delta on flue temps

[jalvideo]

recently installed an insert with 6 inch liner in an uninsulated 30 foot external chimney. measuring temp above insert - is there any calculation that looks at temperature drop over 30 foot travel of flue gas through the chimney to gauge temp near top where creosote buildup occurs?

 

[Dakotas Dad]

Doubt it, every chimney is different in structure and components. You could take measurements on your stove that would be good for yours, but even they would only be good for days when the weather was the same as when you took the measurements. ie your chimney gasses are going to cool a lot faster on 10 degree days then on 32 degree days.

 

[jalvideo]

thanks for quick response - there are pressure drop calculations of the stack effect (http://en.wikipedia.org/wiki/Stack_effect) that factor in outside temps. will keep digging to see if calculations include temp drops over distance where outside temp is known.