Aspects of classroom lighting and de´ cor that can promote discomfort and impair task performance
through glare, and imperceptible 100 Hz flicker from fluorescent lighting, were examined in a sample of
UK schools. In 90 classrooms, across eleven secondary schools and six local education authorities variables
measured included flicker, illuminance at desks, and luminance of whiteboards. Results showed
that 80% of classrooms are lit with 100 Hz fluorescent lighting that can cause headaches and impair
visual performance. Mean illuminance (from excessive day- and artificial lighting) was in excess of
recommended design illuminance in 88% of classrooms, and in 84% exceeded levels beyond which visual
comfort decreases. Lighting could not be adequately controlled due to classroom design and infrastructure.
Ceiling-mounted data-projectors directed at whiteboards mounted vertically on the wall
resulted in specular reflection from the whiteboard, visible as a glare spot with luminance high enough
to cause discomfort and disability glare. The intensity of the glare spot varied between different brands of
whiteboard. Ambient lighting, needed for close work at pupils’ desks, reduced image contrast. Venetian
blinds in 23% of classrooms had spatial characteristics appropriate for inducing pattern glare. There was
significant variation between schools and local authorities. These findings may provide insights into
small-scale reports linking pupils’ attainment, behaviour and learning to classroom lighting, and may
also help explain some of the benefits of coloured overlays for pupils’ reading.