How must exit signs be illuminated according to fire safety regulations?

Exit signs must be illuminated by a backup power source or internal lighting to ensure they remain visible during emergencies, particularly in the event of a power failure. Fire safety regulations dictate that these signs should be easily identifiable and reliable, acting as critical guides for occupants during evacuation. The use of a backup power source, such as batteries, ensures that exit signs continue to function even if the main power supply is interrupted. Internal lighting is also utilized to provide consistent illumination, making sure that the exit path is clear and recognizable at all times.

Natural light, while beneficial for visibility during daylight, cannot be relied upon in emergencies, especially when exits may be used at night or in darkened conditions. Solar-powered lights and external sources may be subject to variability and may not be dependable during emergencies. The requirement for backup power or internal lighting helps to standardize safety measures across different buildings, ensuring a higher level of preparedness in case of an emergency evacuation scenario.