The duration of natural light during the day. Daylight. Natural Lighting Design
Introduction
Premises with permanent residence of people should have natural lighting.
Natural lighting - lighting of premises with direct or reflected light penetrating through light openings in external enclosing structures. Natural lighting should be provided, as a rule, in rooms with a permanent stay of people. Without natural lighting, it is allowed to design certain types of industrial premises in accordance with the Sanitary Standards for the Design of Industrial Enterprises.
Types of natural lighting
There are the following types of natural lighting of premises:
lateral one-sided - when the light openings are located in one of the outer walls of the room,
Figure 1 - Lateral one-sided natural lighting
lateral - light openings in two opposite outer walls of the room,
Figure 2 - Lateral daylight
upper - when the lanterns and light openings in the coating, 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 rationing natural light
Natural lighting is used for general lighting of industrial and utility rooms. It is created by the radiant energy of the sun and has the most beneficial effect on the human body. Using this type of lighting, one should take into account meteorological conditions and their changes during the day and periods of the year in a given area. This is necessary in order to know how much natural light will enter the room through the arranged light openings of the building: windows - with side lighting, skylights of the upper floors of the building - with overhead lighting. With combined natural lighting, side lighting is added to the top lighting.
Premises with permanent residence of people should have natural lighting. The dimensions of the light openings established by calculation can be changed by +5, -10%.
The unevenness of natural lighting in the premises of industrial and public buildings with overhead or overhead and natural side lighting and the main rooms for children and adolescents with side lighting should not exceed 3:1.
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 heat engineering.
The quality of illumination by natural light is characterized by the coefficient of natural illumination to eo, which is the ratio of the illumination on a horizontal surface inside the room to the simultaneous horizontal illumination outside,
where E in -- horizontal illumination indoors in lux;
E n - horizontal illumination outside in lux.
With side lighting, the minimum value of the coefficient of natural illumination is normalized - k eo min, and with upper and combined lighting - its average value - k eo cf. The method for calculating the coefficient of natural illumination is given in the Sanitary Design Standards for Industrial Enterprises.
In order to create the most favorable working conditions, standards for natural lighting have been established. In cases where natural illumination is insufficient, work surfaces should be additionally illuminated by artificial light. Mixed lighting is allowed provided that additional lighting is provided only for working surfaces in general natural lighting.
Building codes and regulations (SNiP 23-05-95) establish the coefficients of natural illumination of industrial premises depending on the nature of the work according to the degree of accuracy.
To maintain the necessary illumination of the premises, the norms provide for the 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.
Standards for natural lighting of industrial buildings, reduced to the rationing of K.E.O., are presented in SNiP 23-05-95. To facilitate the rationing of the illumination of workplaces, all visual works are divided into eight grades 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 production. The territory of Russia is divided into five light zones, for which the K.E.O. are determined by the formula:
where N is the number of the group of the administrative-territorial region according to the provision with natural light;
The value of the coefficient of natural illumination, selected according to SNiP 23-05-95, depending on the characteristics of visual work in a given room and the natural lighting system.
The light climate coefficient, which is found according to the SNiP tables, depending on the type of light openings, their orientation along the sides of the horizon and the group number of the administrative area.
To determine the compliance of natural illumination in the production room with the required standards, the illumination is measured with overhead and combined lighting - at different points in the room, followed by averaging; at the side - at the least illuminated workplaces. At the same time, the external illumination and the K.E.O. determined by calculation are measured. compared with the norm.
Natural Lighting Design
1. The design of natural lighting of buildings should be based on the study of labor processes performed in the premises, as well as on the light and climatic features of the construction site of buildings. In this case, the following parameters must be defined:
characteristics and category of visual works;
a group of the administrative district in which the construction of the building is supposed;
normalized value of KEO, taking into account the nature of visual works and light and climatic features of the location of buildings;
the required uniformity of natural light;
the duration of the use of natural lighting during the day for different months of the year, taking into account the purpose of the premises, the mode of operation and the light climate of the area;
the need to protect the premises from the blinding action of sunlight.
