Vents must terminate at least how many feet above a forced air inlet located within 10 feet?

Vents must terminate at least 3 feet above a forced air inlet located within 10 feet to ensure proper ventilation and to prevent negative pressure or contamination of the air supply. This height requirement is crucial because it minimizes the risk of gases or potential pollutants entering the forced air system.

When vents are placed lower than the specified height, there is a greater chance that exhaust or other harmful emissions can be pulled into the intake, which could compromise the air quality inside a building. By adhering to the 3-foot requirement, systems are designed to maintain safe and effective operation while protecting the health of occupants. This standard reflects best practices in mechanical ventilation as stated in the North Carolina Mechanical Code, which emphasizes safety and efficiency in HVAC systems.