What is required for the termination of gas dryer vents to prevent backdraft?

To prevent backdraft in gas dryer vents, the installation of a backdraft damper is necessary. A backdraft damper is designed to allow airflow in one direction while preventing any potential reverse airflow. This is particularly important in gas dryers since backdrafts can lead to dangerous exhaust gases entering the home instead of being expelled outside.

When a dryer operates, it expels hot, moist air and needs to do so effectively. The backdraft damper opens to allow this airflow during operation but closes when the dryer is off, effectively blocking any outside air or exhaust from flowing back into the ductwork or into the home. This feature is crucial for maintaining safe air quality within the residence.

Other options, such as a one-way valve and a shut-off valve, may allow some form of controlled airflow but do not specifically address the need for preventing reverse airflow in the dryer vent context. An exhaust fan, while useful for increasing airflow, does not inherently prevent backdraft. Thus, the backdraft damper is the most effective solution to ensure safe and proper operation of gas dryer vents.