Duration of natural light. Types of natural lighting

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Surface illuminance represents the ratio of incident luminous flux to the area of the illuminated surface.

In building lighting technology, the sky is considered as a source of natural light for building premises. Since the brightness of individual points in the sky varies significantly and depends on the position of the sun, the degree and nature of cloudiness, the degree of transparency of the atmosphere and other reasons, it is impossible to establish the value of natural illumination in a room in absolute units (lx).

Therefore, to assess the natural light regime of rooms, a relative value is used, which allows taking into account the uneven brightness of the sky - the so-called daylight factor (KEO)

Natural light factor e m at any point in the room M represents the illuminance ratio at that point E to m to simultaneous external illumination of the horizontal plane E n located on open place and illuminated by diffuse light from the entire sky. KEO is measured in relative units and shows what percentage at a given point in the room is the illumination of the simultaneous horizontal illumination under open air, i.e.:

e m = (E in m / E n) × 100%

The coefficient of natural illumination is a value standardized by sanitary and hygienic requirements for natural light premises.

According to SNiP 23-05-95 "Natural and artificial lighting", natural lighting is divided into

lateral,
top,
combined (top and side)

The main document regulating the requirements for natural lighting in residential and public buildings, is SanPiN 2.2.1/2.1.1.1278-03 " Hygienic requirements to natural, artificial and combined lighting of residential and public buildings."

In accordance with SanPiN 2.1.2.1002-00 “Sanitary and epidemiological requirements for residential buildings and premises,” living rooms and kitchens in residential buildings must have direct natural light. According to these requirements of KEO in living rooms and kitchens there should be at least 0.5% in the middle of the room.

According to SNiP 31-01-2003 "Residential multi-apartment buildings" the ratio of the area of light openings to the floor area of residential premises and kitchens should be taken no more than 1:5.5 and no less than 1:8 for the upper floors with light openings in the plane of inclined enclosing structures - not less than 1:10, taking into account the lighting characteristics of windows and shading by opposing buildings.

In accordance with SNiP 23-05-95, the normalized values of KEO - e N for buildings located in different light-climatic areas should be determined by the formula:

e N = e N × m N Where N- number of natural light supply group according to the table

Light openings	Orientation of light openings to cardinal directions	Light climate coefficient, m
		Administrative district group number
		1	2	3	4	5
in the external walls of buildings	northern	1	0,9	1,1	1,2	0,8
	northeast, northwest	1	0,9	1,1	1,2	0,8
	western, eastern	1	0,9	1,1	1,1	0,8
	southeast, southwest	1	0,9	1	1,1	0,8
	southern	1	0,9	1	1,1	0,8

Illumination in the room is achieved due to direct diffuse light from the sky and reflected diffuse light from the internal surfaces of the room, opposing buildings and the surface of the ground adjacent to the building. Accordingly, KEO at the point of placement M is defined as the sum:

e m = e n + e O + e Z + e π Where e n- KEO created by direct diffuse light from a section of the sky visible from a given point through openings, taking into account light losses during
the passage of light flux through a glazed opening; e o - KEO, created by reflected light from the internal surfaces of the room (ceiling, walls, floor); e Z - KEO, created by reflected light from opposing buildings; eπ - KEO, created by reflected light from the surface of the earth adjacent to the building (soil, asphalt, grass, etc.)

Direct light from the sky has the greatest influence on the KEO value.

The component from direct light from the sky is determined by the formula:

e n = e n 0 × τ 0×q Where e n 0- geometric KEO (sky coefficient); τ 0 - the overall light transmittance of the opening; q- coefficient taking into account the uneven brightness of the sky;

The overall light transmission coefficient of the opening τ 0 with side lighting is determined as the product of two components:

τ 0 = τ 1 × τ 2 Where τ 1- transmittance of uncontaminated glass or other translucent filling (in modern regulatory documentation
- directional transmittance of visible light window glass or double glazing) τ 2- transmittance of a window block without glazing, taking into account the shading created by the sashes.

The values of the coefficients τ 1 can be taken according to

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 in premises comes down to the rational use of the natural light resources available in the area.

Daylight 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 point 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.

Values of natural light coefficients for middle zone 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- a characteristic that takes into account the light climate zone and the luminous flux penetrating through the light openings into the room throughout the year due to direct sunlight, the probability of sunshine, the orientation of the light openings along the horizon and their architectural and structural design.

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.

