In duct testing, how do static pressure and velocity pressure differ?

• A. Static pressure is the ambient pressure in the duct, while velocity pressure relates to air velocity; both are measured to determine flow using appropriate formulas.
• B. Static pressure is the air velocity, velocity pressure is ambient pressure; measured to determine humidity.
• C. Static and velocity pressures are the same; used interchangeably.
• D. Velocity pressure is the static pressure; static pressure is the dynamic pressure.

Answer: (A)