What is the minimum cross-sectional area required for an areaway when the duct termination is below 12 inches above finished grade?

The minimum cross-sectional area required for an areaway when the duct termination is below 12 inches above finished grade is established to ensure adequate airflow and to minimize the risk of water intrusion or other environmental elements impacting the ductwork. A minimum area of 200 square inches is specified in the code because this size supports the necessary ventilation and prevents complications that could arise from inadequate air circulation.

Designing duct terminations with such minimum dimensions also considers safety and performance standards, allowing for suitable air exchange, especially in areas close to ground level where conditions might affect air quality. The requirement reflects an understanding of the operating conditions typical in North Carolina, ensuring compliance with local mechanical codes aimed at maintaining effective and efficient HVAC systems.