November 18, 1996

Brian Clarke
Hoffman Construction Co.
PO Box 1300
Portland OR 97207

Dear Mr. Clarke:

This is in response to your October 23, 1996 fax in which you ask for a rule interpretation on the height of the guard rail above the roof line on a catch platform.

Neither the present nor the new scaffold standards address catch platforms. Catch platforms are an acceptable means of fall protection. The fall protection manual on roofing work defines catch platforms but does not set the height of the guardrail above the roof line. The manual states that the platform must extend at least 2 feet past the eave overhang and the guardrail must extend substantially above the slope plane of the roof so as to catch the person who is sliding off the roof. The guard rail as installed must prevent the person from passing over or through the rails. With a 21 inch gap between rails a person could pass through the opening. Either the top or mid rail should be about 12 inches above the roof plane. To prevent people from passing through the rails, netting or canvas skirting should be placed between the top rail and platform.

You go on to ask for a clarification of “substantially” as used in the manual. The standard is a performance based standard and therefore “substantially” cannot be set as a fixed number. Any rail height that prevents workers from passing over the rail would be acceptable.

Finally, you ask about the proper vertical and horizontal distance for the top rail and ask if this is a degree or slope. The distances will vary based on the roof pitch. The steeper the pitch the greater the possibility a person will pass through the rails. On flatter pitches, the guard rail will act more as a stop guard and should extend upward at least 12 inches, but again there is no set height.

If we can be of further assistance to you please contact Jerry Hoard at 378-3272 or through E-mail at: tech.web@state.or.us

Please visit our web site on the Internet for information about OR-OSHA.

We are located at: http://www.cbs.state.or.us/external/osha/index.html.

Sincerely,

Marilyn K. Schuster, Manager
Standards & Technical Resources Section
Oregon Occupational Safety & Health Division