Your Complete Gasket Selection Guide
Flange gaskets are critical sealing components that prevent leakage at flange connections. Understanding the different gasket types and their properties is essential for successful flange system design and operation.
| Category | Materials | Pressure/Temp Range | Common Flange Faces | Characteristics |
|---|---|---|---|---|
| Non-Metallic | Rubber, PTFE, CNAF, Cork | Low to moderate pressure, up to 300°F | Flat Face, Raised Face | Cost-effective, flexible, good corrosion resistance |
| Semi-Metallic | Spiral Wound, Kammprofile, Metal Jacketed | High pressure/temp, up to 1500°F | Raised Face, Ring Joint | Excellent performance, reusable, higher cost |
| Metallic | RTJ, Corrugated Metal, Flat Metal | Very high pressure/temp, up to 2000°F | Ring Joint Face | Superior performance, maximum reliability, premium cost |
Traditional choice for low-to-moderate pressure applications. EPDM, NBR, and natural rubber are common. Cost-effective and provide good sealing characteristics for most general applications.
Polytetrafluoroethylene (PTFE/Teflon) offers excellent chemical resistance and temperature capability up to 400°F. Ideal for aggressive chemical applications and corrosive environments.
Compressed Non-Asbestos Fiber (CNAF) provides reliable sealing for moderate pressure and temperature applications. Good compatibility with aluminum flanges and standard bolting.
Stainless steel or carbon steel wound with filler material. Excellent for high pressure and high temperature applications. Can be reused multiple times, reducing lifecycle costs.
Metal core with serrated grooves filled with elastomer. Exceptional performance across wide pressure and temperature ranges. Excellent for critical applications.
Non-metallic core wrapped in thin metal shell. Combines sealing reliability with metallic properties. Ideal for high-temperature and high-pressure applications.
Oval or octagonal metal rings designed for ring joint faces. Provide superior sealing for extreme pressure and temperature conditions. Standard in oil and gas applications.
Pure metal construction for maximum durability and temperature performance. Used in applications exceeding 1500°F. Premium cost but unmatched reliability.
Consider what fluid or gas will be conveyed. Aggressive chemicals require PTFE or metal gaskets. Water systems can use rubber or CNAF.
Low pressure/temp: Non-metallic options. Moderate: Semi-metallic. Extreme: Metallic gaskets.
Determine your flange type and face type. Match gasket to flange specification for proper sealing.
Follow applicable standards like ASME B16.21 for gasket materials and dimensions.
Some gaskets (especially spiral wound) can be reused if not damaged. Most rubber and elastomer gaskets should be replaced. Always inspect before reuse.
Fugitive emissions are leaks of fluid into the atmosphere. Proper gasket selection and installation prevent fugitive emissions, protecting the environment and complying with regulations.
Visible leaks, weeping, discoloration, hardening, or cracking indicate gasket failure. Replace immediately to prevent environmental contamination or system damage.
Full-face gaskets cover the entire flange face. Ring gaskets are smaller and fit only the bolt circle. Ring gaskets are more common on pressure vessels; full-face on lower-pressure applications.
Choosing the right gasket is crucial for flange system performance. At Texas Flange, we help engineers select the optimal gasket materials and types for their applications.
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