Natural light is most favorable for vision, since sunlight is necessary for normal human life. Visible rays of the solar spectrum (400-760 microns) provide the function of vision, determine the natural biorhythm of the body, 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 room lighting is created through direct, diffuse 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;

Desirable 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 public catering establishments, when designing side natural lighting, the 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 industrial, commercial and administrative premises it should be at least -1:8, in domestic premises - 1:10.

However, this coefficient does not take into account climatic conditions, architectural features of the building and other factors affecting the intensity of lighting. 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 larger angle falls.

Hole angle is 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%.

To make better use of the light flux entering the room, walls, ceilings, and equipment should be painted in light colors. Particularly important is the light coloring of window frames, ceilings, and the upper parts of walls, which provide maximum reflected light rays.

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, natural lighting is advisable for storing flour, cereals, pasta, food concentrates, and dried fruits.

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 standards for the microclimate of sports premises of various specializations. Natural and artificial lighting of sports facilities, taking into account hygienic standards.
2. Hygienic requirements for industrial lighting and ultraviolet irradiation
3. The impact of light on the human body and hygienic requirements for lighting conditions in educational premises
4. Standards for natural and artificial lighting of livestock buildings
5. Sanitary requirements for lighting, heating and ventilation
6. Hygienic principles of school placement. School service radius. Hygienic requirements for land and school buildings

School: basic, secondary general education

Resolution of the Chief State Sanitary Doctor of the Russian Federation dated December 29, 2010 N 189 (as amended on December 25, 2013) “On approval of SanPiN 2.4.2.2821-10 “Sanitary and epidemiological requirements for the conditions and organization of training in general education organizations”

VII. Requirements for natural and artificial lighting.

7.1. Daylight.

7.1.1. All educational premises must have natural lighting in accordance with the hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.

7.1.2. Without natural lighting it is allowed to design: squat rooms, washrooms, showers, toilets in the gymnasium; showers and toilets for staff; storerooms and warehouses, radio centers; film and photo laboratories; book depositories; boiler rooms, pumping water supply and sewerage systems; ventilation and air conditioning chambers; control units and other premises for installation and management of engineering and technological equipment of buildings; premises for storing disinfectants.

7.1.3. In classrooms, natural left-side lighting should be designed. When the depth of classrooms is more than 6 m, it is necessary to install right-side lighting, the height of which must be at least 2.2 m from the floor.

The direction of the main light flux in front and behind the students is not allowed.

7.1.4. In workshops for labor training, acts and gyms two-way side natural lighting can be used.

7.1.5. In the premises of educational institutions, normalized values ​​of the coefficient of natural illumination (NLC) are provided in accordance with the hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.

7.1.6. In classrooms with one-way side natural lighting KEO on work surface desks at the point of the room furthest from the windows should be at least 1.5%. With two-way side natural lighting, the KEO indicator is calculated on the middle rows and should be 1.5%.

The luminous coefficient (LC - the ratio of the area of ​​the glazed surface to the floor area) must be at least 1:6.

7.1.7. The windows of classrooms should be oriented to the southern, southeastern and eastern sides of the horizon. The windows of drawing and painting rooms, as well as the kitchen room, can be oriented towards the northern sides of the horizon. The orientation of computer science classrooms is north, northeast.

7.1.8. Light openings in classrooms, depending on the climate zone, are equipped with adjustable sun-shading devices (tilt-and-turn blinds, fabric curtains) with a length not lower than the level of the window sill.

It is recommended to use curtains made of light-colored fabrics that have a sufficient degree of light transmission and good light-diffusing properties, which should not reduce the level of natural light. The use of curtains (curtains), including curtains with lambrequins, made of polyvinyl chloride film and other curtains or devices that limit natural light, is not permitted.

When not in use, curtains must be placed in the walls between the windows.

7.1.9. For rational use daylight and uniform lighting of classrooms should:

• do not paint over window glass;
• do not place flowers on window sills; they are placed in portable flower boxes 65-70 cm high from the floor or hanging flowerpots in the walls between the windows;
• Clean and wash glass as it gets dirty, but at least twice a year (autumn and spring).

The duration of insolation in classrooms and classrooms must be continuous, with a duration of at least:

• 2.5 hours in the northern zone (north of 580 N);
• 2.0 hours in the central zone (58-480 N);
• 1.5 hours in the southern zone (south of 480 N).

