Dear Reader:

The specification sheet for any lighting fixture typically includes a great deal of information on the fixture – perhaps more than you want or need to know. That said, there is one set of data the Facility Manager may want to tune into, given its importance to the design and layout of any given space.

The photometric data, typically illustrated with a chart, will tell the buyer exactly what the outer limits of the fixture’s distribution curve is. Don’t be intimidated by this phrase, as the chart is quite easy to interpret once it’s understood what its various components are.

dmLights published an informative how-to-do-it on their website, entitled How to Interpret a Light Distribution Curve, and we think it would be worth your time reading it.

Notice first that a photometric chart expresses light intensity in candelas. Many of you might be more familiar with the term ‘lumens’, in wh...