The assessment of natural lighting in production due to its variability depending on the time of day and atmospheric conditions is carried out in relative indicators natural light factor - KEO. KEO is the ratio of natural illumination at the considered point indoors (Ev) to the simultaneous value of external (En) horizontal illumination without direct sunlight.

KEO is expressed as a percentage and is determined by the formula:

The KEO value is influenced by the size and configuration of the room, the size and location of light openings, the reflective ability of the internal surfaces of the room and objects shading it. KEO does not depend on the time of day and the variability of natural light. Depending on the purpose of the room and the location of the light openings in it, KEO is normalized from 0.1 to 10%. The norms for natural lighting of premises are established separately for the side and top locations of light openings. With one-sided side lighting, the minimum KEO value is standardized at a distance of 1 m from the windows, and with two-sided side lighting in the middle of the room. In rooms with overhead or combined lighting, the average KEO value on the working surface is normalized (no closer than 1 m from the walls). In domestic premises of industrial buildings, the KEO value must be at least 0.25%.

KEO values for combined lighting of buildings located in the III light climate zone range from 0.2 to 3%.

The level of natural light in rooms can be reduced due to contamination of glazed surfaces, which reduces transmittance, and contamination of walls and ceilings reduces reflectance. Therefore, the standards provide for cleaning the glass of skylights at least 2 times a year in rooms with insignificant emissions of dust, smoke and soot, and at least 4 times in case of significant contamination. Whitewashing and painting of ceilings and walls should be done at least once a year.

As is known, light stimuli from certain parts of the solar spectrum cause various psychological reactions. Cold tones in the blue-violet part of the spectrum have a depressing, inhibitory effect on the body, yellow-green color has a calming effect, and the orange-red part of the spectrum has an exciting, stimulating effect and enhances the feeling of warmth. This property of the spectral composition of light is used to create light comfort in the aesthetic design of workshops, painting equipment and walls.

When choosing the color of paint for premises and equipment, you should use the “Instructions for lighting finishing of the surface of industrial premises and equipment” issued by the State Construction Committee. technological equipment industrial enterprises" In enterprises where workers, due to the nature and working conditions or due to geographical conditions (northern regions), are completely or partially deprived of natural light, it is necessary to provide ultraviolet prevention with sources of UV radiation (erythema lamps), which compensate for the deficiency of natural UV radiation and have a pronounced bactericidal and psycho-emotional impact on a person. Prevention of “light” starvation is carried out by long-term ultraviolet irradiation installations, which are part of the general artificial lighting system and irradiate workers with a low-intensity UV flux during the entire operating time. Short-term ultraviolet irradiation installations are also used - fotariums, in which UV irradiation occurs within a few minutes.

Insolation of industrial buildings through light openings with a large glazing area significantly increases the natural illumination of the premises, has a blinding effect due to direct or reflected glare from sun rays, and to combat excessive insolation it is necessary to use stationary or adjustable sun protection devices - visors, horizontal and vertical screens, special landscaping, transparent blinds, curtains, etc.

Natural lighting systems are ideal option for almost any building and structure. After all, unlike artificial light, natural light has no flicker, provides full light transmission, is comfortable for the eyes and, of course, is completely free.

And in general, a pleasant, warming ray of light always fills the room with a special atmosphere. Therefore, it is not surprising that since ancient times people have been trying to provide maximum natural light in their buildings.

During its development, humanity has come up with many ways to provide its home with sunlight. But all these methods can be divided into three methods.

So:

The most commonly used is side lighting. IN in this case light streams through the opening in the wall and falls on a person from the side. Where did the name come from?

Side lighting is quite easy to implement and provides high-quality illumination inside the house. At the same time, in wide halls, when the walls opposite the window are located far away, sunlight does not always reach all corners of the room. To do this, increase the height window openings, but such a solution is not always possible.

More interesting for such rooms is overhead lighting.. In this case, the light falls from the openings in the roof and streams onto the person above.

This type of lighting is almost ideal. After all, with proper planning, you can provide illumination to any corner of the house.

But as you understand, it is only possible with a one-story plan. And heat loss from this type of natural lighting is an order of magnitude higher. After all warm air It always goes up, and there are cold windows.

That is why there is natural combined lighting. It allows you to take the best of the first two types. After all, combined lighting is called lighting in which the light falls on a person from both above and below.

But as you understand, this type of lighting is also only possible in a one-story building or on upper floors multi-storey buildings. But here's the cost window systems is an important limiting factor in their use.

