Determination of carbon dioxide as a sanitary indicator of air cleanliness in residential premises and public buildings. Hygienic characteristics of air in residential and public buildings Sanitary hygienic value of air oxidation
premises:
2. carbon dioxide
4. sulfur dioxide
5. Maximum permissible content carbon dioxide in the air
premises is:
6. Waters most often subject to bacterial contamination:
1. ground
2. superficial
3. interlayer pressure
4. interlayer non-pressure
7. Water source sanitary protection zone:
1. territory in which the construction of enterprises is prohibited
2. area near a water source
3. territory in which it is installed special mode aimed at protecting the water source from pollution
4. territory settlement
8. Centralized water supply:
1. delivery of water by road transport
2. water supply through a water pipe
3. drawing water from a well
4. taking water directly from the spring
9. The total hardness of water is determined by the content of:
2. iodine, fluorine
3. calcium, magnesium
4. sulfates, chlorides
10. Increased levels of fluoride in soil and water can lead to:
1. fluorosis
2. caries
3. endemic goiter
4. methemoglobinemia
11. A disease the cause of which is associated with a lack of iodine in external environment and including in water:
1. gigantism
2. endemic goiter
3. fluorosis
4. endemic encephalitis
12. What microelement deficiency in water causes dental caries:
13. Excess of chemical compounds in water that cause disorder
gastrointestinal tract:
2. sulfates
3. nitrates
4. chlorides
14. Disease, to possible occurrence which predisposes
increased water hardness:
1. chronic colitis
2. pancreatitis
3. urolithiasis
4. chronic cholecystitis
15. Waterborne disease:
1. diphtheria
2. gas gangrene
16. Of the listed diseases, endemic include:
1. fluorosis
3. dysentery
17. Water disinfection is:
3. water coagulation
4. water filtration
18. Prevention of soil contamination by solid and liquid waste is achieved:
4. organizing cleanup days once a year
Part 2
Instructions:Complete your answer.
Nutrition, which is an element of complex treatment of patients, is called _____________________.
Nutrition that compensates for the unfavorable effects of environmental and industrial environmental factors is called _____________________.
24. Indicate the main source of protein in food _____________________.
25. Indicate the main source of carbohydrates in food _____________________.
26. Rickets can develop due to a lack of vitamin _____________________ in the body.
27. Bleeding gums and poor wound healing are associated with vitamin deficiency_____________________.
Part 3.
Instructions: Solve the problem.
28. The patient has signs of vitamin A deficiency. List these signs.
29. IN production conditions The issue of introducing measures that are most effective in terms of reducing the impact of unfavorable factors in the working environment on nature and humans was considered. List these activities.
30. In relation to medical workers, technological and technical measures to reduce adverse effects on the body are ineffective. Indicate what measures are applied to medical workers.
Option No. 2
Part 1
Instructions:Choose one correct answer.
1. Increased levels of fluoride in soil and water can lead to:
1. fluorosis
2. caries
3. endemic goiter
4. methemoglobinemia
2. A disease the cause of which is associated with a lack of iodine in the external environment, including in water:
1. gigantism
2. endemic goiter
3. fluorosis
4. endemic encephalitis
3. Lack of which microelement in water causes dental caries:
4. Excess of chemical compounds in water that cause disorder
gastrointestinal tract:
2. sulfates
3. nitrates
4. chlorides
5. Disease to the possible occurrence of which it predisposes
increased water hardness:
1. chronic colitis
2. pancreatitis
3. urolithiasis
4. chronic cholecystitis
6. Waterborne disease:
1. diphtheria
2. gas gangrene
7. Of the listed diseases, endemic include:
1. fluorosis
3. dysentery
8. Water disinfection is:
1. destruction of pathogenic microorganisms and viruses
2. freeing water from turbidity and suspended matter
3. water coagulation
4. water filtration
9. Prevention of soil contamination by solid and liquid waste is achieved:
1. storing waste in a certain area of the household
2. collection of waste in pits dug in household areas
3. sanitary cleaning of populated areas
4. organizing cleanup days once a year
10. Science that studies the influence of environmental factors on the body
person is called:
1. biology
2. hygiene
3. sanitation
4. ecology
11. Impact human activity on nature:
1. abiotic
2. biotic
Hygiene summary No. 1
Chemical composition atmospheric air. The meaning of oxygen.
oxygen=20.93%, CO2=0.03-0.04%, N=78.1%, argon, krypton, helium, etc.
