I built a 40 x 80 addition onto my existing 38' x 40' shop, the ceiling is 18' tall.
I used to have a wood stove in the existing shop that worked really well but I sold it a week ago.

I figured that I'm going to need a bigger wood furnace and I called the mechanical inspector to find out what the code is just to find out that they dont allow a wood stove in a shop where oxygen and acytelene are stored because you never know when a spark might cause the oxygen cylinder to blow up.
I said ( Do you realize that I'm a welding shop and thats what we do make sparks all day long and alot of the time we do it with the oxygen and acytelene torch ) He said
( Ya I know, You can call the state inspector and find out what he says. It turned out to be the same response )

Years ago I would have pushed the issue but because of insurance reasons its easier to do what they say. That and my new stove wont be UL Listed.

I now have to heat 4,720 sq ft with a 18' ceiling.

I bought a 550 cfm blower that kicked butt by itself but was useless when trying to push air out of two 8" ducts so I removed it and ordered a 1,400cfm blower.

I have a 2-1/2" gap on the sides and a 3" gap on the top and bottom, The air has to run back and forth 5 times before it comes out of the 2 ducts 8" diameter.

The inside fire box can take a 35" long log and is 27" wide x 26" tall now that I installed the fire brick

I'm going to start on a fire proof building to put it in tomorrow and my plans are to pack insulation between the walls of the building and the stove, I will install a furnace duct with a filter on it for the cold air return, There will be approximately a 12" gap between the 2 buildings and I will have to insulate the two 8" duct pipe.

All constructive criticism is welcome.