and organs is disturbed, and the growth and development of animals is delayed.
The lack of light reduces the body's need for energy to maintain oxidative processes at a high level, causes the deposition of fat in the muscles and on internal organs. Gilts kept in a bright room absorbed 25% more calcium and 15% more phosphorus from the diet than in a dark room, and 3.6% more of these substances are deposited in the bones. The lack of light, on the contrary, leads to a decrease in the deposition of minerals in the skeleton and to a pathological change in bone tissue. Light contributes to the formation of animals with a strong constitution and strong bones.
According to zoohygienic requirements, the illumination in the area for cows should be 75 lux (with a duration of 14 hours a day), calves - 100 (12 hours), sows, boars and replacement young animals - 100 (12 hours), fattening pigs 50 lux (8 - 10 hours).
The foregoing allows us to conclude that the costs of improving the microclimate are economically justified.
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[Enter text]
Non-state educational institution higher professional education
"WEST URAL INSTITUTE OF ECONOMICS AND LAW"
(NOU VPO ZUIEP)
Faculty of Management
Direction "Management"
Department of Entrepreneurship and Management
Referat
discipline: Fundamentals of labor safety
Topic: "Indoor microclimate"
Perm, 2015
Introduction
1. Industrial microclimate: concept, classification
2. Microclimate parameters, impact on human organism
3. Regulation of the microclimate
4. Systems for ensuring microclimate parameters
Conclusion
Bibliography
ApplicationsI
Introduction
The state of human health, its performance largely depends on the microclimate in the workplace.
Weather conditions, or microclimate, depend on the thermophysical features of the technological process, climate, season of the year, heating and ventilation conditions. The microclimate, having a direct impact on one of the most important physiological processes - thermoregulation, is of great importance to maintain comfortable state organism.
The conditions in which a person works affect the results of production - labor productivity, quality and cost of products.
Labor productivity is increased by maintaining human health, increasing the level of use of working time, extending the period of active labor activity person.
One of necessary conditions healthy and highly productive work is to ensure an optimal microclimate.
The aim of the work is to study the parameters of the microclimate production environment.
To achieve this goal, it is necessary to solve the following tasks:
Define the working climate, classify it;
Consider microclimate parameters and their impact on the human body;
Show systems for providing microclimate parameters.
1. Industrial microclimate: concept, classification
In the process of labor in the production premises, a person is influenced by certain meteorological conditions, or microclimate - the climate of the internal environment of these premises.
Microclimate industrial premises- this is the climate of the internal environment of these premises, which is determined by the combinations of temperature, humidity and air velocity acting on the human body, as well as the temperature of the surrounding surfaces.
Figure 1 shows the classification of the industrial microclimate (see Appendix).
Regulated (features and quality of construction of buildings and structures, the intensity of thermal radiation from heating devices, the frequency of air exchange, the number of people and animals in the room, etc.). To maintain the parameters of the air environment of working areas within the limits of hygienic standards, factors of the second group are of decisive importance.
Uncomfortable microclimate causes tension in the processes of thermoregulation, poor heat sensation occurs, conditioned reflex activity and the function of analyzers deteriorate, efficiency and quality of work decrease, and the body's resistance to adverse factors decreases. Discomfort microclimate can be overheating (hyperthermia) and cooling (hypothermia).
Consequences of exposure to dis comfortable microclimate on the body are presented in table 1. (see Appendix).
2. Microclimate parameters, impact on the human body
To the main normalized indicators of air microclimate working area include temperature, relative humidity, and air velocity. (Fig. 2, see appendix).
Significant impact on microclimate parameters and condition human body also exerts the intensity of thermal radiation of various heated surfaces, the temperature of which exceeds the temperature in the production room.
The meteorological conditions of the working environment (microclimate) affect the process of heat transfer 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.
Proper thermoregulation in the body can only be carried out under a certain state of the external environment, i.e. under certain combinations of temperature, humidity and air velocity. In a person who is at rest and stays in conditions of meteorological comfort (temperature 18º-20ºC); relative humidity 40-60%; air speed 0.2-0.3 m/s, heat transfer is not carried out to the same extent:
Radiation (heating at a distance of objects having a lower temperature ~ 45%;
Convection (heat conduction) for heating clothes and air layers adjacent to the body ~ 30%;
Evaporation of sweat and evaporation of moisture from the surface of the skin and lungs ~ 25%.
As the temperature increases, the proportion of heat given off by radiation and convection decreases, and at a temperature of 30°C it is practically equal to zero. At this temperature, the main (and sometimes the only) source of human heat loss is sweating. It must be borne in mind that heat is released only when sweat evaporates from the surface of the skin, since about 2500 J of heat is spent on the evaporation of 1 g of sweat, and if the sweat flows in drops, then sweating has little effect on heat transfer.
The higher the relative humidity of the air, the more difficult it is for evaporation from the skin surface. Therefore, high air temperatures are much easier to tolerate in dry air than in humid air. High humidity (70-75% or more) at high temperatures ah (25-30 ° C and more) contributes to overheating of the body.
An important factor for thermoregulation of the body is the speed of air movement, which contributes to an increase in heat transfer from the surface of the body by convection, since in this case the layers of air adjacent to the skin are blown away and replaced by colder ones. Naturally, this circumstance will take place only at air temperatures up to 30-36 ° C, and at a higher temperature, air flows do not cool the skin and only contribute to perspiration. The movement of air at low temperatures is extremely undesirable due to a sharp increase in heat transfer due to convection.
Thus, weather conditions are determined by a combination of temperature, humidity, air velocity and thermal radiation. Depending on the significance of these physical factors of the atmosphere, each of which can vary widely, the well-being of a person and his performance can be different.
The researchers found that at an air temperature of more than 30ºC, a person's performance begins to fall. For a person, maximum temperatures are determined depending on the duration of their exposure and the means of protection used. The maximum temperature of inhaled air at which a person is able to breathe for several minutes without special protective equipment is about 116 ° C.
Figure 3 shows indicative data on the tolerance of temperatures in excess of 60°C. Temperature uniformity is essential. Its vertical gradient should not go beyond 5°C. (fig.3, see appendix)
A person's tolerance for temperature, as well as his sense of heat, largely depends on the humidity and speed of the surrounding air. A particularly adverse effect on the thermal well-being of a person is exerted by high humidity at tос 300С, since in this case almost all of the heat released is given off to environment when sweat evaporates. There is a so-called "torrential" flow of sweat, exhausting the body and not providing the necessary heat transfer.
Insufficient air humidity can also be unfavorable for humans due to intensive evaporation of moisture from the mucous membranes, their drying and cracking, and then contamination by pathogens. Therefore, when people stay indoors for a long time, it is recommended to limit the relative humidity in the range of 30-70%.
Contrary to the established opinion, the amount of perspiration depends little on the lack of water in the body or on its excessive consumption. A person working for 3 hours without fluid intake produces only 8% less sweat than with full replacement of lost moisture. When moisture evaporates, the weight of a person also decreases. It is considered acceptable for a person to reduce his body weight by 2-3% by evaporation of moisture (dehydration of the body). Dehydration by 6% entails a violation of mental activity, a decrease in visual acuity; evaporation of moisture by 15-20% leads to death.
Together with sweat, the body loses a significant amount of mineral salts (up to 1%, including 0.4-0.6% NaCl). Under adverse conditions, fluid loss can reach 8-10 liters per work shift, and it contains up to 60 g of table salt (in total, about 140 g of NaCl in the human body). The loss of salt deprives the blood of its ability to retain water and leads to impaired functioning. of cardio-vascular system. At high air temperatures, carbohydrates, fats are easily consumed, and proteins are destroyed.