Oxygen (Oxygenum) is the most important biogenic chemical element, which ensures the respiration of most living organisms on Earth. Oxygen is used by cells and tissues to oxidize organic substances, releasing the energy they contain, which is necessary for life. The physiological effect of oxygen is extremely diverse, but the ability to compensate for oxygen deficiency in the body tissues during hypoxia is crucial in its therapeutic effect.
Chemical composition of atmospheric air. (in the first) The value of nitrogen.
Nitrogen is an element necessary for the existence of animals and plants. It is part of proteins (16-18% by weight), amino acids, nucleic acids, nucleoproteins, chlorophyll, hemoglobin, etc. in the composition of living cells by the number of nitrogen atoms - about 2%, by mass fraction - about 2.5% (fourth place after hydrogen, carbon and oxygen). As a result of the processes of decay and decomposition of nitrogen-containing organic matter, subject to favorable environmental factors, natural deposits of minerals containing nitrogen can be formed, for example, “Chilean saltpeter” (sodium nitrate with admixtures of other compounds), Norwegian, Indian saltpeter.
Chemical composition of atmospheric air. (in the first) The value of ozone.
Ozone. It is a chemically unstable isomer of oxygen. The general biological significance of ozone lies in its ability to absorb short-wave ultraviolet solar radiation, which has a detrimental effect on all living things. Along with this, ozone also absorbs long-wave infrared radiation emanating from the Earth, and thereby prevents its excessive cooling (the Earth's ozone layer). Under influence ultraviolet rays Ozone decomposes into an oxygen molecule and an atom. Ozone is used as a bactericidal agent in water disinfection. In nature, it is formed during electrical discharges, during the evaporation of water, and under the influence of ultraviolet rays. In the free atmosphere, its highest concentrations are observed during thunderstorms, in the mountains and in coniferous forests.
Carbonic gas - indirect indicator of indoor air pollution.
The change in the properties of indoor air, which occurs due to human activity, occurs in parallel with the increase in carbon dioxide in the air, therefore the content of carbon dioxide in the air is considered an indirect sanitary indicator of indoor air pollution.
air is considered sufficiently clean if it contains no more than 0.07% carbon dioxide. maximum permissible carbon dioxide content = 0.1% or 1 ppm.
The air of enclosed spaces may contain bacterial and chemical contaminants. They are a consequence of human physiological metabolic processes, everyday activities (cooking and burning gas in household appliances). A complex of polymer degradation products may also enter indoor air. finishing materials etc. Finally, the gas composition of indoor air is determined by the gas composition of the supply air and chemical pollutants emitted indoors.
The main cause of indoor air pollution in residential and public buildings- accumulation of gaseous human waste products (anthropoxins), such as carbon dioxide, ammonia, ammonium compounds, hydrogen sulfide, volatile fatty acids, indole, etc.
A parallelism has been discovered between the accumulation of carbon dioxide and other impurities in indoor air. He proposed judging the degree of air pollution by the amount of carbon dioxide contained in it. It has now been established that the content of carbon dioxide in indoor air up to 0.7% and even 1% in itself is not capable of adversely affecting the human body and that its accumulation does not always occur in parallel with the accumulation harmful substances and smells.
At the same time, insignificant concentrations of carbon dioxide do not always indicate clean air in the room. Carbon dioxide concentrations can remain low when there is significant air pollution from dust, bacteria and harmful chemicals. Especially if synthetic materials are used in construction, the concentration of which does not always increase simultaneously with the increase in carbon dioxide content.
