Common Valve Packing & Gasket Materials and Their Service Temperatures

Common Valve Packing Materials and Their Service Temperatures

Valve packing materials are selected based on the service conditions, particularly operating temperature. Among the most widely used materials is the flexible graphite packing ring, which can withstand temperatures up to 600°C, making it suitable for high-temperature applications. PTFE packing rings, on the other hand, are limited to 200°C but offer excellent chemical resistance, making them ideal for corrosive environments.

For applications requiring enhanced strength, stainless steel wire reinforced with flexible graphite braided packing provides durability at temperatures up to 600°C. Another option is expanded PTFE graphite tape braided packing, which is suitable for medium-temperature conditions up to 250°C. Traditional materials such as oil-impregnated asbestos rope and graphite-asbestos rope can handle service temperatures of up to 450°C, but due to health and safety concerns, their use is being phased out in many industries.

Common Valve Gasket Materials and Their Service Temperatures

Gasket materials are critical in ensuring leak-free sealing and must be chosen according to their temperature resistance and compatibility with media. Rubber-based gaskets are common in low- to medium-temperature applications. For example, natural rubber performs well between -50°C and 90°C, while neoprene rubber extends the upper limit to 100°C. Nitrile rubber functions between -30°C and 110°C, and styrene-butadiene rubber (SBR) is suitable for temperatures between -30°C and 100°C. EPDM rubber offers good thermal resistance up to 130°C, and fluororubber (FKM/Viton) can withstand more extreme temperatures ranging from -50°C to 200°C.

For higher-temperature applications, asbestos rubber sheets can tolerate up to 300°C, while synthetic fiber rubber gaskets are suitable for conditions between -40°C and 200°C. PTFE gaskets provide reliable sealing up to 200°C with excellent chemical resistance. Composite gaskets, such as low carbon steel combined with flexible graphite, extend service temperatures to 450°C, while SS 304 with flexible graphite can reach 650°C.

Metal-jacketed gaskets combine metals with asbestos rubber for enhanced sealing. For example, pure aluminum sheet (L3) jacketed with asbestos rubber operates up to 200°C, while pure copper (T3) jacketed gaskets reach 300°C. Tin-plated and galvanized copper sheets both extend service up to 400°C, whereas 0Cr18Ni9, 00Cr19Ni10, and 00Cr17Ni14Mo2 jacketed with asbestos rubber are suitable for temperatures up to 500°C.

Spiral wound gaskets are also widely used for their reliability. A 0Cr18Ni9 stainless steel gasket with special asbestos fiber operates up to 500°C, while 0Cr17Ni14Mo2 with flexible graphite tape can withstand 650°C. A 00Cr17Ni14Mo2 with PTFE winding is limited to 200°C but offers chemical compatibility. Serrated composite gaskets provide another option, with 10 or 08 steel combined with flexible graphite operating up to 450°C, 0Cr13 with flexible graphite up to 540°C, SS 304 with flexible graphite up to 650°C, and SS 316 with PTFE limited to 200°C. Finally, PTFE reinforced with glass fiber is suitable for applications ranging from -100°C to 260°C, combining thermal resistance with structural strength.