OSHA Specifications for Handicapped Ramps

Slope and Rise

• A ramp is any slope greater than a 1:20 ratio--1 inch of rise for every 20 inches of run--designed as an accessible route to a building. The minimum suggested incline is 1:12 (which can be difficult for some disabled people to navigate) and, in general, slopes should be between 1:16 and 1:20. To make sure you are within ADA guidelines, the least possible slope should be used when building a wheelchair ramp. The maximum rise for the run of a ramp is 30 inches.

Width and Length

• The minimum width for a wheelchair ramp according to ADA guidelines is 36 inches (3 feet). The maximum length for wheelchair ramp without a landing is 30 feet. If the ramp is longer than 30 feet without a landing (which it shouldn't be if the ramp has been built since the ADA guidelines came into effect), there must be a resting platform at every 30 feet.

Landings

• Ramp landings have to be level. A sloped landing could potentially injure a person in a wheelchair if she were to tip backwards. The ADA requires that a ramp have landings at the top and the bottom, as well as at each ramp run. A landing must be at least as wide as the ramp leading up to it. The minimum length of a landing is 60 inches (5 feet). If the direction of the ramp changes at a landing, the landing can be no smaller than 60 inches by 60 inches. Doors at landings have specific guidelines depending on the type of door. These guidelines can be found at the access-board.gov website.

Handrails and Edge Protection

• When both adults and children may be using a handicapped ramp, two sets of handrails should be present, with more than 9 inches of vertical clearance between the two rails. The maximum height for the rails is 28 inches for a child rail and 38 inches for an adult rail. The minimum height for an adult rail is 34 inches. Handrails must be continuous and on both sides of the ramp. The clear space between a handrail and a wall should be no less than 1 1/2 inches. Ramps and landings with a dropoff need to have a curb or a wall that is at least 2 inches high. Finally, outdoor ramps must be built in such a way as to keep water from accumulating on the surface.