Signed into law in 1990, the ADA, short for the American with Disabilities Act, prohibits discrimination against individuals with disabilities and also dictates federally mandated requirements for buildings. Thus, ADA requirements provide disabled and handicapped people access to buildings -- both public and private -- that they would not have otherwise had. An essential component to a building's ADA compliance are the stairs up to the building. The ADA spells out requirements for stairs in its Accessibility for Buildings and Facilities guidelines.
According to the ADA Accessibility Guidelines for buildings and facilities, stairs are required to be ADA accessible and to, "have uniform riser heights and uniform tread depths." Stair risers (the vertical sections) must be a minimum of 4 inches tall and cannot exceed 7 inches tall. Treads (the horizontal surfaces) must be at least 11 inches in depth, measured from riser to riser. Tread surfaces (from side to side) cannot change in level and treads cannot have a slope greater than 1:48. The ADAAG states that the nosing (or leading edge) of a tread must be a maximum of 1/2 inch. ADAAG also states that, "nosings that project beyond vertical risers shall have the underside of the leading edge curved or beveled." Additional ADA requirements apply to tread nosing.
Handrails and Aisle Ramps for Adults
There are several requirements for to handrails on stairs. For instance the ADAAG states that handrails "shall be provided on both sides of stairs and ramps" and "continuous within the full length of each stair flight or ramp run." "Handrails are not required to be continuous in aisles serving seat", the ADAAG states. Aisle ramps must be, "provided with a handrail at either side or within the aisle width." ADAAG states that handrails are not required on ramps with a maximum rise of 6 inches. Also, clearance between the handrail and wall must be a minimum of 1-1/2 inches.
Height and Gripping Surface of Handrails
The ADAAG dictates the height (gripping surface) of handrails as to not exceed 38 inches and to be a minimum of 34 inches above stair nosings and ramp surfaces. Handrails must be at a "consistent height above the stair nosings and ramp surfaces," the ADAAG states. Gripping surfaces for handrails shall not be obstructed and handrail brackets attached to the bottom surface of the handrail are not considered obstructions given they follow several guidelines spelled out in the ADAAG.
Stair and Ramp Handrail Requirements for Children
ADA ramp and handrails requirements are different for children, or when "children are the principle users in a building or facility," such as an elementary school, requiring all of the ADA handrail specifications for adults and a second set of handrails at a lower height for children. This handrail is required to be at a maximum (gripping surface) height of 28 inches, measured from the ramp or surface or stair nosing. To avoid entrapment with children, the ADAAG states that at least 9 inches of vertical clearance is to be provided between upper and lower handrails.
ADA mandates that handrails with a circular cross section must be 1-1/4 inches minimum and 2 inches maximum on the outside diameter and must follow ADA graspibility requirements. Non-circular cross sections are required to have a minimum perimeter of 4 inches with a corresponding maximum of 6-1/4 inches. The cross-section dimension must be 2-1/4 inches (maximum). Also, the ADAAG states that, "handrails shall not rotate within their fittings", handrails must extend beyond stair and ramp runs. The exception to this handrail length is for aisles serving seating where the handrails are discontinuous for access to seating. Additional ADA requirements apply to top and bottom extensions at ramps.
Additional ADA Requirements
The ADA also requires buildings to have curb ramps. As stated in the ADAAG, "transitions from ramps to walks, or streets shall be flush and free of abrupt changes." ADA compliance applies to ramps, defined as, "any part of an accessible route with a slope greater than 1:20." Additionally, elevators fall under the purview of the ADA as long the elevator is not a only for freight. Additional technical requirements of areas in and around buildings are available in the ADA Accessibility Guidelines for Buildings and Facilities.