It is allowed that there is no insolation in classrooms for computer science, physics, chemistry, drawing and drawing, sports gyms, catering facilities, assembly halls, and administrative and utility rooms.

7.2. Artificial lighting.

7.2.1. In all premises of a general education organization, levels of artificial illumination are provided in accordance with the hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.

7.2.2. In classrooms, the general lighting system is provided by ceiling lights with fluorescent lamps and LEDs. Lighting is provided using lamps according to the color spectrum: white, warm white, natural white.

7.2.3. Light sources of different radiation natures are not used in the same room for general lighting.

7.2.4. In classrooms, classrooms, laboratories, illumination levels must comply with the following standards: on desktops - 300-500 lux, in technical drawing and drawing rooms - 500 lux, in computer science classrooms on tables - 300 - 500 lux, on a blackboard 300-500 lux, in assembly and sports halls (on the floor) - 200 lux, in recreation (on the floor) - 150 lux.

When using computer technology and the need to combine the perception of information from the screen and writing in a notebook, the illumination on students’ desks should be at least 300 lux.

7.2.5. A general lighting system should be used in classrooms. Lamps with fluorescent lamps are located parallel to the light-carrying wall at a distance of 1.2 m from the outer wall and 1.5 m from the inner wall. Lamps with LEDs are located taking into account the requirements for limiting the level of discomfort in accordance with hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.

7.2.6. A blackboard that does not have its own glow is equipped with local lighting - spotlights designed to illuminate blackboards.

7.2.7. When designing an artificial lighting system for classrooms, it is necessary to provide for separate switching of lamp lines.

7.2.8. For the rational use of artificial light and uniform illumination of classrooms, it is necessary to use finishing materials and paints that create a matte surface with reflection coefficients: for the ceiling - 0.7 - 0.9; for walls - 0.5 - 0.7; for the floor - 0.4 - 0.5, for furniture and desks - 0.45; for chalkboards – 0.1-0.2.

It is recommended to use the following paint colors: for ceilings - white, for walls of classrooms - light tones of yellow, beige, pink, green, blue; for furniture (cabinets, desks) – the color of natural wood or light green; for chalkboards - dark green, dark brown; for doors, window frames - white.

7.2.9. Cleaning of lighting fixtures of lamps is carried out as they become dirty, but at least 2 times a year, and faulty light sources are promptly replaced.

7.2.10. Faulty, burnt-out fluorescent lamps are collected in a container in a specially designated room and sent for disposal in accordance with current regulations.

Source excerpt:

Sanitary and epidemiological requirements for schools
Resolution of the Chief State Sanitary Doctor of the Russian Federation dated December 29, 2010 N 189, Moscow “On approval of SanPiN 2.4.2.2821-10 “Sanitary and epidemiological requirements for the conditions and organization of training in educational institutions.”

Published March 16, 2011
Registered with the Ministry of Justice of the Russian Federation on March 3, 2011.
Registration N 19993

