If a wood stove is installed in a fireplace, should the transition piece connecting the stove to the liner always be stainless steel? Specifically, if there is an offset and there are some elbows and/or short lengths of pipe in the damper/smoke chamber area, can those pieces be black stove pipe? I know stainless is always better, but wondering about how NFPA and any other codes apply here, and if there is a generally accepted cut-off point at which you would not want to go any further with black stove pipe.