A frequent question posed to NRCA's Technical Services Section
is whether the numeric values in low-slope roof systems'
uplift-resistance classifications (such as I-90, Class 60)
represent buildings' design wind speeds. If you believe they do or
are unclear about how the values relate to one another, continue
Design wind-uplift pressures on roof systems are determined
based on a number of considerations, including a specific
building's mean roof height and basic wind speed. The fundamental
equation for determining the design wind pressure in the field of a
low-slope roof area is qh =
Log in or register for FREE access to this article and other Professional Roofing online content.