What is the minimum distance above grade that the bottom of a horizontal mechanical draft exhaust must terminate?

The correct answer indicates that the minimum distance above grade for the termination of a horizontal mechanical draft exhaust is 1 foot. This specification is crucial for preventing the recirculation of exhaust gases into the building, which could pose significant safety risks, including carbon monoxide buildup and other harmful emissions.

Terminating the exhaust at least 1 foot above the ground helps ensure that vapors and gases are safely dispersed into the atmosphere, reducing the likelihood of re-entry into occupied spaces. This regulation helps maintain a safe environment for both building occupants and neighboring areas.

Choosing this distance aligns with safety standards and best practices in HVAC and combustion appliance installations, ensuring compliance with building codes designed to protect health and safety.