THE IMPACT OF LIGHTING ON WORKERS’ PERFORMANCE FROM A SELF-ASSESSMENT PERSPECTIVE: A CASE STUDY OF INDUSTRIAL FACILITIES IN SADAT CITY, EGYPT

Lighting in indoor work environments is an essential element for improving worker performance and productivity. This study aims to explore the impact of lighting characteristics on worker performance in industrial environments through self-assessments. A field study was conducted in six factories in Sadat City, Egypt, during the winter and summer seasons. The study assessed workers' perceptions of lighting levels and analyzed their relationship with lighting characteristics (EH, EV, CCT, and CRI). A total of 1,266 questionnaires were collected from 456 workers during day and night shifts. The questionnaire addressed workers' self-assessments of the impact of lighting intensity and color temperature on performance efficiency and task speed. The results showed a statistically significant relationship between lighting levels and performance assessments, with lighting below 300 lux considered insufficient, while levels between 300 and 500 lux showed a clear positive effect. Correlated color temperature (CCT) did not show an effect on performance at light levels (<220 lux), but color rendering index (CRI) (<80) was associated with a negative effect on night shift workers' performance at light levels (<220 lux).