Therefore, to estimate air environment and the efficiency of indoor ventilation, knowing the carbon dioxide content alone is not enough. At this stage, this indicator is not able to serve as a standard for indoor air quality.
Another criterion characterizing the quality of the air environment is the content of ammonia and ammonium compounds in the air. As a result of a detailed study of the harmful effects of altered indoor air on the human body, a high activity of ammonia and ammonium compounds coming from the surface of human skin was established. When inhaling ammonium compounds contained in indoor air, most people developed symptoms within a few hours. headache, feeling tired, performance decreased sharply. Some even experienced a painful condition similar to poisoning. At the same time, the physical properties of the air remained within hygienic standards.
Ammonia and its compounds in concentrations observed in residential areas also affect the mucous membranes of the respiratory tract. However, the determination of ammonia content has not become significant in hygienic assessment air quality. This indicator only relatively indicates the presence of gaseous products that pollute indoor air.
To determine the level of air pollution, it was proposed integral indicator- oxidability. A study of the level of air pollution with organic substances showed that the amount of oxidation can be used to judge its purity. Organic matter in the air is also retained in respiratory tract person and are absorbed. To assess air pollution by organic substances, indicative standards for its oxidation capacity are recommended. Thus, air that has an oxidability of up to 6 mg of oxygen per 1 m 3 is considered clean, and air that is polluted is considered to be from 10 to 20 mg of oxygen per 1 m 3.
Oxidability is relative indicator, since in the presence of polymers it can also change. At the same time, due to the widespread use in construction polymer coatings(structural, finishing materials) and their ability to release chemicals into the environment, it is necessary to take into account this air factor. Polymer release products are in most cases toxic to humans.
MACs have been developed for a number of substances that are part of polymer finishing materials and have toxic properties. This regulates the use of polymer finishing materials in the construction of residential and public buildings.
Air cube. During inhalation, the human body absorbs almost 0.057 m 3 of oxygen within 1 hour, and during exhalation it releases 0.014 m 3 of carbon dioxide. If a person is indoors, then naturally the oxygen content decreases and the concentration of carbon dioxide increases. But this provision is valid only for hermetically sealed premises. In ordinary residential and public buildings, due to the infiltration of outside air through loosely fitted windows and fences, a one and a half times air exchange always occurs. However, despite the exchange of air, a person usually feels stuffy in enclosed spaces. Complaints about stuffiness and lack of oxygen are expressed during stays both in rooms with natural air exchange and in houses equipped with different systems ventilation, including air conditioning. Although the oxygen content in enclosed spaces is natural, the air in them is perceived by humans as stale. The question arises about the reasons for this phenomenon. Isn't there enough fresh air in enclosed spaces? How much air does a person need? The recommended amount of fresh air that should be supplied to premises is determined based on the amount of carbon dioxide released into human respiration per unit of time. This initial value included in the volume calculations ventilation air, depends on many variable components: indoor air temperature, the age of a person, his activity. At a room temperature of 20 °C, an adult emits an average of 21.6 liters of carbon dioxide per hour, being in a state of relative rest. The required volume of ventilation air for one person will be (with a maximum permissible concentration of 0.1% by volume and a carbon dioxide content in the atmospheric air of 0.04%) 36 m 3 /h. If you change any of the initial values, namely, take the maximum permissible concentration of carbon dioxide in the air of residential premises as 0.07%, then the required volume of ventilation will increase to 72 m 3 /h.
In modern cities, where the main sources of CO2 are fuel combustion products, the norm proposed by M. Pettenkofer (0.07%) back in the 19th century loses its significance, since an increase in its concentration under these conditions only indicates insufficient ventilation of the room. However, the carbon dioxide content as a criterion for air quality remains important and is used in calculating the required volume of ventilation.
Lack of clearly established and generally accepted standards for permissible air content various rooms dust and microorganisms does not make it possible to widely use these indicators to normalize air exchange.
The values of the recommended ventilation volume are very variable, as they differ by an order of magnitude. Hygienists have established an optimal figure of -200 m 3 /h, corresponding building regulations and rules - at least 20 m 3 / h for public premises, in which a person remains continuously for no longer than 3 hours.
