CHAPTER 3: BUILDING BLOCKS

TECHNICAL

306.3.4 Clearance Reduction.

Between 9 inches (230 mm) and 27 inches (685 mm) above the

finish floor or ground, the knee clearance shall be permitted to reduce at a rate of 1 inch (25 mm) in

depth for each 6 inches (150 mm) in height.

306.3.5 Width.

Knee clearance shall be 30 inches (760 mm) wide minimum.

307 Protruding Objects

307.1 General.

Protruding objects shall comply with 307.

307.2 Protrusion Limits.

Objects with leading edges more than 27 inches (685 mm) and not more than

80 inches (2030 mm) above the finish floor or ground shall protrude 4 inches (100 mm) maximum

horizontally into the

circulation path

.

EXCEPTION:

Handrails shall be permitted to protrude 4½ inches (115 mm) maximum.

Figure 306.3

Knee Clearance

Advisory 307.2 Protrusion Limits.

When a cane is used and the element is in the

detectable range, it gives a person sufficient time to detect the element with the cane before

there is body contact.

Elements located on circulation paths, including operable elements,

must comply with requirements for protruding objects.

For example, awnings and their

supporting structures cannot reduce the minimum required vertical clearance.

Similarly,

casement windows, when open, cannot encroach more than 4 inches (100 mm) into

circulation paths above 27 inches (685 mm).

2010 Standards: Titles II and III

111

Department of Justice