Hygienic requirements to artificial lighting

Human activity is not only in daylight, but in the conditions of artificial light in the evening time). Poor lighting causes tension, and then the fatigue of the organ of vision.
The lighting must meet several requirements. First of all it should be sufficient for a certain type of work (table. 7), uniform in space, without blastcasta and shadows.

Table 7. Norms of artificial illumination
Name of premises Lowest illuminance (Lux)
with incandescent lamps when fluorescent lamps
Living room
Kitchen
WC, shower
Corridor, front
Staircase
Chamber
Operating
30
30
10
10
10
30
200
75
100
50
50
50
75
400

Eliminating glare is achieved by using the corresponding valves and regulating the height of the suspension. Bleemcast eliminated matte colouring of surfaces and equipment and appropriate light fittings. Uniform illumination is achieved by use of lighting fixtures, giving the scattered light and rational placement of fixtures.
The lamps are divided into three types: giving direct, diffuse and Ohr Hozer (Fig. 19).

lamps
Fig. 19. Different systems of lamps:
1 - luminaires direct light; 2 - lamp direct and partially reflected light; 3 - dairy ball (lamp evenly scattered light); 4 - luceta (lamp reflected light); 5 - lamp scattered light (SC-300).

Luminaires direct light most of the light is directed downwards, creating sharp shadows (lamp alpha).
Lamps scattered light evenly disperse the light flow in all directions (milk ball).
Lights of Ohr Hozer send luminous flux up, and then he reflected from the ceiling and scatters.
Most hygienic lamps scattered and reflected light.
According to the spectral composition of the artificial lighting should be close to daylight. For artificial lighting at present mainly used electric lights, incandescent lamps and fluorescent lamps.
Incandescent lamps thermal energy is converted into light. Heated body (filament) when heated begins to glow. In these lamps only 7-12% of consumed energy is converted into light. In the spectrum of the electric light bulb is dominated by red and orange rays and almost entirely absent ultraviolet.
A fluorescent lamp is a glass tube internal surface of which is coated with substances that can glow (phosphors). Inside the tube there are pairs of mercury and argon at the ends of the tube electrodes are soldered. After the lamp in the network between the electrodes formed arc mercury spectrum emitting ultraviolet rays. Under the influence of ultraviolet rays phosphors give secondary radiation in the visible part of the spectrum.
Unlike incandescent lamps, fluorescent lamps have a number of advantages. They are more economical, since for the same energy have more light yield. The radiation spectrum fluorescent lamp is approaching to the spectrum of natural light. Fluorescent lamps give a soft diffused light, do not give shadow and do not require the use of shades.
When using fluorescent lamps observed "the twilight effect at low illumination (below 75 Lux), subjectively assessed as low light, so the use of these lamps needs more light.
The definition of light is a light meter or by calculation in power density per 1 m2. To do this, the total capacity of the lamps in watts divided by the area of a floor of a premise. Then, multiplying the unit power of the conversion factor (f)receive illumination in Lux (table. 8).

Table 8. The coefficient e
The lamp power (W) Tensions in the network (In)
110, 120, 127 220
Up to 100
100 and more
2,4
3,2
2
2,5

The values of the coefficient e) are given for premises not more than 50 m2.
Example. The area of the room of 50 m2, lighting 5 lamps 200 W, voltage 200 Century
Specific power = 5·200/50=20 W/m2
Illumination =20 W/m2·2,5 = 50 Lux
Artificial lighting can be local, General and combined. Most favorable combined lighting (local and General), which is not creating sharp shadows.