Used 3,780 sq ft stainless steel shell and tube heat exchanger. Mfg Spallinger Millwright Services. (514) SS Tubes 1" OD x 28'3" L, Rated 100 PSI @ 400/-20F.. SS Shell Rated 70 PSI @ 400/-20F. 32" dia x 32' L. HEADS: Stainless Steel With SS Clad end plates. National Board# 108. Serial #07-0125-H409.