The exit terminals of mechanical draft systems must be at least how many feet above finished ground level when adjacent to public walkways?

The correct answer is established based on safety regulations and guidelines that aim to protect public health and ensure safe passageways. Mechanical draft systems, which include exhaust vents and stacks, need to have their exit terminals elevated to minimize the risk of harmful exhaust gases and debris affecting pedestrians on public walkways.

A height of 7 feet above finished ground level provides a sufficient buffer that reduces the potential for inhalation exposure to any emitted substances. This height is also consistent with industry standards that recommend vertical distances that ensure compliance with health and safety protocols. By placing the terminal at this elevation, it also helps prevent obstruction or damage from pedestrian traffic and allows for adequate dissipation of exhaust away from ground level, thereby enhancing overall public safety.

Therefore, these considerations affirm that the correct height of 7 feet is necessary to balance safety and functionality in urban environments.