Nov 1, 2024

A flange gasket is a mechanical seal positioned between two flanges to prevent the leakage of fluids or gases within a piping system. These gaskets are available in various materials and configurations, depending on their intended use and operational requirements. In this blog, we will examine the different types of flange gaskets, their applications, and the factors to consider when selecting the appropriate gasket for your specific application.
Applications of Flange Gaskets
Flange gaskets are integral to maintaining a secure, leak-proof seal between flange faces in pipelines. These gaskets are designed to prevent the escape of process fluids or gases, such as water, oil, chemicals, or steam, thus maintaining the efficiency and safety of the system. Furthermore, they play a critical role in protecting personnel by preventing exposure to hazardous, corrosive, or pressurized substances.
Common Types of Flange Gaskets
The selection of the appropriate flange gasket is determined by the operational conditions and the characteristics of the pipeline. The following are the most commonly used types of flange gaskets:
- Full-face gaskets Full-face gaskets cover the entire flange surface and include bolt holes that correspond to those on the flange. These gaskets are manufactured from materials such as PTFE and flexible graphite, providing versatile sealing solutions for a range of applications.
- Ring-type-joint (RTJ’s) gaskets Typically fabricated from metals like stainless steel, RTJ’s are designed to fit within the bolt circle into the groove of a flange. These gaskets are ideal for high-pressure applications, as they offer robust sealing capabilities in such environments.
- Spiral-wound gaskets Spiral-wound gaskets consist of alternating layers of metal windings and filler materials, such as graphite or PTFE. They are commonly used in applications where high pressures and temperatures are present, offering excellent resilience and sealing performance.
- Kammprofile gaskets Kammprofile gaskets feature serrated metal cores with a soft sealing material, such as graphite or PTFE, on both sides. These gaskets are particularly suited for high-temperature and high-pressure applications, where a reliable seal is required under extreme conditions.
- Jacketed gaskets Jacketed gaskets consist of a soft filler material encased in a metal jacket, providing a durable seal for applications that involve elevated temperatures, such as heat exchangers. These are typically used in non-critical process media applications.
Key Considerations for Selecting a Flange Gasket
When selecting a flange gasket, it is essential to consider several critical factors to ensure reliable performance and longevity. These include:
- Fluid Type
The gasket material must be compatible with the fluid or gas being transported. For example, corrosive chemicals may require a gasket such as Durlon® 9000 (PTFE), while potable water applications may require an NSF/ANSI 61-compliant gasket, such as Durlon® 7910. - Temperature and Pressure
The operating temperature and pressure of the system are key factors in gasket selection. High-pressure, high-temperature applications demand gaskets specifically engineered for these conditions, such as Durlon® ETG. - Flange Load
The gasket must be suitable for the bolt load applied to the flange. In situations with low bolt loads, a low-seating stress gasket, such as Durlon® CFG, may be required. - Compliance with Emissions Regulations
Depending on the regulatory requirements of your industry, it may be necessary to select gaskets that comply with fugitive emissions standards.
Common Causes of Flange Gasket Failure
Despite their durability, flange gaskets can fail under certain conditions. Common causes of gasket failure include:
- Uneven bolt load distribution
- Incorrect bolt torque (over or under-tightened)
- Misaligned flanges
- Excessive loads or vibrations
- Incorrect gasket material or size
- Flange surface contamination or damage
These issues can often be mitigated through proper installation techniques, adherence to recommended bolt torques, and selecting the appropriate gasket for the application.
Flange gaskets are vital components in industrial pipeline systems, providing critical sealing solutions for a variety of applications. By understanding the types of gaskets available and considering key factors such as fluid compatibility, temperature, pressure, and regulatory compliance, you can ensure the long-term performance and reliability of your system. For more information on Durlon® flange gaskets and other sealing solutions, please contact us directly.