Illuminance uniformity on desks: Where is the limit?

Abstract

This paper reviews the current uniformity recommendations and shows that they may no longer be appropriate. A study to investigate the acceptable illuminance uniformity across a desk top is described. The illuminance patterns used were representative of those produced by over-spaced luminaires, selective luminaire dimming, e.g. using HF regulation, or lamp failure. Subjects were asked to carry out simulated office tasks and then to rate the various attributes of the lighting and its acceptability. Their task performance was also measured. The results showed that although the subjects were aware of the lack of evenness of the lighting, for tasks which occupied only part of the desk, an illuminance uniformity across the desk below current recommendations was acceptable and task performance was unaffected.