The effects of illuminance on tasks performed in domestic kitchens

Abstract

Field measurements have shown that the illuminances used in kitchens tend to be much less than those recommended in the CIBS (IES) Code. This may be because people are unaware of the advantages of having higher illuminances or because the recommended illuminances are unnecessarily high. This paper reports an experiment designed to examine the effect of illuminance on the performance of tasks representative of those done in domestic kitchens. Thirty-two subjects performed four tasks at four different illuminances in a kitchen setting. Details of task performance, subjects' behaviour and the subjects' opinions of the lighting conditions, the task difficulty and the effort required to perform the tasks were collected. Statistical analysis of the results revealed that only one of the four tasks showed any variation in performance with illuminance. This lack of effect can be explained by the nature of the tasks and the ways in which the subjects modified their approach to the tasks as the lighting conditions became more difficult. The subjective results showed a consistent variation with illuminance for all four tasks; namely, a rapid increase in satisfaction with lighting conditions and a decrease in task difficulty and effort required with increasing illuminance. Taken together these results suggest that whilst an illuminance of 100 lux would serve reasonably well for many tasks and many people, an illuminance of 300 lux is undoubtedly an improvement for some tasks and groups of people.