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 Footcandles=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.
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