Which term defines the minimum hood induced velocity to capture contaminants?

Which term defines the minimum hood induced velocity to capture contaminants?

• A. Face Velocity
• B. Air Velocity
• C. Vent Velocity
• D. Capture Velocity

Answer: (D)

Capture velocity is the minimum speed of air drawn into the hood that is required to reliably pull contaminants into the hood rather than letting them escape into the room. It accounts for the strength of the contaminant source, the hood’s geometry, and overpowering background room air currents. If the hood doesn’t achieve this velocity, contaminants can bypass the capture zone. Face velocity measures air speed at the hood opening and is related, but it’s not the minimum speed needed to ensure capture at the source. The other terms don’t describe this specific performance requirement.

Capture velocity is the minimum speed of air drawn into the hood that is required to reliably pull contaminants into the hood rather than letting them escape into the room. It accounts for the strength of the contaminant source, the hood’s geometry, and overpowering background room air currents. If the hood doesn’t achieve this velocity, contaminants can bypass the capture zone. Face velocity measures air speed at the hood opening and is related, but it’s not the minimum speed needed to ensure capture at the source. The other terms don’t describe this specific performance requirement.