Expert: Karl Smith - 3/15/2005

Question
Do you have a simple way of determining the no. of fittings and their lumens for lighting a 1000lux hockey pitch? I have got all the computer printouts from suppliers, but how do I check that they are ok. Maybe by using simple calculations? (Inverse square law?) Thanks.

Answer
There are 3 aspects of an answer;

Uniformity: lighting must provide uniform levels across the whole pitch. The rule of thumb is 3 to 1. i.e. the spacing between columns is 3 times as wide as they are high. When you say high mast, how high. When I think of high mast its 16M+ above the working plane in your case the ground.

Light pollution: Excess spill in residential area can cause scheme to fail or be reduced.

Calculation: Flood lighting is based upon isolux intensity outputs which are factored against various lamp types and reflector designs. There is a calculator method but you are required to calculate the trigonometry of each position on the ground and interpret the isolux diagram's for hundreds of points. This is essentially what the print outs do.

If you could provide a little more specific information, I may be able to give a clearer answer.
Country, mounting height, lamp type (Sodium, Halide…), reflector type, 1000Lux ? (semi-pro league level lighting)