The light - receiving, distribution and use of light energy to ensure favorable conditions vision. Force of light. The light of the different sources may differ qualitatively (to have different spectra) and quantitative - in power light. The power light is expressed in the candlelight (see tab. "Units").
Brightness - length value that is directly perceived by the eye, and determined by the density of luminous flux emitted in the direction of the unit of luminous surface. The brightness value expressed in nits (NT) and schilbach (sat). 1 SB= 104 HT (see "Units").
Luminous flux is the power of radiant energy, as measured by the produced light feeling. The luminous flux is expressed in lumen (LM) (see "Units").
Illumination is numerically equal to the luminous flux falling on a unit surface. The degree of lighting is expressed in Lux (LX) (see "Units").
To determine the degree of lighting uses a special device - a light meter.
Adverse lighting conditions are causing a deterioration of the General condition and decrease of physical and mental health. Poor lighting jobs increases fatigue and reduces labour productivity.
The organization of efficient lighting has a large Wellness and cultural value.
Natural lighting. Sources of natural light are the sun and the atmosphere.
Illumination of premises with natural light depends on the length of the climate of the area, Windows orientation, quality and content of the window glass, painting walls, darkened light the subject, located inside and outside the premises, the depth of a premise and the size of the light window surface. High objects, located outside the building in front of Windows, not to darken the light, must be from the Windows at least doubled its height. The depth of a premise (distance from a wall with Windows to the opposite wall) in premises with side-sided lighting should not exceed more than 2 times the distance from the floor to the upper edge of the window openings. About the adequacy of lighting apertures judge largest length ratio.
Light ratio is called the ratio of the luminous surface Windows (glazing) to the area of the floor space.
In residential and public buildings, the value of length ratio varies depending on the purpose of the premises from 1/5 up to 1/15.
Light factor is set in structural design, but may not adequately characterize the lighting of natural light.
Illumination of premises with natural light adequately characterized by natural illumination factor (DF): the ratio of light points in the room, simultaneous illumination horizontal plane, which is located outdoors and covered multiple (diffuse) light the entire firmament. In rooms with side-sided lighting standardized minimum DF (Emin), and in the premises or combined with top lighting - average KEO (URR). The value of the KEO expressed in percentage. Illuminance is defined by the light meter, consisting of solar cells and milliammeter (galvanometer), with a scale graduated in suites. In residential areas the Emine should be not less than 0,5%, nurseries and kindergartens (for children and group rooms)- 1,5%, hospital wards and doctors - 1,0%.
Normalized value KEO for residential, public and industrial buildings are SNiP II - A. 8-62.
The sources of artificial light should ensure adequate and uniform illumination of rooms and working places in them. Illumination of workplaces should provide sufficient visual acuity, speed distinguish small details at work and sustainability of clear vision.
Satisfactory level of visual acuity in distinguishing black objects on a white background is achieved by 50-70 LK. At lower contrasts required illumination up to 150 Lux and more. The lighting in living rooms and wards of the hospitals and health centers accepted in 75 Luke, in offices of physicians-200 Lux. Desirable education sharp shadows on the illuminated surfaces. Important hygienic requirement is to protect the eyes from the glare of the light, which is achieved by the application of appropriate lighting fixtures and height limit of bracket and brightness shone surface of the lamps. The lowest altitude suspension for lamps with a capacity of more than 200 watts is set at 3 m from the floor level. The spectrum of light emitted by a source, have possibly more to come closer to the spectrum of sunlight. The sources of artificial light should not pollute the air space of the combustion products, and should not increase the temperature and humidity of air.
The sources of artificial light must be economically advantageous to have a high coefficient of performance) and to be fire-safe.

The lighting. All the basic functions of view - light and color sensitivity, visual acuity and speed of discernment, contrast sensitivity, and others - dependent lighting conditions. The better light conditions, the higher visibility and visual working capacity and the less common and visual fatigue. Lighting is characterized by a number of qualitative and quantitative indicators. To quantitatively relate the degree of lighting [the suites (LK)]key to quality - terms of brightness distribution [in nits (NT)] in sight, contrast (brightness and color) between discussed the subject and the background, blizkosti (live and recorded), direction, diffusion and the spectral composition of the light flow.
Hygienic can be recognized as lighting, which provides: the optimal amount of light exposure (brightness); uniform coverage; limitation and reflection blizkosti; weakening of the shadows; contrast; the correct colour, biological integrity, stability, and security lighting. Thus, hygienically rational natural and artificial O. provides for the creation of conditions ensuring the best use of light in the totality of its biological, physiological and sanitary properties.
The most common and important indicator hygiene O. is the degree of exhaustion of view.
Optimum can be considered such illumination where the functions of view of the peak, and the exhaustion of view is the least.

