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MARVINi��.�, I Introduction and Product Performance ""'°°°" `�: °`°„ Built around you. Building Categories and Design Factors � EXPOSURES Exposure B: Urban and suburban areas,wooded areas, or other terrain with numerous closely spaced obstructions having the size of single family dwellings or larger. For buildings with a mean roof height of less than or equal to 30ft(9.1 m). Exposure B shall apply , where the ground surface roughness, as defined by Surface Roughness B, prevails in the upwind direction for a distance greater than 1,500ft (457m). For buildings with a mean roof height greater than 30ft (9.1m), Exposure B shall apply where Surface Roughness B prevails in the upwind direction for a distance greater than 2,600ft (792m) or 20 times the height of the building, � whichever is greater. Exposure C: Open terrain with scattered obstructions having heights generally less than 30 ft. (9.1 m). This category includes flat open country,grasslands. Shall apply for all cases where Exposures B or D do not apply. Exposure D: Flat, unobstructed areas and water surfaces. This category includes smooth mud flats, salt flats, and unbroken ice. � Shall apply where the ground surface roughness,as defined by Surface Roughness D, prevails in the upwind direction for a distance greater then 5,OOOft (1,524m) or 20 times the building height, whichever is greater. Exposure D shall also apply where the ground surface roughness immediately upwind of the site is B or C, and the site is within a distance of 600ft(183m)or 20 times the building height, whichever is greater, from the Exposure D condition as defined in the previous sentence. For a site located in the transition � zone between exposure categories, the category resulting in the largest wind forces shall be used. INSTRUCTIONS: .Determine the Basic Wind Speed(V)in mph from Design Wind Load Table based on the location of the building. � .Determine the Roof Height(h)of the building in feet. This is the mean height of the roof above the lowest grade adjacent to the building. Eave height may be used for roof slope of less than 10 degrees. .Determine least width(B)of the building in feet.This is defined as the shortest distance between two parallel lines which contain the entire building floor plan. � .Determine high pressure outside corner loading zones(a)in feet from building illustration on following page.a=(0.10)x(B)or a _(0.4)x(h), whichever is smaller, but not less than either(0.04)x(B)or 3 feet(76). .Determine design pressure from Design Pressure Table. .All design pressure values are assumed for buildings with an importance Factor Category of II. See Design Factors chart on � following page. .If category III, IV is more appropriate then multiply the design pressure by the corresponding Design Factor-See Design Factor chart. � ' � ' ' ' ' � � CHECK MARVIN ONLINE DOCS FOR LATEST VERSION Printed On:Mar 22,2017,11:01 am INTRO/PRODUCT PERFORMANCE-36 19972255 Marvin Architectural Detail Manual �