Used 28 Sq. Ft. Horizontal Inconel Shell & Tube Heat Exchanger. (U-Tube). Carbon steel shell, rated 250 PSI @ 400°F; Tube side: 150 PSI @ 400°F. (24) Inconel 600 Tubes, 1" OD x 54". Built by Richard Armstrong, National Board #9422. Passes: Shell- 2, Tubes- 2. Nozzles: Shell side: 2"; Tube Side 1-1/2".