What practice helps prevent misclassifying wind exposure for a site?

• A. Always classify based on the nearest building
• B. Use the actual open terrain definition for the site
• C. Ignore exposure and rely on historic practices
• D. Choose the higher category by default

Answer: (B)

Assessing wind exposure using the site’s actual open terrain definition ensures the wind loads reflect the real environment around the building. The open terrain criteria in the governing standard are designed to describe how obstruction, distance, and shielding around the site affect wind pressures, so applying them gives a consistent, code-compliant classification of exposure.

Relying on the nearest building can mislead because that building might shield the site in some directions but not others, and its presence doesn’t capture the broader surroundings that influence wind exposure. Ignoring exposure and leaning on historic practices risks using outdated or non-specified methods that may not meet current codes. Choosing the higher category by default is overly conservative and not how exposure is intended to be determined under standard practice.

In short, classify the site based on the actual open terrain around it according to the code, to accurately reflect real wind conditions and ensure appropriate design loads.