Methods for proper planning of natural lighting

But knowing the types of natural lighting, we are not one step closer to uncovering the question of how to organize correct lighting at home? To answer this, let us look at the main stages of planning step by step.

Standards for natural lighting of buildings

In order to properly plan lighting, we first of all must answer the question, what should it be? The answer to this question is given to us by SNiP 23 – 05 – 95, which sets KEO standards for industrial, residential and public buildings.

KEO is the natural light coefficient. It is the ratio between the level of natural light at a certain point in the house and the illumination outside the room.
The optimality of this parameter was calculated by research institutes and summarized in a table, which has become the norm in design. But in order to use this table we need to know our latitude.

From the lessons of BZD and geography, you must remember that the further south you go, the higher the intensity of the solar flux. Therefore, the entire territory of our country was divided into five light climate zones, each of which has two subspecies.
Knowing our light climate zone, we can finally determine the KEO we need. For residential buildings it ranges from 0.2 to 0.5. Moreover, the further south you go, the smaller the KEO.
This is again due to geography. After all, the further south you go, the higher the outdoor illumination. And KEO is the ratio of illumination outside the room and inside it. Accordingly, to create the same level of illumination for houses in the south and north, the latter will have to make more efforts.

To move on, we need to find out where is this point in the house for which we will determine the level of illumination? The answer to this question is given to us by clauses 5.4 - 5.6 SNiP 23 - 05 -95.
According to them, with two-way side lighting of residential premises, the normalized point is the center of the room. With one-way side lighting, the normalized point is a plane one meter from the wall opposite the window. In other rooms, the normalized point is the center of the room.

Note! For one-, two- and three-room apartments This calculation is made for one living room. In a four-room apartment, this calculation is made for two rooms.

For overhead and combined lighting, the normalized point is a plane one meter from the darkest walls. This standard also applies to industrial premises.
But everything that we have given above is prescribed for use in residential and public buildings. With production, everything is a little more complicated. The fact is that production is different. On some I process meter-long workpieces, while on others I deal with microcircuits.
Based on this, all types of work were divided into eight classes depending on the level of visual work. Where products smaller than 0.15 mm are processed, they were assigned to the first group, and where accuracy is not particularly needed, they were assigned to the eighth. And for industrial enterprises, KEO is chosen based on the level of visual work.

Selecting window systems for a building

Natural light will enter our building through the windows. Therefore, knowing the standards that we need to comply with, we can move on to choosing windows.

The very first task is choosing window systems. That is, we must decide what kind of lighting we will have - top, side or combined in each room. To answer this question, you need to take into account the architectural structure of the building, its geographical location, the materials used, the thermal efficiency of the house, and of course the price will play an important role.
If you opt for overhead lighting, then you can use so-called skylights or skylights. These are special structures that often, in addition to light, also provide ventilation for buildings.
Light aeration lanterns in most cases have rectangular shape. This is due to ease of installation. At the same time, the triangular shape is considered the most successful in terms of lighting. But for triangular lanterns there is practically no reliable systems raising windows for ventilation.
Light aeration lamps are usually installed above industrial buildings with high internal heat generation, or on buildings located in southern latitudes, as in the video. This is due to the large heat losses of such window systems.

	Rectangular aeration lanterns are recommended for use in climate zones II-IV. Moreover, if the installation is carried out in areas south of 55° latitude, then the orientation of the lantern should be south and north. Such lamps should be used in buildings with excess sensible heat above 23 W/m 2, and with a level of visual performance of IV-VII category.
	Trapezoidal aeration lanterns are designed for the first climate zone. They are used for buildings in which class II-IV visual work is performed and with excess sensible heat above 23 W/m 2.
	It is recommended to install skylights in climate zones I-IV. In this case, when buildings are located south of 55 0, diffuse or heat-protected glass should be used as light transmitting materials. It is used for buildings with excess sensible heat less than 23 W/m2 and for all classes of visual work. It is important to note that the lights must be evenly spaced across the entire roof area.
	A skylight with a light-conducting shaft can be used for all climatic zones. It is usually used for buildings with air-conditioned air and a small range of temperature differences (for example, it is quite possible to install it yourself in residential buildings), as well as for areas where class II-VI work is performed. They are widely used in buildings with suspended ceilings.

Rooflights in Lately are becoming increasingly widespread both in production and in housing construction. This is due to the ease of installation of such systems and a fairly comfortable cost. The heat losses of such window systems are not so great, which allows them to be successfully used in northern latitudes.

