PDFWAC 296-307-25027

What are the requirements for railing dimensions?

Standard railings must meet the following requirements:
(1) For wood railings:
(a) The posts are of at least two inch by four inch nominal stock spaced six feet apart or less; and
(b) The top and intermediate rails are of at least two inch by four inch nominal stock.
(c) If the top rail is made of two right-angle pieces of 1-inch by 4-inch stock, posts are spaced on 8-foot centers, with 2-inch by 4-inch intermediate rail.
(2) For pipe railings:
(a) The posts and top and intermediate railings are at least 1-1/2 inches nominal diameter (outside diameter); and
(b) The posts are spaced on centers of eight feet or less.
(3) For structural steel railings:
(a) The posts and top and intermediate rails are of 2-inch by 2-inch by 3/8-inch angles or other metal shapes of equivalent bending strength; and
(b) The posts are spaced on centers of eight feet or less.
(4) Post anchors and framing parts for all railings are constructed so that the completed structure can withstand a load of at least two hundred pounds applied in any direction at any point on the top rail.
(5) Other types, sizes, and arrangements of railing construction that meet the following requirements are acceptable:
(a) The top rail is smooth;
(b) The top rail is between thirty-six and forty-two inches nominal above the floor, platform, runway, or ramp level;
(c) The railing is strong enough to withstand two hundred pounds of pressure on the top rail;
(d) The railing provides protection between the top rail and the floor, platform, runway, ramp, or stair treads, equivalent to that of a standard intermediate rail;
(e) There are no overhanging rail ends unless the overhang does not create a hazard; such as baluster railings, scrollwork railings, or paneled railings.
Note:
The dimensions specified are based on the U.S. Department of Agriculture Wood Handbook, No. 72, 1955 (No. 1 (S4S) Southern Yellow Pine (Modulus of Rupture 7,400 psi)) for wood; ANSI G 41.5-1970, American National Standard Specifications for Structural Steel, for structural steel; and ANSI B 125.1-1970, American National Standard Specifications for Welded and Steamless Steel Pipe, for pipe.
[WSR 97-09-013, recodified as § 296-307-25027, filed 4/7/97, effective 4/7/97. Statutory Authority: RCW 49.17.040, [49.17.]050 and [49.17.]060. WSR 96-22-048, § 296-306A-25027, filed 10/31/96, effective 12/1/96.]