Ducts shall not be located within how many inches of the earth?

The correct answer is based on the safety and performance guidelines outlined in the North Carolina Mechanical Code, which specifies that ducts must be installed above a certain height above the ground to prevent issues such as moisture accumulation, soil contact, and potential structural damage.

When ducts are located too close to the earth, such as at a depth of less than 4 inches, they become more susceptible to damage from soil moisture and pests, which can lead to deterioration and negatively impact the overall efficiency of the HVAC system. Additionally, being closer to the ground can compromise proper airflow and cause maintenance challenges.

Maintaining a distance of 4 inches helps ensure that ducts remain clear from direct contact with the earth, thus enhancing their longevity and performance while promoting safe installation practices in alignment with code requirements.