How far above the level of a walkway must the horizontal termination of mechanical draft systems be located?

The correct answer is founded on specific safety and design guidelines outlined in the International Mechanical Code (IMC). Mechanical draft systems, including venting for appliances, must terminate at a minimum height above walkways to ensure safety and minimize the risk of exhaust gases causing harm.

The requirement of 7 feet above a walkway is primarily aimed at preventing accidental contact with the discharge of gases from the system. It also helps in avoiding obstruction from pedestrians, which could inadvertently lead to exposure to harmful emissions. This height standard is consistent with practices promoting safe passage and minimizing risks associated with low-hanging vent outlets.

Understanding this context clarifies why other height options might not be deemed sufficient for safe operation and human interaction with mechanical systems. The chosen height helps reinforce safe design practices in both residential and commercial applications of mechanical systems.