Note! To eliminate the possibility of injury to a person, all horizontal and inclined surfaces vertical lighting must have special grids. They are necessary to prevent falling glass fragments.

If you decide to use natural side-type room lighting, then SNiP II-4-79 recommends giving preference to standard-type window systems. For such systems, all the necessary calculations have already been made and there are even recommendations. You can see these recommendations in the table below.

For side natural lighting important aspect is the shading of window systems from adjacent buildings. This must be taken into account when making calculations.

For buildings in which the wall opposite the window is located at a considerable distance, multi-tiered window systems are often installed. But it should be remembered that the height of one tier should not exceed 7.2 meters.
A very important aspect when choosing window systems is their correct orientation to the cardinal points. After all, it’s no secret that windows facing south provide significantly more light. This should be used to the maximum in buildings constructed in northern latitudes. At the same time, for buildings built in southern latitudes, it is recommended to orient windows to the north and west.

This will not only make it possible to use daylight more efficiently, but also reduce costs. Indeed, for buildings in southern latitudes, special light-blocking devices are installed to limit the glare of the sun, and with the correct orientation of the windows this can be avoided.

Combination of KEO standards and illumination standards

But KEO standards are not designed for every type of building. Sometimes it may happen that, according to KEO standards, the illumination is sufficient, but the illumination standards for the workplace are not met.

This lack of natural light can be compensated by creating combined lighting, or linked through critical outdoor lighting.

Critical outdoor illumination is the natural illumination in an open area equal to the standardized value of artificial lighting. This value allows you to bring the KEO in accordance with the requirements for artificial lighting.
For this, the formula E n =0.01eE cr is used, where E n is the standardized value of illumination, e is the selected KEO standard, and E cr is our critical external illumination.

But even this method does not always allow achieving the required standards. After all, natural light indicators do not always make it possible to achieve standardized values of workplace illumination. First of all, this applies to buildings located in northern latitudes, where the intensity of the light flux is lower and heat losses they don't give you the option to install a large number of windows

Especially for finding the golden mean, there is a so-called calculation of reduced costs for natural lighting. It allows you to determine whether it is more profitable for a building to create high-quality natural lighting or to limit it to combined, or perhaps even artificial, lighting.

Conclusion

Rooms without natural light are not nearly as comfortable as buildings with direct sunlight. Therefore, if such a possibility exists, natural light should definitely be created for any buildings and structures.

Of course, the issue of natural lighting is much more voluminous and multifaceted, but we have fully covered the main aspects of natural lighting in buildings, and we really hope that this will help you in making the right choice lighting for home or business.

Natural light is used for general lighting production and utility rooms. It is created by the radiant energy of the sun and has the most beneficial effect on the human body. When using this type of lighting, meteorological conditions and their changes during the day and periods of the year in a given area should be taken into account. This is necessary in order to know how much natural light will enter the room through the building's light openings: windows - with side lighting, skylights on the upper floors of the building - with overhead lighting. With combined natural lighting, side lighting is added to the overhead lighting.

Premises with constant occupancy should have natural light. Established by calculation The dimensions of light openings can be changed by +5, -10%.

Sun protection devices in public and residential buildings should be provided in accordance with the chapters of SNiP on the design of these buildings, as well as with the chapters on building heating engineering.

Distinguish the following types natural lighting of premises:

lateral one-sided - when the light openings are located in one of the external walls of the room,

Figure 1. Lateral one-way natural lighting

side - light openings in two opposite external walls of the room,

Figure 2. Lateral natural lighting

upper - when lanterns and light openings in the covering, as well as light openings in the walls of the height difference of the building,
combined - light openings provided for side (top and side) and overhead lighting.

The principle of normalizing natural light

The quality of lighting with natural light is characterized by the coefficient of natural light to eo, which is the ratio of illumination on a horizontal surface indoors to the simultaneous horizontal illumination outside,

WhereE V- horizontal illumination indoors in lux;

E n- horizontal illumination outside in lux.

With side lighting, the minimum value of the natural illumination coefficient is normalized - k eo min, and with overhead and combined lighting - its average value - k eo sr. The method for calculating the natural light factor is given in Sanitary standards design of industrial enterprises.

In order to create the most favorable conditions labor standards for natural light have been established. In cases where natural light is insufficient, work surfaces should be additionally illuminated with artificial light. Mixed lighting is allowed provided additional lighting of only working surfaces with general natural lighting.

Building codes and regulations (SNiP 23-05-95) set the coefficients of natural illumination of industrial premises depending on the nature of the work and the degree of accuracy.

