Shell side Tube side Special Service Wet H2S – NI-1706 Category 1 -Corrosion Allowance 6mm 3mm PWHT Yes (Wet H2S Service) - MATERIALS Shell Carbon Steel SA-516 + 6mm c.a. Tubes Duplex Stainless Steel SA-789 UNS S31803 (seamless) Channel Carbon Steel SA-516 + 3mm c.a. Tubesheet Carbon Steel SA-516 + 6mm c.a. shell side + 3mm clad SS304L tube side Baffles Stainless Steel 304/304L