August 29, 1989
BCAB #1088
Re: Roof Assembly Fire Rating
With reference to your letter of July 6, 1989 regarding fire rating a roof assembly.
The building in question is an F2 occupancy, previously falling under Part 9 of the Building Code but now being almost doubled in size, bringing it under Part 3. It also appears, from the information submitted, that the major portion of the size increase will be in the actual workshop area.
While we appreciate your statement that the occupant load will be extremely low, this factor does not affect the Code requirement for the roof assembly. Under the circumstances we are unable to relax the 3/4 hour rating for the roof, we do not have the authority.
For dealing with existing buildings there is some latitude, outlined in Appendix Note A-1.2.1. If the remarkably low occupant load indicated in your letter can be substantiated to the authority having jurisdiction, they may be of assistance, as they would also be responsible for subsequent fire inspections; however, this is a matter for them, we will not become involved.
J.C. Currie, Chair