Natural light is most beneficial for vision because sunlight necessary for normal human life. Visible rays solar spectrum(400-760 microns) provide vision function, determine the body’s natural biorhythm, have a positive effect on emotions and the intensity of metabolic processes; ultraviolet spectrum (290-400 microns) - stimulates the processes of metabolism, hematopoiesis, tissue regeneration and has an antirachitic (vitamin D synthesis) and bactericidal effect.

All rooms with constant occupancy should, as a rule, have natural light.

Natural lighting of the premises is created due to direct, diffused and reflected sunlight. It can be side, top, combined. Side lighting - through light openings in the external walls, top lighting - through light openings in the covering and lanterns, and combined lighting - in external walls and coverings.

The most hygienic is side lighting penetrating through windows, since overhead light with the same glazing area creates less illumination in the room; in addition, light openings and lanterns located in the ceiling are less convenient for cleaning and require special devices for this purpose. It is possible to use secondary lighting, i.e. lighting through glazed partitions from an adjacent room equipped with windows. However, it does not meet hygienic requirements and is allowed only in such areas as corridors, wardrobes, bathrooms, showers, utility rooms, and washing departments.

The design of natural lighting in buildings should be based on a detailed study of technological or other processes carried out indoors, as well as on the light-climatic features of the territory. This takes into account:

Characteristics of visual work; location of the building on the light climate map;

Required uniformity of natural light;

Equipment location;

The desired direction of incidence of the light flux on the working surface;

Duration of use of natural light during the day;

The need for protection from the glare of direct sunlight.

The following are used as hygienic indicators of natural light in premises:

Natural illumination coefficient (NLC) - the ratio of natural illumination indoors at control measurement points (at least 5) to the illumination outside the building (%). There are two groups of methods for determining KEO - instrumental and calculated.

In rooms with side lighting, the minimum value of the coefficient is normalized, and in rooms with overhead and combined lighting - the average value. For example, KEO in trading floors with side lighting it should be 0.4-0.5%, with top lighting - 2%.

For enterprises catering when designing side natural lighting, KEO should be: for halls, buffets - 0.4-0.5%; hot, cold, confectionery, pre-cooking and procurement shops - 0.8-1%; washing kitchen and tableware - 0.4-0.5%.

Luminous coefficient is the ratio of the area of ​​the glazed surface of windows to the floor area. In production, trade and administrative premises it should be at least -1:8, in household ones - 1:10.

However, this coefficient does not take into account climatic conditions, architectural features buildings and other factors affecting lighting intensity. Thus, the intensity of natural light largely depends on the design and location of windows, their orientation to the cardinal directions, and the shading of windows by nearby buildings and green spaces.

The angle of incidence is the angle formed by two lines, one of which runs from the workplace to the upper edge of the glazed part of the window opening, the other - horizontally from the workplace to the window. The angle of incidence decreases as you move away from the window. It is believed that for normal illumination by natural light, the angle of incidence should be at least 27o. The higher the window, the greater the angle of incidence.

Hole angle - the angle formed by two lines, one of which connects workplace with the top edge of the window, the other with the highest point of the light-obscuring object located in front of the window (opposing building, tree, etc.). With such darkness, the illumination in the room may be unsatisfactory, although the angle of incidence and luminous coefficient are quite sufficient. The hole angle must be at least 5°.

The illumination of the premises is directly dependent on the number, shape and size of windows, as well as on the quality and cleanliness of the glass.

Dirty glass with double glazing reduces natural light to 50-70%, smooth glass retains 6-10% of light, frosted glass - 60%, frozen glass - up to 80%.

The illumination of rooms is affected by the color of the walls: white reflects up to 80% sun rays, gray and yellow - 40%, and blue and green - 10-17%.

For best use to ensure that the light flow entering the room, walls, ceilings, and equipment should be painted in light colors. Particularly important is the light coloring of window frames, ceilings, upper parts walls that provide maximum reflected light rays.

