Subject: Chimneys and drafts

From: Dan Nibbelink <[email-masked]>
Date: Mon, 19 Aug 1996 23:29:03 -0700

A metal chimney, outside of the building, should be double wall. This is 
to prevent the smoke, etc, from cooling off to quickly. If it cools too 
quickly it will not draw well. I am pretty sure that code requires double 
wall for residential wood burning stoves for this reason.

If your shop is not heated and you forge in the winter then the pipe 
inside should also be double wall for the same reason.

The top of the chimney should be 3 feet above where it passes thru the 
roof, AND 2 feet higher than any part of the roof within 10 feet, 
measured horizontally. With false walls you should be at least 3 feet 
above them.
            /\       _
           /  \    ||_2
	  /   |\   ||
	 /    | \  ||
	/     |  \ ||
       /      |   \||
	      |-10-|

Some things that might help: A turbine exhaust cap or a "weather vaning" 
cap.  I haven't tried them and don't recall reading about them so you 
should check code or with a woodstove store. Either will probably vent 
your shop (and the heat in the winter) --  you may want to add a shutoff 
butterfly valve. 

-- 
Dan Nibbelink
RedHawk Forge
Berthoud, Colorado
[email-masked]
http://www.csn.net/~dannibb