500 Sq. Ft. Horizontal Shell and Tube Heat Exchanger. 304SS Shell Side rated 100 PSI @ 300° F; SS Tube Side rated 100 PSI @ 300° F. Shell- 1 Pass, Tubes- 2 Pass. (136) Tubes with 1†OD x 14’ long. Shell diameter-20â€, OAL-17’ Mfg: Standard Boiler & Tank, S/N: 94-337, NB #1180.