1. Junior Member
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## Lighting Design

I would like to know the basic formula for designing a indoor and outdoor lights. Let's suppose i am going to light a room with an area of 50m2(10*5), so the formula what i know is Illumination = Area*Lumen/Watts*Total Wattage*Light depreciation factor*Maintenance factor. But how to add height into it i mean what's the exact method or formula when considering height as well!! confused :/ Please help!!

2. Senior Member
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That would make my head hurt.

All manufacturers have data, design guides and photometrics for their products.

-Hal

3. I sort of get where you are going but I am not clear as to what you wish to include as a feature in your design.

as far as ceiling height you need to look at the inverse square law. :
"the power of the light will be inversely proportional to the square of the distance. So if we take a distance of 2 and square it, we get 4, the inverse of which would be 1/4 or rather, a quarter of the original power - not half."

from Wikipedia:
Mathematically formulated:

It can also be mathematically expressed as:

or as a constant quantity

------------------------------------------------------------------------------------

Are you looking for efficiency?

Long life?

I would not think that illumination would include all those things you list unless you are trying to achieve a certain illumination vs overall efficiency as well as life of the lamp.

Things to consider:

Lumens per watt
Lumen maintenance - any light source output is diminished over life of the lamp.
cost of replacement

4. For simple calculations and a sample fixture data sheet you want to use, Google "zonal cavity lighting calculator'

5. Moderator
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Originally Posted by ron
For simple calculations and a sample fixture data sheet you want to use, Google "zonal cavity lighting calculator'
And if you really want to know the formulas, here they are:

http://aesl.hanyang.ac.kr/class/are1...o%20method.pdf

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