Bit of a scare tonight...

[colebrookman]

Not to steal the thread firefighterjake, many thanks for the info.
Ed

 

[jjhof0306]

That happened in my former hometown, Barre, Vermont - a mother and four children were killed and when the firefighters got there, the fully functioning smoke detectors were not sounding. It was a horrible tragedy. apparently slow, smoldering fires do not set off the old ionization detectors. Here's a link to their site. Lots of good info there.

http://www.barrecityfire.org/

 

[oconnor]

I have to read more about downdraft, but that's a good point about using smoke to track air leaving the house.
IR would be useless there.
I like the fizzing beer analogy too.
Thanks.

Give the link in my signature block a read - Guide to residential wood heat. Pay specific attention to the concept of "stack effect" (chapter 10), as that is (edit - a possible cause) of a backflowing flue.

 

[thechimneysweep]

Pay specific attention to the concept of “stack effect” (chapter 10), as that is what causes a backflowing flue.

The stack effect is only one possible cause of a backflowing flue, and is far from the most common. We generally only see the stack effect in older multi-story houses, where heated air rises and exits out the (leaky) upper story, vacuuming replacement air down the chimney.

In our area, largely populated by newer, one-story homes without leaky attic doors, it is very rare to see smoke backflow caused by the stack effect. The most prevalent causes of chimney backflow are mechanical depressurization, wind-induced downdrafting, flue blockage and atmospheric air inversion. There are many other common causes, some of which can be viewed at (broken link removed to http://www.chimneysweeponline.com/hodraft.htm).

However, I must agree with the other posters that failure to prime a cold flue will result in smoke spillage nearly every time. Until the cold-air "plug" has been displaced, the chimney wants to flow backward, carrying the smoke back into the house.

 

[bfunk13]

Funny you post this, last night i was fast asleep, my wife is a night owl and was trying to start a fire.
At 1:30am i happened to wake up and smell smoke. I came out to see what was going on. There she was in front of the stove.
At this point she had it going, but the smoke was strong enough to wake me up. Our smoke detector didnt go off either.
I tested it about a month ago. I suppose it wasnt quite enough to set it off. Still a bit scary.

 

[oconnor]

Pay specific attention to the concept of “stack effect” (chapter 10), as that is what causes a backflowing flue.

The stack effect is only one possible cause of a backflowing flue, and is far from the most common. We generally only see the stack effect in older multi-story houses, where heated air rises and exits out the (leaky) upper story, vacuuming replacement air down the chimney.

In our area, largely populated by newer, one-story homes without leaky attic doors, it is very rare to see smoke backflow caused by the stack effect. The most prevalent causes of chimney backflow are mechanical depressurization, wind-induced downdrafting, flue blockage and atmospheric air inversion. There are many other common causes, some of which can be viewed at (broken link removed to http://www.chimneysweeponline.com/hodraft.htm).

However, I must agree with the other posters that failure to prime a cold flue will result in smoke spillage nearly every time. Until the cold-air "plug" has been displaced, the chimney wants to flow backward, carrying the smoke back into the house.

Tom is totally correct - edited my post above. Thanks for the correction.