When I was at Ft Benning in '68 we had heaters just like that at the sound branch in several areas including my bunk room. The building was an old WWII wood framed with a large central bay (20 X 200 ft) we ran trucks through. We had no problems with getting fresh air in that old barn.
That was A LOT safer than the diesel stoves we used in Korea. The carburetor floats on those would get stuck sometimes and if you were lucky you caught it before the 5 gallon jerry can exploded. Lost a few buildings with them.
Smith G8-3 with EZ Gas @76,700 BTU, Single pipe steam