WindPy Engineering Suite

NSCP 2015 / ASCE 7-16 Wind Load Analysis Tools

Site Parameters
Upwind Distances
ParameterDistance
Case 1 — d1--
Case 2 — d1--
Case 2 — d2--
Case 2 — d1+d2--
Surface Roughness

B: Urban/suburban areas, wooded areas, or terrain with numerous closely spaced obstructions (single-family dwelling size or larger).

C: Open terrain with scattered obstructions generally less than 9.1 m (30 ft) in height.

D: Flat, unobstructed areas and water surfaces (mud flats, salt flats, ice).

Site Map — Upwind Fetch Rings
Exposure Category Decision Flow
Case 1: Within 457 m of site,
is Surface Roughness B prevailing in all directions?
YES
Exposure B
NO (C or D found)
Case 2: Within 1707 m,
is Surface Roughness D prevailing?
YES
Exposure D
NO
Exposure C