WAC 296-56-60189
WAC 296-56-60189. Hoistway guide rails
(1) Employers must make sure there are a minimum of two opposing guide rails extending to a point six inches beyond the full height of travel of the car when the counterweight buffer is fully compressed.
(2) Employers must make sure all rails are attached by bolts, lag screws or other approved methods to a vertical supporting member which does not exceed one-half inch deflection with the application of a 250 pound horizontal thrust at any point.
(3) Employers must make sure wood guide rails are at least one and one-half inch by one and one-half inch vertical grain fir or equivalent and must not vary more than three-sixteenth inch in thickness on the sides which the brakes contact. All joints must be kept smooth and even.