What is the restriction regarding the passage of single-wall metal pipe vent connectors through ceilings, floors, or walls?

The correct answer states that single-wall metal pipe vent connectors must not pass through ceilings, floors, or walls. This restriction is in place primarily due to safety concerns. When vent connectors are allowed to penetrate through these structural elements, there is a risk of heat transfer that could potentially lead to combustion of surrounding materials.

Single-wall metal pipes can become very hot during operation, and if they were to pass through combustible materials without proper safety measures in place, such as insulation or a specially designed venting system, this could create a fire hazard. Thus, code regulations have been established to ensure safety by prohibiting this practice entirely, encouraging the use of double-wall venting systems or other types specifically designed for such applications when a connection through structural elements is necessary.

Adhering to this requirement is essential for installation practices to prevent any hazardous situations from arising in residential or commercial buildings.