To restore the water balance, people working in hot shops are installing vending machines with salted (about 0.5% NaCl) carbonated drinking water at the rate of 4-5 liters per person per shift. At a number of factories, a protein-vitamin drink is used for these purposes. In hot climates, it is recommended to drink chilled drinking water or tea.
Prolonged exposure of a person to high temperature, especially in combination with high humidity, can lead to a significant accumulation of heat in the body and the development of its overheating above the permissible level - hyperthermia - a condition in which body temperature rises to 38-39 ° C. Hyperthermia and, as a result, heat stroke are accompanied by headache, dizziness, general weakness, distortion of color perception, dry mouth, nausea, vomiting, and profuse sweating. The pulse and respiration become more frequent, the content of nitrogen and lactic acid in the blood increases. In this case, pallor, cyanosis, dilated pupils are observed, at times convulsions and loss of consciousness occur.
Production processes performed at low temperatures, high air mobility and humidity can cause cooling and even hypothermia of the body - hypothermia. In the initial period of exposure to moderate cold on a person, there is a decrease in the frequency of breathing and an increase in the volume of inhalation. With prolonged exposure to cold, breathing becomes irregular, the frequency and volume of inspiration increase, change carbohydrate metabolism. The increase in metabolic processes with an increase in temperature by 1°C is about 10%, and with intensive cooling it can increase by 3 times compared with the level of basal metabolism. The result of the action of low temperatures are cold injuries.
Microclimate parameters have a significant impact on labor productivity. Thus, an increase in temperature from 25 to 30°C in the spinning shop of the Ivanovo worsted mill led to a decrease in labor productivity by 7%.
In hot shops of industrial enterprises, most technological processes take place at temperatures that are significantly higher than the ambient air temperature. Heated surfaces emit streams of radiant energy into space, which can lead to negative consequences. At temperatures up to 500 ° C, thermal (infrared) rays with a wavelength of 0.74 ... 0.76 μm are emitted from the heated surface, and at higher temperatures, along with an increase in infrared radiation, visible light and ultraviolet rays appear.
Infrared rays have an effect on the human body mainly thermal effect. Under the influence of thermal irradiation, biochemical changes occur in the body, oxygen saturation of the blood decreases, blood pressure decreases, blood flow slows down and, as a result, the activity of the cardiovascular and nervous systems is disturbed.
According to the nature of the impact on the human body, infrared rays are divided into short-wave with a wavelength of 0.76 ... 1.5 microns and long-wave with a wavelength of more than 1.5 microns. Thermal radiation of the short-wave range penetrates deeply into the tissues and heats them up, causing rapid fatigue, decreased attention, increased sweating, and with prolonged exposure - heat stroke. Long-wave rays do not penetrate deep into the tissues and are absorbed mainly in the epidermis of the skin. They can cause skin and eye burns. The most common and severe eye damage due to exposure to infrared rays is the cataract of the eye.
In addition to direct impact on a person, radiant heat heats the surrounding structures. These secondary sources give off heat to the environment by radiation and convection, as a result of which the air temperature inside the room rises.
Irradiation of the body with small doses of radiant heat is useful, but a significant intensity of thermal radiation and high air temperature can have an adverse effect on a person. Thermal irradiation with an intensity of up to 350 W / m2 does not cause an unpleasant sensation, at 1050 W / m2 after 3 ... 5 minutes an unpleasant burning sensation appears on the skin surface (skin temperature rises by 8 ... 10 ° C), and at 3500 W /m2 can cause burns after a few seconds. When irradiated with an intensity of 700 ... 1400 W / m2, the pulse rate increases by 5 ... 7 beats per minute. The time spent in the zone of thermal irradiation is limited primarily by the temperature of the skin, the pain sensation appears at a skin temperature of 40 ... 45 ° C (depending on the area).
The intensity of thermal exposure at individual workplaces can be significant.
Atmospheric pressure has a significant impact on the process of breathing and human well-being. If a person can live without water and food for several days, then without oxygen - only a few minutes. The main human respiratory organ, through which gas exchange with the environment (mainly O2 and CO2) is carried out, is the tracheobronchial tree and a large number of pulmonary vesicles (alveoli), the walls of which are penetrated by a dense network of capillary vessels. The total surface of the alveoli of an adult is 90 ... 150 m2. Through the walls of the alveoli, oxygen enters the bloodstream to nourish body tissues.
Excessive air pressure leads to an increase in the partial pressure in the alveolar air, a decrease in lung volume and an increase in the strength of the respiratory muscles necessary for inhalation-exhalation. In this regard, work at depth requires maintaining high blood pressure with the help of special equipment or equipment, in particular xenons or diving equipment.
When working under conditions of overpressure, the indicators of lung ventilation decrease due to some decrease in the respiratory rate and pulse. Prolonged exposure to excess pressure leads to the toxic effect of some gases that make up the inhaled air. It manifests itself in impaired coordination of movements, agitation or depression, hallucinations, memory loss, impaired vision and hearing.
The most dangerous period of decompression, during which and shortly after exit under conditions of normal atmospheric pressure, decompression (caisson) sickness can develop. Its essence lies in the fact that during the period of decompression and stay at elevated atmospheric pressure, it is saturated with nitrogen through the blood. Complete saturation of the body with nitrogen occurs after 4 hours of exposure to high pressure.
3. Rationing the microclimate
The industrial microclimate standards are established by the labor safety system GOST 12.1.005-88, as well as SanPiN 2.2.4.548-96.
According to the degree of influence on the well-being of a person, his performance, microclimatic conditions are divided into optimal, permissible, harmful and dangerous.
Optimal microclimatic conditions are characterized by such parameters of microclimate indicators that, with their combined effect on a person during a work shift, ensure the preservation of the thermal state of the body. Under these conditions, the thermoregulation stress is minimal, there are no general and/or local uncomfortable heat sensations, which is a prerequisite for maintaining high performance. AT optimal microclimate the optimal thermal state of the human body is ensured.
Permissible microclimatic conditions are characterized by such parameters of microclimate indicators, which, with their combined effect on a person during a work shift, can cause a change in the thermal state. This leads to a moderate tension of thermoregulation mechanisms, slight uncomfortable general and/or local heat sensations. At the same time, relative thermal stability is preserved, there may be a temporary (during the work shift) decrease in working capacity, but health is not disturbed (during the entire period of labor activity). Such parameters of the microclimate are acceptable, which, when they act together on a person, provide an acceptable thermal state of the body.
Harmful microclimatic conditions are microclimate parameters that, when combined with their impact on a person during a work shift, cause changes in the thermal state of the body: pronounced general and / or local uncomfortable heat sensations, significant stress on thermoregulation mechanisms, and decreased performance. At the same time, the thermal stability of the human body and the preservation of its health during the period of labor activity and after its completion are not guaranteed. At the same time, the degree of harmfulness of the microclimate is determined both by the magnitude of its components and the duration of their impact on workers (continuously and in total for the work shift, for the period of labor activity).
Extreme (dangerous) microclimatic conditions are microclimate parameters that, when combined with a person, even for a short time (less than 1 hour), cause a change in the thermal state, characterized by excessive stress on the mechanisms of thermoregulation, which can lead to a violation of the state of health and the risk of death.
The characteristics of individual categories of work are given below.
