Diaphragm, Seat, and O-Ring Materials Code Application Temperature Wear Resistance Available Forms Nitrile (none) General purpose, petroleum fluids, ethylene glycol, water, small amounts of methanol -30° to +200° F 1 O-Rings, Seats, Diaphragms Polyacrylate H Heat resistance, oils, natural gas 0° to +300° F .5 Ethylene Propylene EP Steam, water, alcohols -65° to +300° F 1.5 Highly Saturated HSN Petroleum fluids, H2S, CO2 -20° to +300° F 2 Polyurethane P Petroleum fluids, CO2, abrasion, toughness -40° to +200° F 5 Seats, 106P Diaphragm Viton® V Heat, acids, propane gasoline, no methanol, not for hot water or steam, not for wet CO2 -15° to +350° F .75 O-Ring, Seats, Diaphragms Geothermal EPDM GEP Steam, water, petroleum fluids 0° to +500° F Seats HPMV PB Aflas® AF High heat, steam, amine, acids, bases, petroleum fluids, no methanol 25° to +450° F 3 O-Rings, Seats Gylon® 3521 GY High heat, high chemical resistance, highly resistant to gas permeation -350° to +500° F 4 Seats, Diaphragms Low Temp Nitrile LTN Petroleum, low temperature -65° to +225° F O-Rings, Diaphragms Multi-Nylon MN Petroleum, abrasion, water, steam 100° to +250° F Seats