Factors influencing workers' impressions of glare in open offices.

Abstract

Currently, standards and design principles for open office lighting application are based on laboratory studies conducted under limited conditions, or are based on the consensus of opinions of lighting design experts. These standards, which have not been systematically verified in the field, assume that the environment alone affects office workers' impressions of reflected glare. Data from a study of lighting quality in three office buildings were used to examine conditions in open offices and impressions of the buildings' occupants relevant to bothersome reflected glare at the task areas. It was found that workers' perception of environmental conditions in their offices were most predictive of whether they were bothered by reflected glare. Among the specific findings, it was shown that the perceived amount of light in the office and distractions by glare from electric light fixtures best predicted whether open office workers were bothered by reflected glare at their desks. Furthermore, characteristics of the office workers such as age, gender, and type and duration of tasks performed each day, in addition to selected environmental conditions, influenced workers' perception of their offices. Environmental conditions associated with reports of bothersome reflected glare included uneven distribution of light within the open office area and high illuminance levels on the task surface caused by task light fixtures. The results of the study allowed for recommendations relative to the application of ambient and task lighting systems; brightness levels on vertical surfaces; luminance ratios; daylight control; and workers with special lighting needs. Results were inconclusive as to how glare impacts open office workers who extensively use computers.