Cable strength and deflection for steel erection railings

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

May 22, 1989
Mr. William Dillon
Assistant Commissioner for Enforcement
Department of Labor and Industry
Commonwealth of Virginia
[Recipient address omitted]
Dear Mr. Dillon:
This is in response to the questions posed in the letter from Jay Withrow regarding safety railing(s) required by OSHA Standard 29 CFR 1926.750(b)(1)(iii). The standard reads as follows:

"Floor periphery - safety railing. A safety railing of ½-inch wire rope or equal shall be installed, approximately 42 inches high, around the periphery of all temporary - planked or temporary metal-decked floors of tier buildings and other multifloored structures during structural steel assembly." (emphasis added).

The questions and responses to them are as follows:
Question 1: Is orange plastic-coated 3/16-inch aircraft wire "equal" to ½-inch wire rope? (Note: This product is seeing extensive use in Northern Virginia).
Answer: The response is a qualified yes. The key to whether the 3/16 aircraft wire is equal to ½-inch wire rope is whether a the 3/16 aircraft wire is equal in strength to ½-inch wire rope.
The standard does not set forth any specifications for the design and construction of the ½-inch wire rope. Thus any wire rope ½-inch in diameter of any design or construction could be used to comply with this standard.
There is at least one 3/16-inch aircraft cable (Galvanized and tinned aircraft cord and strand Construction 1x19 - Nominal Breaking Strength 4700 pounds) that has a greater nominal breaking strength than does at least one type of ½-inch wire rope (Iron Galvanized Running Rope - Construction 6x12 - Nominal Breaking Strength 4560 pounds). Therefore, the previously referenced aircraft cable would have to be considered equal to ½-inch wire rope.
Question 2: Although it is not stated anywhere, does 1926.750(b)(1)(iii) require either a midrail or supports (e.g. at intervals not to exceed 8 feet - 1926.451(a)(5))?
Answer: The response is no.
Question 3: Although it is not stated anywhere, must the wire rope used to comply with 1926.750(b)(1)(iii) (½-inch wire rope; or 3/16-inch aircraft wire if you find that to be equivalent) have a maximum permissible deflection of 3-inches in one direction when a load of 200 pounds is applied in any direction at any point?
Answer: The response to this question is a qualified yes. OSHA Standard 29 CFR 1926.750(b)(1)(iii) does not address the issue of deflection. The standard, as written, could be enforced so that no deflection is permitted. However that would be contrary to guidance relating to wire rope used for guardrails contained in directives (STD 3-10.3), memoranda and proposed standards (Fall Protection In Construction.)
Therefore in Region III, for the purpose of complying with OSHA Standard 29 CFR 1926.750(b)(1)(iii), a safety railing that meets the following criteria would be considered to be equal to a ½-inch wire rope:

1) safety railing must be ¼-inch in diameter (a plastic coating could be used to bring the diameter up to ¼-inch)
2) the safety railing must be 42 inches high, plus or minus 3 inches
3) the top must not fail and may deflect to a point no lower than 39 inches above the floor when a 200 pound load is imposed on it in a downward or outward direction.

If you require any additional information regarding this matter, please contact [the Directorate of Construction at 202 693-2020].
Sincerely,
LINDA R. ANKU
REGIONAL ADMINISTRATOR
[Correction 6/20/2005. See OSHA Directive CPL 02-01-034 "Inspection policy and procedures for OSHA's steel erection standards for construction" published on 3/22/2002 for the current policy on OSHA's steel erection standards (1926 Subpart R) for construction.]