Calculation method of illuminance
Average illuminance (Eav) = total luminous flux of light source (N*Ф) * utilization factor (CU) * maintenance factor (MF)
/ area area (㎡) (suitable for indoor or stadium lighting calculations).
Utilization coefficient: 0.4 for general indoor use and 0.3 for sports.
Maintenance factor: generally take 0.7 ~ 0.8.
Example:
(1) Indoor lighting: 9 sets of 3×36W grille lights for a room of 4×5 meters.
Average illuminance=total luminous flux of light source×CU×MF/area=(2500×3×9)×0.4×0.8÷4÷5=1080
Lux
(2) Stadium lighting: 20×40m field, using POWRSPOT
60 sets of 1000W metal halide lamps,
Average illuminance=total luminous flux of light source×CU×MF/area=(105000×60)×0.3×0.8÷20÷40
=1890
Lux
Extended information:
Illumination standard value according to 0.5, 1, 3, 5, 10, 15, 20, 30, 50, 75, 100, 150,
200, 300, 500, 750, 1000, 1500, 2000, 3000, 5000lx Grading. lx (lux) is the unit of illuminance.
The illuminance standard value classification is to clearly feel the minimum change of illuminance in terms of subjective effect, and the illuminance difference is about 1.5 times. This classification is roughly consistent with the classification of the CIE International Luminous Lighting Committee standard "Indoor Workplace Lighting" S008/E--2001.
Under direct sunlight in summer, the light intensity can reach 60,000-100,000 lx, 10,000-10,000 lx outdoors without the sun, 100-550 lx indoors in bright summer, and 0.2 lx at night under the full moon.
Incandescent lamps emit about 12.56 per watt
lx light, but the value varies with the size of the bulb. Small bulbs can emit more lumens, while large bulbs can emit less. The luminous efficiency of fluorescent lamps is 3 to 4 times that of incandescent lamps, and the life span is 9 times that of incandescent lamps, but the price is higher.
