Which signage feature must extend at least 1 mm from the surface of walls or doors?

The requirement for signage features to extend at least 1 mm from the surface of walls or doors is an important aspect of accessibility regulations, particularly under standards such as the Americans with Disabilities Act (ADA). This stipulation applies to letters, logos, and numbers, as all these elements contribute to the effectiveness of signage in aiding individuals with visual impairments.

When signage features are raised from the surface, it enhances tactile feedback, allowing individuals to recognize and interpret the information through touch. This is especially critical in environments where individuals may rely on their sense of touch to navigate and understand their surroundings. Therefore, all these components—letters, logos, and numbers—must comply with the same dimensional guidelines to ensure consistency and promote accessibility.

Each of these elements plays a distinct role in identification and orientation for users, and their combined adherence to the raised feature standard helps create an inclusive environment. Thus, the requirement for extensions applies uniformly to all types of signage interactive elements, validating the choice that all must extend at least 1 mm from the surface.