What is the vent diameter specified for a 5 ft lateral single-wall metal vent?

What is the vent diameter specified for a 5 ft lateral single-wall metal vent?

• A. 4 Inch Diameter Vent
• B. 3 Inch Diameter Vent
• C. 5 Inch Diameter Vent
• D. 6 Inch Diameter Vent

Answer: (A)

Vent sizing follows a chart that couples run length with the appliance’s venting requirements to pick the right diameter. For a five-foot horizontal (lateral) run using a single-wall metal vent, the standard recommendation is a four-inch diameter. This size provides enough cross-sectional area to move the combustion products out efficiently while avoiding excessive resistance that could hinder draft. A smaller diameter, like three inches, would be too restrictive for typical appliances, risking poor draft, backpressure, or condensation. A larger diameter, such as five or six inches, would slow the gas flow too much over a short run, reducing draft effectiveness and potentially causing moisture or venting issues. Always refer to the appliance’s venting table, but four inches is the common choice for a 5 ft lateral single-wall vent.

Vent sizing follows a chart that couples run length with the appliance’s venting requirements to pick the right diameter. For a five-foot horizontal (lateral) run using a single-wall metal vent, the standard recommendation is a four-inch diameter. This size provides enough cross-sectional area to move the combustion products out efficiently while avoiding excessive resistance that could hinder draft. A smaller diameter, like three inches, would be too restrictive for typical appliances, risking poor draft, backpressure, or condensation. A larger diameter, such as five or six inches, would slow the gas flow too much over a short run, reducing draft effectiveness and potentially causing moisture or venting issues. Always refer to the appliance’s venting table, but four inches is the common choice for a 5 ft lateral single-wall vent.