Flange Insulation Gasket Kit

A complete flange insulation kit from Jade Special Metals comprises four component groups. Each component is precision-manufactured to ensure the electrical resistance properties are balanced for the intended service location:

In order to achieve optimum results, it is essential that all four components are correctly matched — the electrical resistance properties must be balanced for the purpose and location in the insulation system, and all components must be manufactured from insulating materials with high compressive strength and good dimensional stability.

There are 4 main gasket types of Flange Insulation Kit. Each Type uses the same bolt sleeve, washer, and back-up washer components — only the central flange gasket differs. Selection is based on the flange face style and installation access:

Full Face Flanges

• • • Type E — Full Face Kit
      The gasket has the same outside diameter as the flange with precision bolt holes, allowing bolts to slide through. Full-face coverage minimises the risk of electrical bridging and prevents foreign matter ingress between the mating faces. Best overall electrical isolation. Requires flange separation for installation.
      Compliant with: ANSI B16.5, API, BS, DIN

   

  • • Ring Type Joint (RTJ) Flanges
      Type D — RTJ Kit
      The gasket is an insulating oval ring specifically designed to fit into the ring groove of RTJ (ring-type-joint) flanges. Available in oval and octagonal profiles. Manufactured from fabric-reinforced phenolic; complies with ASME B16.20.
      Compliant with: ANSI B16.5, API, BS, DIN, ASME B16.20

   

  • • Raised Face Flanges
      Type F — Raised Face / IBC Kit
      The gasket sits inside the bolt circle (IBC) of the flange, resting on the raised face only. Not as thorough as Type E for electrical bridging protection, but considerably easier to install — flange separation is not required. Suitable for maintenance replacements.
      Compliant with: ANSI B16.5, API, BS, DIN

   

  • Full Face or IBC — Enhanced Sealing
    Type G — Elastomeric Seal Kit
    Available in both Full Face and IBC versions. Incorporates an elastomeric sealing ring bonded into the gasket faces, providing superior sealing performance alongside electrical isolation. With the correct choice of insulating materials, Type G kits achieve greater chemical and temperature resistance than standard phenolic kits.
    Compliant with: ASME, API, EN, BS, DIN

Jade Special Metals supplies flange insulation kits in a range of insulating materials to suit standard, elevated-temperature, cryogenic, fire-safe, and chemically aggressive service conditions:

Standard — Neoprene-Faced Phenolic

The standard kit uses a Neoprene-faced phenolic central gasket — the Neoprene facing provides an effective sealing surface; the phenolic core provides the necessary electrical isolation and compressive strength. Bolt sleeves are Mylar; washers are reinforced phenolic; back-up washers are zinc-plated carbon steel.

• Basic pipeline flange isolation in oil, gas, and other processing application.
• Compatible with ASME, API, EN, BS, and DIN flange specifications
• Flange insulation in conjunction with cathodic protection
• Isolating dissimilar metal flange and piping systems
• Temperature Range: −20°C to +100°C

Type G-11 — Higher Temperature GRE Composite

Follows the same highly effective design as G-10 but uses G-11 GRE composite material for extended temperature rating. The G-11 gasket features a modified u-shaped TFM seal energised with a phynox spring, chosen for its advanced mechanical properties and improved resistance to permeation, bonded to a high-strength G-11 GRE and 316L SS composite core.

• Critical oil and gas applications requiring higher temperature capability
• Compatible with the same broad range of hydrocarbon and corrosive media as G-10
• Suitable for ring joint and raised face flanges
• Temperature Range: −150°C to +150°C (higher temp ratings vs G-10 in certain conditions)

Type FS — Fire Safe Isolation Gasket

Premium fire-safe isolation gasket utilising a triple seal design: a coated metallic core housing a modified u-shaped TFM seal energised with a phynox spring, flanked by two kammprofile sections (inner faced with modified PTFE, outer with proprietary high-temperature material). G-11 GRE faces the outer section of the metallic core. Kit includes FS gasket, G-11 bolt sleeves, high-temperature isolating washers, and 316 SS back-up washers.

• Maintains sealing performance after API 6FB 3rd Edition fire test
• Combines exceptional chemical compatibility and electrical isolation
• Compatible with natural gas, oils, hydrocarbons, and corrosive media
• Suitable for ring joint and raised face flanges
• Temperature Range: −45°C to +180°C

Type GRE — G-10 Carrier with PTFE Sealing Faces

The GRE gasket consists of a G-10 glass reinforced carrier with two modified PTFE sealing faces. Proprietary machining of the carrier ensures correct location of the sealing faces, with depth and profile designed to achieve correct compression and groove fill. Kit includes GRE gasket, G-10 bolt sleeves, G-10 washers, and zinc-plated or 316 SS back-up washers.

• Suitable for ASME, API, EN, BS, and DIN flange specifications
• Electrical isolation in conjunction with cathodic protection
• Isolating dissimilar metals to prevent galvanic corrosion
• Temperature Range: −128°C to +120°C

G-10 and G-11 offer the best combination of dielectric strength and low water absorption for critical and offshore service. Phenolic is the most economical option for standard pipeline service.

Flange insulation gasket kits are specified across a broad range of critical pipeline and process industries wherever galvanic corrosion, stray electrical currents, or cathodic protection are design considerations:

• Long-distance oil, water, and gas pipelines — electrical isolation at all flanged joints to protect cathodic protection systems
• Offshore installations and subsea pipelines — preventing galvanic corrosion between dissimilar metal flanges in seawater environments
• Oil refinery pipelines — isolation at process flange joints handling volatile hydrocarbons and explosive media
• Petrochemical industry — process piping in acid, alkali, and solvent service where stray currents are a risk
• Sour gas service (H₂S) — NACE MR0175 compatible kits for downhole and surface wellhead pipelines
• LNG and cryogenic pipelines — G-10 and G-11 kits rated to −150°C for liquefied gas service
• Flue gas desulphurisation (FGD) — corrosion-resistant kits in wet scrubber and SO₂ handling systems
• Power generation — electrical isolation in cooling water, steam, and process piping
• Marine exhaust and seawater systems — preventing electrolytic corrosion in seawater heat exchangers
• Chemical processing — isolating flanges in acid reactors, evaporators, and chemical transfer lines

Advantages of JSM Flange Insulation Gasket Kits

• Complete assemblies supplied as ready-to-install kits — all components matched and balanced\
• Wide material range covers −150°C to +180°C service temperatures in a single product family
• Compatible with all major flange standards: ASME B16.5, API, EN, BS, DIN, NORSOK
• Balanced electrical resistance properties across all four kit components for optimum isolation
• High compressive strength materials ensure no creep relaxation under full bolt load
• G-10 and G-11 kits offer 550 V/mil dielectric strength and 0.01% water absorption — ideal for offshore and cryogenic service
• Type FS kit maintains sealing performance after API 6FB 3rd Edition fire test
• 316 SS back-up washers available for corrosive or offshore environments
• Custom sizes, materials, and pressure classes manufactured on request
• Supplied with EN 10204 Type 3.1 Material Test Certificate and ISO 9001:2015 quality documentation
• Compliant with ASTM, ANSI, API, EN, BS, DIN, and NORSOK standards