Category IIa includes work with an intensity of energy consumption of 175-232 W, associated with constant walking, moving small (up to 1 kg) products or objects in a standing or sitting position and requiring a certain physical effort.
Category IIb includes work with an intensity of energy consumption of 233-290 W, associated with walking, moving and carrying loads up to 10 kg and accompanied by moderate physical effort.
Category III includes work with an energy intensity of more than 290 W, associated with constant movement, moving and carrying significant (over 10 kg) weights and requiring great physical effort.
With a long and systematic stay of a person in optimal microclimatic conditions, the normal functional and thermal state of the body is maintained without straining the mechanisms of thermoregulation. At the same time, thermal comfort is felt (a state of satisfaction with the external environment), a high level of performance is ensured. Such conditions are preferred in the workplace.
Permissible microclimatic conditions with prolonged and systematic exposure to a person can cause transient and rapidly normalizing changes in the functional and thermal state of the body and tension in the mechanisms of thermoregulation that do not go beyond the limits of physiological adaptive capabilities. At the same time, the state of health is not disturbed, but uncomfortable heat sensations, deterioration of well-being and decreased performance are possible.
Table 2 shows that the parameters of the microclimate of industrial premises depend on the severity of the work performed and the period of the year (the period of the year with an average daily outdoor temperature above 10 ° C is considered warm, and cold - with a temperature of 10 ° C and below). (table 2, see appendix)
Optimal microclimate parameters apply to the entire working area of industrial premises without dividing jobs into permanent and non-permanent.
If, due to technological requirements, technically and economically justified reasons, the optimal microclimate parameters cannot be provided, then the limits of their permissible values are set. When determining the characteristics of the premises according to the category of work performed (the level of energy consumption), they are guided by those that are performed by 50% (or more) of the workers. Providing comfortable working conditions improves the quality and productivity of labor, ensures good health and the best environmental parameters and characteristics of the labor process for maintaining health.
industrial microclimate ventilation aeration
4. Systems for ensuring microclimate parameters
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.
Aeration - organized natural ventilation premises through transoms, vents, windows.
Mechanical ventilation is such ventilation in which air is supplied (supply) or removed (exhaust) using special devices - compressors, pumps, etc. There are general exchange ventilation (for the entire room) and local ventilation (for certain workplaces). With mechanical ventilation, the air can first pass through the filter system, be cleaned, and harmful impurities can be trapped in the exhaust air. The disadvantage of mechanical ventilation is the noise it creates. The most advanced type of industrial ventilation is air conditioning.
Air conditioning - artificial automatic air processing 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 resistant, helmets, felt helmets, goggles, masks with a screen, etc.
Measures to prevent the adverse effects of cold should include the prevention of cooling of industrial premises, the use of personal protective equipment, selection rational regime labor and rest.
Conclusion
Meteorological parameters such as temperature, air velocity and relative humidity determine the heat exchange of a person with the environment and, consequently, the well-being of a person. The combination of these parameters is called the microclimate.
Prolonged exposure of a person to unfavorable meteorological conditions sharply worsens his state of health, reduces labor productivity and leads to diseases.
Factors affecting the microclimate can be divided into two groups:
Unregulated (a complex of climate-forming factors of a given area);
Adjustable (features and quality of construction of buildings and structures, intensity of thermal radiation from heating
According to the degree of influence on the well-being of a person, his performance, microclimatic conditions are divided into optimal, permissible, harmful and dangerous. Rationing of the microclimate of industrial premises is carried out in accordance with San-PiN 2.2.4.548-96.
To create normal working conditions in industrial premises, the normative values of the microclimate parameters, air temperature, its relative humidity and speed of movement, as well as the intensity of thermal radiation.
The main method of ensuring the required parameters of the microclimate and the composition of the air environment is the use of ventilation, heating and air conditioning systems.
Not being able to effectively influence the climate-forming processes occurring in the atmosphere, people have quality systems management of factors of the air environment in production rooms.
Bibliography
1. Life safety. Safety of technological processes and production (Labor protection). / P.P. Kukin, V.L. Lapin, N.L. Ponomarev and others - M .: Higher. school, 2012. - 335 p.
2. Devisilov V.A. Occupational Safety and Health. - M.: FORUM, 2009. - 496 p.
3. Zotov B.I. Life safety at work. - M.: KolosS, 2009. - 432 p.
4. Sergeev V.S. Life safety. - M.: OJSC "Publishing House" Gorodets ", 2013. - 416 p.
5. Frolov A.V. Life safety. Occupational Safety and Health. - Rostov n / D .: Phoenix, 2010. - 736 p.
6. Hwang T.A., Hwang P.A. Life safety. - Rostov n / a: "Phoenix", 2010. - 416 p.
ApplicationsI
Figure 1 - Types of industrial microclimate
Figure 2 - Parameters of human heat exchange with the environment
Figure 3 - Tolerance to high temperatures by a person, depending on the duration of their exposure: 1 - the upper limit of endurance; 2 - average endurance time; 3 - the border of the appearance of symptoms of overheating
Table 1 - Consequences of exposure to uncomfortable microclimate on the body
|
Uncomfortable climate |
chronic hyperthermia |
acute local hypothermia |
acute general hypothermia |
chronic hypothermia |
|
|
acute hyperthermia |
Almost all physiological systems are affected: 1. On the part of digestion - loss of appetite, decreased gastric secretion, gastritis, enteritis, colitis. 2. From the side of the cardiovascular system - vasodilation, increased heart rate, malnutrition of the heart muscle. 3. On the part of the kidneys, nephrolithiasis most often occurs or worsens. 4. From the side of the central nervous system - fatigue, neurosis, decreased attention, traumatism |
1. Frostbite 2. Neuralgia, myositis. 3.Colds, sore throats, inflammation of the kidneys, inflammation of the middle ear |
1. Generalized hypothermia (freezing) 2. Reduced immunity to infectious diseases. 3. Allergic diseases, because. during hypothermia, histamine-like substances are formed. 4. Decrease in efficiency, attention, increase in the frequency of accidents |
Decrease in efficiency, decrease in the body's resistance to adverse factors |
Table 2 - Optimal values microclimate parameters at workplaces of industrial premises at relative air humidity in the range of 40 ... 60%
|
Period of the year |
Air temperature, °С |
Surface temperature, °С |
Air speed, m/s |
||
|
Cold |
|||||
|
IIa (175. ..232) |
|||||
|
IIb (233. ..290) |
|||||
|
III (more than 290) |
|||||
|
IIa (175.. .232) |
|||||
|
IIb (233. ..290) |
|||||
|
III (more than 290) |
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TOPIC 1. HYGIENIC ASSESSMENT OF THE MICROCLIMATE
TOPIC 1. HYGIENIC ASSESSMENT OF THE MICROCLIMATE
Purpose of the lesson:study of the influence of microclimatic factors on the human body, measurement of microclimate parameters, hygienic assessment of individual indicators and the microclimate as a whole.
In preparation for the lesson, students should work on the following theory questions.
1. Weather, climate, microclimate.
2. Physical properties of air, their hygienic significance.
3. Comprehensive impact of meteorological environmental factors on the body, its assessment. Heat exchange of the body with the environment. Thermal Load Index (THS).
4. Hygienic standards for the microclimate of premises for various purposes.
After mastering the topic the student must know:
Methodology for determining and assessing the microclimate of pharmacy premises;
Determination and assessment of the complex impact of meteorological environmental factors on the body of workers;
be able to:
Evaluate the results of studies for compliance with hygienic standards;
Assess the working conditions of pharmacy personnel in terms of microclimate parameters;
Use basic regulations and information sources of a reference nature for the development of hygienic recommendations for improving the microclimate of pharmacy premises.
