Fire barriers and alternative precautions in tunnel work

March 15, 1996

Patrick Freeman, Safety Director
and Len Postregna, Project Manager
KAJIMA Engineering and Construction, Inc.
[Recipient address omitted]
Dear Messrs. Freeman and Postregna:

This letter is in response to your January 2 request for a permanent variance from 29 CFR 1926.800(m)(7)(ii) concerning fire prevention and protection requirements applicable to underground construction. Your request which was addressed to Mr. Joseph A Dear, the Assistant Secretary of Labor for the Occupational Safety and Health Administration (OSHA), was forwarded to the Directorate of Technical Support for a response. Our technical staff has reviewed your request for a variance and concluded that you may chose any appropriate precaution to protect flammable and combustible materials from sources of ignition.

The above standard requires that a fire resistant barrier of not less than one-hour rating be located as far as practicable from the opening. The standard, however, allows the use of other than one-hour rated barriers as long as additional precautions are taken to protect the flammable and combustible materials from any source of ignition. Therefore, adopting an effective alternate measure that protect the materials from the sources of ignition is within the scope of the standard and a variance is unnecessary for your particular conditions.

Alternative precautionary measures may be adopted from industry practices used under similar working conditions or measures recommended under industry consensus standards. We suggest that you perform a site hazard analysis to determine whether the additional precautions you have already taken will protect the materials from all ignition sources.

No further action will be taken on your variance request. If you have any questions regarding this letter, please contact Ms. Juanita Jones in the Office of Variance Determination at (202) 219-7193.

Sincerely,
Stephen J. Mallinger
Acting Director
Directorate of Technical Support