# Several Common Lighting Calculation Methods

- Jun 30, 2018-

If any lighting designer tells you: lighting calculations don't matter!

Then he must have lied to you.

I have met many lighting masters, and they pay great attention to the lighting calculation. In their lighting scheme, there will be no problem to have a considerable part of the simulation calculation about the lighting quantity design. (LED Tube Light)

Moreover, the more complex the space, the more lighting calculations are required. (LED Tube Light)

As a quantitative design method, illumination calculation is indispensable in most cases. (LED Tube Light)

It is not difficult to calculate the necessary illumination in lighting design if some error is allowed. (LED Tube Light)

Today we will introduce two methods. (LED Tube Light)

1. Luminous flux method

Flux method is mainly in space such as spacing configuration lighting lamps and lanterns, used when calculating the average intensity of illumination, in addition to offices and factories use, bright space such as in the hotel, restaurant, housing and other needs to improve the atmosphere of the space, to make sure about the intensity of illumination, the intensity of illumination calculation method is very convenient. (LED Tube Light)

2. Point-by-point calculation method

The point by point lighting method is used to calculate the illumination required for the operation surface of local lighting and the key display part. (LED Tube Light)

Optical flux calculation

For example 1

When installing the 100w naked bulb of 500lm, suppose 30% of the light beam should be irradiated uniformly and directly on the ground. Then, what is the average direct illumination on the ground? (LED Tube Light)

E = F/A = 1500 * 0.3/10 = 45 lx

In addition to the beam that hits the ground, other beams illuminate the ceiling and walls. (LED Tube Light)

If the ceiling and wall have high reflectivity, the reflected light will also be added to the direct illumination of the ground, so the actual illumination is above 45lx. (LED Tube Light)

The lamps and lanterns that basis illuminates USES, it is the tube lamp that has direct type to match illuminative mostly and the lamps and lanterns of embedded or direct installation of fluorescent lamp, still have the ceiling such as luminous lamp groove indirect illume. (LED Tube Light)

The illuminance of direct type matches a light to calculate, more be affected by the ceiling, wall reflectance less match light, although the setting of room reflectance is a little bit different, the error of average illuminance is also very little. (LED Tube Light)

However, if there is a high partition wall and furniture, etc., the calculation results of the shaded part will deviate. (LED Tube Light)

In addition, the ceiling of the indirect lighting, not only by the influence of the ceiling, but also is affected by the Great Wall surface reflectivity, even like glow lamp chamfer lighting, architectural lighting, because the size of the opening part and the light source and the distance from the ceiling to different, also the efficiency of lighting will have change, so it is difficult to do without error calculation. (LED Tube Light)

For example 2

A positive studio 8 m, 10 m deep, room ceiling height of 2.4 m, in order to make indoor illumination uniformity, the 20 tube lamp lighting lamps and lanterns were arranged in A configuration, calculate the average illuminance on the ground right now? (LED Tube Light)

(ceiling: 70%, wall: 50%, ground: 20%)

As can be seen from the figure above, the room space index 1.85 is roughly between 1.5 and 2.0, where it intersects with the vertical line of the room reflectance, and the lighting utilization rate is about 0.6. (LED Tube Light)

Maintenance rate M, incandescent lamp 0.7~0.9, fluorescent lamp 0.65~0.75, here 0.8. (LED Tube Light)

E = F * U * * N M/A

20 * 0.6 * 0.6 = 1520 *

= 180 lx

The average illuminance multiplied by H (high light source) is within the luminaire interval, which means there will be no uneven spots on the ground or working surfaces. (LED Tube Light)

Calculate the illumination at a particular point

Due to the use of suspended decorative lighting and the local lighting of spotlights, the point-by-point lighting method can be used to calculate the illumination intensity of a certain point of the vertical plane or vertical plane. (LED Tube Light)

For example, 3

As shown in figure, the b with high light lamps and lanterns is installed in 2 m (h), middle intensity of illumination and deviating from the point of just 20 ° horizontal illumination is how much? (LED Tube Light)

(cos after 20 ° material 0.83)

Vertical illumination: P=1000/4=250lx

Deviating from the right point of 20 ° horizontal strength: P = 500/4 * 0.83 material 104 lx

Therefore, the luminance of local lighting can be calculated not only by knowing the light distribution data, but also by calculating the intensity of vertical plane. (LED Tube Light)

Especially in drawing the illumination distribution map of outdoor roads, squares and exterior walls without reflecting each other, it is suitable to use the lighting point by point method. (LED Tube Light)