Artificial lighting of open and closed spaces or specific objects is performed by lighting installations. On functional purpose are distinguished: lighting, operating in the normal mode - working; O. acting at emergency switching-off worker,- emergency. The principle of a distinguished General, local and combined O.
General lighting is uniform (for the Acting of the total volume of the premises) and localized (Acting jobs). Local O. (O. individual workplace) is typically used in industrial, office and residential premises with the total O. Distinguish between stationary and portable local O.
Combined lighting is a collection of General and local O. When combined O. standardized greater light than a General one.
Local O. should ensure at least 80% of the normalized light from combined.
Active in the USSR norms artificial O. install double rationing lighting - separately for incandescent and fluorescent lamps. The current standards of industrial O. installed 7 digits of the visual work of various precision, illumination for which standardized depending on the size of the object of discernment with allowance for of coefficient of reflection of the background and degree of contrast object (distinguish from the background). Illumination from one General Acting in production premises with fluorescent lamps set from 75 to 750 LK, with incandescent lamps - in the range from 20 to 300 Lux.
Also built the Acting norms of residential and public buildings: houses of hospitals respectively 75 and 30 Lux, doctor's offices - 200 and 100 LX, classroom - 300 and 150 Lux.
Standards for fluorescent lamps are the main, for incandescent lamps - temporarily valid. For hygienic minimum accepted values light from one General lighting. Brightening is achieved by the combined O., at which levels normalized values increased in 3 - 5 times.
In order to limit blindness standardized least the height of hanging lamps common name and a valid brightness of fluorescent surfaces of lamps; the latter should not exceed 2000 - 5000 NT.
Electric light sources by way of radiation is divided into temperature and electroluminescent. There are three groups of sources: incandescent lamps, discharge lamps and mixed (in the latter combined both kinds of radiation).
Gas-discharge light sources have a linear spectrum, usually distort color. The use phosphors in combination with a gas discharge allowed to create a fluorescent lamp with a continuous spectrum with high light yield on average 2-3 times higher than that of incandescent lamps. Industry produces 4 main types of fluorescent lamps, differing in color: fluorescent light (LD), the cold white light (LHV), white light (LB), warm white light (fully).
The brightness of these lamps not exceeding 1 NT the duration of burning lamps reaches 3000-7500 hour. The spectrum of radiation is approaching day. Mixed light sources - arc lamp, solar lamp light and others - provide long-wave ultraviolet radiation. These sources are noteworthy from the hygienic point of view, as they allow to create artificial O. enriched by ultraviolet radiation.
In lighting installations light sources are enclosed in lighting fittings, guide or light-scattering in the lighted space,the so - called fixtures. On functional purpose there are lamps for indoor, outdoor O., vehicles, etc. On lighting classification lamps Acting General are divided into three classes - the direct, indirect and diffused light. Each of these classes is divided into three sub-classes - concentrated, medium and wide light distribution. Lamps local O. also divided into three specified subclass.
Important hygienic importance warning blinding the eyes. Eye protection from blizkosti is determined by a protective corner lamp, i.e. the angle between the horizontal line through the filament incandescent bulbs, and a line running from the filament to the bottom of the lamp (Fig.).

Protective corner lamp "alpha".

Natural lighting. Hygiene is the natural Acting is determined by a high level of illumination, favorable spectral composition and biological value of natural light. Natural O. space created mainly scattered light atmosphere that penetrates into the room through a window (in the walls of buildings) and "lights" (on the roof). Direct sun rays that penetrate into the premises, can significantly increase the illumination, but this factor is not constant, and when rationing O. ignored.
There are three systems of natural O.: side (through the window), top (through lanterns) and combined (through Windows and lights). The application of a system depends on the purpose of the room, its size and location in the plan, as well as the climatic peculiarities of the region. Side Acting as a rule, used in residential and public buildings, upper and combined - industrial. For illumination of inside spaces affect the configuration and size of the aperture, the remoteness of the neighboring buildings, the orientation of the Windows, the size and shape of the premises, and also the state of glasses and reflecting surfaces of the ceiling, step, sex). The norms of the Acting premises of residential, public and industrial buildings are set depending on the purpose of buildings and individual rooms.
There are two methods of regulation of natural light - geometric and lighting. Geometric regulation sets the ratio of the area lighting apertures to floor space - light ratio. In side O. provides light factor for schools - 1 : 4 to 1 : 6; chambers hospitals - 1 : 6 to 1 : 8; living rooms - 1 : 8-1 : 10; service support facilities - 1 : 10-1 : 12; corridors - 1 : 14. Lighting regulation establishes the daylight factor is the ratio of the horizontal illuminance at this point indoors for simultaneous horizontal light outside, created the firmament.
According to the norms of natural light in all premises of industrial, civil and public buildings are divided into six digits (see table). When the top and combined O. standardized average value of the rate of natural light, with the side - minimal.