2. The design of natural lighting of the building should be carried out in the following sequence:
determination of requirements for natural lighting of premises;
choice of lighting systems;
choice of types of light openings and light-transmitting materials;
the choice of means to limit the blinding effect of direct sunlight;
taking into account the orientation of the building and light openings on the sides of the horizon;
performing a preliminary calculation of the natural lighting of the premises (determining the required area of light openings);
clarification of the parameters of light openings and rooms;
performing a test calculation of natural lighting of premises;
determination of premises, zones and areas with insufficient natural lighting according to the norms;
determination of requirements for additional artificial lighting of premises, zones and areas with insufficient natural light;
determination of requirements for the operation of light openings;
making the necessary adjustments to the natural lighting project and re-checking the calculation (if necessary).
3. The natural lighting system of the building (side, overhead or combined) should be selected taking into account the following factors:
purpose and adopted architectural and planning, volumetric and spatial and constructive solution 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 mainly in one-story public buildings of a large area (covered 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 conditional working surface does not exceed 8.
6. When choosing light openings and light-transmitting materials, the following should be taken into account:
requirements for natural lighting of premises;
purpose, volume-spatial and constructive solution of the building;
orientation of the building on the sides of the horizon;
climatic and light-climatic features of the construction site;
the need to protect the premises from insolation;
degree of air pollution.
7. Consideration should be given to the shading created by opposing buildings when designing side daylight.
8. Translucent fillings of light openings in residential and public buildings are selected taking into account the requirements of SNiP 23-02.
9. With lateral natural lighting of public buildings with increased requirements for the constancy of natural lighting and sun protection (for example, art galleries), light openings should be oriented to the northern quarter of the horizon (N-NW-N-NE).
10. The choice of devices for protection against glare from 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 a room with a fixed line of sight (a student at a desk, a draftsman at a drawing board, etc.);
working hours of the day and year, depending on the purpose of the premises;
the difference between solar time, according to which solar maps are built, and the decree time adopted on the territory of the Russian Federation.
When choosing means to protect against glare from direct sunlight, one should be guided by the requirements of building codes and rules for the design of residential and public buildings (SNiP 31-01, SNiP 2.08.02).
11. In the case of a one-shift work (educational) process and the operation of premises mainly in the first half of the day (for example, lecture halls), when the premises are oriented to the western quarter of the horizon, the use of sunscreen is not necessary.
When illuminating industrial premises, use daylight, is carried out due to direct and reflected light of the sky.
From a physiological point of view, natural lighting is the most favorable for humans. During the day, it varies within a fairly wide range depending on the state of the atmosphere (cloudiness). Light, once in the room, is repeatedly reflected from the walls and ceiling, hits the illuminated surface at the point under study. Thus, the illumination at the point under study is the sum of the illuminations.
Structurally, natural lighting is divided into:
lateral(one-, two-sided) - carried out through light openings (windows) in the outer walls;
upper- through light openings located in the upper part (roof) of the building;
combined– a combination of top and side lighting.
Natural lighting is characterized by the fact that the created illumination varies depending on the time of day, year, meteorological conditions. Therefore, as a criterion for assessing natural lighting, a relative value is taken - daylight ratio(KEO), or e, independent of the above parameters.
Daylight ratio (KEO) - the ratio of illumination at a given point inside the room E ext to the simultaneous value of the external horizontal illumination E n, created by the light of a completely open sky (not covered by buildings, structures, trees) expressed as a percentage, i.e.:
(8) where E ext– illumination indoors at the control point, lux;
E n - simultaneously measured illumination outside the room, lx.
For measuring actual KEO needs to be carried out simultaneous measurements indoor lighting E ext at the control point and outdoor illumination on a horizontal platform under the fully open sky E n , free from objects(buildings, trees ) covering parts of the sky. KEO measurements can only be carried out with continuous uniform ten-point cloudiness(overcast, no gaps). Measurements are taken by two observers using two lux meters simultaneously (observers must be equipped with chronometers).
Checkpoints for measurements should be selected in accordance with GOST 24940–96 “Buildings and structures. Methods for measuring illumination.
The KEO values for various premises lie in the range of 0.1–12%. Rationing of natural lighting is carried out in accordance with SNiP 23-05-95 "Natural and artificial lighting".
In small rooms with unilateral lateral illumination is normalized (i.e. the actual illumination is measured and compared with the norms) minimum KEO value at a point located at the intersection of the vertical plane of the characteristic section of the premises and the conditional working surface at a distance of 1 m from the wall, most remote from light openings.
Working surface- the surface on which the work is performed and on which the illumination is normalized or measured.
Conditional work surface- a horizontal surface at a height of 0.8 m from the floor.
