How far must a mechanical draft vent terminate from gravity air inlets into any building?

The correct answer is 4 feet because this distance is established to ensure safe and effective venting of exhaust gases from mechanical draft systems. Terminating a mechanical draft vent at least 4 feet away from any gravity air inlets into buildings helps to prevent the potential for exhaust gases to enter the building through those inlets. This distance is important in maintaining proper indoor air quality and ventilation, as well as preventing issues related to the backdrafting of exhaust gases.

Maintaining this separation reduces the likelihood of harmful substances swirling back into the building, which could lead to health hazards for occupants. Adhering to this regulation is crucial for compliance with safety standards and codes relating to venting systems in residential and commercial structures.