The cluttering of light openings sharply reduces the natural illumination of the premises. Therefore, at enterprises it is prohibited to fill windows with equipment, products, containers both inside and outside the building, as well as to replace glass with plywood, cardboard, etc.

IN warehouses Lighting is usually not provided, and in some cases it is undesirable (for example, in pantries for storing vegetables), and is not allowed (in refrigerators). However, for storing flour, cereals, pasta, food concentrates, dried fruits, natural lighting is advisable.

In case of insufficient natural light, combined lighting is allowed, in which natural and artificial light are used simultaneously.

More on the topic Hygienic requirements for natural lighting:

1. Hygienic requirements for natural and artificial lighting of pharmacies, warehouses for small wholesale trade of pharmaceutical products.
2. Hygienic standards for the microclimate of sports premises of various specializations. Natural and artificial lighting of sports premises taking into account hygienic standards.
3. Research and hygienic assessment of natural lighting conditions.
4. Topic 7. Hygienic assessment of the conditions of natural and artificial lighting in the premises of pharmacies and pharmaceutical industry enterprises.
5. Hygienic assessment of insolation regime, natural and artificial lighting (using the example of premises of medical, preventive and educational institutions)

Natural lighting is used during the daytime. It provides good illumination and uniformity; Due to its high diffuseness (scattering), it has a beneficial effect on vision and is economical. In addition, sunlight has a biologically healing and tonic effect on humans.

The primary source of natural (daylight) light is the Sun, which emits a powerful stream of light energy into space. This energy reaches the Earth's surface in the form of direct or scattered (diffuse) light. In lighting calculations for natural lighting in rooms, only diffuse light is taken into account.

The amount of natural outdoor illumination has large fluctuations, both seasons, and by the hour of the day. Significant fluctuations in natural light levels during the day depend not only on the time of day, but also on changes in cloud cover.

Thus, natural light sources have characteristics that create dramatically changing lighting conditions. The task of designing natural lighting for premises comes down to the rational use of the natural light resources available in the area.

Natural light of premises is carried out through light openings and can be made in the form of side, top or combined.

Lateral- carried out through windows in the external walls of the building; top- through skylights located in the ceilings and having various shapes and sizes; combined- through windows and skylights.

In natural light, the distribution of illumination throughout the room, depending on the type of lighting, is characterized by the curves shown in Fig. 36, a-g.

Rice. 36. Scheme of distribution of natural light coefficients in rooms depending on the location of light openings:

a - one-sided - lateral; b - bilateral - lateral; in - upper; g - combined (lateral and upper)

The natural light curves of the premises must be taken into account when arranging equipment so that it does not shade the workplaces furthest from the light openings.

Natural light in the room is determined natural light factor(KEO) - e, which is the ratio, expressed as a percentage, of the illumination of any point in the room to a point on a horizontal plane outside the room, illuminated by the diffused light of the entire sky, at the same moment in time:

where E in - illumination of a point indoors; Enar - illumination of a point outdoors.

The point for measuring the illumination inside the room is determined: with side lighting - at the line of intersection of the vertical plane of the characteristic section of the room (axis of the window opening, etc.) and the horizontal plane located at a height of 1.0 m from the floor and at the distance furthest from light opening; with overhead lighting or combined (side and top) - at the line of intersection of the vertical plane of the characteristic section of the room and the horizontal plane at a height of 0.8 m from the floor.

The coefficient of natural illumination is established by standards and with side lighting it is defined as minimum - e min, and with overhead and combined lighting as average - e avg.

The values ​​of natural illumination coefficients for the central zone of the European part of the USSR, established by SNiP II-A.8-72, are given in table. 6.

Table 6

Under the concept object of distinction means the object in question, a separate part of it or a discernible defect (for example, a thread of fabric, a dot, a mark, a crack, a line forming a letter, etc.) that must be taken into account during the work process.

