Which factors do exposure categories affect?

Which factors do exposure categories affect?

• A. Velocity pressure (Kz), overall wind demand, and uplift pressures.
• B. Only velocity pressure (Kz).
• C. Temperature and humidity.
• D. Snow load and rainfall.

Answer: (A)

Exposure categories describe how surrounding terrain and nearby obstructions affect how wind translates into force on a structure. They change the velocity pressure at a given height, expressed as Kz, because rougher, more sheltered sites damp or amplify wind differently than open, unobstructed sites. This tailoring of velocity pressure feeds directly into the overall wind demand the building must resist and the uplift pressures acting on roofing and cladding. In short, exposure category modifies the wind pressure calculations themselves, which is why it influences velocity pressure, the total wind demand, and uplift pressures. Temperature and humidity, as well as snow load and rainfall, come from climate data and geographic conditions independent of the exposure category, so they aren’t altered by how the site is categorized for wind design.

Exposure categories describe how surrounding terrain and nearby obstructions affect how wind translates into force on a structure. They change the velocity pressure at a given height, expressed as Kz, because rougher, more sheltered sites damp or amplify wind differently than open, unobstructed sites. This tailoring of velocity pressure feeds directly into the overall wind demand the building must resist and the uplift pressures acting on roofing and cladding. In short, exposure category modifies the wind pressure calculations themselves, which is why it influences velocity pressure, the total wind demand, and uplift pressures.

Temperature and humidity, as well as snow load and rainfall, come from climate data and geographic conditions independent of the exposure category, so they aren’t altered by how the site is categorized for wind design.