HVAC - Mechanical

The Lumens per Watt information for the lighting device is required.

Type of lamp? Distance from lamp to measurment?

1 lux is 1 lumen per sq-meter. 1 candle power is 1 lumen per sq-ft.

1 sq-m = 10.76 sq-ft

1 candle power per sq-ft is 1/683 W (for visible light of a freq 540 x 10^12)

1600 LUX is therefore 1600(lumen/sq-m)/10.76(sq-ft/sq-m) * 1/683 = .2177 W/sq-ft

That is the energy of the light hitting the surface. The amount of power required to get that light to the surface depends on the efficiency of the lamp, the lamp fixture (luminaire) and the environment. A metal halide lamp is about 20% efficient in producing visible light. If the Luminaire is 100% efficient, the lighting power is .2177/.20 = 1.1 W per sq-ft. The Luminaire will not be 100% efficient. Reflected light from the surroundings will probably be very small when compared to the source and might not need to be considered.