What size must the letters on an exit sign be?

The requirement for exit sign lettering size is crucial for ensuring visibility and safety during an emergency. The standard specifies that letters on an exit sign must be at least 6 inches high with the stroke width of at least 3/4 inch. This size is designed to ensure that the signs can be seen easily from a distance, especially in low light or smoke-filled conditions where evacuation might be necessary.

The height and width of the letters are specifically chosen to provide optimal legibility in various conditions, allowing individuals to quickly identify exit routes. This standard is in line with fire safety codes, which are aimed at minimizing confusion and ensuring people can safely exit a building during a fire or other emergencies.