Flange Insulating Gasket Sets — Sealing and Electrical Isolation for Oil, Gas, Water, Refinery and Chemical Plant Piping
Flange Insulating Gasket Sets are used to solve the sealing and insulating problems of flanges, and to control losses due to corrosion and leakage of pipelines. They are widely used to seal flanges and control stray electric currents in piping at oil, gas, water, refinery, and chemical plants, to increase the effectiveness of cathodic protection systems.
Kaxite produces three standard insulating gasket types — Type E (full face gasket), Type F (ring type gasket) and Type D (RTJ gasket) — in five standard retainer materials: plain phenolic, neoprene faced phenolic, silicone glass G-7, epoxy glass G-10 and epoxy glass G-11.
A Flange Insulating Gasket Set is a complete matched set used to solve the sealing and insulating problems of flanges, and to control losses due to corrosion and leakage of pipelines. The set normally contains a central insulating gasket, one insulating sleeve per bolt, two insulating washers per bolt and two plated steel washers per bolt. Together these components seal the joint and break every electrical path through it — across the flange faces, through the bolt holes and around the bolts.
Flange Insulating Gasket Sets are widely used to seal flanges and control stray electric currents in piping at oil, gas, water, refinery and chemical plants, to increase the effectiveness of cathodic protection systems. By breaking the electrical circuit between two adjacent flanges, the set prevents galvanic corrosion between dissimilar metals and preserves the cathodic protection current on the pipeline.
Kaxite produces a complete range of Flange Insulating Gasket Sets in three standard gasket geometries and five retainer materials. The same set design can be supplied for water, gas, oil and petrochemical pipeline isolation joints, in a single order, so a mixed pipeline system can be protected with a consistent isolation standard throughout.
Flange Insulating Gasket Sets are used for five main application reasons. All five reasons relate to controlling the flow of electrical current through the pipeline so that the cathodic protection system works more effectively.
Flange Insulating Gasket Sets are produced in three standard gasket geometries. The geometry is set by the flange type, not by the retainer material — so the same G10 or G11 retainer can be cut into any of the three types.
Type E (Full Face Gasket)
This gasket kit provides complete protection of both flange faces. The gasket has same outside diameter of flanges. This feature will prevent collection of foreign matter between the flange faces to ensure complete cathodic isolation.
Type F (Ring Type Gasket)
This gasket is manufactured to fit only the raised face surface of the flanges. Outside diameter of the gasket is designed to be slightly less than the inside diameter of the bolt circle. It is recommended that the flanges be wrapped to prevent foreign material from "shorting out" the flanges.
Type D (RTJ Gaskets)
To fit RTJ flanges. Type D insulating ring joint gaskets seat in the ring groove of a ring type joint flange. They can be produced according to ASME and API flange standards, in oval or octagonal shape, and customised to customer drawing.
Flange Insulating Gasket Sets are available in five standard retainer materials. Each material has a different combination of dielectric strength, compressive strength, water absorption, insulating resistance, flexural strength and operating temperature. The table below compares the five materials side by side.
| Property | Plain Phenolic | Neo-faced Phenolic | Silicone Glass G-7 | Epoxy Glass G-10 | Epoxy Glass G-11 |
|---|---|---|---|---|---|
| Dielectric strength (Volts/mil) | 500 | 500 | 350–400 | 550 | 550 |
| Compressive strength (psi) | 25,000 | 25,000 | 40,000 | 50,000 | 50,000+ |
| Water absorption (%) | 1.6 | 1.6 | 0.07 | 0.10 | 0.10 |
| Insulating resistance (Megohms) | 40,000 | 40,000 | 2,500 | 200,000 | 200,000 |
| Flexural strength (psi) | 22,500 | 22,500 | 27,000 | 45,000 | 43,000 |
| Operating temp (°F) | -65 to +220 | -65 to +175 | -292 to +450 | -292 to +280 | -292 to +349 |
| Operating temp (°C) | -54 to +104 | -54 to +79 | -180 to +232 | -180 to +138 | -180 to +176 |
Flange Insulating Gasket Sets are available with five standard seal element materials. The seal element is the primary sealing component of the gasket — it must be compatible with the process fluid and resistant to the operating temperature.
