Most computer projectors used in shows and presentations and in interactive whiteboards applications, have projection distances that are large enough to allow people to stand in front of them and look at the very intense light that they produce. Anyone who does this, runs the risk of exposing their eyes to light intensities that could exceed one of the exposure limits that HSE uses as a guide for determining compliance with applicable legislation. Therefore, although these exposure limits are not statutory, HSE considers the following advice to be good practice in respect of the use of these projectors by employers, particularly in the education sector.
Guidelines
Employers should establish work procedures for teachers/lecturers and pupils/students and give instruction on their adoption so that:
- Staring directly into the projector beam is avoided at all times.
- Standing in the beam, whilst facing the projector, is minimised. Users, especially pupils and students, should try to keep their backs to the beam as much as possible.
In this regard, the use of a stick or laser pointer to avoid the need for the user to enter the projector beam is recommended. - Pupils and students are adequately supervised when they are asked to point out something on the screen.
Employers should also try to ensure that projectors are located so that they are not in a presenter's line-of-sight when they stand in front of the screen to address an audience; this ensures that, when presenters look at the audience, they do not also have to stare directly at the projector lamp. The best way to achieve this is by ceiling-mounting rather than floor or table-mounting the projector.
In order to minimise the lamp power needed to project a visible presentation, employers should use room blinds to reduce ambient light levels.
Recent technological developments in projector and interactive whiteboard design have allowed inherently safer "ultra-short throw" devices to be brought to market. These employ sophisticated optics to enable the projector to be mounted above the display screen and so close to it that it becomes impossible for a user to directly expose their eyes to the beam. Employers who use these designs therefore do not need to follow the foregoing work procedure guidance because residual eye exposure risks are wholly removed by this type of equipment's design and construction. Given that safe work procedures may sometimes be disregarded by users, HSE considers that the improved inherent safety of "ultra-short throw" devices is sufficient reason for employers and organisations to actively consider them as an option when they purchase new or replacement equipment.
Similar advice is available at the following web sites:
Department for Children Schools and Families (DCSF):
Teachernet.gov.uk - Computer projector safety advice from the HSE