When determining the required natural illumination of workplaces in industrial premises, in addition to the natural illumination coefficient, it is necessary to take into account the depth of the room, floor area, windows and lanterns, shading by neighboring buildings, shading of windows by opposing buildings, etc. The influence of these factors is taken into account using the correction factors of Appendix 2 of SNiP II -A.8-72.

Using this application, you can determine the area of ​​light openings (windows or lanterns) using the following formulas, depending on the type of lighting in the room:

with side lighting

where m is the light climate coefficient (excluding direct sunlight), determined depending on the area where the building is located; c is the coefficient of climate sunshine (taking into account direct sunlight). The normalized value e n is the minimum acceptable.

The territory of the USSR according to the light climate is divided into V zones (I - the northernmost, V - the southernmost):

Sunny climate- characteristic taking into account the zone of light climate and luminous flux, penetrating through the light openings into the room throughout the year due to direct sunlight, the likelihood of sunshine, the orientation of the light openings to the sides of the horizon and their architectural and constructive solution.

Sunshine factor With ranges from 0.65 to 1.

The task of calculating natural lighting is to determine the ratio total area glazed openings of windows and lanterns to the floor area (S f / S p). The minimum values ​​of this ratio are given in table. 7.

Table 7

Indicated in the table. 7 values ​​are determined based on the condition that cleaning the glass in the room, as well as painting the walls and ceilings, are carried out regularly within the following periods. If there is a slight emission of dust, smoke and soot - at least twice a year; painting - at least once every three years. In case of significant emissions of dust, smoke and soot - at least four times a year; painting - at least once a year.

Dirty glass in light openings (windows and skylights) can reduce the illumination of rooms by five to seven times.

GENERAL INFORMATION

Organization of rational lighting of workplaces is one of the main issues of labor safety. Occupational injuries, productivity and quality of work performed largely depend on the correct lighting arrangement.

There are two types of lighting: natural And artificial. When calculating them, it is necessary to be guided by the building codes and rules of SNiP 23-05-95 “Natural and artificial lighting”.

IN methodological guidelines calculation methods are given various types natural lighting.

In accordance with the requirements of SNiP 23-05-95, all production, warehouse, household and administrative office premises must, as a rule, have natural lighting. It is not installed in rooms where photochemical exposure to natural light is contraindicated for technical and other reasons.

Natural lighting may not be provided: in sanitary premises; waiting health centers; premises for personal hygiene of women; corridors, passages and passages of industrial, auxiliary and public buildings. Natural lighting can be side, top, combined or combined.

Side natural lighting- this is the natural illumination of a room with light entering through light openings in the external walls of the building.

With one-sided side lighting it is normalized daylight factor value (KEO) at a point located at a distance of 1 m from the wall (Fig. 1.1a), i.e., farthest from the light openings at the intersection of the vertical plane of the characteristic section of the room and the conventional work surface(or gender). With side lighting, the influence of shading from opposing buildings is taken into account by the shading coefficient To ZD(Fig. 1.26).

With two-sided side lighting it is normalized minimum value KEO at a point in the middle of the room at the intersection of the vertical plane of the characteristic section of the room and the conventional working surface (or floor) (Figure 1.16).

Overhead natural lighting- this is the natural illumination of a room with light penetrating through light openings in the building’s roof and lanterns, as well as through light openings in places where there are differences in heights of adjacent buildings.

Figure 1.1 - Natural light distribution curves: A - with one-way side lighting; b - bilateral lateral; 1 - level of the conditional working surface; 2 - curve characterizing the change in illumination in the section plane of the room; RT - point of minimum illumination for lateral one-sided and two-sided illumination e min.

With top or top and side natural lighting it is normalized average value KEO at points located at the intersection of the vertical plane of the characteristic section of the room and the conventional working surface (or floor). The first and last points are taken at a distance of 1 m from the surface of walls or partitions or from the axes of rows of columns (Fig. 3.1a).