Training material for the assignment
The atmosphere has a multilayer structure. Adjacent to the earth's surface troposphere- the densest layer of air ranging in size from 8 to 18 km in different latitudes. The troposphere is characterized by the instability of physical properties (fluctuations in temperature, humidity, atmospheric pressure), the presence of water vapor, a large number dust, soot, various toxic substances, gases, microorganisms. It is constantly moving air masses in different directions. Above the troposphere is stratosphere- a layer of air up to 40-60 km in size, characterized by rarefied air. Under the influence of cosmic and short-wave ultraviolet radiation of the Sun, as a result of the ionization of air gas molecules, especially oxygen, ozone molecules are formed in the stratosphere, which make up the ozone layer of the atmosphere. The ozone layer delays short-wave UV radiation, which, reaching the Earth's surface, can cause a variety of negative effects in the biosphere, and increase the level of cancer in the human population. An even more rarefied layer of air extends over the stratosphere up to 80 km in size - mesosphere, the above follows thermosphere- layer of the atmosphere up to 300 km high, the temperature in which reaches 1500? Behind her is ionosphere- a layer of ionized air, the size of which, depending on the time of year and day, is 500-1000 km. Still higher are sequentially placed exosphere(up to 3000 km), the density of which almost does not differ from the density of airless outer space, and the upper boundary of the Earth's atmosphere - magnetosphere(from 3000 to 50000 km), which includes radiation belts.
In recent decades, biological activity has been established permanent geomagnetic field (GMF) of the Earth. Changes (or pulsations) of the geomagnetic field are usually divided into regular, stable, continuous (Pc - pulsations continues), which are recorded in the morning and afternoon hours, and irregular, noise-like, impulsive (Pi - irregular pulsations), which are noted in the evening and night hours . All kinds of irregular pulsations are signs of geomagnetic disturbances, while regular pulsations are also observed in very calm conditions. The Earth's geomagnetic field is an essential component of the human environment. If the mode of stable oscillations
banium is “usual” for biosystems, then isolation from it can have negative consequences for the body. As a result of the penetration into the atmosphere of a stream of charged particles flying at great speed from the Sun (the so-called solar wind), which are formed during periods of increased solar activity, GMF disturbances arise, which are expressed in the global excitation of ordinary pulsations of its intensity (geomagnetic storms) recorded throughout the earth. ball for tens of hours. The formation of the natural electromagnetic background of the Earth includes global and local thunderstorm activity. Magnetoreceptors in humans are located in the structures of the brain and in the adrenal glands. Geomagnetic disturbances can have a desynchronizing effect on biological rhythms and other processes in the body, contribute to an increase in the number of myocardial infarctions and strokes, as well as the number of traffic accidents and aircraft accidents. However, long-term stay of people in shielded rooms in conditions of deficiency of natural GMF causes a deterioration in their well-being and health. GMF deficiency entails disorders of the central nervous system: an imbalance of the main nervous processes in the form of a predominance of inhibition, deterioration in coordination of movements and a decrease in the level of attention, a decrease in the speed of motor reactions to light and sound stimuli. There may be disorders of the cardiovascular system, immune and endocrine systems. A person gets into hypogeomagnetic conditions in residential high-rise buildings, built of reinforced concrete structures, in subway cars, salons cars, in the premises of aircraft, ships, submarines, in bank vaults.
From a hygienic point of view, the air environment is not homogeneous. Given the diversity physical properties and harmful impurities, as well as the conditions for the formation and pollution of air, there are several categories of the air environment: atmospheric air, air of residential and public buildings and industrial air.
Characteristics of meteorological factors
The physical properties of atmospheric air are unstable and are associated with the climatic features of the geographical region. Weather is a set of physical properties of the near-Earth layer
atmosphere (barometric pressure, temperature, humidity, wind speed and direction, solar radiation) over a specific area for a certain period of time.
The complex characteristic of the weather is called weather type. From a hygienic point of view (impact on human health), it is convenient clinical classification of weather types.
1. Clinically optimal the type of weather has a favorable, sparing effect on the human body, causes a cheerful mood - this is weather with relatively even meteorological properties: moderately humid or dry, quiet (wind speed not higher than 3 m / s), clear (sunny), day-to-day temperature fluctuations air do not exceed 2? C, atmospheric pressure - 3 mm Hg.
2. Clinically annoying type of weather - weather with a violation of the optimal level of one or more meteorological parameters: this weather is sunny and cloudy, dry and humid (not higher than 90% relative humidity), daily fluctuations in air temperature do not exceed 4 ° C, atmospheric pressure - 6 mm Hg ., wind speed not more than 9 m/s.
3. Clinically the acute type of weather is characterized by abrupt changes in meteorological parameters: it is damp weather (above 90% relative humidity), rainy, cloudy and very windy (wind speed over 9 m/s), daily fluctuations in air temperature exceed 4 °C, atmospheric pressure - more than 6 mmHg.
Weather changes can occur gradually (periodically) or abruptly (aperiodically) over a certain period (day, week). Unlike periodic weather changes, sharp fluctuations in meteorological stimuli (movement of air masses, barometric pressure, temperature, etc.) are unexpected for the organism. They create an increased load on the regulatory apparatus of the human body, causing an overstrain of the physiological adaptation mechanisms, which leads to various violations of the body's functions. (heliometeotropic reactions) in weather-sensitive (or weather-labile) people. Often this manifests itself in a decrease in working capacity, rapid fatigue and a deterioration in well-being: sleep disturbance, headaches, dizziness, tinnitus, pain in the heart, legs, arms, pain in closed body cavities (joints,
tooth cavities). Heliometeotropic reactions can be considered as a clinical syndrome of maladjustment, i.e. meteoneurosis of maladaptive origin. This reduces the sensitivity to drugs, which can lead to their overdose. At present, the negative impact of adverse weather on the course of diseases of the cardiovascular, respiratory, digestive and nervous systems, skin and eye diseases, as well as the growth of injuries, car accidents, cases of murders and suicides has been proven. Often, heliometeotropic reactions are observed in infants, then at 5-6 and 11-14 years old, when the physiological restructuring of adaptation mechanisms occurs. Sensitivity increases in women during pregnancy and childbirth, which is expressed in the aggravation of toxicosis of pregnancy, an increase in the number of threatened abortions, and premature births. Prevention of heliometeotropic reactions is carried out with the help of hardening, rational clothing and footwear, improvement of working and rest conditions, normalization of the microclimate of the premises, the use of specific and non-specific means and medicines.
Climate- statistical long-term weather regime, characteristic of a particular area due to its geographical location. According to the average annual temperatures on earth, 7 climatic zones are distinguished: tropical(0?13? geographic latitude; average annual temperature = +20...+24 ?FROM); hot(13-26? Northern and southern latitude and +16...+30? С); warm(26-39? latitude and +12...+16? С); moderate(39-52? latitude and +8...+12? С); cold(52-65? latitude and +4...+8? С); severe(65-78? latitude and 0.. -4? C); polar(69-90? latitude and -4? C and below).
