ABSTRACT
Several forces have shaped how the use of commercial lighting equipment has evolved over the last two decades:
An increasing emphasis on obtaining higher worker productivity — An interest in quality lighting that improves the employee’s visual task performance even by a few percent can quickly pay for itself through increased productivity.
Moving toward an electronic office environment — The advent of the visual display terminal (VDT) raised concern for the worker’s visual comfort. At the same time the introduction of easily changeable, open-plan office furnishings, including cubicle walls of varying heights plus overhead file and shelves, has necessitated the installation of additional luminaires to offset shadows caused by those structures. This additional light on the work task has produced an opportunity to reduce the quantity of ambient light from the general lighting system. It also led to the need to improve the quality of the system’s available light in order to reduce glare on VDT screens.
The lighting equipment market is legislated — In the late 1980s lawmakers established minimum efficiency standards for ballasts that operate the fluorescent lamps in the most commonly used luminaires made since April 1991. At the same time, the Energy Policy Act of 1992 is affecting lamps. First in May 1994 with the most popular 8-ft lamps, then in November 1995 with the most popular 4-ft straight and 2-ft U-shaped lamps, this law prohibited the least efficient models from being produced or imported in the U.S. It also banned the most inefficient incandescent reflector lamps. The net effect of these laws will be to raise minimum efficiency levels for both major components of fluorescent luminaires. Another result of the Energy Policy Act is 100the federally mandated requirement that each state adopt laws to meet minimum energy efficiency standards for both new construction and renovations. For lighting, these standards can take the form of maximum unit power density limits in watts per square foot for each space within and outside a facility. In some cases the use of lighting controls — photocells, time clocks, occupancy sensors, and/or ambient light level sensing plus dimming — will be necessary to achieve these standards.
Environmental issues — PCBs were banned from ballasts in 1979, followed in 1991 by elimination of DEHP. Both were used in the p.f. correction capacitors of most ballasts. More recently manufacturers have begun to reduce the amount of mercury in each lamp to a level much lower than before. Disposal of lighting equipment containing those materials is regulated under one or more federal laws. Both fluorescent and HID lamps as well as types of ballasts containing toxic materials can now be recycled by qualified and licensed waste disposal organizations.
Proper maintenance — It will be much more cost effective to periodically clean the lens and inside of the luminaire. This type of proactive lighting maintenance can result in energy saving with improved quality of lighting; reduced lamp and ballast inventory carrying costs; and reduction of unnecessary ballast degradation from trying to start expired lamps.