Clean atmospheric air at the surface of the Earth is a mechanical mixture various gases, among which, in descending order by volume, contain nitrogen, oxygen, argon, carbon dioxide and a number of other gases, the total amount of which does not exceed 1%.
The composition of clean dry atmospheric air in volume percent is shown in Fig. 1,2,
During a day at rest, an adult passes 13-14 m3 of air through the lungs - a significant volume that increases with exercise. physical activity. This means that the body is not indifferent to the air of what chemical composition it breathes.
Oxygen is the most important air gas for life. It is consumed in the body for oxidative processes, entering the blood through the lungs, and delivered to the tissues and cells of the body as part of oxyhemoglobin,
Rice. 1.2. Chemical composition of atmospheric air under normal conditions.
In the surrounding nature, oxygen is also necessary for the oxidation of organic substances found in water, air and soil, as well as for maintaining combustion processes.
The source of oxygen in the atmosphere is green plants, which form it under the influence of solar radiation in the process of photosynthesis and released into the air during respiration. We are talking about phytoplankton of the seas and oceans, as well as plants of tropical forests and evergreen taiga, which are figuratively called the “lungs of the planet.”
Green plants produce oxygen in very large quantities, and due to the constant mixing of layers of atmospheric air, its content in atmospheric air remains practically constant everywhere - about 21%. Low concentrations of oxygen, essential for the life of the human body, are observed when rising to a height and when people stay in hermetically sealed rooms in the event of emergency situations when technical means of maintaining life are disrupted. Increased oxygen content is observed under conditions of high atmospheric pressure (in caissons). At partial pressure over 600 mm Hg. it behaves as a toxic substance, causing pulmonary edema and pneumonia.
Atmospheric air contains a dynamic isomer of oxygen - triatomic oxygen ozone, which is a strong oxidizing agent. It is formed in natural conditions V upper layers atmosphere under the influence of short-wave ultraviolet radiation from the Sun, during lightning discharges, and during the evaporation of water.
Ozone plays a vital role in protecting the planet’s biological objects from the harmful effects of hard ultraviolet radiation, trapping it in the stratosphere at an altitude of 20-30 km.
Ozone has a peculiar pleasant smell of freshness, and its presence can be easily detected in the forest after a thunderstorm, in the mountains, in clean natural environment, where it is considered an indicator of air cleanliness. However, excess ozone is unfavorable for the life of the body, and starting from a concentration of 0.1 mg/m3 it acts as an irritant gas.
The presence of ozone in the air of large industrial cities, polluted by emissions from vehicles and industrial facilities, in the light of the latest scientific data is considered an unfavorable sign, since under these conditions it is formed as a result of photochemical reactions during the formation of smog.
The high oxidizing power of ozone is used in water disinfection.
Carbon dioxide, or carbon dioxide, enters the air during the breathing of people, animals, plants (at night), the oxidation of organic substances during combustion, fermentation, decay, being in the environment in free and bound states.
The constant content of this gas at the level of 0.03% in the atmosphere is ensured by its absorption in the light by green plants, dissolution in the water of the seas and oceans, and removal with precipitation.
Significant amounts of CO2 are formed as a result of work industrial enterprises and vehicles that burn huge amounts of fuel, resulting in last years Data has emerged that the carbon dioxide content in the air of large modern cities is approaching 0.04%, which raises concerns among environmentalists about the formation of the “greenhouse effect,” which will be discussed in more detail later.
Carbon dioxide participates in the body's metabolic processes, being a physiological stimulant of the respiratory center.
