Phillip Dregger, PE, RRC, FRCI - Pacific Building Consultants, Concord, CA
Roof wind design in the 2001 California Building Code was based on the 50 year “fastest mile” wind speed, a fairly generous definition of an “enclosed” building, and made no reference to FM or UL wind uplift test standards. By 2013, the California Building Code had “evolved” to require roof wind design to be based on “ultimate” 700-year 3-second gust wind speeds, a much more restrictive definition of an enclosed structure, and required all low sloped roof system be tested in accordance with FM and/or UL test standards. And, BTW, there is still no clear direction in the building code regarding how to assess the wind uplift resistance of an existing roof covering (e.g., no reference to FM Global LPDS 1-52).
1. How to apply evolving and still incomplete code requirements to forensic analyses of roof coverings
2. Code Required Wind Uplift Tests - FM 4474, UL 580, or UL 1897