In accordance with the simplified classification on the territory of Russia, taking into account the average temperatures of January and July, 4 climatic regions: 1st - cold with January temperature from -28 to -14 ?С and July from 4 to 10 ?С, 2nd - moderate with January temperature from -14 to -4 ?С and July from 10 to 22 ?С, 3rd - warm with January temperature from -4 to 0 ?С and July from 22 to 28 ?С, 4th - hot with January temperatures above -4 ?С and July from 28 to 34 ?С. In addition, local varieties of climate are distinguished: marine, continental, steppe, mountainous and others.
In medical practice, climate is divided into sparing and annoying. The gentle climate is characterized by slight fluctuations in meteorological factors and minimal
ny requirements to the adaptive physiological mechanisms of the human body, annoying The climate is characterized by significant fluctuations in meteorological factors that require greater stress on the body's adaptive mechanism. An example of a gentle climate is the forest climate middle lane Russia, the climate of the southern coast of Crimea. Irritating is the cold climate of the North, the high mountain climate (above 2000 m), the hot climate of the steppes and deserts. This classification is also used in the hygienic regulation of some harmful environmental factors.
Acclimatizationis the adaptation of the human body to new climatic conditions. Acclimatization is achieved by developing a dynamic stereotype in people that corresponds to changed climatic conditions, through the use of the features of the arrangement of residential and public buildings, clothing and footwear, nutrition and the rhythm of life. When acclimatizing to low temperatures, there is an increase in metabolism, an increase in heat production, an increase in circulating blood volume, a decrease in vitamins C and B1 in the blood, and a violation of the synthesis of vitamin D. Adaptation to a hot climate is usually more difficult than to a cold one; at the same time, there are changes in the cardiovascular system (decrease in heart rate, a decrease in blood pressure and by 15-25 mm Hg), a decrease in respiratory rate, sweating increases, a decrease in body temperature and basal metabolism by 10-15%.
There are three phases acclimatization: primary, at which physiological adaptive reactions occur in the body; phase rearrangement of the dynamic stereotype, which can develop favorably or unfavorably, and then the third phase does not occur; phase sustainable adaptation.
Microclimateis a complex of physical properties of air that affect the heat exchange of a person with the environment, his thermal state in a limited space (in separate rooms, a city, a forest, etc.) and determine his well-being, working capacity, health and labor productivity. Indicators of the microclimate are the temperature and humidity of the air, the speed of air movement and the thermal radiation of surrounding objects and people.
The state of microclimatic factors determines the features of thermoregulation of the human body, which in turn determines the heat balance. It is achieved by the ratio of processes
heat production and heat transfer of the body. Heat production occurs during the oxidation of nutrients, as well as during the contraction of skeletal muscles (Q cont.). In addition, the human body can receive convection and radiation heat from the surrounding air and heated objects if their temperature is higher than the temperature of the skin of open parts of the body. (Q ext.). The main mechanisms of heat transfer by the human body: conduction into the layers of air adjacent to the skin and less warm objects (Q cond.) and subsequent convection of heated air (Q conv.), radiation towards cooler objects (Q izd.), evaporation of sweat from the skin and moisture from the surface of the respiratory tract (Q isp.), heating up to 37 ° C of the inhaled air Qload. ). Heat balance in general view can be represented by the equation:
Opprod. + Qext. -(< >) Qcond. + Qconv. + Qred. + Check + - load.
The normal vital activity of the organism and high performance are possible only if the temperature constancy of the organism is maintained within certain limits (36.1-37.2 ° C), there is a thermal equilibrium with the environment, i.e. correspondence between the processes of heat production and heat transfer.
The adverse effect of the microclimate is due to the complex effect of physical factors of the air environment: an increase or decrease in temperature, humidity or air velocity. At elevated air temperatures, high humidity prevents the evaporation of sweat and moisture and increases the risk of overheating of the body. High humidity at low temperatures increases the risk of hypothermia because wet air, filling the pores of clothing, unlike dry - good conductor heat. High air velocity increases heat transfer through convection and evaporation and contributes to faster cooling of the body if its temperature is below skin temperature, and, conversely, increases the heat load on the body at a temperature exceeding skin temperature.
For a pharmacist, information about the microclimate of the premises is necessary to assess working conditions in pharmacies, since the microclimate affects the thermoregulation of the body, to assess the effectiveness of ventilation and the characteristics of the production environment in which medicines are stored, manufactured and dispensed. The safety of many drugs and
medicinal forms, their biological activity depend on microclimatic conditions, thermoregulation of people.
The hygienic norm of the microclimate is thermal comfort, which is determined by the combined action of all microclimatic components that provide the optimal level of physiological reactions of the body and the least stress of the thermoregulatory system, i.e. optimal thermal state of a person. When normalizing the microclimate, optimal the values of its parameters and admissible the boundaries of their fluctuations, characterized by slight general or local uncomfortable heat sensations and moderate tension of the thermoregulation mechanism, i.e. the inclusion of adaptive (adaptive) reactions of the body. Depending on the state (overheating or hypothermia), these reactions are manifested in a moderate expansion (or narrowing) of skin vessels, an increase (or decrease) in sweating, an increase (or decrease) in the pulse. Under these conditions, a long stay of a person is possible without a violation of working capacity and danger to health. In conditions close to comfort, indoor microclimate standards can be the same for adults and children; when establishing permissible fluctuations in microclimate indicators, the individual nature of people's thermoregulation, due to gender, age, weight, and the degree of physiological adaptive capabilities, should be taken into account. The normalized parameters of the microclimate should guarantee the preservation of health and performance even for a person with a reduced individual tolerance for fluctuations in environmental factors.
The most optimal values of the microclimate parameters for residential premises are: temperature 18-20 ºС, relative humidity 40-60%, air velocity 0.1-0.2 m/s.
The hygienic parameters of the microclimate in the premises are normalized depending on the climate for the warm and cold periods of the year. The optimal temperature for a cold climatic region is considered to be 21-22 ºС, moderate - 18-20 ºС, warm - 18-19 ºС, hot - 17-18 ºС. The calculated norms of temperature in the premises are differentiated depending on their functional purpose. Thus, in the majority of pharmacy premises (assistant, aseptic, defector, procurement, packaging, premises for the storage of medicinal raw materials and medicinal
means) the most favorable air temperature - 18? C; in the premises of medical institutions: in the operating room, preoperative room, resuscitation room, wards for children, burn patients, postoperative wards, intensive care wards, procedural rooms - 22 ° C, in wards for adults, doctors' offices and other medical auxiliary rooms - 20 ºС, in wards for patients with hypothyroidism - 24 ºС, in wards for premature babies and newborns - 25 ºС, in wards for patients with thyrotoxicosis - 15 ºС at relative humidity - 30-60% and air velocity - no more 0.15-0.25 m/s; in classrooms: classrooms, classrooms, classrooms, laboratories - 18? C, in gyms, training workshops - 15-17? C at a relative humidity of 40-60% and an air velocity of 0.1-0.2 m / With.
The microclimate of the premises is assessed by the temperature regime, i.e. differences in air temperature horizontally and vertically in different parts of the room. To ensure thermal comfort, the air temperature in the rooms must be relatively uniform. The change in temperature horizontally from the outer wall to the inner wall should not exceed 2 ° C, and vertically - 2.5 ° C for each meter of height. Temperature fluctuations in the room during the day should not exceed 3?
For an integral assessment of the microclimate, we use environment thermal load index (THS-index), characterizing the combined effect on the human body of temperature, humidity, air velocity and thermal radiation from surrounding surfaces. This indicator is recommended to be used when the air speed is less than 0.6 m/s and the intensity of thermal radiation is less than 1000 W/m 2 .
