Expert: James Ball - 2/11/2011

Question
I am investigating a residential fire involving a pellet stove insert.  The pellet stove replaced an existing fireplace vented to a 12" double-wall pipe.  The vent pipe for the pellet stove is 3" flexpipe ran up into the existing double-wall.

My question is, does the new vent pipe have to terminate at the existing rain cap or can it terminate at some point within the existing pipe?  Second, does the new vent pipe have to be insulated with thermix or ceramic wool wrap and if so what length of the pipe needs this insulation?

I have checked NFPA 211 for any code language on this.  I believe the pipe has to terminate above the roof line but cannot find any language on insulating this pipe.  Are there any other code resources that cover insulating requirements?

I am just looking for some direction on this issue, not a professional opinion.

Answer
Ryan, you have 2 places you have to start, 1 local building codes (NFPA, IRC...etc) then and more importantly 2  the manufactures installation  manual this must be followed to the letter unless altered by local code.
NFPA has (don't have the book in front of me as am at a chimney sweep convention) but all chimneys much vent the 3', 10' 2' rule 3' above where the chimney breaks the roof line Min. then a 10' horizon circle Min.  if you don't hit any thing you are ok if you do you keep going up till you don't then 2' about that, MIn.
in most cases you should run the 3" all the way to the top
hope this helps
James