I wasn't "Drafted" .......I Volunteered!!

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

soupy1957

Minister of Fire
Jan 8, 2010
1,365
Connecticut
www.youtube.com
Speaking of the "Draft," I found THIS rather interesting:

"The atmospheric condition known as 'air inversion,' causes high-density air to be trapped at fluetop altitudes normally occupied by the low-density air that creates ambient updraft.
During periods of air inversion, chimneys in the affected area simply don't draw properly. One way to tell if air inversion is causing temporary draft problems is to look at the smoke that exits the flue: if it eddies around the top of the chimney or flows downward onto the roof instead of rising as heated air normally would, an inversion layer is most likely present.
Having established that a draft problem is being caused by air inversion, several solutions present themselves:

(A) Don't attempt to start a fire during inversion days. These don't happen very often in most areas, and seldom occur during the long periods of Winter cold when we use our woodstoves most. Air inversion episodes occur most often when cold weather turns warmer, or when warm weather suddenly turns cooler, as sometimes happens in the Spring or late Fall. Some areas are more subject to air inversion than others: if your house is totally surrounded by tall trees, hills or buildings, you may experience local "inversion" every time the wind blows across the top of the taller obstruction, pressurizing the air below.

(B) During air inversion episodes, remove all possible draft resistance at the bottom of the chimney. Today's woodstoves have very small air intakes and very restrictive baffle systems through which air must be drawn by the chimney. Opening a nearby door or window a crack often reduces this resistance considerably, and may allow the stove to be burned even on heavy inversion days.

(C) Elevate the top of the chimney to a point above the inversion layer. This is a sort of hit-or-miss solution, for three reasons: (1) nobody can accurately predict exactly how high the inversion air tends to stack over a given neighborhood, (2) the density of an inversion layer can vary from one episode to the next, and (3) there is a limit to how high a chimney can extend before it gets too top-heavy to support.
If there's a chimney in your neighborhood that is taller than yours, you might ask the owners if the additional height overcomes the effects of inversion you are experiencing. If so, try extending yours to the same height. Note: never extend your woodstove chimney with uninsulated metal pipe, or excessive creosote formation will result."

-Soupy1957
 
Likewise in our area, usually about 2-3 times a winter. The stove will burn fine on these heavy inversion days, though the exhaust from the flue will sometimes sink instead of rise. When they get bad, burn bans are put into effect. They are correct about the impracticality of having the chimney higher than the inversion layer. This can be around 1000 feet. Getting the top of my flue up there could be a challenge.
 
Yup. Inversions happen every now and then but we don't have any problems with the stove. Sometimes we have to give a bit more draft but that is all. Actually, during the winter months it is very common on reloads to see the smoke coming down.

There has always been a saying along with this. If the smoke is hanging towards the ground, look for a snow or rain coming. If the smoke goes really straight up, it will be fair and cold. There is much truth to this saying too.

Here's another for those weather watchers. During winter months when I was a young lad, we still milked cows in stanchions. While cleaning the barn, unless the weather was bad we liked to let the cows out into the barnyard. They were usually just walking around but if you saw some running and kicking up their heels, prepare for a snowstorm.

Here's another: During summer, when it starts to rain, watch the chickens. If they run for the coop, it is just a shower. If they keep feeding and stay outside, it will rain all day.

Just a couple free tips from the Backwoods Savage.
 
As long a your exhaust gases are warmer than the ambient air at chimney-top , they'll rise out of the chimney just the same. It's only when they mix with surrounding air & cool to ambient temps that they can be blocked from rising further by a temp inversion (a layer of warm air above cold air btw).
That first sentence: “The atmospheric condition known as ‘air inversion,’ causes high-density air to be trapped at fluetop altitudes normally occupied by the low-density air that creates ambient updraft." seems like a bunch of BS to me. It's basically saying that cold (high-density) air at "flue-top" will keep a chimney from drafting which is contrary to both common sense and common experience.
As suggested, temp inversions create problems with local air quality. That's the only reason I see to consider not burning.
 
"Red sky in the morning, Sailors take warning:
Red sky at night, Sailor's delight!"

Interpretation: If you have a red sky in the early morning, it's gonna be a WINDY day! If at night, it'll be a pleasant sailing day, the next day.

Also "works" (true)

-Soupy1957
 
I'm going to have to chime in with supporting evidence for the handsome, talented and grossly underpaid author of the quote in the original post. Whenever a heavy inversion episode hits, the first 50 phone calls to our shop that morning will be from people who are convinced their chimneys suddenly need cleaning because when they try to start a fire the smoke just billows back into the room.

In the early days we'd send a Sweep over, only to find that (a) the chimney didn't need cleaning, and (b) we couldn't get a fire going either.

In the ensuing 20+ years, we've learned to check with the weather service whenever we get inundated with back-smoking calls: an inversion episode is always underway. We finally published the quoted passage in the OP on our website so we could direct frustrated callers there and avoid having to repeat the lengthy explanation all morning.

Here in the Pacific Northwest, we have thousands of topographical "bowls", many of which have bodies of water at the bottom, which might be a contributing factor. We tend to get more complaint calls on inversion days from residents of Sudden Valley and Happy Valley, for example. Over the years, we've received fewer complaint calls from folks who already have a fire going, so we've come to believe that an established thermal updraft can allow some chimneys to ride out the episode. Nonetheless, I assure you that the negative affect of air inversion on chimneys is a very real phenomenon.
 
Seen any 100 ft flue solutions Tom? :)
 
Now how "cool" is THAT!! To hear from the originator of the info that I quoted!

I guess the content leaves me wondering if "I" should expect to experience this condition, and how to keep my home warm if I can't light a fire on a day like that. Please don't say I have to use my FURNACE!! That's the whole thing I'm trying to avoid!

I guess (to quote again from that OP quote) "Opening a nearby door or window a crack often reduces this resistance considerably, and may allow the stove to be burned even on heavy inversion days" is the only viable option.

But this whole thing pertains to attempting to START a fire when there is an air inversion going on, right? If I have a fire and draft already established, there should be no problem, correct?

-Soupy1957
 
Boy I consider my self lucky, I have had this chimney for 30 years and have never had it back puff on me no matter what the temp or conditions, plus I can start a fire easily no matter what, it will draw harder at times but no back puffs.
 
The guy that installed my stove said that West Virginia was one of the hardest states to burn wood in because of the constant high pressure systems we have. I'm sure that lots of homes (including mine) being at the foot of a mountain doesn't help much either.

Many of rainy, dreary days I have watched smoke from my chimney go by the living room window but I'm still able to burn on these days even though the fire seems a little "lazy".
 
Did you mean constant low pressure systems?
 
So, the distance above sea level matters? Hmmmmmmm.....I'll have to look into that. Dunno how many feet above sea level I am here.......but I'll bet I can "Google" it!

Yep.......Googled my home town.....it said:

"Elevation: 82 metres (269 feet) -- validated against 83 metres (271 feet) from NED Contiguous U. S. 1/3E"

Not sure I understand everything I'm reading there, but. Looks like I am 269 Feet above sea level, if that means anything in relationship to air inversion potential. What the rest of that statement means, I haven't got a clue! (lol)

-Soupy1957
 
Status
Not open for further replies.