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-   -   can foam insulation touch type B venting? (http://www.diychatroom.com/f17/can-foam-insulation-touch-type-b-venting-120500/)

amakarevic 10-18-2011 03:00 PM

can foam insulation touch type B venting?
 
i have PVC pipe that comes to nearly the minimum legal distance from type B venting (1"). just to be safe, i was thinking of wrapping a couple of layers of that light blue insulation wrap that comes in 6" wide rolls. was wondering if that can come in contact with type B.

also, is type B allowed to come in contact with 2x4 framing?

thanks

brandonmcginnis 10-18-2011 03:43 PM

Mechanical code for B Vent requires a 1" clearance to combustibles. I'm pretty sure that wrap is considered a combustible. Leave it alone, it's not gonna hurt your PVC. Nothing should touch B Vent except metal straps or roof flashings.

amakarevic 10-18-2011 04:11 PM

Quote:

Originally Posted by brandonmcginnis (Post 751438)
Nothing should touch B Vent except metal straps or roof flashings.

but what can happen if it touches 2x4 ?

hvac122 10-18-2011 04:12 PM

A fire

amakarevic 10-18-2011 04:21 PM

Quote:

Originally Posted by hvac122 (Post 751455)
A fire

come on... it NEVER gets that hot

Marty S. 10-18-2011 05:43 PM

Quote:

Originally Posted by amakarevic (Post 751461)
come on... it NEVER gets that hot

Tell that to the inspector and see how far it gets you. Mechanical code states 1" minimum from combustibles for double wall flue and there are no exemptions.

Doc Holliday 10-18-2011 06:10 PM

Quote:

Originally Posted by amakarevic (Post 751461)
come on... it NEVER gets that hot

No, never. And the furnace in my old home didn't do this, either...
http://i87.photobucket.com/albums/k1...e/IMG_5571.jpg
http://i87.photobucket.com/albums/k1...e/IMG_5568.jpg

http://i87.photobucket.com/albums/k1...e/IMG_5565.jpg

http://i87.photobucket.com/albums/k1...e/IMG_5523.jpg

sammy37 10-18-2011 08:27 PM

Dang Doc! What exactly happened?:eek:

amakarevic 10-18-2011 08:38 PM

Quote:

Originally Posted by sammy37 (Post 751635)
Dang Doc! What exactly happened?:eek:

did your furnace get caught on fire itself or the related venting? i am talking about venting here.

Doc Holliday 10-18-2011 08:56 PM

Quote:

Originally Posted by sammy37 (Post 751635)
Dang Doc! What exactly happened?:eek:


We'll never really know but that wood was so dry and brittle the firefighters spent 4 hours putting it out as it kept coming back. It could have been the flue pipe (I've seen burn marks on the rafters in homes where it has rested against the wood) or it could have been the motor or a wire or who knows.

All I know is I was renting that home (there for four months) and offered the HO my services up front in checking over the system and fixing it up, cleaning coils, patching air leaks, checking amperage, etc., in return for reduced rent for a few months and he declined, saying it was good enough as "it's worked fine all these years" and he couldn't afford to knock of rent. That system had been turned on in heating mode at night for two weeks prior but one night, after only about 20 minutes of it being on, it just went up in flames.

I sat and watched it burn for those four hours.

COLDIRON 10-19-2011 05:39 PM

1" all around live by that and keep living, it can get real hot if you have a heater running for long periods of time along with other appliances venting.

The 1" all around no touch was developed for a reason, FIRE.


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