Illuminated signs must still comply with the colour coding and pictogram regulations of standard signage; and must be bright enough to be seen clearly and yet not cause glare.
Confusion should be avoided by taking care if illuminated signs are grouped together; or are close to other forms of illumination that they do not lose their impact.
Flashing illuminated signs should have long enough timings in between the pulses to ensure workers can readily understand the information. The use of a flashing sign should alert workers to a greater level of danger; or a more serious need for rapid action.
Flashing signs that work together with an acoustic warning signal, should be synchronised to be in time with each other. The light flashing (on and off) pulsations must be such as to ensure that they do not to trigger epilepsy; in susceptible individuals; or that electronic pulse rates will not be a risk in warehouses containing volatile explosives. Where flashing lights are used there must be detection mechanisms to alert to failure of bulbs or other electrical fault.