Type BW Vent

Does anyone know of any application where a Type BW vent is allowed for anything other than venting of a wall furnace?

Code reference or appliance manufacturer please.

Okay, how about this?

Transition from Type BW to Type B is allowed with listed components, but is the opposite allowed (B-vent to BW-vent)?



Does this help Jeff? Pg 36

Good question

Not really, but I appreciate the effort.

Definition from IRC and UBC = ****Type BW vent. ****A vent listed and labeled for use with wall

I found these fireplaces vented with Type BW. This is new to me. Also, I can’t find any information that supports the B to BW transition as in the picture.

The dilemma? 400 + units completed, about a hundred to go (construction in progress) :roll: I don’t want to “unnecessarily” open up a hornets nest, but I want my client(s) to be aware if the installation is improper.



Still looking, sure it is not oval B vent?

Oval B is BW


Hmmm, Than this should do it.

Check out near the bottom “oval vent” #1

That helps. Thanks Brian.

My pleasure Jeff, learned something new.

Jeff what did you decide about this installation?

I have sent a letter to the BW vent manufacturer and am waiting for a reply. . .

How about clearance to combustibles?

Anything yet?

Conflicting information.

The BW vent manufacturer says “no problem.”

Anywhere a B-vent is used, a BW-vent can be used as well (generally speaking). The manufacturer of the fireplace says the vent system must be specifically listed for the fireplace, B or BW.

The code books say that BW vents are listed for specific wall furnaces (not water heaters, not fireplaces - just wall furnaces).

The code “enforcers” follow the BW manufacturers recommendations (allowed for all gas appliance vent systems). I will follow that lead. . .

Anyone who wants the manufacturers info in a pdf file, send me an email. It’s too large to attach to the message board. . .

Sorry, I missed that post Hank.

Clearances for type BW are the same as a standard B-vent - 1 inch minimum. In this case, there were several clearance issues that were addressed and corrected.