Joining PVC and round duct

[dbooksta]

I am trying to use an existing 4" round metal duct to vent a radon fan, and of course the fan is designed for 4" PVC connection. Is there a standard way to join round metal to PVC, or do I just have to kludge something with crimping and lots of tape?

[ct2]

use PVC

[johnsp]

I think a metal 4" flex connector or coupling should fit over the 4" PVC also.