How does having multiple hoods affect the duct design?

How does having multiple hoods affect the duct design?

• A. Use a single duct with no balancing.
• B. Place hoods randomly.
• C. Ducts should be oversized to ensure high flow.
• D. It requires balancing airflow among hoods, often via a common plenum and properly sized ducts to avoid excessive pressure loss.

Answer: (D)

Balancing airflow across multiple hoods is essential. When several hoods share the same exhaust system, air doesn’t split evenly by default, so you need a design that distributes it evenly. Feeding the hoods from a common plenum helps keep static pressure relatively constant across all branches, so each hood can pull its intended amount of air. Properly sized ducts minimize pressure losses, which keeps the system efficient and makes it easier to tune each hood with balancing dampers if needed. This approach prevents problems that other setups can create. A single duct with no balancing won’t guarantee equal distribution, random hood placement leads to unpredictable flow, and simply pushing higher flow by oversizing ducts can waste energy without solving the underlying balance issue. The balanced plenum-and-matched-duct design ensures stable performance and appropriate capture at every hood.

Balancing airflow across multiple hoods is essential. When several hoods share the same exhaust system, air doesn’t split evenly by default, so you need a design that distributes it evenly. Feeding the hoods from a common plenum helps keep static pressure relatively constant across all branches, so each hood can pull its intended amount of air. Properly sized ducts minimize pressure losses, which keeps the system efficient and makes it easier to tune each hood with balancing dampers if needed.

This approach prevents problems that other setups can create. A single duct with no balancing won’t guarantee equal distribution, random hood placement leads to unpredictable flow, and simply pushing higher flow by oversizing ducts can waste energy without solving the underlying balance issue. The balanced plenum-and-matched-duct design ensures stable performance and appropriate capture at every hood.