stadium lighting-illuminance calculation

In previous articles, we respectively interpreted How to design stadium lighting. In this issue, we will talk about an important part before the implementation of stadium lighting design: illuminance calculation!

How much illuminance a gymnasium needs to use, how many lights to use, and what lights to use, all need to be calculated in advance. Including the position and angle of the lamp, it also needs to be designed in advance, and the slot needs to be opened in advance.

Generally speaking, there are three methods for calculating the illuminance of stadiums. Let's explain them separately:

1. The basic formula of the capacity estimation method per unit area: N=P×A/PL2

In the formula: N represents the number of floodlights; PL represents the power of each floodlight W; P represents the power per unit area W/m2; A represents the illuminated area m2.

　M=1/η×η1×U×U1×K3

In the formula: m represents the simplification factor; η represents the efficiency of the lamp; η1 represents the efficiency of the light source, 1m/W; U represents the utilization factor; U1 represents the uniformity of the illuminance; K represents the maintenance factor of the lamp, generally taken from 0.7 to 0.8.

Generally, the m value of different light sources is given according to η=0.6, U=0.75, U1=0.7, and K=0.7. Using these commonly used values ​​can make our calculations easier.

　P=m×E4

　In the formula, E is the minimum illuminance lx.

2. The average illuminance calculation method, calculate the number of lamps: N=E×A/η×F×K5

Among them: N represents the number of lamps; E represents the average surface illuminance lx; A represents the illuminated area m2; η represents the efficiency of the luminaire; F represents the luminous flux 1m; K represents the maintenance coefficient, which is taken from 0.7 to 0.8.

Note: The above two illuminance calculation methods are widely used, and are mainly used in the preliminary stage of scheme design to estimate illuminance.

3. Point-by-point calculation method for point light source: EΦcosα±D/h×sinαEh=ΨEh

Point-by-point calculation mainly uses computer software to perform point-by-point calculations. The size of the floodlight is much smaller than the distance it illuminates, so the floodlight can be regarded as a point light source.

In the formula, Eh represents the average illuminance lx produced by a lamp illuminating the vertical facade, and Eh is calculated by formula 7: Eh=Iθ×cosθ/R27

Iθ represents the light intensity cd in the irradiation direction at angle θ; R represents the distance m from the light source to the illuminated surface; h represents the vertical calculation distance m from the light source to the vertical elevation; D represents the projection m of R on the vertical elevation; α represents the inclined plane The angle with the horizontal plane, the unit is degree; θ is the angle between the center of the light beam of the lamp and the horizontal plane, the unit is degree; Ψ is the coefficient, Ψ=cosα±D/h×sinα.

Only by comprehensively using these three illuminance calculation methods and repeatedly checking calculations can we get relatively accurate calculation results.

Of course, even in accurate calculations, there will still be gaps in the measurements after the actual construction, which is normal. If necessary, the lighting designer also needs to make appropriate adjustments to the on-site lighting and installation methods.