| Unit | Nitrile | Viton | Teflon | Neoprene | EPDM |
|---|---|---|---|---|---|
| Temperature range (°F) | -65 to +250 | -20 to +350 | -292 to +450 | -40 to +248 | -65 to +248 |
| Temperature range (°C) | -54 to +121 | -29 to +177 | -180 to +232 | -40 to +120 | -54 to +120 |
The table below summarises the fit, function and options of the Kaxite Flange Insulating Gasket Set range. Confirm the exact flange size, pressure class, gasket type, retainer material and seal element on the enquiry — custom sets to drawing are accepted.
350 – 550 Volts/mil depending on retainer material
25,000 – 50,000+ psi depending on retainer material
2,500 – 200,000 Megohms depending on retainer material
-180 °C to +232 °C depending on retainer material
What are Flange Insulating Gasket Sets?
Flange Insulating Gasket Sets are complete matched sets used to solve the sealing and insulating problems of flanges, and to control losses due to corrosion and leakage of pipelines. They are widely used to seal flanges and control stray electric currents in piping at oil, gas, water, refinery and chemical plants, to increase the effectiveness of cathodic protection systems. A set normally contains the central insulating gasket, one insulating sleeve per bolt, two insulating washers per bolt and two plated steel washers per bolt.
What are Flange Insulating Gasket Sets used for?
Flange Insulating Gasket Sets are used for five main application reasons: to limit the extent and cost of cathodic protection current to only those pipes that need protection, to electrically split up long pipelines into distinctive cathodic protection systems, to isolate a pipeline so that cathodic protection or stray electricity currents do not cause increased corrosion or a hazard, to isolate piping systems where dissimilar metals are present, and to eliminate static loading charge transfer in discharge or loading operations at oil storage terminals.
What types of Flange Insulating Gasket Sets are available?
Kaxite produces three standard types. Type E (full face gasket) provides complete protection of both flange faces — the gasket has the same outside diameter as the flange, which prevents collection of foreign matter between the flange faces and ensures complete cathodic isolation. Type F (ring type gasket) is manufactured to fit only the raised face surface of the flange, with outside diameter slightly less than the inside diameter of the bolt circle. Type D (RTJ gasket) fits RTJ flanges and can be produced according to ASME and API flange standards.
What retainer materials are available for Flange Insulating Gasket Sets?
Retainer materials include plain phenolic, neoprene faced phenolic, silicone glass G-7, epoxy glass G-10 and epoxy glass G-11. Each material has a different combination of dielectric strength, compressive strength, water absorption, insulating resistance, flexural strength and operating temperature. G-7 material should not be used with hydrocarbons, not even trace amounts.
What seal element materials are available for Flange Insulating Gasket Sets?
Seal element materials include Nitrile, Viton, Teflon, Neoprene and EPDM. Nitrile service range is -54 to +121 °C. Viton service range is -29 to +177 °C. Teflon service range is -180 to +232 °C. Neoprene service range is -40 to +120 °C. EPDM service range is -54 to +120 °C. For KXT-110 and KXT-120 sealing gaskets, both the retainer and the seal element temperature limits should be considered together.
How do you choose the right retainer and seal material?
Choose the retainer material first, based on the process fluid, the operating temperature and the required dielectric strength. Plain phenolic and G-10 are the most common for general water, gas, oil and petrochemical service. G-11 is selected for higher temperature service. G-7 is selected for very high temperature dry service, but must not be used with hydrocarbons. Then choose the seal element based on the chemical compatibility and temperature limit. For KXT-110 and KXT-120 sealing gaskets, both the retainer and seal element temperature limits must be considered together.
Send us your specification — we reply within 24 hours
Tell us the flange size, the pressure class, the gasket type (Type E full face, Type F ring type or Type D RTJ), the retainer material (plain phenolic, neoprene faced phenolic, G-7, G-10 or G-11), the seal element (Nitrile, Viton, Teflon, Neoprene or EPDM), the quantity, and the flange standard (ASME, API, BS, DIN, AS and others). If you are not sure which retainer and seal combination fits your service, send us the flange drawing and the process conditions and we will match the correct set.
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