Furnance vent...Is a heat collar required ?

It looks like its double vented ( a vent within a vent ) …

Does the vent construction look ok?..or is this a write up?

David

http://i187.photobucket.com/albums/x296/dawlita/Nachi/100_9036.jpg

http://i187.photobucket.com/albums/x296/dawlita/Nachi/100_9038.jpg

What is holding the b-vent up?
I don’t see fire stopping nor a support bracket.
Is it 1" from combustibles?
It looks cobbled up from here.

That is wrong. Class “B” double walled vent requires a 1" gap to all combustible materials.

Write it up.

thanks Cameron…