SECTION 02930
DETECTABLE WARNING AT HANDICAP RAMP
SCOPE
A curb ramp shall have a detectable warning. The detectable warning shall extend the full
width of the curb ramp (exclusive of flared sides) and shall extend either the full depth of
the curb ramp or 24 inches (610 mm) deep minimum measured from the back of the curb
on the ramp surface.
MATERIALS AND CONSTRUCTION
Detectable warnings shall consist of a surface of truncated domes and shall comply with
section 705 of the ADA and ABA Guidelines for Buildings and Facilities. Truncated
domes in a detectable warning surface shall have a base diameter of 0.9 inch (23 mm)
minimum and 1.4 inches (36 mm) maximum, a top diameter of 50 percent of the base
diameter minimum to 65 percent of the base diameter maximum, and a height of 0.2 inch
(5.1 mm). Truncated domes shall have a center-to-center spacing of 1.6 inches (41 mm)
minimum and 2.4 inches (61 mm) maximum, and a base-to-base spacing of 0.65 inch (17
mm) minimum, measured between the most adjacent domes on a square grid. Detectable
warning surfaces shall contrast visually with adjacent walking surfaces either light-on-
dark, or dark-on-light.
1,6-2.4
41-61 '
top diameter of 0.65 min —— 1.6-2.4
50% Got of the base diameter \, 02 SS NO OF O- OD) art
base diameter of . ‘ eq iO O Os-o
0.9-1.4 (23-36 mimi aE
oo 68 66
(a)
elevation ib)
(enlarged) plan
Figure 705.1 Size and Spacing of Truncated Domes
END OF SECTION
02930-1
