How can you verify that return air from one zone is not undesirably entering another zone?

How can you verify that return air from one zone is not undesirably entering another zone?

• A. Monitor room pressures, use doors/pressure differentials, perform smoke visualization, and verify that return paths do not cause crossflow.
• B. Seal all doors and never open them during testing.
• C. Return air crossflow is acceptable as long as zones meet CFM targets.
• D. Only measure differential pressure between the supply and return plenums.

Answer: (A)