Rationing of microclimatic conditions in industrial premises is carried out in relation to the warm and cold periods of the year, taking into account the category of work and the corresponding energy consumption of the body (Table 1).
For employees of pharmacies, related to the level of energy consumption (up to 139 W) to category 1a, the optimal values of microclimate indicators are regulated: during the cold season, the temperature is at the level of 22-24 ° C, relative humidity 40-60%, air velocity 0.1 m/s; during the warm period of the year, the temperature is 23-25 ? C, relative humidity 40-60%, air speed 0.1 m/s.
Table 1.Optimal values of microclimate parameters for industrial premises (SanPiN 2.2.4.548-96)
Period of the year | (according to the level of energy consumption), W | Air temperature, ?С | Surface temperature, ?С | Relative humidity,% | Air speed, m/s |
1a (< 139) | 22-24 | 21-25 | 40-60 | ||
16 (140-174) | 21-23 | 20-24 | 40-60 | ||
Cold | 11a (175-232) | 19-21 | 18-22 | 40-60 | |
116 (233-290) | 17-19 | 16-20 | 40-60 | ||
111 (> 290) | 16-18 | 15-19 | 40-60 | ||
1a (< 139) | 23-25 | 22-26 | 40-60 | ||
16 (140-174) | 22-24 | 21-25 | 40-60 | ||
Warm | 11a (175-232) | 20-22 | 19-23 | 40-60 | |
116 (233-290) | 19-21 | 18-22 | 40-60 | ||
111 (> 290) | 18-20 | 17-21 | 40-60 |
Laboratory work "Determination and hygienic assessment of the microclimate of the room"
Student assignments
1. Get acquainted with the device and the principle of operation of devices for determining the parameters of the microclimate and its assessment.
2. Determine with an aneroid barometer Atmosphere pressure.
3. Determine the air temperature at 4 points in the room, calculate the average room temperature, horizontal and vertical temperature drops per 1 m height, evaluate the temperature regime.
4. Using an aspiration psychrometer, determine and calculate the absolute air humidity in the training room, using the table of maximum air humidity, calculate the relative humidity.
5. Using a catathermometer, determine the cooling capacity of the air and calculate the speed of air movement in the training room.
6. Examine the skin temperature of 2-3 students with an electrothermometer and make a sweat test. Subjectively evaluate your own heat sensation.
7. Evaluate the parameters of the microclimate of the room, comparing them with hygienic standards, and give a comprehensive hygienic assessment of the microclimate of the classroom, taking into account the objective and subjective reactions of the body to microclimatic factors.
Method of work
1. Determination of atmospheric pressure produced using aneroid barometer. Atmospheric pressure is measured in hectopascals (hPa) or mmHg. 1 hPa \u003d 1 g / cm 2 \u003d 0.75 mm Hg. Normal atmospheric pressure fluctuates on average within 1013+26.5 hPa (760+20 mmHg).
For continuous recording of fluctuations in atmospheric pressure, a self-recording device is used - barograph(Fig. 1). It consists of a set of aneroid boxes that react to changes in air pressure, a transmission mechanism, an arrow with a feather and a drum with a clockwork. The vibrations of the box walls are transmitted by means of a system of levers to the pen of the recorder. Pressure fluctuations are recorded on a paper tape mounted on a rotating drum.
Rice. one. Barograph
2. Determination of air temperature
Isolated determination of air temperature can be carried out mercury thermometers type TM-6 (measurement range from -30 to +50? C) or laboratory alcohol thermometers with a scale from 0 to +100? To fix the maximum or minimum temperatures are used maximum and minimum thermometers. The measurement of air temperature in industrial premises is usually combined with the determination of its humidity and is carried out using a psychrometer. In the presence of sources of infrared radiation, temperature measurement is carried out using the dry thermometer of an aspiration psychrometer, since the thermometer tanks are reliably protected from the influence of thermal radiation by double polished and nickel-plated screens.
Using alcohol thermometers mounted on a portable stand at a height of 1.5 m and 0.5 m from the floor, measure the air temperature at each point for 7-10 minutes at the following 4 points:
In the center of the room at a height of 0.5 m (T1) and 1.5 m from the floor (T2);
At a height of 1.5 m at a distance of 5-10 cm from the outer wall (window glass in the room) (T3) and from the opposite inner wall (T4);
To study the temperature dynamics, when it becomes necessary to determine temperature fluctuations in the room, self-recording devices are used - thermographs (daily or weekly) of the M-16 type (measurement range from -20 to +50 ? C) (Fig. 2).
Rice. 2. Thermograph
The thermograph sensor is a curved bimetallic plate, the inner surface of which consists of an Invar alloy, which practically does not expand when heated, and the outer surface is made of constantan, which has a relatively large coefficient of thermal expansion. With an increase or decrease in temperature, the curvature of the bimetallic plate changes. The oscillations of the plate are transmitted through a system of levers to a pen with ink, which registers a temperature curve on a tape fixed on a drum rotating at a certain speed.
3. Determination of thermal radiation carried out if there are heating devices or heated equipment in the room. Thermal radiation is infrared radiation with a wavelength of 760 to 15,000 nm. To measure thermal radiation is used actinometer. The actinometer sensor (Fig. 3) is a thermopile and consists of alternating black and silver-white metal plates attached to different ends of an electrical
chains. With a temperature difference at the ends electrical circuit due to the heating of the black plates as a result of the absorption of infrared rays, a thermoelectric current arises, which is recorded by a galvanometer calibrated in units of thermal radiation - cal / cm 2. min or W / m 2. The maximum allowable level of thermal radiation at the workplace = 20 cal / cm 2. min.
Rice. 3. Actinometer
Before starting the measurement, the arrow on the galvanometer scale must be set to zero, then open the cover on the rear surface of the actinometer. The readings of the galvanometer are written off 3 seconds after the installation of the thermal receiver (sensor) of the actinometer towards the source of thermal radiation.
4. Determination of air humidity.
The humidity of the air depends on the content of water vapor in it. To characterize humidity, the following concepts are distinguished: absolute, maximum, relative humidity, saturation deficit, physiological saturation deficit, dew point.
Absolute humidity - elasticity (partial pressure) of water vapor in the air at the time of measurement (in g / m 3 or mm Hg). Maximum humidity- the elasticity of water vapor when the air is fully saturated with moisture at a certain temperature (in g / m 3 or mm Hg). Relative Humidity- the ratio of absolute humidity to maximum, expressed as a percentage. saturation deficit- the difference between the maximum and absolute humidity
density (in mm Hg). Dew point The temperature at which the air is most saturated with water vapor. Only relative humidity is normalized, which is considered normal in the range of 40-60%.
Measurement of air humidity can be carried out using various instruments. Absolute humidity can be determined using psychrometers. There are 2 types of it: the Assmann aspiration psychrometer and the August station psychrometer (Fig. 4). The psychrometer consists of two identical thermometers, the tank of one of which is wrapped in a light hygroscopic cloth moistened with distilled water before measurement, and the second remains dry.
Rice. four.Psychrometers: a) aspiration; b) station
Station psychrometer Augusta it is used in stationary conditions, excluding the effect of wind and radiant heat on it. It consists of two alcohol thermometers. Based on their readings, the absolute humidity is determined from the tables or by the formula:
K= f- a (tc - tv) b,
where: K - absolute air humidity at a given temperature, mm Hg;
f- maximum air humidity at the temperature of the wet bulb, mm Hg. (see Table 2);
a - psychrometric coefficient, equal to 0.001 with a slight movement of air;
tc and tВ - temperature of dry and wet thermometers, ?С; AT- atmospheric pressure at the time of measurement, mm Hg.
