• Height requirements for stair rail systems vary depending on when the system was installed.
• Additional requirements for stair rail systems include minimum clearance for fingers, smooth surfaces to avoid injury, and strength criteria.

Handrails must not be less than 30 inches and not more than 38 inches measured from the leading edge of the stair tread to the top surface of the handrail (see 1910.29(f)(1)(i) and Figure D-12 to section 1910.29).

Stair rail systems, which provide fall protection, must meet the following height criteria:

• For stair rail systems installed before January 17, 2017, the height must not be less than 30 inches from the leading edge of the stair tread to the top surface of the top rail, per 1910.29(f)(1)(ii)(A).
• For stair rail systems installed on or after January 17, 2017, the height must not be less than 42 inches from the leading edge of the stair tread to the top surface of the top rail, per 1910.29(f)(1)(ii)(B).

For systems installed prior to January 17, 2017, the top rail of a stair rail system may serve as a handrail only when:

• The height of the stair rail system is not less than 36 inches and not more than 38 inches as measured at the leading edge of the stair tread to the top surface of the top rail (see 1910.29(f)(1)(iii)(A) and Figure D-13 to section 1910.29).
• The top rail of the stair rail system meets the other handrail requirements in 1910.29(f).

Other criteria are found in 1910.29(f). These include:

• A minimum clearance for fingers between handrails and any other object of 2.25 inches.
• Handrails and stair rail systems that are smooth surfaced to protect employees from injury, and to prevent catching or snagging of clothing.
• No opening in a stair rail system that exceeds 19 inches at its least dimension.
• Handrails and the top rails of stair rail systems that are capable of withstanding, without failure, a force of at least 200 pounds applied in any downward or outward direction within 2 inches of any point along the top edge of the rail.