Capture Velocity refers to

Capture Velocity refers to

• A. The velocity of air in moving to the hood
• B. Air velocity required to capture and transport a contaminant into a ventilation hood
• C. The area of the duct opening
• D. The static pressure at the hood

Answer: (B)

Capture velocity is the minimum airspeed at the hood face needed to pull a contaminant from its source and transport it into the hood, preventing it from escaping into the room. This definition focuses on the specific movement of contaminated air being captured by the hood, not just general airflow toward the hood, the size of the duct opening, or the static pressure. In practice, capture velocity depends on how strong the contaminant source is, how far the source sits from the hood face, room air currents, and hood design, with typical hood face velocities set to overcome surrounding air and reliably draw the plume into the exhaust.

Capture velocity is the minimum airspeed at the hood face needed to pull a contaminant from its source and transport it into the hood, preventing it from escaping into the room. This definition focuses on the specific movement of contaminated air being captured by the hood, not just general airflow toward the hood, the size of the duct opening, or the static pressure. In practice, capture velocity depends on how strong the contaminant source is, how far the source sits from the hood face, room air currents, and hood design, with typical hood face velocities set to overcome surrounding air and reliably draw the plume into the exhaust.