Neal Lewis Posted January 23, 2013 Report Share Posted January 23, 2013 Here's a picture of a B-vent in an attic. It looks like the lower section was modified and screwed into the elbow. I've looked throught the Simpson installation instructions and don't see any mention of field modification. Is this allowed? Click to Enlarge 51.4 KB And here's a pic of the B-vent at the attic floor. No firestopping and it's in direct contact with the framing. Click to Enlarge 42.91 KB And yeah, there's a problem with drafting, too. Link to comment Share on other sites More sharing options...
Brandon Whitmore Posted January 23, 2013 Report Share Posted January 23, 2013 That doesn't look right to me. Link to comment Share on other sites More sharing options...
kurt Posted January 23, 2013 Report Share Posted January 23, 2013 You can use 1/4" galvanized screws, but you can't have a screw penetrate the inner liner. Screws for 3" and 8" pipe. In my Simpson guide, they actually recommend screws in some cases. Elbows have to be strapped and supported; the elbow can't bear the weight of the pipe. And, you got the combustible contact thing and no firestop. Which is stupid; Simpson makes a nice little transition plate for firestopping. Link to comment Share on other sites More sharing options...
Hearthman Posted February 17, 2013 Report Share Posted February 17, 2013 B-vent must be installed per the listing, which this is not. No listed firestop, no fireblocking per the code, no support at offset, single walled vent connector used in unconditioned space, inadequate clearance to combustibles and lack of draft hood connector for transition to single walled connector(recommended but not required for listing. As stated, you can screw at joint overlaps with 1/4" screws as long as they don't penetrate inner liner. Usually, what I find is the screw is too long and pushes the inner liner inwards like daisy petals thus restricting the vent. Link to comment Share on other sites More sharing options...
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