ISF, Inc. Horizontal Ammonia Surge Drum. Certified by Industrial Service & Fabricators, Inc. – Burleson, TX USA. MAWP: 250 PSIG at 200F. MDMT: -20F at 250 PSI. External Pressure: 0 PSIG at 0F. S/N: 04-5505. Nat’l Bd. No.: 5173. Year: 2004. (2) Safety relief valves. Previously used with an ammonia-glycol plate-Frame chilling system. Estimated capacity: 900 gallons. Sidewall dimensions: 116 in. L x 48 in. dia. Ports: (4) 8 in., (1) 2 in. Overall dimensions: 148 in. L x 54 in. W x 115 in. H.