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1991 ADA Standards for Accessible Design

Note: This document, portion of document or referenced document was published prior to the 2010 ADA Standards, and is still applicable.

4.5 Ground and Floor Surfaces.

4.5.1* General.

Ground and floor surfaces along accessible routes and in accessible rooms and spaces including floors, walks, ramps, stairs, and curb ramps, shall be stable, firm, slip-resistant, and shall comply with 4.5.

4.5.2 Changes in Level.

Changes in level up to 1/4 in (6 mm) may be vertical and without edge treatment (see Fig. 7(c)). Changes in level between 1/4 in and 1/2 in (6 mm and 13 mm) shall be beveled with a slope no greater than 1:2 (see Fig. 7(d)). Changes in level greater than 1/2 in (13 mm) shall be accomplished by means of a ramp that complies with 4.7 or 4.8.

Cross section drawing showing a maximum 1/4 inch vertical change in level.

Fig. 7 Accessible Route

Cross section drawing showing a change in level 1/4 to 1/2 inch high with a 1:2 slope.

Fig. 7 Accessible Route

4.5.3* Carpet.

If carpet or carpet tile is used on a ground or floor surface, then it shall be securely attached; have a firm cushion, pad, or backing, or no cushion or pad; and have a level loop, textured loop, level cut pile, or level cut/ uncut pile texture. The maximum pile thickness shall be 1/2 in (13 mm) (see Fig. 8(f)). Exposed edges of carpet shall be fastened to floor surfaces and have trim along the entire length of the exposed edge. Carpet edge trim shall comply with 4.5.2.

Figure 8(f) Carpet Pile Thickness: Carpet pile thickness shown to be 1/2 inch high maximum.

4.5.4 Gratings.

If gratings are located in walking surfaces, then they shall have spaces no greater than 1/2 in (13 mm) wide in one direction (see Fig. 8(g)). If gratings have elongated openings, then they shall be placed so that the long dimension is perpendicular to the dominant direction of travel (see Fig. 8(h)).

Figure 8(g) Gratings: Gratings shown with one dimension 1/2 inch maximum measured parallel to the predominant direction of travel.

Figure 8(h) Grating Orientation:  Gratings shown with long dimension perpendicular to route of travel.


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