Two different design requirements for handrail and scaffolding.

Standard Number: 1926.451(a)(1); 1926.451(g)(4)(vii)

October 4, 1989

Mr. K.W. Ludwig
Hercules Aerospace Company
Aerospace Products Group
Bacchus Works
Magna, Utah 84044-0098

Dear Mr. Ludwig:

In reply to your letter of September 27, 1989, we concur with you that there are two different design requirements for handrail (Standard Guardrails) and scaffolding.

In general the material and sizes of members are specified for standard guardrails. The performance test of a 200 pound force controls the connection means and is used for the design of equivalent protection. The 200 pound force also controls the safety of the product as it is exposed to wear and damage. There is no safety factor that has to be applied to standard guardrails.

Scaffolding, which includes work platform, bracing and supporting members, is controlled by the safety factor of 4 which is applied to the design load. If more than one platform can be provided then the design load must include this added working load. The American National Standard, ANSI A10.8-1988, Scaffolding - Safety Requirement in section 4.6 states: "Scaffolds shall be capable of supporting, without failure, their own weight and at least four times the maximum intended load. The requirement has exceptions as specifically noted herein for guardrail systems, suspension ropes, and for the design application for solid sawn wood components and other wood-based members and connection to wood. (see 4.11)"

Neither OSHA's regulations nor ANSI's requirements address the strength of the materials as ultimate or yield. It would be a better practice to use the strength which would provide a safer product.

If you should have further questions feel free to contact us again.

Sincerely,

BYRON R. CHADWICK
Regional Administrator