Chimney and Steam Vent Height

[theraven06]

So I am moving my operation inside this year and just purchased a used Lapierre Mini Pro (19x48). I am going to be setting it up inside a detached 2 car garage and I will have a steam hood. I'm trying to figure out what my chimney height above the peak of the roof should be. Total height from the top of the arch to the roof will be 10', 8' of it will be with 7" single wall stainless pipe, then switching to Class A pipe to exit through the roof. The steam pipe will be 8" duct.

What should my total height above the roof be in order to get a good draw? If I use 4' of Class A, that would be about 2' above the roof, but only about 1.5' above the peak (unit is NOT centered in the garage).

Also, should my chimney height be taller than the steam vent?

[MN Jake]

Top of stack needs to be 2' above any part of the roof thats within 10' of the stack. So if the peak of the roof is less than ten feet away you must be 2' above it.

[maple flats]

MN Jake is correct on the smoke stack, but the steam stack can be just 1' out without regard for the peak. That is, unless you you get more than a foot of snowfall in some storms, in that case make it 6" taller than you might expect in a bad snow storm.
For the smoke stack you can go back to single wall to gain height once thru the roof. The steam stack can be single all the way up.