Appreciation of localised task lighting in shift work—A field study in the food industry

Localised task lighting was installed in addition to the general lighting installation in the food factory. Research has been carried out to test appreciation of this additional task lighting by workers working in fast-rotating shifts: viz. five shifts over the full year. There were between six and eight persons in one shift. Average age of workers was 42, most of whom were men. Employees’ opinions and performance was measured in three ways: repeated working environment and lighting questionnaires, Karolinska Sleepiness Scale questionnaires (KSS), and measurements of the time that employees needed to solve small operating problems at packaging machines. Questionnaire results showed that employees liked the new lighting. They felt that higher lighting levels made them feel less sleepy and able to perform better. Direct performance measurements showed on average a statistically significant 3 per cent improvement with the higher illuminance. This difference and its direction was not clear for all error types. The KSS measurements showed no significant effect of higher or lower illuminances. However, there was a significant pattern revealed by the KSS, namely that employees felt sleepy during the first and third breaks and sleepier during the second break and at the end of the working day.