Actually, I think Giovanni was following my line of reasoning.
It is not unusual at all to have piping connections that someone erroneously specs out as D1.1. Same with stainless, aluminum, sheet steel, and you name it - they have all been "required" to be welded to D1.1 at one time or another.
Joey,
No, you can't. B31.3 refers to piping systems in oil refineries and chemical and petrochemical plants. They (the piping systems) carry some kind of fluid and are subjected to internal (or seldom external) pressure, and quite often to high (or seldom sub zero) temperatures.
D1.1 refers to structural steel, subjected to structural stresses: tension, compression, torsion, flexion, buckling and shear (the primary stresses) and all of the others that derive from them. In this case, as Rick described it, his piece of pipe will be used as a column and will be subjected presumably to compression and buckling.
Giovanni S. Crisi