In Canada we typically use FC(foot-candles). But on the odd occasion a Canadian company comes to us with a lux reading and prefer the layout done in that measurement. More often for the US we use lux but FC has been requested. Either way the difference is easily calculated by:
1FC = 10 Lux
note: 0.0929030436 = 1 Lux to be exact.
Light Loss Factor or also known as LLF in short form is one of the hardest parts to remember in the lighting industry. Each fixture can have a different value and some are better designed to eliminate some of the common losses we encounter when doing a lighting design. Each manufaturer of fixture, or lamp would have it's own value to be totally accurate.
A common issue we encounter when doing layouts is how to accurately know what the reflectance is in a building. The reflectivity of the surface is calculated by a numerical value 0.0 behind jet black(no reflectance) and 1.0 being as white(full reflectivity).
I've had this question asked a lot, what makes a good light meter? Well first off, toss out any idea of using a light meter from your phone. I've never found them to work very well. Any stand alone version seems to work just fine, it's how you use them. A light meter that has a white globe to difuse direct lighting is why the stand alone units work the best.