Which statement best describes the interconnection of building ventilation ducts?

• A. All ducts shall not be interconnected with any other building ventilation system or exhaust system.
• B. Ducts may be interconnected with other systems if dampers isolate airflow.
• C. Ducts must be directed to the interior spaces for climate control.
• D. Ducts may share a common chase with other utilities.

Answer: (C)

Ducts exist to deliver conditioned air where it’s needed: the interior spaces. Directing the ventilation ducts to interior rooms and zones ensures that the climate control—temperature, humidity, and air quality—reaches the occupied areas effectively. Interconnecting ducts with other systems or sharing a chase can create unexpected air paths, cross-contamination, and balancing challenges, which undermine precise climate control. While isolating airflow with dampers can manage some interconnections, the core idea is that the ducts’ primary role is to supply interior spaces with conditioned air, maintaining the intended environment for occupants.