What is the requirement for exit signs posted above doors within the building?

The requirement for exit signs posted above doors within a building is that they must be illuminated. Illuminated exit signs are critical for ensuring visibility in case of an emergency, particularly in low-light situations. Invariably, during an evacuation or fire incident, clear and conspicuous exit signage can make the difference in guiding occupants to safety quickly and efficiently.

Illumination in exit signs can be provided by a variety of means, such as electric lighting or photoluminescent materials, enhancing safety by ensuring that the signs are always visible, regardless of external conditions. This requirement is particularly emphasized in fire safety protocols and building codes to maximize the effectiveness of emergency egress plans.

While the other options may refer to various standards or preferences that may exist for exit signs, such as materials or colors, the illumination of the signs is essential for them to serve their primary purpose effectively.