What is the required minimum diameter for a gas vent for residential use?

The correct minimum diameter for a gas vent for residential use is 3 inches. This specification is crucial for ensuring the safe and efficient venting of combustion gases from appliances such as gas-fired furnaces, water heaters, and ovens. A vent that is too small can lead to inadequate exhaust, which might result in the buildup of dangerous gases inside the home, such as carbon monoxide.

The National Fuel Gas Code outlines these standards to ensure that residential gas appliances operate safely and effectively. A 3-inch diameter vent provides a balance between the capacity to exhaust gases and the physical space available for installation in typical residential settings.

Inadequate venting can lead to back drafting and could compromise the performance of the appliance, making adherence to this minimum size vital for safety and compliance with regulations. Therefore, using a vent with a diameter significantly smaller than 3 inches may not meet the requirements outlined in the code and could pose serious health risks.