In your March issue, the article "Understanding wind-resistant design," page 43, by Mark S. Graham, NRCA's associate executive director of technical services, makes several good points, including that a safety factor of 2.0 is appropriate for wind design of roof systems.
However, I would like to clarify some points the article addresses.
First, the article does not reflect the most recent changes and enhancements published in the February 2007 version of FM 1-29, "Roof Deck Securement and Above-Deck Roof Components." The updated data sheet is available at no cost at www.roofnav.com along with updates to FM 1-28, "Design Wind Loads," and FM 1-52, "Field Uplift Tests."
Second, the article states FM Global recommends design wind loads up to 49 percent greater than those stated in ASCE 7-05, "Minimum Design Loads for Buildings and Other Structures." In fact, FM Global recommendations are at most 15 percent higher than ASCE 7-05 requirements for most buildings.