The number of light fixtures in a 20' x 30' room is being calculated. The desired level of illumination at the working plane within the room is 50 foot-candles. Each luminaire uses three 12-watt bulbs that produce 1500 lumens with 75% efficiency.
How many luminaires are required?
I got 27 from rounding up of the 26.67 = 27, but didn't divide b3 to give me the 9 luminaire correct response.
I did use the correct reference equation, but didn't RE divide my total by 3 to account for the 3 bulbs/ fixture. I am not sure this is correct. I mean, aren't you calculating for the total fixture already when you use the 1500 lumens in the denominator? So wouldn't you be getting the fixture answer from the beginning?
I think so, If not wouldn't you have been doing the calculation/ bulb and then multiplying it by 3 to get the fixture count? I am glad I pretty much got this correct, but want to know for future in case I need to do this again. I always want to understand from my mistakes, if I did make one on this. please advise. I appreciate your feedback.
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