1609.4.3 Exposure categories.
BC § 1609.4.3
An exposure category shall be determined in accordance with the following: Figure 1609.4.3 provides the exposure categories at the shore lines for wind directions approaching over the water within the city boundaries. Exposure B. For buildings with a mean roof height of less than or equal to 30 feet (9144 mm), Exposure B shall apply where the ground surface roughness, as defined by Surface Roughness B, prevails in the upwind direction for a distance of at least 1,500 feet (457.2 m). For buildings with a mean roof height greater than 30 feet (9144 mm), Exposure B shall apply where Surface Roughness B prevails in the upwind direction for a distance of at least 2,600 feet (792.5 m) or 20 times the height of the building, whichever is greater. Exposure C. Exposure C shall apply where it is shown in Figure 1609.4.3 or for all cases where Exposure B or D does not apply. Exposure D. Exposure D shall apply where the ground surface roughness, as defined by Surface Roughness D, prevails in the upwind direction for a distance of at least 5,000 feet (1524 m) or 20 times the height of the building, 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 600 feet (182.9 m) or 20 times the building height, whichever is greater, from an Exposure D condition as defined in the previous sentence. Figure 1609.4.3(1)New York City Wind Exposure: Manhattan Shoreline Notes: Exposure C: Buildings within a distance of 2,600 feet from shoreline.Exposure C: Buildings within a distance of 2,600 feet or 20 times building height from shoreline, whichever is greaterExposure D: Coastal zone, see Section 1609.4 Figure 1609.4.3(2)New York City Wind Exposure: Bronx Shoreline Notes: Exposure C: Buildings within a distance of 2,600 feet from shoreline.Exposure C: Buildings within a distance of 2,600 feet or 20 times building height from shoreline, whichever is greaterExposure D: Coastal zone, see Section 1609.4 Figure 1609.4.3(3)New York City Wind Exposure: Brooklyn Shoreline Notes: Exposure C: Buildings within a distance of 2,600 feet from shoreline.Exposure C: Buildings within a distance of 2,600 feet or 20 times building height from shoreline, whichever is greaterExposure D: Coastal zone, see Section 1609.4 Figure 1609.4.3(4)New York City Wind Exposure: Queens Shoreline Notes: Exposure C: Buildings within a distance of 2,600 feet from shoreline.Exposure C: Buildings within a distance of 2,600 feet or 20 times building height from shoreline, whichever is greaterExposure D: Coastal zone, see Section 1609.4 Figure 1609.4.3(5)New York City Wind Exposure: Staten Island Shoreline Notes: Exposure C: Buildings within a distance of 2,600 feet from shoreline.Exposure C: Buildings within a distance of 2,600 feet or 20 times building height from shoreline, whichever is greaterExposure D: Coastal zone, see Section 1609.4