Typical section of the room- this is a cross section in the middle of the room, the plane of which is perpendicular to the plane of the glazing of the light openings (with side lighting) or the longitudinal axis of the spans of the room.
At bilateral lateral lighting rationing minimum KEO value- in the plane in the middle premises.
AT oversized industrial premises at lateral lighting, the minimum value of KEO is normalized at the point remote from light openings:
at 1.5 heights of the room - for works of I-IV categories;
at 2 heights of the room - for works of V-VII categories;
at 3 heights of the room for work of the VIII category.
At upper and combined lighting is normalized average KEO value at points located at the intersection of the vertical plane of the characteristic section of the room and the conditional work surface or floor. The first and last points are taken at a distance of 1 m from the surface of walls or partitions.
(9)
where e 1 , e 2 ,..., e n - KEO values at individual points;
n- number of lighting control points.
It is allowed to divide the room into zones with different conditions of natural light, the calculation of natural light is carried out in each zone independently of each other.
At inadequate by standards natural light in the production premises supplement with artificial lighting. Such lighting is called combined .
In industrial premises with visual work of I-III categories, combined lighting should be arranged.
In large-span assembly shops, in which work is carried out in a significant part of the volume of the room at different levels from the floor and on work surfaces differently oriented in space, overhead natural lighting is used.
Natural light should evenly illuminate workplaces. For overhead and combined natural lighting, determine irregularity natural lighting of industrial premises, which should not exceed 3:1 for works I–VI discharges according to visual conditions, i.e.
(10)
certain according to table 1 SNiP 23-05-95 KEO value, to be specified taking into account the characteristics of visual work, lighting systems, location of buildings in the country according to the formula
,
(11)
where N- number of the natural light supply group (Appendix D SNiP 23-05-95);
e n- coefficient of natural lighting (Table 1 SNiP 23-05-95);
m N- coefficient of light climate, determined depending on the location of the building on the territory of the country and the orientation of the building relative to the cardinal points (see Table 4 SNiP 23–05–95).
9.1 A technical and economic assessment of various options for natural and combined lighting of premises should be carried out for the whole year or its individual seasons. The duration of the use of natural lighting should be determined by the intermediate time between the moments of turning off (in the morning) and turning on (in the evening) artificial lighting, when natural illumination becomes equal to the normalized illumination value from the installation of artificial lighting.
In the premises of residential and public buildings, in which the calculated value of KEO is 80% or less than the normalized value of KEO, the norms of artificial illumination are increased by one step on the illumination scale.
9.2 The calculation of natural illumination in the premises should be made depending on the groups of administrative districts according to the resources of the light climate of the Russian Federation and the period of the year under consideration:
a) when buildings are located in the 1st, 3rd and 4th groups of administrative districts for all months of the year - according to the cloudy year;
b) when buildings are located in the 2nd and 5th groups of administrative districts for the winter half of the year (November, December, January, February, March, April) - according to the cloudy sky, for the summer half of the year (May, June, July, August , September, October) - over a cloudless sky.
9.3 The average natural illumination in a room with overhead illumination from a cloudy sky at any time of the day is determined by the formula
where e cf- average value of KEO; determined by the formula (B.8) of Appendix B;
Outdoor horizontal illumination in overcast conditions; taken according to Table B.1 of Appendix B.
Note - The values of outdoor illumination in Appendix D are given for local mean solar time T M. The transition from local standard time to local mean solar time is carried out according to the formula
T M = T D – N+ l - 1, (14)
where T D- local standard time;
N- time zone number (Figure 25);
l is the geographical longitude of the point, expressed in hours (15° = 1 hour).
9.4 The value of natural light at a given point BUT under side illumination in conditions of continuous cloudiness is determined by the formula
where is the calculated value of KEO at the point BUT rooms with side lighting; determined by the formula (B.1) of Appendix B;
Outdoor illumination on a horizontal surface with a cloudy sky.
Calculation of natural light at a given point M rooms from windows in a cloudless sky should be done:
a) in the absence of sun protection in light openings and opposing buildings according to the formula
; (16)
b) when windows are shaded by opposing buildings according to the formula
c) in the presence of sunscreens in the light openings according to the formula
, (18)
where e b i- geometric KEO, determined by the formula (B.9);
b b- coefficient of relative brightness of the area of the sky, visible through the aperture; take according to table 11;
Outdoor illumination on a vertical surface, created by the diffused light of a cloudless sky; taken depending on the orientation of the surface of the facade of the building and the time of day according to Table B.3 of Appendix B;
Figure 25- Map of time zones
b f i- average relative brightness of the facades of opposing buildings; determined according to Table B.2 of Appendix B;
Determined by the formula (B.5);
r f- weighted average reflection coefficient of the facades of opposing buildings; accept according to table B.3 of Appendix B;
Outdoor total illumination on a vertical surface, created by the diffused light of the sky, the direct light of the sun and the light reflected from the earth's surface; taken according to Table B.4 of Appendix B.
