How high must mechanical draft system vents terminate above any forced air inlet located within 10 feet?

Mechanical draft system vents must terminate at least 3 feet above any forced air inlet located within 10 feet to prevent potential backdrafts and ensure proper venting of combustion gases. This height requirement is in place to minimize the chance of harmful exhaust from the vent re-entering the building through the air intake system. Vents that are too low may allow fumes or gases that could contain carbon monoxide or other harmful substances to flow back into the living space, posing health risks to occupants.

In residential and commercial HVAC systems, keeping the vent termination at this specified height helps maintain the safety and efficiency of the system. Standards set by codes such as the International Residential Code (IRC) and local building codes often guide these requirements, underscoring their importance in building safety and HVAC performance.