OOps silly me, how many fixtures are needed???
When you look at fixtures and lamps they will tell how many LUMENS they produce (if 2 bulbs and each are 100 lumens, that would be 200 lumens per fixture) ............. Then you decide how many FOOT CANDLES you want at what level off the floor.............. 60 to 70 would be plenty for a shop, we only designed for maybe 100 in an drafting room..........Next use the formula Foot Candles = Lumens x CU (Coefficient of utilization, we used the Zonal cavity Method to compute that) divided by the area in square feet.
With a dark floor and a high dark ceiling Id "guess" the CU may be as low as 40%
THEREFORE Foot candles (say 60) = Lumens x .4 divided by the square feet you want to light. Then all you do is plug in the Lumens the fixtures are rated at and plug in the square feet AND YOU GET HOW MANY LIGHT FIXTURES ARE NEEDED
NOTE its been yearssssssssss since I had to do that so no warranty no way lol