What is the total length of an accessible ramp needed for a 42-inch vertical rise?

To determine the total length of an accessible ramp needed for a vertical rise of 42 inches, one must consider the slope requirements established by accessibility standards, such as the Americans with Disabilities Act (ADA). The ADA typically recommends a maximum slope of 1:12 for wheelchairs, meaning that for every inch of vertical rise, there should be at least 12 inches of ramp run.

Given that the vertical rise is 42 inches, the calculation for the ramp run using the 1:12 slope ratio is as follows:

1. Multiply the vertical rise by the slope ratio:

42 inches (rise) x 12 inches (run per inch of rise) = 504 inches of ramp run.

2. To convert the run from inches to feet:

504 inches ÷ 12 inches/foot = 42 feet of horizontal run.

3. To calculate the total length of the ramp (the hypotenuse of the right triangle formed by the rise and run), we use the Pythagorean theorem:

Total length = √(rise² + run²)

= √(42² + 504²)

= √(1764 + 254016)

= √(255780)

=