The calculation of the average natural illumination in the room from a cloudless sky with overhead lighting, depending on the type of light opening, is carried out:
a) with light openings in the plane of the coating, filled with light-scattering materials, according to the formula
b) with light openings in the plane of the coating, filled with translucent materials, according to the formula
c) with lanterns shed according to the formula
d) with rectangular lanterns according to the formula
where t about- see formula (B.1);
r 2 and k f- see formula (B.2);
e Wed- see formula (B.7);
The total outdoor illumination on a horizontal surface, created by a cloudless sky and direct sunlight; accept according to Table B.3 of Appendix B;
Outdoor illumination on a horizontal surface, created by a cloudless sky; accept according to Table B.3 of Appendix B;
b B- coefficient of relative brightness of cloudless sky areas visible through light openings; take according to table 12;
See formula (16);
I - outdoor illumination on two opposite sides of the vertical surface; taken according to Table B.4 of Appendix B.
Notes
1 Direct sunlight in the calculations of illumination is taken into account if there are sunscreens or light-scattering materials in the light openings; otherwise, direct sunlight is ignored.
2 The values of the calculated coefficients in tables 11 and 12 are given for local mean solar time.
Table 11
| Orientation of light apertures | The value of the coefficient b b | ||||||||||||||
| Time of day, h | |||||||||||||||
| AT | 3,1 | 1,9 | 1,4 | 1,25 | 1,2 | 1,3 | 1,4 | 1,55 | 1,7 | 1,8 | 1,9 | 1,95 | 1,85 | ||
| SE | 1,05 | 1,1 | 1,45 | 2,5 | 2,6 | 1,9 | 1,5 | 1,3 | 1,25 | 1,3 | 1,35 | 1,45 | 1,6 | 1,85 | 1,9 |
| YU | 1,5 | 1,35 | 1,1 | 1,2 | 1,3 | 1,5 | 1,7 | 1,85 | 1,7 | 1,5 | 1,3 | 1,2 | 1,1 | 1,35 | 1,5 |
| SW | 1,9 | 1,85 | 1,6 | 1,45 | 1,35 | 1,3 | 1,25 | 1,3 | 1,5 | 1,9 | 2,6 | 2,5 | 1,45 | 1,1 | 1,05 |
| W | 1,85 | 1,95 | 1,9 | 1,8 | 1,7 | 1,55 | 1,4 | 1,3 | 1,2 | 1,25 | 1,4 | 1,9 | 3,1 | ||
| NW | 1,3 | 1,5 | 1,7 | 1,75 | 1,75 | 1,7 | 1,6 | 1,5 | 1,4 | 1,3 | 1,25 | 1,25 | 1,3 | 1,9 | 2,9 |
| FROM | 1,2 | 1,2 | 1,3 | 1,45 | 1,5 | 1,6 | 1,6 | 1,65 | 1,6 | 1,6 | 1,5 | 1,45 | 1,3 | 1,2 | 1,2 |
| SW | 2,9 | 1,9 | 1,3 | 1,25 | 1,25 | 1,3 | 1,4 | 1,5 | 1,6 | 1,7 | 1,75 | 1,75 | 1,7 | 1,5 | 1,3 |
Table 12
| Light opening type | The value of the coefficient b B | ||||||||||||||
| Time of day, h | |||||||||||||||
| Rectangular lantern | 1,3 | 1,42 | 1,52 | 1,54 | 1,42 | 1,23 | 1,15 | 1,14 | 1,15 | 1,23 | 1,42 | 1,54 | 1,52 | 1,42 | 1,3 |
| In-plane coverage | 0,7 | 0,85 | 0,95 | 1,05 | 1,1 | 1,14 | 1,16 | 1,17 | 1,16 | 1,14 | 1,1 | 1,05 | 0,95 | 0,85 | 0,7 |
| Shed (NW, N, NE oriented) | 1,17 | 1,13 | 1,04 | 0,95 | 0,9 | 0,85 | 0,8 | 0,85 | 0,9 | 0,95 | 1,04 | 1,13 | 1,17 |
Examples of calculating the time of using natural light in rooms
Example 1
It is required to determine how the duration of the use of natural lighting in March will change for an average day in a workroom with overhead natural lighting through skylights and with a general fluorescent lighting system if the designed area of skylights is halved and switched to combined lighting.
