UNK Shell and Tube Heat Exchanger. Mild steel shell. Number of copper tubes: 150. Tube dimensions: 3/4 in. dia. x 84 in. L. Heat transfer surface area: approx. 68.7 sq. ft. Two-pass. Inlets: (1) 6 in. dia. FNPT fitting, (1) 8 in. dia. port with ANSI class 150 flange (media). Outlets: (1) 6 in. dia. FNPT fitting, (1) 2-1/2 in. dia. FNPT fitting (media). Overall dimensions: 93-1/2 in. L x 29 in. W x 18 in. H.