It is allowed to divide the room into zones with side lighting (zones adjacent to external walls with windows) and zones with overhead lighting; rationing and calculation of natural light in each zone are carried out independently. In this case, the nature of visual work is taken into account. Conditional working surface - conditionally accepted horizontal surface, located at a height of 0.8 m from the floor.

Combined lighting is lighting in which natural and artificial light are used simultaneously during daylight hours. At the same time, natural lighting, which is insufficient for visual work conditions, is constantly supplemented with artificial lighting that meets special requirements for premises (SNiP 23-05-95 for lighting design) with insufficient natural lighting.

Figure 1.2 - Scheme for designating building dimensions for calculating natural lateral lighting:

A - size designation diagram for calculating natural side lighting: - width of the room;

L PT - distance from outer wall to the design point (RT);

1 m - distance from the wall surface to the design point (PT);

In p- depth of the room; h 1 - height from the level of the conventional working surface to the top of the window;

h 2- height from floor level to conventional working surface (0.8 m);

L p- length of the room; N- room height; d- wall thickness;

6 - scheme for determining the coefficient To ZD: Nkz- cornice height

of the opposing building above the window sill of the building in question; Lj# - distance

between the building in question and the opposing building; M- shading border

Minimum room illumination standards are determined KEO, representing the ratio of natural light , created at a certain point of a given plane indoors by sky light (directly or after reflections), to the simultaneous value of external horizontal illumination , created by the light of a completely open sky, determined in %.

Values KEO for premises requiring various conditions illumination, taken in accordance with SNiP 23-05-95, table. 1.1.

The design of natural lighting of buildings should be based on a detailed study of technological or other labor processes carried out in the premises, as well as on the light-climatic features of the building construction site. In this case, the following characteristics must be determined:

Characteristics of visual work, determined depending on smallest size object of discrimination, category of visual work;

Location of the building on the light climate map;

Normalized value KEO taking into account the characteristics of visual work and the light-climatic features of the location of the buildings;

Required uniformity of natural light;

Dimensions and the location of the equipment, its possible darkening of the working surfaces;

The desired direction of incidence of the light flux on the working surface;

Duration of use of natural light during the day for different months of the year, taking into account the purpose of the room, operating mode and light climate of the area;

The need to protect the room from the glare of direct sunlight;

Additional lighting requirements arising from the specifics technological process and architectural requirements for the interior.

Design of natural lighting is carried out in a certain sequence:

Stage 1 - determining the requirements for natural lighting of premises; definition of normative value KEO according to the category of visual work predominant in the room:

Selecting a lighting system;

Selection of types of light opening and light-transmitting material;

Selecting means to limit the glare of direct sunlight;

Taking into account the orientation of buildings and light openings on the sides of the horizon;

Stage 2 - performing a preliminary calculation of the natural lighting of the premises; i.e. calculation of glazing area Soc:

Clarification of light openings and room parameters;

Stage 3 - performing a verification calculation of the natural lighting of the premises:

Identification of rooms, zones and areas that have insufficient natural lighting according to standards;

Determination of requirements for additional artificial lighting of premises, zones and areas with insufficient natural light;

Stage 4 - making the necessary adjustments to the natural lighting design and repeating the verification calculation (if necessary).

CALCULATION OF LATERAL ONE-SIDED NATURAL LIGHT

In most cases, natural lighting of industrial and administrative and office premises is provided by side one-way lighting (Fig. 1.1a; Fig. 1.2a).

The method for calculating natural side lighting can be reduced to the following.

1.1.The level of visual work and the standard value of the coefficient of natural illumination are determined.

The category of visual work is determined depending on the value of the smallest size of the object of discrimination (according to the task) and in accordance with this, according to SNiP 23-05-95 (Table 1.1), a standard value for the coefficient of natural illumination is established , %.

Object of distinction- this is the object in question, its individual parts or a defect that needs to be distinguished during the work process.