The working room is located in Moscow, the accuracy of the visual work performed in it corresponds to the B-1 category of the norms according to Appendix I SNiP 23-05.
The originally designed area of the lanterns provided an average KEO in the working room of 5%; when the area of the lanterns is halved, the average value of KEO is 2.5%. The work is carried out in two shifts from 07:00 to 21:00 local time.
Solution
1 In accordance with Table 1 of the list of administrative districts according to the light climate resources of the Russian Federation, Moscow is located in the first group and, therefore, the calculation of natural illumination in the room is performed for cloudy sky conditions.
2 From table B.1 of Appendix B, write out in table 13 the value of the external horizontal illumination with continuous cloudiness for different hours of the day in March.
Table 13
| Time of day (local solar time) | Outdoor horizontal illumination, lx | Average natural light indoors E Wed, OK | |
| at KEO = 5% | at KEO = 2.5% | ||
| - | - | - | |
| - | - | - | |
| - | - | - |
3 Sequentially substituting the value in the formula (13), determine for the corresponding time points the values of the average illumination inside the room E cp. The calculation results are recorded in table 13.
4 According to the found values E cp build a graph (Figure 26) of changes in natural light in the room during the working day at KEO = 5% and 2.5%.
5 In Appendix AND SNiP 23-05, they find that for a workroom located in Moscow, the normalized KEO value for B-1 work category is 3%.
1 - change in natural illumination in the room at KEO equal to 5%; 2 - the same, 2.5%; BUT- point corresponding to the time of turning off the artificial lighting in the morning;
B- a point corresponding to the time when artificial lighting is turned on in the evening
Figure 26- Graph of changes in natural light in the room during the working day
The normalized illumination is 300 lux. When the area of the lanterns is halved, the average calculated value of the KEO is 0.5 of the normalized value of the KEO; in this case, in the working room, the normalized value of illumination from artificial lighting must be increased by one step, i.e., instead of 300 lux, 400 lux should be taken.
6 On the ordinate of the graph of Figure 26, a point is found corresponding to an illumination of 300 lux, through which a horizontal line is drawn until it intersects with the curve in the first and second half of the day. points BUT and B intersections with the curve are projected onto the x-axis. Dot a on the x-axis corresponds to the time ta= 8 h 20 min, dot b - t b= 15 h 45 min.
The time of using natural lighting in the working room with an average KEO of 3% is determined as the difference t b - t a= 7 h 25 min.
7 It follows from Figure 26 that the horizontal corresponding to the illumination of 400 lux does not intersect with the curve of change in natural illumination at an average KEO = 2.5%, which means that the time of using natural lighting in a workroom with a halved area of lamps is equal to zero , i.e., during the entire working time, constant additional artificial lighting should work in the working room.
Example 2
It is required to determine the natural illumination and the duration of the use of natural illumination during the day in September with continuous cloudiness at three points A, B and C (Figure 27) of the characteristic section of the school class at the level of desks (0.8 m from the floor). The points are located at the following distances from the outer wall with windows: BUT- 1.5 m, B- 3 m and AT- 4.5 m. Estimated value of KEO at the point A e A= 4.5%, at the point B e B= 2.3, at the point B e B= 1.6%. The normalized illumination in the classroom from the installation of artificial lighting is 300 lux. The school is located in Belgorod (50°N) and operates in one shift from 8 am to 2 pm (local solar time).
Solution
1 From table B.1 of Appendix B, write out the values of outdoor illumination during the day for September. By successively substituting the values into formula (15), we obtain the values of natural illumination at given points E ha, E GB, E gV. The calculation results are recorded in table 14.
BUT, B, AT- Estimated points
Figure 27- Schematic cross section of a school classroom
Note - Given that in Table B.1 of Appendix B for 50 ° N. sh. outdoor illumination is not given, find the required value of outdoor illumination by linear interpolation.
