Since 1992, accessible signage has been a requirement in the United States under the Americans with Disabilities Act (ADA).   ADA guidelines are intended to remove barriers and make facilities accessible to all people with disabilities. 

All public facilities must take steps to comply with ADA guidelines.  ADA signs fall into two categories: Signs that must have tactile copy and braille and signs that do not need the tactile/braille but must meet design guidelines and visual copy. 

When determining signage for a facility, a general rule of thumb is - if a room has an entry door, an ADA compliant sign with tactile lettering and braille should identify that room or space.  Any permanent rooms that have permanent fixtures which are not likely to change require ADA compliant tactile and braille signs. Therefore these rooms are labeled by room names and not just room numbers. Examples are cafeterias, electrical rooms, and restrooms.  If a room is considered permanent but can change its function easily, they may be labeled numerically with ADA room number signs.  Great examples of these are class rooms, and some offices. 

Signs providing direction or information about interior rooms or spaces must meet the ADA visual guidelines but are not required to be have tactile copy or braille. Signs listing rules of conduct, evacuation instructions, exit route maps, and directional signs all fall into this category.