1.2. The required glazing area is calculated Soc:

where is the normalized value KEO for buildings located in different areas;

Light characteristics of the window;

A coefficient that takes into account the darkening of windows by opposing buildings;

- floor area, m2;

Total light transmittance;

A coefficient that takes into account the reflection of light from surfaces in a room.

The values ​​of the parameters included in formula (1.1) are determined using formulas, tables and graphs in a certain sequence.

Normalized value KEO e N for buildings located in different areas should be determined by the formula

e N =e H -m N (%),(1.2)

where is the value KEO,%, determined according to table. 1.1;

m N- light climate coefficient (Table 1.2), taken into account the group of administrative districts according to light climate resources (Table 1.3).

The value obtained from formula (1.2) KEO round to the nearest tenth.

1,5%; m N = 1,1

where is the length of the room (according to appendix 1);

Room depth, m, side view one-way lighting equal +d,(Fig. 1.2a);

Width of the room (according to appendix 1);

d- wall thickness (according to appendix 1);

- height from the level of the conventional working surface to the top of the window, m (Appendix 1).

Knowing the values ​​of the relations (1.3), according to table. 1.4 find the value of the light characteristic of the window

To calculate the coefficient , taking into account the darkening of windows by a neighboring building (Fig. 1.26), it is necessary to determine the ratio

where is the distance between the building under consideration and the opposing building, m;

The height of the cornice of the opposing building above the window sill of the window in question, m.

Depending on the value according to the table. 1.5 find coefficient

The total light transmittance is determined by the expression

where is the light transmittance of the material (Table 1.6);

Coefficient taking into account light loss in window sashes of light openings (Table 1.7);

Coefficient taking into account light loss in load-bearing structures with side natural lighting = 1;

- coefficient taking into account light loss in sun protection devices (Table 1.8).

When determining the coefficient taking into account the reflection of light from surfaces in a room, it is necessary to calculate:

a) weighted average coefficient of light reflection from walls, ceiling and floor:

Where - area of ​​walls, ceiling, floor, m 2, determined by the formulas:

where are the width, length and height of the walls of the room, respectively (as specified in Appendix 1).

The source of natural light is the radiant energy of the sun. The natural average outdoor illumination throughout the year fluctuates sharply by month and hour, reaching middle lane our country's maximum is in June and minimum in December. In addition, during the day, illumination first increases - up to 12 hours, then decreases - in the period from 12 to 14 hours and gradually decreases - until 20 hours.

Natural light has both positive and negative sides.

Solar radiation greatly affects the skin, internal organs and tissues and, above all, the central nervous system. Interestingly, this effect is not limited to the time a person is in the sun, but continues after he goes indoors or night falls. Doctors call it reflex.

The effect of sunlight begins with its influence on skin. Human skin unprotected by clothing reflects from 20 to 40% of the visible and closest in wavelength invisible infrared rays that fall on it (20% is reflected by the skin of a tanned person, and 40% is reflected by the most untanned, white skin). The absorbed part (60...65%) of radiant energy penetrates under the outer skin and affects the deeper layers of the body.

Ultraviolet and some infrared rays are reflected by the skin to a lesser extent and are more strongly absorbed by the horny, rougher layer of the skin.

In people long time working in the North, in mines, metro or simply in cities in central Russia, those who are mostly indoors during the daytime and travel along the streets by transport develop solar starvation. The fact is that ordinary window glass in buildings transmits physiologically active ultraviolet rays to an insignificant extent, and in cities already little of them reaches the surface of the Earth as a result of air pollution with dust, smoke, and exhaust gases.

During sun starvation, the skin becomes pale, cold, and loses its freshness. She is poorly supplied nutrients and oxygen. Blood and lymph circulate weaker in it, waste products are poorly removed from it, and poisoning of the body with waste substances begins. In addition, the capillaries become more fragile, and therefore the tendency to hemorrhage increases.

