Tech Today


Complying with ANSI/SPRI ES-1, "Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems," is required for edge-metal flashings (except gutters) for low-slope membrane roof systems in the 2003 and 2006 editions of the International Building Code (IBC). Therefore, it's important you become familiar with the standard.

Design wind loads

ANSI/SPRI ES-1 provides a means for determining design wind loads and testing wind resistances of metal gravel stops, fascias and copings. Determining design wind loads at a roof area's perimeter edges is accomplished by first determining the roof area's uplift pressure, factoring in an appropriate importance factor and applying appropriate external pressure coefficients applicable to roof area perimeter edges.

To determine a roof area's uplift pressure, the standard's look-up tables, which are based on building height, exposure category and basic wind speed applicable to the specific building and roof area being evaluated, can be used. An importance factor is applied to the velocity pressure, resulting in a value representative of the design wind-uplift load for the roof area's field.