Intermediate rail

A standard railing must consist of a top rail, intermediate rail, and posts. It must have a vertical height of 42 inches nominal from the upper surface of the top rail to floor, platform, runway, or ramp. The top rail must be smooth-surfaced throughout the length of the railing. The intermediate rail must be approximately halfway between the top rail and the floor, platform, runway, or ramp. The ends of the rails must not overhang the terminal posts except where such overhang does not constitute a projection hazard. 

The place of work and access must be safe and for anyone who has to work in a place where he is liable to fall 2 m (6ft 6 in) or more a handrail must be provided including intermediate rail and toe board (s. 29). 

For wood railings Wood components shall be minimum 1500 Ib-ft/in2 fiber (stress grade) construction grade lumber the posts shall be at least 2-inch by 4-inch (5 cm X10 cm) lumber spaced not more than 8 feet (2.4 m) apart on centers the top rail shall be at least 2-inch by 4-inch (5 cm X 10 cm) lumber, the intermediate rail shall be at least 1-inch by 6-inch (2.5 cm x 15 cm) lumber. All lumber dimensions are nominal sizes as provided by the American Softwood Lumber Standards, dated January 1970. 

For pipe railings posts, top rails, and intermediate railings shall be at least one and one-half inches nominal diameter (schedule 40 pipe) with posts spaced not more than 8 feet (2.4 m) apart on centers. 

A mobile access tower Figure 4.6.6) is a tower constructed of prefabricated aluminium units that click together to form a rigid frame. The use of prefabricated units allows a range of tower sizes to be assembled. Each working platform level is provided with handrail, intermediate rail and toe board on all four sides and is capable of supporting an evenly distributed load of 275 kg. Towers can be assembled up to a maximum height of... 

OSHA does permit the use of safety chains and has addressed the issue in two Letters of Interpretation (LOI). In the first, dated February 12, 1982, OSHA makes mention of chains with regard to safety gates by saying, if in fact the safety chains used for top and intermediate rails afford employees protection at least as effective as the swinging gate, the safety chains would be adequate and noted as a de minimis violation. [bold emphasis added] The top rail must have a vertical height of 42 inches nominal and the intermediate rail must be approximately halfways between the top rail and the floor as required by 1910.23(d). 

CFR 1910.23(a)(2) does require ladderway openings to be provided with a swinging gate or offset passage. However, if in fact the safety chains used for top and intermediate rails afford employees protection at least as effective as the swinging gate, the safety chains would be adequate and noted as a de minimis violation. 

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