May 21, 1992

Dr. Richard F. Andree, CSP, P.E., Ph.D.
Executive Vice President
Safety and Health Management Consultants, Inc.
161 William Street
New York, New York 10038

Dear Dr. Andree:

This is in response to your April 20 letter to Acting Assistant Secretary Dorothy Strunk requesting an interpretation of the Occupational Safety and Health Administration (OSHA) regulations addressing the riding of manually propelled mobile scaffolds at construction sites.

You are correct in noting that 29 CFR [1926.452(w)(6)] does not specify how a mobile scaffold is to be moved when there is a worker on the scaffold. Such language is unnecessary because of the requirements in other provisions such as [1926.452(w)(2)] which states: "Scaffolds in use by any persons shall rest upon a suitable footing and shall stand plumb. The castors or wheels shall be locked to prevent any movement."      (Correction 10/02/98) ["Scaffold casters and wheels shall be locked with positive wheel and/or wheel and swivel locks, or equivalent means, to prevent movement of the scaffold while the scaffold is used in a stationary manner."]      The rules clearly imply that there must be someone at the floor level to lock and unlock the castors between movements. In this situation, a person is available to move the scaffold from the floor level and there is no need to pull or "hump" the scaffold from the work platform. Those actions can cause the scaffold to tip over, and that is why [1926.452(w)(3)] requires that "the force necessary to move the mobile scaffold shall be applied near or as close to the base as practicable...."      (Correction 10/02/98) ["Manual force used to move the scaffold shall be applied as close to the base as practicable, but not more than 5 feet (1.5 m) above the supporting surface."]

For one-person operations, these rules require the user to climb down and up between moves. However, as [1926.452(w)(6)(ii)] and the 1982 American National Standards Institute recommended standard A10.8 indicate, only scaffolds with a two to one or less height to base width ratio should be ridden by employees. Therefore, the effort to climb up and down is minimal. If such climbing proves to be an "inefficient use of time" then a co-worker could be used to propel the scaffold.

If you require further assistance, please contact Mr. Roy F. Gurnham of Mr. Dale Cavanaugh of my staff in the Office of Construction and Maritime Compliance Assistance at (202) 523- 8136.

Sincerely,



Patricia K. Clark, Director
Directorate of Compliance Programs