[GBlist]Outdoor combustion air supplies

[Norbert Senf <mheat@mha-net.org>]

At 08:15 AM 2001-02-22 -0700, mac12 wrote:
>A note of caution:
>
>As we work harder to seal buildings for energy efficiency (or perhaps to 
>reduce radon infiltration), we run the risk of not having a source for 
>combustion air.  Picture a perfectly sealed basement with a furnace using 
>room air for combustion.  You would have a bad case of negative pressure 
>in the basement which would prevent combustion products from exhausting up 
>the flue.  (snip)

This is a complicated issue. Excessive negative pressure in the basement is 
actually more likely to result from pot lights in a cathedral ceiling than 
from air consumption by a furnace.

We did a study a number of years ago on masonry heaters, and concluded that 
if the air consumption was under 30 litres/sec (64 cfm), there was no 
chance of the appliance causing appreciable depressurization, even in the 
tightest house that we could find, which had an Equivalent Leakage Area of 
25 sq. in.

There is a good discussion of outdoor combustion air supplies by John 
Gulland at
http://www.woodheat.org/outdoorair/outdoorair.htm

Best ........ Norbert Senf

----------------------------------------
Norbert Senf---------- mheat@mha-net.org-nospam
Masonry Stove Builders	(remove -nospam)
RR 5, Shawville------- www.heatkit.com		
Quebec J0X 2Y0-------- fax:-----819.647.6082
---------------------- voice:---819.647.5092