ASME B16.20 spiral wound gaskets play an essential role in sealing high-pressure and high-temperature environments, especially within steel pipeline systems. These gaskets are constructed by winding together multiple layers of shaped metal strips—often made of stainless steel, nickel alloy, or carbon steel—and flexible filler material such as graphite or PTFE. The resulting concentric spiral structure creates a durable and adaptable seal capable of accommodating surface imperfections in the flanges, as well as compensating for thermal expansion and variations in pressure. This reliability makes spiral wound gaskets a preferred choice for demanding industrial flange applications.This article will focus on the application of ASME B16.20 spiral wound gaskets.
Structural Design of Metal Wound Gaskets：
ASME B16.20 spiral wound gaskets feature a V-shaped metal strip wound concentrically with a soft filler material, forming multiple resilient sealing points. This design creates a spring-like response under compression, allowing the gasket to maintain seal integrity despite fluctuations in temperature and pressure. According to the ASME Boiler and Pressure Vessel Code, Section VIII, the elastic recovery of the metal winding and the plastic deformation of the filler work synergistically to accommodate flange rotation and surface irregularities, preventing leakage through self-compensating mechanisms.
ASME B16.20 Standards：
This Standard covers materials, dimensions,tolerances, and markings for metal ring-joint gaskets, spiral wound metal gaskets, and grooved metal gaskets with covering layers. These gaskets are dimensionally suitable for use with flanges described in reference flange standards ASME B16.5, ASME B16.47, API Specification 6A, and ISO 10423.
This Standard states values in both SI (Metric) and U.S. Customary units. These systems of units are to be regarded separately as standard. Within the text, the U.S. Customary units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, it is required that each system of units be used independently of the other. Combining values from the two systems constitutes nonconformance with the Standard.
Dimensions for Spiral-Wound Gaskets Used With ASME B16.5 Flanges:
The following are the dimensions for ASME B16.20 spiral spiral wound gaskets used with ASME B16.5 flanges.
https://www.zzflange.com/wp-content/uploads/2025/08/Metallic-Gaskets-for-Pipe-Flanges-2.pdf
How Spiral Wound Gaskets Function？
The sealing performance of spiral wound gaskets relies primarily on the combined effects of the metal strip’s springback properties and the sealing characteristics of the filler material. During installation, pressure applied by flange bolts moderately compresses the gasket, forming an initial seal. The V-shaped or W-shaped metal strips function similarly to springs, continuously providing springback force even under temperature fluctuations or pressure changes to ensure the sealing surfaces remain in constant contact.
This gasket structure is specifically engineered to withstand compression and elastic recovery. It automatically adjusts compression levels in response to system pressure fluctuations, maintaining a stable seal. Its excellent vibration and shock resistance also make it particularly suitable for applications involving mechanical vibration or frequent pressure changes.
Owing to its superior elasticity, the spiral wound gasket exhibits a self-tightening effect—as internal pressure increases, the gasket further compresses the gap, enhancing sealing reliability. This characteristic makes it highly trusted in demanding sealing applications across industries such as petroleum, chemical processing, and power generation.
Application Selection: Matching Steel to Service Conditions
Selecting the right steel requires a scientific analysis of the operating environment.
✅ Temperature: Carbon steel is economical for high temperatures in inert environments, but oxidizes rapidly in steam. SS304 is usable up to 800°C, while SS316 is limited to about 750°C due to carbide precipitation. For temperatures beyond this, stabilized grades like 321 or special alloys are mandatory.
✅ Corrosion: The selection is based on corrosion charts and industry standards like NACE MR0175 for sour service. 316SS is often the minimum for chemical environments, with alloys like Hastelloy used for reducing acids (HCl) and Inconel for oxidizing acids (HNO3).
✅ Pressure: The yield strength of the steel determines the maximum seating stress the gasket can withstand without collapsing. Higher strength steels are required for higher pressure Class flanges (e.g., Class 900 and above).
Industrial Applications：
| Industry | Common Applications |
| Oil & Gas | Pipeline flanges, heat exchangers, pressure vessels |
| Petrochemical | Reactors, towers, storage tanks |
| Power Plants | Steam lines, boilers, turbines |
| Marine & Offshore | Ship engine flanges, underwater pipeline joints |
| Chemical Processing | Acid lines, chemical vessels, reactors |
| Food & Pharma | Sanitary pipelines, process vessels (PTFE-filled gaskets used) |
Spiral Wound Gasket Color Chart：
Installation and Best Practices:
1.Proper installation ensures long-term performance:
2.Clean and inspect flange surfaces before assembly.
3.Choose gasket dimensions according to flange standards.
4.Apply even bolt torque in a cross-pattern for uniform compression.
5.Replace gaskets during scheduled maintenance to prevent leakage.
Key Advantages：
•Reliable sealing under high temperature and pressure.
•Elastic recovery to withstand pressure and thermal cycling.
•Wide material options to resist corrosion and chemical attack.
•Reduced maintenance with long service life.
•Compatibility with raised face, flat face, and tongue-and-groove flanges.
Failure Prevention and Maintenance：
Common failures include over-compression (leading to filler extrusion) and thermal creep. Regular inspections using ultrasonic leak detection or thermal imaging can identify early seal degradation. Replace gaskets after 3-5 cycles of disassembly or if surface cracks are observed.
Conclusion：
ASME B16.20 Spiral wound gaskets enhance the safety and longevity of steel flange systems through adaptive sealing and material science. Selecting the right combination of metal and filler materials ensures compliance with international standards (ISO 9001, ASME B16.20) and operational reliability.
Related Articles：
What Is a Spiral Wound Gasket?
How to Install a Gasket on a Flange?
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