Inhalation of large concentrations of CO2 disrupts redox processes, and its accumulation in the blood and tissues leads to tissue anoxia. Long-term stay of people in enclosed spaces (residential, industrial, public) is accompanied by the release of products of their vital activity into the air: carbon dioxide with exhaled air and volatile organic compounds (ammonia, hydrogen sulfide, indole, mercaptan), called anthropotoxins, from the surface of the skin, dirty shoes and clothes. There is also a slight decrease in the oxygen content in the air. Under these conditions, people may experience complaints of poor health, decreased performance, drowsiness, headache and other functional symptoms. What explains this symptom complex? It can be assumed that the reason lies in the lack of oxygen, the amount of which, as already mentioned, is slightly reduced compared to its content in the atmospheric air. However, it was found that its reduction in the most unfavorable conditions does not exceed 1%, since due to the leakage of these premises, oxygen easily penetrates from the atmosphere into the indoor air, replenishing its supply. The human body does not respond to such a decrease in oxygen content. Sick people note a decrease in oxygen in the air if it is 18%, healthy people - 16%. Life is impossible with an oxygen concentration in the air of 7-8%. However, these oxygen concentrations never exist in unsealed spaces, but they can exist in a sunken submarine, collapsed mine, and other sealed spaces. Consequently, in unsealed rooms, a decrease in oxygen content cannot cause a deterioration in people’s well-being. Then isn’t this reason due to the accumulation of excess carbon dioxide in the indoor air? However, it is known that the unfavorable concentration of CO2 for human health is 4-5%, when headaches, tinnitus, palpitations, etc. appear. When the air contains 8% carbon dioxide, death occurs. The indicated concentrations are typical only for sealed rooms with a faulty life support system. In ordinary enclosed spaces, such concentrations of carbon dioxide cannot exist due to the constant exchange of air with environment.
And yet, the content of CO2 in the air of enclosed spaces has sanitary significance, being indirect indicator air purity. The fact is that in parallel with the accumulation of CO2, usually not higher than 0.2%, other properties of the air deteriorate: temperature and humidity, dust content, the content of microorganisms, the number of heavy ions increase, and anthropotoxins appear. It is this complex of changed physical properties of air, along with chemical pollution, that causes a deterioration in people’s well-being. This change in air properties corresponds to a carbon dioxide content equal to OD%, and therefore this concentration is considered the maximum permissible for indoor air.
In recent years, it has been found that this indicator is not enough to assess the sanitary condition of indoor air, since it is necessary to determine the content of some toxic chemicals released into the air from polymers. building materials, widely used for interior decoration premises (phenol, ammonia, formaldehyde, etc.).
Nitrogen and other inert gases. Nitrogen in terms of quantitative content is the most significant part of atmospheric air, accounting for 78.1% and diluting other gases, primarily oxygen. Nitrogen is physiologically indifferent, does not support the processes of respiration and combustion, its content in the atmosphere is constant, its quantity is the same in inhaled and exhaled air. Under conditions of high atmospheric pressure, nitrogen can have a narcotic effect, and its role in the pathogenesis of decompression sickness is also known.
The nitrogen cycle in nature is known, carried out with the help of certain types of soil microflora, plants and animals, as well as electrical discharges in the atmosphere, as a result of which nitrogen is bound by biological objects and then released back into the atmosphere.
3.4 Lighting. Rational lighting is necessary primarily for the optimal function of the visual analyzer. Light also has a psychophysiological effect. Rational lighting has a positive effect on the functional state of the cortex big brain, improves the function of other analyzers. In general, light comfort, improving the functional state of the central nervous system and increasing the performance of the eye, leads to increased productivity and quality of work, delays fatigue, and helps reduce industrial injuries. The above applies to both natural and artificial lighting. But natural light, in addition, has a pronounced general biological action is synchronizer of biological rhythms, has thermal and bactericidal action (see chapter III). Therefore, residential, industrial and public buildings must be provided with rational daylighting.
On the other hand, with the help artificial lighting You can create a specified and stable illumination throughout the day anywhere in the room. The role of artificial lighting is currently high: second shifts, night work, underground work, evening home activities, cultural leisure, etc.
TO main indicators, characterizing lighting include: 1) spectral composition of light (from the source and reflected), 2) illumination, 3) brightness (of the light source, reflective surfaces), 4) uniformity of illumination.
