# Lighting Calculation Discrepancy

So I came across this calculation in MEEB, chapter 16, and it seems to be different than the usual **Inverse Square Law** calculation for footcandles... MEEB shows as follows (notice the highlights):

The "Typical" calculation as shown in Ballast, Amber, Black Spectacles, Kaplan, literally everywhere, etc. is NEVER elevating **cos** and** sin** to the power of 3 (highlighted). Any idea what's going on here? CP is candlepower and we get 6600 from a candlepower chart provided in the MEEB.

Lastly, do we need to consider the vertical distance (30" work plane maybe?) when using the cavity ratio calculation of F**ootcandles=Lumens/Area **as given in the NCARB resources? For example, if you need to calculate how many fixtures you would need to cover for X area at X footcandles.

Good times.

Please sign in to leave a comment.

## Comments

0 comments