Portable Assmann aspiration psychrometers, having protection from wind and thermal radiation. The psychrometer consists of two mercury thermometers (having a scale from -30 to +50 ? C), which are enclosed in a common frame, and their reservoirs are in double nickel-plated metal tubes to protect against radiant heat. A clockwork fan mounted in the instrument head sucks air along the thermometers at a constant speed of 2 m/s.
Before starting measurements with a pipette, it is necessary to moisten the tissue on the reservoir of the wet thermometer, start the mechanism of the device to failure with the key and hang it vertically on the bracket at the point under study, usually in the center of the room, and then after 3-5 minutes record the readings of the dry and wet thermometers .
The absolute humidity of the air in this case is calculated by the formula:
K= / 755.
Relative humidity (in %) is calculated by the formula:
P= K. 100/F
where: P- relative humidity, %,
F- maximum air humidity at dry bulb temperature, mm Hg. (see Table 2).
Table 2.Maximum air humidity at different temperatures
Air temperature, +? С | Air temperature, +? С | Maximum humidity, mm Hg |
|
10,5 | 30,04 |
||
11,23 | 31,84 |
||
11,99 | 33,69 |
||
12,73 | 35,66 |
||
13,63 | 37,73 |
||
14,53 | 39,90 |
||
15,48 | 42,17 |
||
16,48 | 44,16 |
||
17,73 | 46,65 |
||
18,65 | 49,26 |
||
19,83 | 52,00 |
||
21,07 | 55,32 |
||
22,38 | 58,34 |
||
23,76 | 61,50 |
||
25,20 | 64,80 |
||
26,74 | 68,26 |
||
28,34 | 71,88 |
Relative humidity can be measured directly hygrometer(Fig. 5). The fat-free human hair in the hygrometer is stretched along the frame of the device and attached to the arrow. The property of the hair to change its length depending on the humidity is used. When changing the degree of its tension, the arrow moves along a scale calibrated in percent. Relative humidity is usually measured in the center of the room.
For continuous graphical recording of relative air humidity for a certain period of time, self-recording instruments are used. - hygrographs(daily or weekly) of the M-21 type (measurement range from 30 to 100% at temperatures from -30 to +45 °C), in which a bundle of fat-free human hair stretched in a frame serves as a sensor (Fig. 6).
Rice. 5. Hygrometer
Rice. 6. hygrograph
5. Determining the speed of air movement
The movement of air in the atmosphere is characterized by the direction of movement and speed. The direction is determined by the side
light, from where the wind blows, and the speed - the distance traveled by the mass of air per unit time (m / s). The prevailing wind direction in a particular area must be taken into account when planning and constructing populated areas, placing residential buildings, pharmacy organizations, kindergartens, schools, hospitals and other institutions on their territory, which should be located on the windward side in relation to sources of atmospheric air pollution and other environmental objects (industrial enterprises, thermal power plants, etc.).
The prevailing wind direction for a given place is determined by the wind rose. Rose of Wind is a graphical representation of the frequency (recurrence) of winds in points (directions) observed in a given area during the year. To designate rhumbs, the initial letters of the names of the cardinal directions are used. To build a wind rose from the center of the graph on the main (N, S, O, W) and intermediate (N-O, N-W, S-O, S-W) points, segments are plotted on a certain scale corresponding to the number of days in a year with a given wind direction. Then the ends of the segments along the points are connected by straight lines. Calm (lack of wind) is indicated by a circle from the center of the graph with a radius corresponding to the number of days of calm.
Rice. 7. Rose of Wind
On fig. 7, the wind rose indicates the prevailing northeast wind direction in the study area during the year, so residential buildings, pharmacies, hospitals and child care facilities should be located on the windward side (in the northeast direction), and industrial enterprises and other sources of pollution - from the leeward side (in the southwest direction). Industrial enterprises and other sources of negative impact on the environment and human health must be separated from residential buildings sanitary protection zones (SPZ). The width of the sanitary protection zone is established in accordance with the sanitary classification of industrial enterprises, structures and other facilities, depending on the degree of harmfulness of production, its capacity, the nature and amount of pollutants released into the environment, generated noise, vibration and other harmful physical factors (Sanitary protection zones and sanitary classification of enterprises, structures and other objects. SanPiN 2.2.1/2.1.1.1200-03). According to these characteristics, industrial enterprises are divided into 5 classes, for each the size of the SPZ is set: for enterprises of the 1st class - 1000 m with at least 40% of landscaping, for the 2nd - 500 m, 3rd - 300 m with at least 50 % landscaping, for the 4th - 100 m and the 5th - 50 m with at least 60% landscaping.
Rice. eight.Anemometers (left - cup, right - vane)
The measurement of relatively high air velocities is carried out anemometers various designs. The choice of anemometer type is determined by the value of the measured air velocity. Cup anemometer MS-13 measures velocities from 1 to 30 m/s. It is most often used in meteorological practice. Vane anemometer ASO-3 is used in industrial premises to measure air velocities in the range of 0.3-5.0 m/s (Fig. 8).
The principle of operation of the devices is based on the transmission of the rotation of the blades mounted on the axis to a counting mechanism that fixes the number of revolutions. To determine the speed of the air medium, the difference between the readings of the anemometer after it has been in the air stream for 3 minutes and the initial readings of the device is divided by the number of seconds of measurement. The number of revolutions per sunda corresponds to the air velocity in m/s.
To measure low air velocities in a room, glass spherical or cylindrical catathermometers, which allow you to measure the speed in the range of 0.05-2.0 m/s (Fig. 9).
Rice. 9.Ball catathermometer
The scale of the spherical catathermometer consists of 7? (from 33 to 40?), Cylindrical scale - from 3? (from 35 to 38?). The definition is based on an assessment of the intensity of cooling of a heated device due to the cooling capacity of the air. Air cooling capacity "N" determined by catathermometer factor (F) and cooling time of its reservoir (t) in chests from 38? up to 35? C or from 40? up to 33? From the scale of the device. The value of F is indicated in the upper part of the catathermometer; it corresponds to the amount of heat in millicalories lost from 1 cm 2 of the surface of the device when it is cooled from 40? up to 33? C or from 38? up to 35?С. The apparatus is heated in a beaker with hot water with a temperature of 66-75 ° C in order for the alcohol to rise slightly above the upper mark of the device scale, wipe the device dry and, hanging it in the center of the room, note the time required to cool the alcohol from 40? up to 33? C or from 38? up to 35?С. Air cooling capacity "N" found by the formula:
H\u003d [(F / 3) (40-33)] / t, mcal / cm 2.
To take into account the cooling effect of the surrounding air, it is necessary to calculate the factor Q, equal to the difference between the average temperature of the catathermometer (36.5 ° C) and the air temperature in the room. Calculating H/Q, the speed of air movement at the measurement point is found according to the table. 3.
The air velocity can also be calculated using the empirical formula: V= [(H/Q- 0.20)/0.40] 2 m/s. In summer, atmospheric air speeds are favorable in the range of 1-4 m/s, and indoors - 0.2-0.4 m/s.
Special devices are currently used to measure and control the parameters of the air environment. meteometers type MES-200, designed to measure atmospheric pressure, relative humidity, air temperature and air flow rate inside the room. Thermistors and a humidity sensor with an amplifier unit are used as sensors for measuring parameters in the device.
