Gas Fitter Practice Test

What is the minimum distance a direct vent propane appliance vent can terminate from a mechanical air supply inlet to a building?

1. Within 2 ft. of a property line

2. Less than 3 ft. from a gas service regulator

3. Within 3 ft. of a mechanical air supply inlet to a building

4. Within 10 ft. of a mechanical air supply inlet to a building

The correct answer is: Within 3 ft. of a mechanical air supply inlet to a building

The correct answer is based on the importance of proper ventilation and the safety standards that govern the installation of gas appliances. A direct vent propane appliance operates by drawing in air for combustion from outside and expelling exhaust gases. Proper distancing from mechanical air supply inlets is crucial to prevent the possibility that exhaust from the vent could be drawn back into the building, which might lead to dangerous situations such as the accumulation of carbon monoxide or other harmful gases indoors. In this context, the regulation states that a direct vent appliance should terminate at least 3 feet away from a mechanical air supply inlet. This distance helps ensure that combustion products do not inadvertently re-enter the ventilation system of the building, maintaining indoor air quality and overall safety. The other options do not align with the safety regulations regarding gas appliance installation, focusing instead on distances that either do not offer appropriate safety margins or pertain to unrelated factors such as property lines and gas service regulators.