Those who experience solar starvation experience painful, unpleasant metamorphoses that affect both the psyche and the physical state. First of all, activity disturbances appear nervous system: memory and sleep deteriorate, excitability increases in some and indifference, lethargy in others. With the deterioration of calcium metabolism (the appearance of difficulties in the absorption of dietary calcium and phosphorus, which continue to be excreted from the body, and consequently, tissue depletion occurs in these necessary substances) teeth begin to rapidly deteriorate, bone fragility increases. Thus, with prolonged solar fasting, mental abilities and performance decrease, fatigue and irritation set in very quickly, mobility decreases, and the ability to fight microbes entering the body deteriorates (immunity decreases). Undoubtedly, a person experiencing sun starvation is more likely to get colds and other infectious diseases, and the disease is protracted. In these cases, fractures, cuts and any wounds heal slowly and poorly. There is a tendency to pustular diseases in those who have not previously suffered from this, and the course of chronic diseases in those who already have them worsens, inflammatory processes are more severe, which is associated with an increase in the permeability of the vascular walls, and the tendency to edema increases.

Given the degree of beneficial effects of natural light on the human body, occupational health requires maximum use of natural light. It is not arranged only where it is contraindicated technological conditions production, for example, when storing photosensitive chemicals and products.

Thus, solar lighting increases labor productivity by up to 10%, and the creation of a rational artificial lighting- up to 13%, while in a number of industries defects are reduced to 20...25%. Rational lighting provides psychological comfort, helps reduce visual and general fatigue, and reduces the risk of occupational injuries.

According to their design, natural lighting is divided into:

Lateral, carried out through window openings, one- or two-sided (Fig. 4.3 A, b);

Upper, when light enters the room through aeration or skylights, openings in the ceilings (Fig. 4.3 V);

Combined, when side lighting is added to the top lighting (Fig. 4.3 G).

Premises with constant occupancy should, as a rule, have natural lighting - illumination of the premises with sky light (direct or reflected). Natural lighting is divided into side, top and combined (top and side).

ЎNatural lighting of premises depends on:

• 1. Light climate - a set of natural lighting conditions in a particular area, which are made up of general climatic conditions, degree of transparency of the atmosphere, as well as reflectivity environment(albedo of the underlying surface).
• 2. Insolation mode - the duration and intensity of room illumination by direct sunlight, depending on geographical latitude location, orientation of buildings to cardinal directions, shading of windows by trees or houses, size of light openings, etc.

Insolation is an important healing, psycho-physiological factor and should be used in all residential and public buildings with permanent occupancy, with the exception of individual premises public buildings, where insolation is not allowed due to technological and medical requirements. According to SanPiN No. RB, such premises include:

• § operating rooms;
• § hospital intensive care rooms;
• § exhibition halls of museums;
• § chemical laboratories of universities and research institutes;
• § book depositories;
• § archives.

The insolation regime is assessed by the duration of insolation during the day, the percentage of the insolated area of ​​the room and the amount of radiation heat entering the room through the openings. Optimal insolation efficiency is achieved by daily continuous irradiation of premises with direct sunlight for 2.5 - 3 hours. natural lighting insolation

ЎDepending on the orientation of building windows to the cardinal points, three types of insolation regime are distinguished: maximum, moderate, minimum. (Appendix, Table 1).

With a western orientation, a mixed insolation regime is created. In terms of duration it corresponds to a moderate insolation regime, and in terms of air heating - to a maximum insolation regime. Therefore, according to SNiP 2.08.02-89, the orientation of the windows of the chambers to the west intensive care, children's wards (up to 3 years), playrooms in children's departments are not allowed.

In mid-latitudes (territory of the Republic of Belarus) for hospital wards, rooms day stay patients, classrooms, group rooms of children's institutions, the best orientation, providing sufficient illumination and insolation of the premises without overheating, is the south and southeast (acceptable - SW, E).