6. Study of the body's reactions to the microclimate
* Human heat sensation depends on the complex action of microclimatic factors, as well as on the intensity of the work performed, the degree of fatigue, the nature of nutrition, clothing, emotional state, a person's fitness for cold
Table 3The air speed is less than 1 m/s at various bands room air temperature
H/Q | 17,5? | 20,0? | 22,5? | 25,0? |
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0,27 | 0,035 | 0,041 | 0,047 | 0,051 |
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0,28 | 0,049 | 0,051 | 0,061 | 0,070 |
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0,29 | 0,060 | 0,067 | 0,076 | 0,085 |
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0,30 | 0,073 | 0,082 | 0,091 | 0,101 |
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0,31 | 0,088 | 0,098 | 0,107 | 0,116 |
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0,32 | 0,104 | 0,113 | 0,124 | 0,136 |
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0,33 | 0,119 | 0,128 | 0,140 | 0,153 |
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0,34 | 0,139 | 0,148 | 0,160 | 0,174 |
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0,35 | 0,154 | 0,167 | 0,180 | 0,196 |
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0,36 | 0,179 | 0,192 | 0,206 | 0,220 |
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0,37 | 0,198 | 0,212 | ||||||||||||||||||||||||
Vertical, m | Horizontally,? |
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At the outer wall | In the center | At the inner wall | drop |
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1.5 m from the floor | T h | T 2 | T 4 | T 3 -T 4 |
0.5 m from the floor | ||||
Drop,? | T 2 -T 1 | |||
Calculation of the average air temperature in the room:
T?av =(T1 + T 2 + T h + T4) / 4 ... 3. Determination of air humidity:
Determination of absolute humidity using an Assmann aspiration psychrometer:
Dry thermometer readings. Wet thermometer readings. Calculation of absolute humidity according to the formula: Calculation of relative humidity according to the formula: (t)... Appliance factor (F) ...
Air cooling capacity: H= [(F/3) (40-33)] / t...
Q(36,5? - T?cp) =..., H/ Q= ..., V = ... Conclusion(sample)
The microclimate of this room provides comfortable conditions (or it is unacceptably hot and causes a significant tension in thermoregulation; slightly above the comfort zone - it is acceptable warm and causes some tension in thermoregulation; below the comfort zone - unacceptably cold and causes a feeling of cold, etc.). To improve the microclimate, it is recommended ...
Dust, fumes, stuffiness. Unfortunately, we have to "communicate" with them everywhere: in the office, at home, on the street. You can talk for a long time about the gas pollution of the city and endless traffic jams, about the perniciousness of the neighborhood with industrial enterprises and the poor state of the environment in general. But hours of conversations on this topic can be reduced to just one question: where is it - clean air?
Surely each of us felt a surge of vivacity, relaxing at a resort in some heavenly corner of the world. Surprisingly, but the fact is that at least 30% of well-being on vacation gives oxygenated, clean, fresh, humid air. Think for yourself, an adult consumes about 3 kg of food per day, and as much as 15 (!) kg of air! And if we can choose the quality of food, then we have to breathe the air as it is. Although, there is still a choice.
Progress does not stand still. Our high-tech apartments and offices today are equipped with all the benefits of civilization. Finally, the moment has come when devices for creating a comfortable microclimate and the ecology of the house began to take a firm place in our lives.
Factors that determine the microclimate in the room:
- air purity,
- humidity,
- temperature,
- freshness,
- oxygen saturation,
- the absence of harmful impurities in it.
What do you want to clean?
To make the air at home or in the office clean, there are several various types air purifiers.
1. Household air cleaners. They come with and without filters. Do not be surprised - air cleaners without filters clean the air with water, they are also called "air washers". Among the leaders in this field are devices Venta and Boneco. The principle of cleaning with water is good only because the devices humidify the air, but there are a lot of disadvantages, for example, low cleaning efficiency. The most terrible air pollutants - the smallest dust, soot, bacteria and viruses are not wetted by water, "air washers" are powerless against them.
Air cleaners with filters will be more effective against such pollutants. Devices with HEPA filters (this is a dense filter made of fibers and having antibacterial impregnation), supplemented with deodorizing carbon filters and coarse filters, are quite popular.
2. Professional air cleaners. In Russia, these devices are represented by the Dutch company EUROMATE BV., the European leader in the production of devices for air purification and smoke removal. EUROMATE is a European plant with more than 30 years of history. What makes air purifiers of this brand professional?
The quality of any air purifier is determined by the quality of its filters. EUROMATE specialists have developed 2 main types of filters: MediaMax and ElectroMax. MediaMax filters are the next step in the development of HEPA filters - they have a three-dimensional volumetric structure, a capacity increased by up to 100 times compared to HEPA filters. The filter contains an activated carbon section that removes odors. MediaMax-filter has antibacterial impregnation.
The EUROMATE ElectroMax filter is a washable electrostatic filter. It does not need to be changed - just wash it and it is ready to use again! The effective surface area of the ElectroMax filter for a small EUROMATE Grace device is 1.44 sq.m (!), the particle size is less than 0.01 micron - smaller than particles of tobacco smoke or car smog! There is also a type of filter capable of retaining specific contaminants - mercury vapor.
beautiful air
The design of Grace professional air purifiers is elegant and concise. Perhaps that is why they fit perfectly into the interior completely. different rooms. They can be found in cottages, apartments, offices, as well as in small cafes and restaurants, smoking rooms. Especially for people who care not only about their health, but also about the beauty and style of the room, Grace MediaMax and Grace ElectroMax are presented in seven colors.
Euromate VisionAir1 and VisionAir2 are designed for larger spaces. As a rule, they are equipped with offices of directors of reputable companies, smoking rooms of offices, bars, restaurants, cottages, casino halls, billiard rooms. Any large premises where clean air is required, or where there is a lot of smoking. This type of cleaner can be installed on the floor, mounted on the wall, built into the ceiling.
smoking room
New in 2006 - Smoke "n" GO smoking cabins - a revolutionary product of the company - a ready-to-work place for public smoking in offices. The cabin can be installed in any room, and after connecting to the network, it is completely ready for operation. A powerful fan and a filter system are located in the upper part of the cabin, allowing you to quickly remove tobacco smoke from the smoking area and completely trap tobacco particles and its smell, purifying the air from these impurities and re-feeding it into the room in recirculation mode. The cabin is made in several versions and can accommodate 4.6 or 12 people, equipped with seats and a table for negotiations.
Three big differences
Ventilation, air conditioning and air purification are three different areas.
Ventilation only brings fresh outdoor air into the room. The opinion that the problems associated with air pollution can be solved along the way with the help of ventilation is not confirmed in practice.
A more adequate solution is additional air purification. The air cleaner is specially designed for this purpose.
Air conditioners are designed to regulate the temperature of the air in the room. Sometimes they are equipped with filters, but these filters are mainly designed to protect the air conditioner itself, and not to clean the exhaust air. In addition, the efficiency of such filters is very low.
The air purifier passes air through filters that trap tobacco smoke, and clean air is sent back into the room. The air purifier is very convenient to use near the source of pollution - where most tobacco smoke is generated (in the smoking area, at the bar, above the pool tables ...) or in places where it is difficult to provide ventilation air flow.
Summing up, we can say that controlled or uncontrolled ventilation, as well as air conditioning, is not enough if they are not supplemented by an appropriate number of air cleaners.
Article provided by the climate company "Air Flow Engineering"