To maintain the necessary illumination of the premises, the standards provide for mandatory cleaning of windows and skylights from 3 times a year to 4 times a month. In addition, walls and equipment should be systematically cleaned and painted in light colors.

Natural light standards industrial buildings, reduced to the standardization of K.E.O., are presented in SNiP 05/23/95. To facilitate the regulation of workplace illumination, all visual work is divided into eight categories according to the degree of accuracy.

SNiP 23-05-95 establish the required value of K.E.O. depending on the accuracy of the work, the type of lighting and the geographical location of the production. The territory of Russia is divided into five light belts, for which the values of K.E.O. are determined by the formula:

WhereN– number of the administrative-territorial district group for the provision of natural light;

e n- the value of the natural illumination coefficient, selected according to SNiP 23-05-95, depending on the characteristics of visual work in a given room and the natural lighting system.

m N— light climate coefficient, which is found according to SNiP tables depending on the type of light openings, their orientation along the horizon and the group number of the administrative region.

To determine the suitability of natural light in production premises Illumination to the required standards is measured with overhead and combined lighting at various points in the room, followed by averaging; at the side - at the least illuminated workplaces. At the same time, the external illumination and the calculated K.E.O. are measured. compared with the norm.

Natural Light Design

1. The design of natural lighting in buildings should be based on the study of labor processes performed indoors, as well as on the light-climatic features of the building construction site. In this case, the following parameters must be defined:

characteristics and category of visual work;
group of the administrative district in which the construction of the building is proposed;
the normalized value of KEO, taking into account the nature of visual work and the light-climatic features of the location of the buildings;
required uniformity of natural light;
the 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 premises from the glare of sunlight.

2. Design of natural lighting of a building should be carried out in the following sequence:

1st stage:
- determination of requirements for natural lighting of premises;
- choice of lighting systems;
- selection of types of light openings and light-transmitting materials;
- choosing means to limit the glare of direct sunlight;
- taking into account the orientation of the building and light openings on the sides of the horizon;
2nd stage:
- performance preliminary calculation natural lighting of premises (definition required area light openings);
- clarification of the parameters of light openings and rooms;
3rd stage:
- 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 rooms, zones and areas with insufficient natural light;
- determination of requirements for the operation of light openings;
4th stage: making the necessary adjustments to the natural lighting design and repeating the verification calculation (if necessary).

3. The natural lighting system of the building (side, top or combined) should be selected taking into account the following factors:

the purpose and adopted architectural, planning, volumetric and structural design of the building;
requirements for natural lighting of premises arising from the peculiarities of production technology and visual work;
climatic and light-climatic features of the construction site;
efficiency of natural lighting (in terms of energy costs).

4. Overhead and combined natural lighting should be used primarily in one-story public buildings large area(indoor markets, stadiums, exhibition pavilions, etc.).

5. Lateral natural lighting should be used in multi-story public and residential buildings, one-story residential buildings, as well as in one-story public buildings, in which the ratio of the depth of the premises to the height of the upper edge of the light opening above the conventional work surface does not exceed 8.

6. When choosing light openings and light-transmitting materials, you should consider:

requirements for natural lighting of premises;
purpose, volumetric-spatial and constructive solution building;
orientation of the building along the horizon;
climatic and light climatic features of the construction site;
the need to protect premises from insolation;
degree of air pollution.

7. When designing side natural lighting, shading created by opposing buildings should be taken into account.

8. Translucent fillings of light openings in residential and public buildings are selected taking into account the requirements of SNiP 23-02.

9. For side natural lighting of public buildings with increased requirements for constant natural lighting and sun protection (for example, art galleries), light openings should be oriented towards the northern quarter of the horizon (N-NW-N-NE).

10. The selection of devices for protection from the glare of direct sunlight should be made taking into account:

orientation of light openings on the sides of the horizon;
the direction of the sun's rays relative to a person in the room who has a fixed line of sight (student at his desk, draftsman at the drawing board, etc.);
working hours of the day and year, depending on the purpose of the premises;
differences between solar time, on which solar maps are constructed, and maternity time adopted on the territory of the Russian Federation.

When choosing products to protect against the glare of direct sunlight, you should be guided by the requirements building codes and rules for the design of residential and public buildings (SNiP 31-01, SNiP 2.08.02).

11. During a single-shift work (educational) process and when operating premises mainly in the first half of the day (for example, lecture halls), when the premises are oriented towards the western quarter of the horizon, the use of sunscreen is not necessary.