The sum of the bright period in a photoperiod is the photoperiod. In natural light, the sunlight time (bright period) is generally calculated as the sunshine time in artificial light, the light exposure time is the light time, and the 24h light period is the natural light period the longer or shorter than 24h is called unnatural light Cycle if there is only one bright period and one dark period within 24h, it is called single-period illumination if there are two or more bright or dark periods within 24h, it is intermittent illumination. The time with light is the bright period, and the time without light is the dark period. ![]() In nature, 24 hours a day and night is a light cycle. Sunlight is natural lighting, and light lighting is artificial lighting. *Reflectivity in the venue, such as lawns, walls, stands, etc. The main factors affecting the utilization factor are as follows: Remarks: The lighting design must require an accurate utilization factor, otherwise there will be great deviations. What is the average illuminance in the football field? The utilization factor is 0.7, the maintenance factor is 0.8, the number of lamps is 36 sets, A design case of the average illuminance of a football field:ĭesign conditions: Standard football field is 105 meters long, 68 meters wide, light poles are 18 meters high, and the distance between light poles is 36 meters.Use LedsMaster 1000W LED floodlight 60 setsĬonclusion: The average horizontal illuminance is above 2000 Lux Example 2: Stadium lighting: 20×40m venue,.Example 1: Indoor lighting: 4×5m room, using 9 sets of 3×36W grid lightsĪverage illuminance=total luminous flux of light source×CU×MF/areaĬonclusion: The average illuminance is above 1000 Lux.Utilization factor: 0.4 for general indoor, 0.3 for sports Illumination calculation method: use coefficient method to calculate average illuminance–Īverage illuminance (Eav) = total luminous flux of light source (N*Ф) * utilization factor (CU) * maintenance factor (MF) / area area (m2) (applicable to indoor or stadium lighting calculation) But today’s definition has changed: heating with a black luminous body of one cubic centimeter until the luminous body melts into liquid, 1/60 of the amount of light emitted is the standard light source, and candlelight is the standard light source. The concept of candlelight was first invented by the British, and it is a unit of luminous intensity.Īt that time, the British used a pound of white wax to make a one-foot-long candle to define the unit of candlelight. Lumen is a unit of luminous flux.Ī point light source with a luminous intensity of 1 candela has a luminous flux of “1 lumen” per unit solid angle (1 steradian).Ĭandlelight (Candela), transliteration “Candela”. When an object is uniformly illuminated by light, when the luminous flux obtained on an area of 1 square meter is 1 lumen, its illuminance is 1 lux. ![]() Suppose the luminous flux on the surface element dS is dΦ, then the illuminance E on this surface element is: E=dΦ/dS.ġ lx=1 lm/㎡. The illumination/illuminance on a surface illuminated by light is defined as the luminous flux illuminating a unit area. It can be measured with an illuminance meter. The light intensity has a great influence on the photosynthesis of organisms. The international unit of luminosity is the candlelight received per square meter. In photometry, “luminance” is the density of luminous intensity in a specified direction, but it is often misunderstood as illuminance. It is used to indicate the intensity of light and the amount of illumination of the surface area of the object. Abbreviated as illuminance, unit Lux (Lux or lx). Illumination intensity is a physical term that refers to the luminous flux of visible light received per unit area.
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