What must be the illumination status of exit signs?

The illumination status of exit signs is critical for ensuring safety in buildings. The requirement for exit signs to be either internally or externally illuminated is based on the need to ensure visibility in various lighting conditions, especially during emergencies when power might be lost or when visibility is drastically reduced.

Internally illuminated exit signs often rely on LED or fluorescent lighting to make the sign visible from a distance. On the other hand, externally illuminated signs may have a separate light fixture that shines on the sign to ensure it is visible. By permitting both options, regulations ensure that buildings can choose the type of sign that best fits their design and operational needs while maintaining safety.

This flexibility enhances compliance with local codes and can accommodate different architectural styles while still prioritizing the main purpose of exit signs: providing clear guidance for safe egress during emergencies.

In contrast to the other choices, the requirements do not limit illumination to just one type, nor do they permit unlit signs, since visibility is paramount for effective emergency evacuation. Ensuring that exit signs are illuminated, whether by internal or external means, is a key aspect of building safety regulations.