It is obvious from the above that the effective candle power of the lamps depends upon the cleanliness of their surface to increase the value of maintenance factor (P). In new condition, the value of (P) approaches 1, which is the ideal condition.
Hence, to maintain the candle power nearer to the ideal condition, it is necessary to keep them clean.
Lighting systems are designed to provide a desired level of illumination adequate for the activity that must take place in an area. Maximum illumination begins to decrease almost immediately, however, and maintenance must address dirt on the lamps, decreasing lamp output, and dirt on the walls and ceilings, all of which reduce reflectance.
Indicates procedures that should be included in a lighting system inspection program. Neglected lamp out a gas reduces illumination. Moreover, if burned-out lamps are not promptly replaced, illumination may drop to unsafe levels in a short time.
Lamp replacement is done either by an individual or group method. Individual methods involve replacing burned-out lamps on request; group replacement involves installing new lamps in all fixtures in the prescribed areas after they have been in use 70 to 75 percent of their rated life.
(I) Operating fluorescent lamps at a line voltage higher than the maximum range reduces illumination and may cause inconsistent starting.
(II) Incandescent lamps operated at line voltage higher than the maximum lamp range will increase light output but will shorten lamp life; line voltage below the minimum range will extend lamp life but reduce light output approximately 3 percent for each 1 percent in voltage drop.
(III) Operating mercury lamps at higher than maximum voltage will shorten lamp life and below the minimum range will reduce illumination, causing uncertain starting.