Which term describes pressure created by a fan that exerts outward pressure perpendicular to the direction of airflow?

Which term describes pressure created by a fan that exerts outward pressure perpendicular to the direction of airflow?

• A. Velocity Pressure (VP)
• B. Static Pressure (SP)
• C. Gauge Pressure
• D. Total Pressure

Answer: (B)

The main idea is distinguishing the pressure components in a ventilation system. Static pressure is the pressure component that acts equally in all directions and pushes air through the ductwork. A fan creates this pressure by forcing air to move, and it acts perpendicular to the airflow—outward from the flow path—so it’s what overcomes resistance in the ducts and fittings. Velocity pressure, by contrast, comes from the air’s motion and relates to kinetic energy; it acts in the direction of flow, not perpendicular. Total pressure is the sum of static and velocity pressures, representing the overall energy of the moving air. Gauge pressure is pressure relative to ambient atmosphere. So the term for the outward pressure perpendicular to the airflow is static pressure.

The main idea is distinguishing the pressure components in a ventilation system. Static pressure is the pressure component that acts equally in all directions and pushes air through the ductwork. A fan creates this pressure by forcing air to move, and it acts perpendicular to the airflow—outward from the flow path—so it’s what overcomes resistance in the ducts and fittings. Velocity pressure, by contrast, comes from the air’s motion and relates to kinetic energy; it acts in the direction of flow, not perpendicular. Total pressure is the sum of static and velocity pressures, representing the overall energy of the moving air. Gauge pressure is pressure relative to ambient atmosphere. So the term for the outward pressure perpendicular to the airflow is static pressure.