Table 14
2 According to Table 14, a graph of Figure 28 is built, for this, a horizontal line is drawn through the point of the y-axis, which corresponds to an illumination of 300 lux, until it intersects with the illumination curves E ha, E GB, E gV(curves 1 , 2 , 3 ).
3 Project the points of intersection of the horizontal with the curves on the x-axis; time of use of natural light at the point BUT determined from the ratio:
t 2 - t 1 = 14:00 - 8:20 = 5:40
From figure 28 it follows that at the points B and AT with continuous cloudiness in autumn, it is necessary to have constant additional artificial lighting, since throughout the day on the second and third rows of desks, natural illumination is below the normalized value.
1 - at the point BUT; 2 - at the point B; 3 - at the point AT
Figure 28- Graph of changes in natural light at three calculated points of the school class during the working day
Assessment of natural lighting in production due to its variability depending on the time of day and atmospheric conditions is carried out in relative terms of the coefficient of natural illumination - KEO. KEO - the ratio of natural illumination at the considered point inside the room (Eb) to the simultaneous value of outdoor (En) horizontal illumination without direct sunlight.
KEO is expressed as a percentage and is determined by the formula:
The KEO value is affected by the size and configuration of the room, the size and location of light openings, reflecting the ability of the interior surfaces of the room and the objects that shade it. KEO does not depend on the time of day and the variability of natural light. Depending on the purpose of the premises and the location of light apertures in it, KEO is standardized from 0.1 to 10%. The norms of natural lighting of the premises are set separately for the side and top location of the light openings. With one-sided side lighting, the minimum KEO value is normalized 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 the amenity premises of industrial buildings, the KEO value should be at least 0.25%.
The KEO values for the combined lighting of buildings located in the III zone of the light climate range from 0.2 to 3%.
The level of natural light in the premises may decrease due to contamination of glazed surfaces, which reduces the transmittance, and contamination of walls and ceilings reduces the reflection coefficient. Therefore, the norms provide for cleaning the glass of light openings at least 2 times a year in rooms with a slight emission of dust, smoke and soot, and at least 4 times in case of significant pollution. Whitewashing and painting of ceilings and walls should be done at least once a year.
As you know, light stimuli of 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 for painting rooms and equipment, you should use the “Instructions for the light finishing of the surface of industrial premises and technological equipment of industrial enterprises” issued by the State Construction Committee. At enterprises where workers, due to the nature and conditions of work or due to geographical conditions (northern regions), are completely or partially deprived of natural light, it is necessary to provide ultraviolet prophylaxis with sources of UV radiation (erythema lamps) that 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-acting ultraviolet irradiation installations, which are part of the general artificial lighting system and irradiate workers with a low-intensity UV stream during the entire time of work. Short-term ultraviolet irradiation installations are also used - fotaria, in which UV irradiation occurs for several minutes.
Insolation of industrial buildings through skylights with a large glazing area significantly increases the natural illumination of the premises, has a blinding effect due to direct or reflected glare from the sun's 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.
While reading the text, try to visualize everything that is written. This will help you not get confused by the endless colors and shades, and will also help you understand the article more clearly. In general, forward and with a song! By the way, who plays what? Please write in the comments - it is interesting to know what people are listening to while surfing the Internet.
Dawn
At dawn, the lighting changes very quickly. Natural light has a bluish tint just before sunrise. And if the sky is clear at this time, the effect of a red sunset can also be observed. In nature, a combination of high stratus or cirrus clouds with low spreading fog is often found. In such conditions, there is a transition of sunlight from directed from below upwards to a general more diffused light, in which the shadows are washed out. At negative temperatures, the effect is more pronounced.
At dawn, excellent shots of plants, open landscapes, reservoirs, churches oriented to the east are obtained. Often fog spreads in the lowlands, near the water surface. Valley landscapes, photographed from a high point to the east, look very impressive. It is often at dawn that scenes with equipment, metal structures and any other objects that have a glossy shiny surface are filmed. In natural light, these surfaces and the reflections from them look just great.
Photographer: Slava Stepanov.
The quality of light in the mountains is determined by the location. If the relief hides the sunrise, it is almost impossible to get interesting lighting effects. It should also be mentioned that calm is most often observed at dawn. This helps to get perfect shots of flat water surfaces.
natural light in the morning
After sunrise, the light changes very quickly. In warm months, the sun can disperse fog or haze, in cold months it can create them (as a result of frost evaporation). Weak evaporation from reservoirs, rivers, wet roads can be spectacular. If it rained at night, then in the morning the wet streets and plants, dull under normal conditions, will shine with many bright sparks.
