Which of the following appliances is exempt from the prohibited locations rule for fuel-fired appliances?

Direct-vent appliances are specifically designed to draw combustion air from outside the building and vent exhaust gases directly outside through a sealed venting system. This unique configuration allows them to operate safely in locations that might otherwise be prohibited for traditional fuel-fired appliances.

Because these appliances do not utilize indoor air for combustion and do not pose a risk of backdraft or combustion gas leakage into the living space, they can be installed in areas that would be dangerous or inappropriate for standard fuel-fired appliances. This feature significantly enhances safety and operational flexibility, making direct-vent appliances exempt from the common prohibitions that apply to their conventional counterparts.

In contrast, standard appliances, non-vented appliances, and electric appliances often have more stringent location requirements due to safety concerns related to combustion air access and exhaust. This is why the distinction with direct-vent appliances is important within mechanical codes.