Dryer vent

[Wade Johnson]

Can you use 4.5 inch double wall pipe for a dryer vent?

[Bruce Ramsey]

1502.3 Duct Size. The diameter of the exhaust duct shall be as required by the clothes dryer's listing and the manufacturer's installation instructions.

1502.4 Duct construction. Exhaust ducts shall be constructed of minimum 0.016 inch-thick rigid metal ducts, having smooth interior surfaces with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet metal screws or fastening means which extend into the duct.

The most common duct size is 4 inch single wall. 4.5 double wall would be about 4 inch interior diameter. It would be smooth wall metal duct with joints running in direction of air flow. Unusual but seems to meet the basic criteria. The clothes dryer mfg instructions may be the gotcha.

[Jerry Peck]

Can you use 4.5 inch double wall pipe for a dryer vent?

You mean Type B Gas vent for dryer ducts? No.

[Wade Johnson]

Thank you. I have tried to log into your website "askcodeman" but it won't let me.

[Bruce Ramsey]

Jerry, Can you help me undestand why B Vent is not allowed?