Fixture Replacement Estimator Copyright ©2004 R & D Electronics All Rights Reserved Figure out how many fixtures with lamp B can replace the fixtures with lamp A while maintaining the same light level. Or, if you leave the number of fixtures unchanged, figure out the percentage change in light level. .SEE INSTRUCTIONS AT BOTTOM. LAMP A LAMP B Lamp or System Name (optional) No. of Lamps per Fixture Lamp Mean Lumens Ballast Factor (BF) Coeff. of Utilization (CU) No. of Existing Fixtures (Lamp A) . SOURCE MEAN LUMENS PER FIXTURE USABLE MEAN LUMENS PER FIXTURE (1) Change in Average Light level if number of fixtures is left unchanged. (2) No. of Fixtures (Lamp B) required to maintain same average light level. INSTRUCTIONS: Enter the correct numbers in the gray cells and press "Calculate". For an explanation of the terms "Ballast Factor" and "Coefficient of Utilization," you may click on the labels. This tool may be used to estimate the reduction (or increase) in light levels when you replace lamps without changing the number of fixtures, OR it can estimate the number of fixtures (with lamp B) required to maintain the same average light level.