Spectral composition of light. The greatest productivity and the least eye fatigue occurs when illuminated with standard daylight. The spectrum of diffused light from the blue sky, i.e., entering a room whose windows are oriented to the north, is taken as the standard for daylight in lighting engineering. The best color discrimination is observed in daylight. If the dimensions of the parts in question are one millimeter or more, then for visual work Illumination from sources generating white daylight and yellowish light is approximately the same.
The spectral composition of light is also important in the psychophysiological aspect. Thus, red, orange and yellow colors, by association with flames and the sun, evoke a feeling of warmth. Red color excites, yellow tones, improves mood and performance. Blue, indigo and violet appear cold. Thus, painting the walls of a hot shop in Blue colour creates a feeling of coolness. Blue color is calming, blue and violet are depressing. Green color is neutral - pleasant in association with green vegetation, it tires the eyes less than others. Painting walls, cars, and desk tops in green tones has a beneficial effect on well-being, performance, and visual function of the eye.
Painting walls and ceilings in White color has long been considered hygienic, as it provides the best illumination of the room due to its high reflectance coefficient of 0.8-0.85. Surfaces painted in other colors have a lower reflectance: light yellow - 0.5-0.6, green, gray - 0.3, dark red - 0.15, dark blue - 0.1, black - - 0.01. But white color (due to its association with snow) evokes a feeling of cold, it seems to increase the size of the room, making it uncomfortable. Therefore, walls are often painted light green, light yellow and similar colors.
The next indicator characterizing lighting is illumination Illuminance is the surface density luminous flux. The unit of illumination is 1 lux - the illumination of a surface of 1 m2 on which a luminous flux of one lumen falls and is evenly distributed. Lumen- luminous flux that is emitted by a complete emitter (absolute black body) at the solidification temperature of platinum from an area of 0.53 mm 2. Illumination is inversely proportional to the square of the distance between the light source and the illuminated surface. Therefore, in order to economically create high illumination, the source is brought closer to the illuminated surface (local lighting). Illumination is determined with a lux meter.
Hygienic regulation of illumination is difficult, since it affects the function of the central nervous system and the function of the eye. Experiments have shown that with an increase in illumination to 600 lux, the functional state of the central nervous system significantly improves; further increasing the illumination to 1200 lux to a lesser extent, but also improves its function; illumination above 1200 lux has almost no effect. Thus, wherever people work, an illumination of about 1200 lux is desirable, with a minimum of 600 lux.
Illumination affects the visual function of the eye during various sizes the items in question. If the parts in question have a size of less than 0.1 mm, when illuminated with incandescent lamps, an illumination of 400-1500 lux is needed", 0.1-0.3 mm -300-1000 lux, 0.3-1 mm -200-500 lux, 1 - 10 mm - 100-150 lux, more than 10 mm - 50-100 lux. With these standards, the illumination is sufficient for the function of vision, but in some cases it is less than 600 lux, that is, insufficient from a psychophysiological point of view. Therefore, when illuminated with fluorescent With lamps (since they are more economical), all the listed standards increase by 2 times and then the illumination approaches optimal in psychophysiological terms.
When writing and reading (schools, libraries, classrooms), the illumination in the workplace should be at least 300 (150) lux, in living rooms 100 (50), kitchens 100 (30).
For lighting characteristics great importance It has brightness. Brightness- the intensity of light emitted from a unit surface. In fact, when examining an object, we see not illumination, but brightness. The unit of brightness is candela per square meter (cd/m2) - the brightness of a uniformly luminous flat surface emitting in a perpendicular direction from each square meter luminous intensity equal to one candela. Brightness is determined with a brightness meter.
