A Flange Gasket is a type of gasket made to fit between two sections of pipe that are flared to provide a higher surface area. They come in a variety of sizes and are categorized by their inside diameter and their outside diameter.  Flange Gaskets are mechanical seals used in fluid processing and handling equipment to prevent process fluids from escaping and contaminants from entering sensitive areas. Due to the critical function they serve, it is essential to choose the right one for a given system. The material of a Flange Gasket significantly influences how it performs in the intended application. However, given the broad range of Flange Gasket material options available, some companies may find it challenging to pick the one for their needs. Contact National Pipeline Supplies and we can help you with choosing the correct Flange Gasket.
 
 

The 3 types of Flange Gaskets

 
Non-Metallic Metallic  Semi-Metallic
Compressed Non-Asbestos Fibre Gasket (CNAF) Oval Ring Gasket Spiral Wound Gaskets
PTFE Gasket Octagonal Ring Gasket Camprofile Gaskets
Rubber Gasket   Metal Jacketed Gasket
 
 
 

Flange Gasket by ProjectMaterials

 

Non-Metallic Flange Gaskets are used in low pressure, low temperature and non-critical service applications. These are supplied as a Ring Gasket for Raised Face Flanges and a Full Face Flange Gasket for Utility or Water Works Service in 150# and 300# ratings. These Flange Gaskets are made from a soft material to seat in the Grooves of the Flange Face.

Metallic Flange Gaskets or Ring Type Joint Flange Gaskets are an all metal Flange Gasket made from Carbon Steel, Stainless Steel or other Exotic Alloy and is commonly called a RTJ Gasket. The RTJ Flange Gaskets are designed to be used in high pressure, high temperature critical applications. The RTJ Flange Gasket fits into either an oval or rectangular cut groove cut into the face of the mating Flanges. When tightened these Flange Gaskets are squeezed into the grooves and will provide a strong and long lasting seal at the Flanged connection.

Semi-Metallic Flange Gaskets or Composite Flange Gaskets are a combination of metal and non-metal materials based on product and service requirements. The most widely used is the Spiral wound Flange Gasket, it is suitable for a wide range of temperature and pressure classes. Normally a filler of Graphite or PTFE combined with a Stainless Steel or other Alloy is formed into a spiral winding with a metal outer ring to seal the Flanged joint when compressed.

 

Key Selection Considerations for Flange Gasket Materials

When choosing a Flange Gasket material, there are several factors to keep in mind to ensure the one chosen is appropriate for the intended application. Some of the key considerations are:

  • Temperature: what temperature range is it expected to withstand?
  • Pressure: what pressure range is it expected to withstand?
  • Media: what materials will it be exposed to? (e.g. are the process fluids abrasive or corrosive?)
  • UV and ozone exposure: will it be exposed to UV radiation and ozone?
  • Product standards: is it subject to any industry-specific product requirements? (e.g. does it need EMI shielding properties?)
  • Industry standards: is it subject to any other industry-specific standards? (e.g. does it need to meet ASTM, UL, or Mil-spec requirements?)

 

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