Illumination is a physical quantity characterized by the ratio of the flux of light falling on a surface to its area. Moreover, it is understood that the surface plane must be perpendicular to the axis of the light flux.
In addition to the hygienic value directly for humans, in practice, the measurement of illumination is used in animal husbandry to create the proper indoor microclimate, in breeding aquarium fish and plants, for growing indoor plants, to describe the characteristics of photo and video equipment, including outdoor surveillance cameras.
Light sources
It is known that there is natural and artificial light. It is created by appropriate light sources: the diffused light of the sky, of course, the sun, as well as the reflected light of the moon, belong to the natural ones. Artificial sources - various lamps (incandescent, gas discharge, fluorescent), TV screens, computers.
Why measure illumination
Illumination is one of the most important hygienic indicators, from whichdirectly related to human he alth. Illumination measurement is a procedure included in the SanPin (sanitary rules and norms), which must be carried out at the workplace along with measurements of noise levels, vibration, dust and gas pollution.
Doctors say that insufficient lighting leads to a decrease in visual acuity, overwork, reduces concentration and overall productivity, and can even cause an accident. In animals and birds, lack of light causes growth and development disorders, poor body weight gain, reduced productivity (for farm animals) and reproductive ability.
What and in what units is this physical quantity measured
Illumination is measured with a device called a luxmeter, a portable device that is a type of photometer. Modern high-end devices are equipped with light filters. The unit of measurement of illumination in the system of international units (SI) is lux, which is equal to the ratio of 1 lumen to a square meter of surface area. Lumens measure the amount of light emitted. The US and English measurement systems use lumens per square foot, the footcandela (the degree of illumination from a source of luminous intensity of 1 candela 1 foot from the surface) to measure illumination.
How is illumination measured? This is done using a light meter, the meter of the latter must be in a horizontal position, place it inrequired points in the room. For buildings and livestock complexes, there are special control measurement points prescribed in state standards. Use the instructions for the device, when using nozzles, you need to take into account the attenuation coefficient by which the result is multiplied. Then, using various formulas, the minimum, average, maximum illumination, as well as the coefficient of natural illumination are calculated.
