Double or triple wall?

[chris-mcpherson]

This will be a through the wall application...out and up. About half of the pipe will be enclosed in what's now a direct vent exterior bump out and half will be exposed. Can I use double wall or should it be triple?
I'm looking at DuraTech from WoodlandDirect.

 

[North of 60]

Neither... Class A

 

[chris-mcpherson]

It looks to me that class A comes in both double and triple...right?

 

[North of 60]

dougand3 has your answer in your other thread.