Illumination is a physical quantity characterized by the ratio of the flux of light incident on the surface to its area. Moreover, it is understood that the surface plane should be perpendicular to the axis of the light flux.
In addition to the hygienic significance directly for humans, the measurement of illumination is practically used in animal husbandry to create the proper
indoor climate, to breed aquarium fish and plants, to grow indoor plants, to describe the characteristics of photo and video equipment, including
outdoor surveillance cameras
.Lighting sources
It is known that there is natural and artificial lighting. It is created by the corresponding light sources: the scattered light of the sky, of course, the sun, and also the reflected light of the moon, are natural. Artificial sources - various lamps (incandescent, gas-discharge, fluorescent), TV screens, computers.
Why measure light?
Illumination is one of the most important hygiene indicators on which human health directly depends. Measurement of illumination - the procedure included in SanPin (sanitary rules and regulations) must be performed at the workplace along with measurements of noise levels, vibration, dust and gas pollution.
Doctors say that inadequate lighting entails a decrease in visual acuity, overwork, lowers concentration and general productivity, and can even cause an accident. In animals and birds, a lack of illumination causes impaired growth, development, poor weight gain, decreased productivity (for farm animals) and reproductive ability.
What and in what units is this physical quantity measured
The measurement of illumination is carried out by a device called a luxmeter, a portable device that is a type of photometer. Modern high-end devices are equipped with 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 square meter of surface area. In lumens, the amount of light flux is measured. In the American and English measuring systems, such units of illumination are used as lumen per square foot, foot-candela (the degree of illumination from a source by a luminous force of 1 candela, which is 1 foot apart from the surface).
How is light measured? This is done using a light meter, the meter of the latter should be in a horizontal position, place it at the necessary points in the room. For buildings and livestock complexes there are special control points of measurement 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, according to various formulas, the minimum, average, maximum illumination, as well as the coefficient of natural illumination, are calculated.