As the distance increases, the landscape blurs and brightens. This can be used to convey the 3rd dimension. During this period of the day, the color of the lighting changes from a warm bright yellow with golden notes to a warmish neutral tone. In the pictures taken in the morning, human skin looks very even. The fact is that at night our skin tightens, and in the morning the face seems refreshed - the main thing is how to wash.
Photographer: Maria Kilina.
An hour later, as the sun has risen, the lighting is ideal for photography. Professional photographers often get up well before dawn in order to have time to prepare for the session and “catch” the optimal light. The weather forecast is almost irrelevant, because morning weather is difficult to predict.
There are other reasons to get up early and get to the location well in advance. You will be able to independently trace the changes in the weather and, focusing on the position of the sun, understand at what time there will be optimal natural light for photographing specific scenes. It is advisable to keep appropriate records. Also do not forget that the results of observations will be valid only for a particular time of the year.
Noon
The timing and duration of ideal light depends on the latitude of the area and the season. In the northern regions, where the sun does not set, but does not rise too high, such light is observed most of the night and all day. In temperate latitudes, suitable light persists for several hours. But do not forget that in this case the position of the star changes. In winter, it can be low all day (I will talk about this in detail).
The maximum brightness is observed for four hours in the very middle of the day. In the hot summer, there are also 4 hours ideal for photography. Two of them - in the afternoon, and two more - in the morning. Between them is a dead period. At this time, there is a very high probability of getting overexposure in the photo.
Photographer: Ovchinnikova Elena.
In equatorial and tropical regions, natural light at noon is not suitable for photography. The sun is located high overhead and creates an annoying, blinding light that makes the surrounding landscapes featureless.
Sequential shooting of people can only be done using fill light through direct supplementary lighting or reflectors. It is recommended to use light having a color temperature of approximately 5.2 thousand Kelvin.
Midday light in such regions can only be used to shoot canyons and gorges, densely covered with vegetation. At other times of the day, sunlight does not fall into such corners. The presence of direct rays helps the photographer to get bright contrast pictures.
Afternoon and evening
During daytime heating, the air absorbs moisture from the water or the ground. Therefore, in the second half of the day, changes in the spectral composition (color) of natural light are observed, which are not always present in the morning. Warm air absorbs more moisture. Cooling as the star moves towards sunset, it loses its ability to retain moisture. The latter condenses into tiny invisible drops that remain in the form of a suspension. When it gets colder it gets foggy. This is especially true for maritime regions.
Fog is usually very faint and visually noticeable by the presence of a slight haze that can "dim" the light. For this reason, summer afternoons can seem dreary and gloomy, even when the sun is shining brightly. In the photographs, this is expressed by “pressed down” colors and tones. In the late afternoon, the situation improves as the sun's rays begin to make their way through the mist, consisting of dust and water particles, and reveal the aerial perspective.
Photographer: Maria Kilina.
In the second half of a summer day, the air in the city can look gray. If you look at the city from an airplane, you can see a veil of bluish light haze around it. Keep in mind that dust and moisture scatter the rays of natural light. When the sun is high, red rays are absorbed and blue rays are scattered, raising the color temperature. A cold metallic blue appears in the pictures, looking unattractive.
The above partly explains how afternoon light differs from morning light. There are other factors, such as the characteristic orientation of building and other structures in different places. The same gardens are arranged in such a way as to capture sunlight as much as possible. Trees and plants take on their final form, which depends on how the sun's rays hit them. But in general, morning light is more preferable than afternoon light.
Sunset
At sunset, specific natural lighting is created, characteristic of the low position of the luminary, when the atmosphere allows red long-wave radiation to pass through and reflects short-wave blue radiation. During the day, some of the red rays were absorbed by the haze, while the blue ones were scattered. Now the situation is reversed. The upper part of the sky remains blue because the angle of its illumination has changed. The result is cool color combinations and smooth tone gradients.
A sunset can become both a source of light and the subject of the shooting itself. In this case, we will consider only the quality of radiation characteristic of this time of day. At sunset, the sun's rays break through haze or light clouds. Their color gradually warms up (color temperature decreases).
Many photographers consider this state of the atmosphere the most favorable for the transmission of natural light in the evening and interesting in the context of colors. If there is a need to make adjustments, this can be done through the use of blue filters.
