The Americans with Disabilities Act (ADA) accessibility guidelines suggest ramp specifications that include preferred slopes, width, landings, surfaces, handrails, and environmental conditions. The next area to the point list of these factors for building, purchasing, and using ramps for wheelchairs:
Wheelchair ramp slopes
A ratio of rise over run is used to define ramp slopes (e. g. 16 inches of level run for each one inch of upright rise would be expressed as 1:16). The preferred ADA ramp slope is between 1:16 and 1:20. New construction slopes shall not exceed 1:12. Slope alone is not the only issue to consider; ramp distance and maximum rise are to be minimized. Maximum rise shall not exceed 30 inches (760 mm), and ramp distance should avoid lengths greater than 30 feet (9 m).
Wheelchair ramp width and landing
Ramp widths shall not be less than 36 inches (915 mm) and apparent. Landings, at both the top and bottom, shall be level and accommodate the slope of the connecting ramp. The next added landing features are necessary:
• Landings shall minimally be as extensive as the ramp.
• Landing length shall at smallest amount be 60 inches (1, 525 mm).
• Landings with a direct turn require a minimum of 60 x 60 inches (1, 525 mm x 1, 525 mm).
Wheelchair ramp handrails
Wheelchair ramp handrail guidelines are for adults. If children are the most important users, such as in schools, then a following, subordinate rail should be provided. If two handrails are being used, one above the other, a minimum distance between rails shall be 9 inches to avoid entrapment. Handrails shall be a maximum of 28 inches from the surface of the ramp to the top of the rail. Ramp rises greater than 6 inches (150 mm), or level projections superior than 72 inches (1, 830 mm), require railings on both sides of the ramp. Handrails are not necessary for curb ramps and ramps next to audience seating. The next added handrail features are necessary:
• Both sides of ramp segments require handrails; where doglegs and switch – backs exist, the inside railing must be continuous.
• If handrails are continuous, they shall extend 12 inches (305 mm) beyond the end of the ramp, and run equivalent to the ground.
• The apparent space between the wall and handrail shall be a minimum of 1 ½ inches (38 mm).
• Gripping surfaces shall be continuous.
• Handrail ending shall be round or returned smoothly to post, walls, or ground.
• Handrails shall not rotate, or otherwise move, within their fittings.
Wheelchair ramp surfaces, edges, and environments
Ramps for wheelchairs require surfaces compliant with ADA regulations for such. Ramp edges shall be provided if drop offs exist. These edges can be in the form of walls, lips, or other projections that are at a minimum of 2 inches (50 mm) in height. Design and construction of outside ramps for wheelchairs shall not allow for the accumulation of water or snow at the approach or on the ramp.