The role of the level and diversity of horizontal illumination in an appraisal of a simple office task

Abstract

Observers were asked to rate their preferences for the lighting of a simple office task under a range of illumination levels and diversities. It is concluded that an increase by a factor of 2 in the current IES minimum service value of illumination for offices (400 lux), would be appreciated by the majority of observers and that the recommendation of a minimum uniformity ratio of 0.7 in the total working area, or at least in each unit of this area when the office space is broken up in some manner, is applicable at both low and high levels of illumination. Results were also obtained which indicate that the experimental conditions were reasonably well related to more normal office situations.