Preferred task-lighting levels in an industrial work area without daylight

Abstract

In a luminaire factory an experiment was performed to determine the preferred lighting levels in an industrial work environment. A dimmable task-lighting system was installed above 10 individual assembly workstations. The illuminances selected by the users (regular workers) were recorded. The differences between the individual settings were large. Weak, but significant trends in using different lighting levels at different times during the working day were found. Subjects exhibited different weekly rhythms in their preferred illuminance, and as a group they showed a tendency to use lower lighting levels on Fridays than on Thursdays during the summer, and the reverse during the winter. There was also a trend towards using lower illuminances on the task in the summer than in the winter.