Wash. Admin. Code § 296-24-74010

Current through Register Vol. 24-23, December 1, 2024

Section 296-24-74010 - Standard stairs

In addition to WAC 296-24-74005, you must also ensure standard stairs:

(1) Are installed at angles between 30 to 50 degrees from the horizontal.

(2) Have a maximum riser height of 9.5 inches (24 cm).

(3) Have a minimum tread depth of 9.5 inches (24 cm).

(4) Have a minimum width of 22 inches (56 cm) between vertical barriers (see Figure D-8 of this section).

EXCEPTION:

Subsections (2) and (3) of this section do not apply to standard stairs installed prior to October 1, 2020, provided those stairs meet the dimension requirements specified in Table D-1 of this section or they use a combination that achieves the angle requirements of subsection (1) of this section.

TABLE D-1

Angle to Horizontal	(Rise in inches)	Tread Run (in inches)
30°35'.........................	6 1/2	11
32°08'.........................	6 3/4	10 3/4
33°41'.........................	7	10 1/2
35°16'.........................	7 1/4	10 1/4
36°52'.........................	7 1/2	10
38°29'.........................	7 3/4	9 3/4
40°08'.........................	8	9 1/2
41°44'.........................	8 1/4	9 1/4
43°22'.........................	8 1/2	9
45°00'.........................	8 3/4	8 3/4
46°38'.........................	9	8 1/2
48°16'.........................	9 1/4	8 1/4
49°54'.........................	9 1/2	8

Click to view image

Figure D-8

Wash. Admin. Code § 296-24-74010

Adopted by WSR 20-09-146, Filed 4/21/2020, effective 10/1/2020