Tin knocker question on Class 1 duct

[Owen1508]

I am interested in finding out if Class 1 air duct, specifically Dundas-Jafine Class 1, can be used coming off a plenum. The spec sheet has it rated at 140 degree continous and 250 max. This seems low. It is UL181 listed and complies to ASTM c518 but is it heat rated high enogh to be used coming right off a furnaces plenum?

here is the products link.
(broken link removed to http://www.dundasjafine.com/products/27-insulated/72-insulated-air-duct-black-jacket.html)


Thanks in advance.

 

[brant2000]

I've glanced at a few code sections, this happens to be VA's version of the IMC (International Mechanical Code) and I haven't seen anything that would specifically prohibit you from using nonmetallic. I looked at NY's quickly, but their codes are different and I'm not that familiar with them. I also didn't see anything that would specifically prohibit it there, either. A lot of the specifics about solid fueled appliances is often left up to the UL listed manufacturer's installation requirements, so I would certainly check there also.

 

[heaterman]

On gas or oil fired equipment no problem. Personally I wouldn't use it on a wood furnace. Too many things can go wrong with limit controls and uncontrollable fires.

 

[Owen1508]

On gas or oil fired equipment no problem. Personally I wouldn't use it on a wood furnace. Too many things can go wrong with limit controls and uncontrollable fires.

That's where I have a problem with being used. The furnace owner is wanting to use it as a main trunk line and it is only rated 140 continuous just like you said too many thing can go wrong. He had a Building Inspector sign off on using it, but I'm not sold. I'm still looking into the NFPA 90 A & B and the IMC to get a heat rating on supply ducts coming off the plenum on a soild fuel furnace. Personally I wouldn't use it except to tie the main trunk to a register

 

[brenndatomu]

All the wood furnaces manuals I have read say that all supply ducts must be metal...

 

[STIHLY DAN]

All the wood furnaces manuals I have read say that all supply ducts must be metal...

Which supersedes state code.

 

[TheBigIron]

Sheet metal must be used and proper CTCs must be maintained.

 

[Owen1508]

Thanks for all the help guys. I have the customer finally convinced to change the class 1. Since he didn't even install a return air at all he is going to use that class 1 for that. Hard to convince anyone without codes to show him, since his local building inspector signed off on it already. But he is fixing it all.

Thanks again guys Hearth.com still the best.

EDIT: lesson I learned....brush up on NFPA 90a and 90B

 

[heaterman]

Code on wood fired equipment here for hot air duct is basically 2 things.

Plenum and all supply duct/branches must be metal. Period. End of discussion.
Plenum, duct and branches must maintain 2" clearance to combustibles for a minimum of 10' from the furnace. 1" thereafter.

 

[Owen1508]

Code on wood fired equipment here for hot air duct is basically 2 things.

Plenum and all supply duct/branches must be metal. Period. End of discussion.
Plenum, duct and branches must maintain 2" clearance to combustibles for a minimum of 10' from the furnace. 1" thereafter.

Great info the guy happens to be from MI.
Thanks

 

[brenndatomu]

Plenum, duct and branches must maintain 2" clearance to combustibles for a minimum of 10' from the furnace. 1" thereafter.

Some call for more. Such as Yukon, they want 6" clearance for the first 6'...might be because they are UL certified to be able to run with the power out though

 

[STIHLY DAN]

Kuuma the same as above also.