VII. Requirements for natural and artificial lighting

7.1.1. All educational premises must have natural lighting in accordance with the hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.
7.1.2. Without natural lighting it is allowed to design: squat rooms, washrooms, showers, toilets in the gymnasium; showers and toilets for staff; storerooms and warehouses, radio centers; film and photo laboratories; book depositories; boiler rooms, pumping water supply and sewerage systems; ventilation and air conditioning chambers; control units and other premises for installation and management of engineering and technological equipment of buildings; premises for storing disinfectants.
7.1.3. In classrooms, natural left-side lighting should be designed. When the depth of classrooms is more than 6 m, it is necessary to install right-side lighting, the height of which must be at least 2.2 m from the floor. The direction of the main light flux in front and behind the students is not allowed.
7.1.4. In workshops for labor training, assembly and sports halls, two-way side natural lighting can be used.
7.1.5. Indoors educational institutions Standardized values ​​of the coefficient of natural illumination (KEO) are provided in accordance with hygienic requirements for natural, artificial, combined lighting of residential and public buildings.
7.1.6. In classrooms with one-way side natural lighting, the KEO on the working surface of the desks at the point of the room farthest from the windows should be at least 1.5%. With two-way side natural lighting, the KEO indicator is calculated on the middle rows and should be 1.5%.
The luminous coefficient (LC - the ratio of the area of ​​the glazed surface to the floor area) must be at least 1:6.
7.1.7. The windows of classrooms should be oriented to the southern, southeastern and eastern sides of the horizon. The windows of drawing and painting rooms, as well as the kitchen room, can be oriented towards the northern sides of the horizon. The orientation of computer science classrooms is north, northeast.
7.1.8. Light openings in classrooms, depending on the climate zone, are equipped with adjustable sun-shading devices (tilt-and-turn blinds, fabric curtains) with a length not lower than the level of the window sill.
It is recommended to use curtains made of light-colored fabrics that have a sufficient degree of light transmission and good light-diffusing properties, which should not reduce the level of natural light. The use of curtains (curtains), including curtains with lambrequins, made of polyvinyl chloride film and other curtains or devices that limit natural light, is not permitted. When not in use, curtains must be placed in the walls between the windows.
7.1.9. To rationally use daylight and uniformly illuminate classrooms, you should:
- do not paint over window glass;
- do not place flowers on window sills; they are placed in portable flower boxes 65 - 70 cm high from the floor or hanging flowerpots in the walls between the windows;
- Clean and wash glass as it gets dirty, but at least 2 times a year (autumn and spring).
The duration of insolation in classrooms and classrooms must be continuous, with a duration of at least:
- 2.5 hours in the northern zone (north of 58 degrees N);
- 2.0 hours in the central zone (58 - 48 degrees N);
- 1.5 hours in the southern zone (south of 48 degrees N).
It is allowed that there is no insolation in classrooms for computer science, physics, chemistry, drawing and drawing, sports gyms, catering facilities, assembly halls, and administrative and utility rooms.

7.2. Artificial lighting

7.2.1. In all premises of a general education institution, levels of artificial illumination are provided in accordance with the hygienic requirements for natural, artificial, and combined lighting of residential and public buildings.
7.2.2. In classrooms, the general lighting system is provided by ceiling lamps. Fluorescent lighting is provided using lamps according to the color spectrum: white, warm white, natural white. Lamps used for artificial lighting of classrooms must provide a favorable distribution of brightness in the field of view, which is limited by the discomfort indicator (Mt). The discomfort index of a general lighting lighting installation for any workplace in a classroom should not exceed 40 units.
7.2.3. Fluorescent lamps and incandescent lamps should not be used in the same room for general lighting.
7.2.4. In classrooms, classrooms, laboratories, illumination levels must comply with the following standards: on desktops - 300 - 500 lux, in technical drawing and drawing rooms - 500 lux, in computer science classrooms on tables - 300 - 500 lux, on a blackboard - 300 - 500 lux, in assembly and sports halls (on the floor) - 200 lux, in recreation (on the floor) - 150 lux. When using computer technology and the need to combine the perception of information from the screen and writing in a notebook, the illumination on students’ desks should be at least 300 lux.
7.2.5. A general lighting system should be used in classrooms. Lamps with fluorescent lamps are located parallel to the light-carrying wall at a distance of 1.2 m from the outer wall and 1.5 m from the inner wall.
7.2.6. A blackboard that does not have its own glow is equipped with local lighting - spotlights designed to illuminate blackboards. It is recommended to place the lamps 0.3 m above the top edge of the board and 0.6 m towards the classroom in front of the board.
7.2.7. When designing an artificial lighting system for classrooms, it is necessary to provide for separate switching of lamp lines.
7.2.8. For the rational use of artificial light and uniform illumination of classrooms, it is necessary to use finishing materials and paints that create a matte surface with reflection coefficients: for the ceiling - 0.7 - 0.9; for walls - 0.5 - 0.7; for the floor - 0.4 - 0.5; for furniture and desks - 0.45; for chalkboards - 0.1 - 0.2. It is recommended to use the following paint colors: for ceilings - white, for walls of classrooms - light tones of yellow, beige, pink, green, blue; for furniture (cabinets, desks) - the color of natural wood or light green; for chalkboards - dark green, dark brown; for doors, window frames - white.
7.2.9. It is necessary to clean the lighting fixtures of the lamps as they become dirty, but at least 2 times a year, and promptly replace burnt-out lamps.
7.2.10. Faulty, burnt-out fluorescent lamps are collected in a container in a specially designated room and sent for disposal in accordance with current regulations.