The windows of operating rooms, resuscitation rooms, dressing rooms, treatment rooms, delivery rooms, therapeutic and surgical dentistry rooms are oriented to the north, northwest, northeast, which ensures uniform natural illumination of these rooms with diffused light, eliminates overheating of the rooms and the blinding effect of sunlight, and also the appearance of shine from a medical instrument.

Standardization and assessment of natural lighting in premises

Standardization and hygienic assessment of natural lighting of existing and designed buildings and premises is carried out in accordance with SNiP II-4-79 using lighting engineering (instrumental) and geometric (calculation) methods.

The main lighting indicator of natural lighting of premises is the natural illumination coefficient (KEO) - the ratio of natural illumination created at some point on a given plane inside a room by sky light to the simultaneous value of external horizontal illumination created by the light of a completely open sky (excluding direct sunlight), expressed in percent:

KEO = E1/E2 100%,

where E1 is indoor illumination, lux;

E2 - outdoor illumination, lux.

This coefficient is an integral indicator that determines the level of natural light, taking into account all factors influencing the conditions for the distribution of natural light in the room. Measurement of illumination on the working surface and in the open air is carried out with a lux meter (U116, Yu117), the operating principle of which is based on converting the energy of the luminous flux into electric current. The receiving part is a selenium photocell having light-absorbing filters with coefficients of 10, 100 and 1000. The photocell of the device is connected to a galvanometer, the scale of which is calibrated in lux.

ЎWhen working with a lux meter, you must observe the following requirements(MU RB 11.11.12-2002):

• · the receiving plate of the photocell must be placed on the working surface in the plane of its location (horizontal, vertical, inclined);
• · random shadows or shadows from people and equipment should not fall on the photocell; if the workplace is shaded during work by the worker himself or by protruding parts of equipment, then the illumination should be measured under these actual conditions;
• · meter should not be located near sources of strong magnetic fields; Installation of the meter on metal surfaces is not allowed.

The natural light factor (according to SNB 2.04.05-98) is normalized for various rooms taking into account their purpose, the nature and accuracy of the visual work performed. In total, 8 categories of visual accuracy are provided (depending on the smallest size of the discrimination object, mm) and four subcategories in each category (depending on the contrast of the object of observation with the background and the characteristics of the background itself - light, medium, dark). (Appendix, Table 2).

With side one-sided lighting, the minimum value of KEO is standardized at the point of the conventional working surface (at the level of the workplace) at a distance of 1 m from the wall farthest from the light opening. (Appendix, Table 3).

ЎGeometric method for assessing natural light:

• 1) Light coefficient (LC) - the ratio of the glazed area of ​​windows to the floor area of ​​a given room (the numerator and denominator of the fraction are divided by the value of the numerator). The disadvantage of this indicator is that it does not take into account the configuration and placement of windows, and the depth of the room.
• 2) Laying depth (depth) coefficient (CD) - the ratio of the distance from the light-carrying wall to the opposite wall to the distance from the floor to the upper edge of the window. The short circuit should not exceed 2.5, which is ensured by the width of the ceiling (20-30 cm) and the depth of the room (6 m). However, neither SK nor KZ do not take into account the darkening of windows by opposing buildings, so they additionally determine the angle of incidence of light and the angle of the opening.
• 3) The angle of incidence shows at what angle the rays of light fall on a horizontal working surface. The angle of incidence is formed by two lines emanating from the point of assessment of lighting conditions (workplace), one of which is directed towards the window along the horizontal working surface, the other - towards the upper edge of the window. It must be at least 270.
• 4) The angle of the hole gives an idea of ​​the size of the visible part of the sky illuminating the workplace. The opening angle is formed by two lines emanating from the measuring point, one of which is directed to the upper edge of the window, the other to the upper edge of the opposing building. It must be at least 50.

The assessment of the angles of incidence and opening should be carried out in relation to the workstations furthest from the window. (Appendix, Fig. 1).