At rational lighting There should be no bright light sources or reflective surfaces in a person’s field of vision. If the surface in question is excessively bright, then this will negatively affect the functioning of the eye: a feeling of visual discomfort appears (from 2000 cd/m2), visual performance decreases (from 5000 cd/m2), causes glare (from 32,000 cd/m2 ) and even painful sensation(with 160,000 cd/m2). The optimal brightness of working surfaces is several hundred cd/m2. The permissible brightness of light sources located in a person’s field of vision is desirable no more than 1000-2000 cd/m2, and the brightness of sources that rarely fall into a person’s field of vision is no more than 3000-5000 cd/m2
Lighting should be uniform and do not create shadows. If the brightness in a person’s field of vision often changes, then fatigue occurs in the eye muscles that take part in adaptation (constriction and dilation of the pupil) and the accommodation that occurs synchronously with it (changes in the curvature of the lens). The lighting should be uniform throughout the room and at the workplace. At a distance of 5 m from the floor of the room, the ratio of the greatest to the least illumination should not exceed 3:1, at a distance of 0.75 m of the workplace - no more than 2:1. The brightness of two adjacent surfaces (for example, notebook - desk, blackboard - wall, wound - surgical linen) should not differ more than 2:1-3:1.
Illumination created general lighting, must be at least 10% of the value normalized for combined, but not less than 50 lux for incandescent lamps and 150 lux for fluorescent lamps.
Daylight. The sun produces outdoor illumination usually on the order of tens of thousands of lux. Natural lighting of premises depends on the light climate of the area, the orientation of building windows, the presence of shading objects (buildings, trees), the design and size of windows, the width of the inter-window partitions, the reflectivity of walls, ceilings, floors, the cleanliness of glass, etc.
For good daylighting The area of the windows should correspond to the area of the premises. Therefore, a common way to evaluate natural light premises is geometric, at which the so-called luminous coefficient, i.e. the ratio of the glazed window area to the floor area. The higher the luminous coefficient, the better lighting. For residential premises, the luminous coefficient must be at least 1/8-1/10, for classrooms and hospital wards 1/5-1/6, for operating rooms 1/4-1/5, for utility rooms 1/10-1/12.
Estimation of natural light only by light coefficient may be inaccurate, since illumination is influenced by the inclination of light rays to the illuminated surface ( angle of incidence rays). If, due to an opposing building or trees, not direct sunlight enters the room, but only reflected rays, their spectrum is devoid of the short-wave, most biologically effective part - ultraviolet rays. The angle within which direct rays from the sky fall at a certain point in the room is called hole angle.
Angle of incidence formed by two lines, one of which goes from the top edge of the window to the point where lighting conditions are determined, the second is a line on horizontal plane, connecting the measurement point to the wall on which the window is located.
Hole angle is formed by two lines running from the workplace: one to the upper edge of the window, the other to the highest point of the opposing building or any fence (fence, trees, etc.). The angle of incidence must be at least 27º, and the opening angle must be at least 5º. Illumination interior wall the room also depends on the depth of the room, and therefore, to assess daylight conditions, the penetration factor- the ratio of the distance from the top edge of the window to the floor to the depth of the room. The penetration ratio must be at least 1:2.
None of the geometric indicators reflects the complete influence of all factors on natural lighting. The influence of all factors is taken into account photovoltaic indicator-coefficient natural light(KEO). KEO= E p: E 0 *100%, where E p is the illumination (in lux) of a point located indoors 1 m from the wall opposite the window: E 0 - illumination (in lux) of a point located outdoors, provided its illumination by diffused light (solid cloudiness) of the entire sky. Thus, KEO is defined as the ratio of indoor illumination to simultaneous outdoor illumination, expressed as a percentage.
For residential premises, the KEO must be at least 0.5%, for hospital wards - at least 1%, for school classrooms - at least 1.5%, for operating rooms - at least 2.5%.
Artificial lighting must answer following requirements: be sufficiently intense, uniform; ensure proper shadow formation; do not dazzle or distort colors: do not heat; the spectral composition approaches daytime.
There are two artificial lighting systems: general And combined, when the general is complemented by the local, concentrating the light directly on the workplace..
