Where should motors for fans conveying flammable vapors be located?

The correct answer indicates that motors for fans conveying flammable vapors should be located outside the building. This practice is crucial for ensuring safety and minimizing the risk of ignition in environments where flammable vapors are present. By positioning the motors outside, any potential sparks or heat generated by the motor will not be in the vicinity of flammable materials, thereby reducing the chances of a fire or explosion.

This approach aligns with safety regulations and best practices in mechanical installations, particularly those involving volatile substances. Outside placement allows for better ventilation and decreases the likelihood of flammable vapors accumulating near the motor or electrical components.

Choosing an alternative location, such as inside the duct, exposes the motor to the same hazardous vapors it is meant to manage. An uncontrolled environment would similarly put the motor at risk of exposure to flammable materials. A protective enclosure might provide some safety benefits, but it doesn't completely eliminate the risk associated with being in proximity to flammable vapors. Therefore, locating the motors outside the building is the most effective strategy to mitigate hazards related to flammable vapors.