The 2010 Florida Building Code, Residential and Asphalt Shingle Wind Classifications

Introduction

The selection of asphalt shingles to meet the 2010 Florida Building Code, Residential (FBC-R) requirements for wind

resistance relies on three separate sets of standards, integrated into the building code and captured in asphalt shingle selection table R905.2.6.1 (below). The 2010 FBC-R requires that shingles be tested to product standards ASTM D7158 or D3161, and contains new wind design requirements that rely on a recently updated reference standard, ASCE 7. Developed and maintained by The American Society of Civil Engineers (ASCE), ASCE 7-10 provides building designers with detailed engineering criteria for the application of loads on structures.

For asphalt shingles, the code also relies on the ASTM product standards to help define the resistance of asphalt shingles to wind uplift forces. Additionally, the FBC-R includes detailed underlayment and fastening requirements for asphalt shingles. The end result is the proper selection and installation of an asphalt shingle that meets the test standards for the particular wind region.

ASCE 7-10

The ASCE 7 standard describes wind load requirements using wind maps that establish regional design conditions based upon measured, historical wind events. The wind maps in ASCE 7 provide design wind speeds for specific wind durations and a likely frequency. While previous versions of ASCE 7 contained a single wind map that established design wind speeds for 3-second gusts and a 50 year mean recurrence interval, the standard was revised to re-define the reference wind speeds in the maps. In an effort to simplify the design process, the new standard contains three separate maps that define “ultimate wind speeds” for differing building risk categories and varying return periods.

Because the FBC-R applies only to certain residential structures including one and two family dwellings, the code contains a single map.

Note: It is important to note that the wind speeds did not change significantly; rather it is the method of expressing the

design wind speeds that changed. Again, these changes were made only to simplify the calculations, not increase the

required level of shingle wind resistance.

The 2010 FBC-R Code and Shingle Selection

Follow the steps below to select asphalt shingles:

1.     Refer to the map in Figure R301.2(4) to determine the design wind speed for the specific project.

2.     Review the values for Maximum Basic Wind Speed in Table R905.2.6.1 to determine the lowest value that equals or exceeds the design wind speed in step 1 above.

3.     Select a shingle with a classification from either ASTM D 7158 or D 3161 that corresponds to the Maximum Basic Wind Speed determined in step 2 above.

 

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Residential Roofing