The main sources of artificial lighting are incandescent and fluorescent lamps. Incandescent lamp-- convenient and trouble-free light source. Some of its disadvantages are low light output, a predominance of yellow and red rays in the spectrum and a lower content of blue and violet. Although, from a psychophysiological point of view, such a spectral composition makes the radiation pleasant and warm. In terms of visual work, incandescent lamp light is inferior to daylight only when it is necessary to examine very small parts. It is unsuitable in cases where good color discrimination is required. Since the surface of the filament is negligible, rage incandescent lamps significantly exceeds that which blinds. To combat brightness, they use lighting fixtures that protect from the glare of direct rays of light and hang the lamps out of people’s field of vision.
There are lighting fixtures direct light, reflected, semi-reflected and diffused. Armature direct The light directs over 90% of the lamp light to the illuminated area, providing it with high illumination. At the same time, a significant contrast is created between the illuminated and unlit areas of the room. Sharp shadows are formed and blinding effects are possible. This fixture is used for lighting auxiliary rooms and sanitary facilities. Armature reflected light characterized by the fact that the rays from the lamp are directed to the ceiling and to the top of the walls. From here they are reflected and evenly, without the formation of shadows, distributed throughout the room, illuminating it with soft diffused light. This type of fixture creates the most acceptable lighting from a hygienic point of view, but it is not economical, since over 50% of the light is lost. Therefore, to illuminate homes, classrooms, and wards, more economical fittings of semi-reflected and diffused light are often used. In this case, part of the rays illuminates the room, passing through the dairy or frosted glass, and part - after reflection from the ceiling and walls. Such fittings create satisfactory lighting conditions; they do not dazzle the eyes and do not create sharp shadows.
Fluorescent lamps meet most of the requirements above. Fluorescent Lamp is a tube made of ordinary glass, inner surface which is coated with phosphor. The tube is filled with mercury vapor, and electrodes are soldered at both ends. When the lamp is turned on electrical network occurs between the electrodes electricity(“gas discharge”), generating ultraviolet radiation. Under the influence of ultraviolet rays, the phosphor begins to glow. By selecting phosphors, fluorescent lamps with different visible radiation spectrums are manufactured. The most commonly used fluorescent lamps (LD), white light lamps (WL) and warm white light (WLT). The emission spectrum of the LD lamp approaches the spectrum of natural lighting in rooms with a northern orientation. With it, the eyes get the least tired even when looking at small details. The LD lamp is indispensable in rooms where correct color discrimination is required. The disadvantage of the lamp is that the skin of people's faces looks unhealthy and cyanotic in this light, rich in blue rays, which is why these lamps are not used in hospitals, school classrooms and a number of similar premises. Compared to LD lamps, the spectrum of LB lamps is richer in yellow rays. When illuminated with these lamps, the high efficiency eyes and complexion looks better. Therefore, LB lamps are used in schools, classrooms, homes, hospital wards, etc. The spectrum of LB lamps is richer in yellow and pink rays, which somewhat reduces the performance of the eye, but significantly revitalizes the complexion of the skin. These lamps are used to illuminate train stations, cinema lobbies, subway rooms, etc.
Spectrum diversity is one of hygienic items advantages of these lamps. The light output of fluorescent lamps is 3-4 times greater than incandescent lamps (with 1 W 30-80 lm), so they more economical. The brightness of fluorescent lamps is 4000-8000 cd/m2, i.e. higher than permissible. Therefore, they are also used with protective fittings. In numerous comparative tests with incandescent lamps in production, in schools, and classrooms, objective indicators characterizing the state of the nervous system, eye fatigue, and performance almost always indicated the hygienic advantage of fluorescent lamps. However, this requires qualified use of them. Required right choice lamps according to the spectrum depending on the purpose of the room. Since the sensitivity of vision to the light of fluorescent lamps is the same as to daylight, lower than the light of incandescent lamps, illumination standards for them are set 2-3 times higher than for incandescent lamps (Table 7.6.).
If with fluorescent lamps the illumination is below 75-150 lux, then a “twilight effect” is observed, i.e. illumination is perceived as insufficient even when viewing large details. Therefore, with fluorescent lamps, the illumination should be at least 75-150 lux.
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