"damncold" wrote in message
...

Recently I had a home energy audit done. The auditor said there was
quite a bit of air leakage where the furnace stack (a round sheet metal
stack) comes into the attic. He said I should seal the by-pass in the
attic and "thought" expandable foam would be OK. Anyone know if this
could be a fire hazard?

I'd use fiberglass.

He also pointed out that the furnace stack is not insulated and is
giving off a good deal of heat in the attic - which is evident by the
size of the icicles hanging from my eaves. Is there any safe way to
insulate a metal furnace stack?


Thee is fiberglass insulation made for pipes and stacks. Check with a
plumbing supply house. Comes in about 3' lengths and is curved to fit
pipes.