High-Reliability Isolation Gasket for Services Where Failure Cannot Be Accepted
The FIK 600-VCS VCS very critical service flange insulation gasket kit is a significant reliability gasket used for both insulation and typical sealing uses in very critical services. The central big gasket is made of insulation material such as G10 with a metallic SS 316L core. The VCS very critical service flange insulation gasket kit is suitable in all services as much as and as well as ANSI 2500# and API 15,000 PSI. The VCS High Pressure Flange Insulation Gasket Kit is ideal for service where the cost of gasket malfunction cannot be accepted.
A VCS very critical service flange insulation gasket kit — FIK 600-VCS — is a high-reliability flange isolation gasket built for services where the cost of gasket failure cannot be accepted. The central gasket retainer is a G10 glass-reinforced epoxy laminate bonded with an SS 316L metallic core, and the seal is a spring-energized PTFE ring seated in the retainer groove.
Unlike a standard phenolic or neoprene faced isolation gasket, the VCS very critical service flange insulation gasket kit uses a pressure-triggered sealing system. Because the seal is pressure-energized rather than relying on bolt load alone, the gasket demands far less bolt stress to seal than a conventional isolation gasket. Lower bolt stress means lower flange stress, lower bolt stress and less risk of over-compression at the joint.
The VCS flange insulation gasket kit inner diameter is matched to the flange bore to remove turbulent flow and flange face corrosion, and the seal components are generally replaceable in the reusable gasket retainer. It can be supplied for raised face, full face and ring type joint flanges — one kit covers all three flange geometries, in all ANSI, ASME B16.5 and AWWA sizes.
By using high-quality materials and a professional sealing design, the VCS very critical service flange insulation gasket kit delivers the greatest safety and consistency in the most challenging, hazardous conditions. It is used for cathodic protection, insulation between dissimilar metals to prevent galvanic corrosion, and wellhead isolation from interconnected flow lines.
The table below defines the fit, function and limits of the FIK 600-VCS kit. Confirm the exact flange size, pressure class, bore and seal material on the enquiry.
| Specification | Value |
|---|---|
| Model | FIK 600-VCS |
| Retainer Material | G10 glass-reinforced epoxy laminate (standard); G11 available |
| Metallic Core | SS 316L (standard); SS 304 or super duplex S31803 on request |
| Seal Type | Spring-energized PTFE ring (standard); Viton O-ring available |
| Pressure Rating | Up to ANSI 2500# and API 15,000 PSI |
| Flange Compatibility | Raised face (RF), full face (FF) and ring type joint (RTJ) |
| Standard Thickness | Per ANSI class and bore — confirmed on enquiry |
| Sizes | ASME B16.5, AWWA; other standards on request |
| Isolation Sleeves | GRE (G10 / G11), Nomex, Mylar |
| Isolation Washers | G10, G11, Mylar, Nomex, Mica |
| Metallic Washers | ZPS, HCS, SS 316, SS 304 |
| Primary Function | Cathodic protection, galvanic corrosion protection, sealing in very critical service |
| Custom Gaskets | Available to customer drawing |
The FIK 600-VCS kit is built from six matched components. Each component plays a specific role in sealing the joint and breaking every electrical path through the flange connection.
Central Big Gasket Retainer
The big gasket retainer is usually a G10 gasket bonded with an SS 316L metal core; sometimes the metal core is SS 304 or super duplex S31803. Because of its exclusive pressure-triggered sealing system, the gasket demands far less bolt stress to seal than other gaskets. The VCS insulation gasket inner diameter is matched to the flange bore to remove turbulent flow and flange face corrosion. The seal components are generally replaceable in the reusable gasket retainer.
PTFE (Teflon) Spring-Energized Seal
The VCS very critical service flange insulation gasket kit includes a PTFE (Teflon) spring-energized seal — or optionally a rubber elastomeric O-ring — seated in an insulating laminate of the big central gasket retainer and permanently bonded to the high-strength central gasket. The encapsulation of PTFE in the seal groove eliminates creep and cold flow.
Isolation Washers
The isolation washer materials can be G10, G11, Mylar, Nomex, Mica or other materials. The isolation washers sit between the steel washer and the flange face and break the electrical path around the bolt.
Metallic Washers
The metallic washers of the VCS flange insulation gasket kit can be zinc-plated carbon steel washer (ZPS), HCS (hardened coated steel), or stainless steel such as SS 316 and SS 304. The metallic washer spreads the bolt load and prevents the isolation washer from being crushed.
Isolation Sleeves
The isolation sleeves of the VCS flange insulation gasket kit can be Mylar, G10, G11, G7 or Mica. The sleeve sits inside the bolt hole and prevents the bolt shank from contacting the flange, breaking the electrical path through the bolt hole.
Complete Matched Kit
Gasket, sleeves, isolation washers and metallic washers are supplied together as a matched set — one purchase order, one supplier, one quality standard. This ensures every component meets the same isolation and pressure rating for the joint.
The FIK 600-VCS kit is available in a range of materials for the core, the seal, the isolation sleeves and the metallic washers. Each material is selected for a different combination of pressure, temperature, chemical resistance and electrical resistance.
The core of each central gasket is made of annealed 316 stainless steel. Other metals including Duplex and Inconel are available upon special order.
NEMA Grade G-10 Glass-Reinforced Epoxy (GRE) Laminate
The standard retainer material for the FIK 600-VCS kit. High mechanical strength, low water absorption, excellent electrical insulation for general very critical service.
| Property | Value |
|---|---|
| Compressive Strength | 65 KSI |
| Dielectric Strength | 750–800 V/mil |
| Max Continuous Operating Temp | 150 °C |
| Water Absorption | 0.05 % |
| Flexural Strength | 65 KSI |
| Tensile Strength | 50 KSI |
| Shear Strength | 22,000 lb |
NEMA Grade G-11 Glass-Reinforced Epoxy (GRE) Laminate
Higher temperature rating than G10, with improved thermal and chemical resistance. Selected for refinery and petrochemical service where the joint runs hotter than 150 °C.
| Property | Value |
|---|---|
| Compressive Strength | 50 KSI |
| Dielectric Strength | 500 V/mil |
| Max Continuous Operating Temp | 202 °C |
| Water Absorption | 0.085 % |
| Flexural Strength | 57 KSI |
| Tensile Strength | 41 KSI |
| Bond Strength | 2,200 lb |
| Shear Strength | 21,200 lb |
Teflon Ring (Spring-Energized Teflon Ring)
Spring-energized Teflon ring is recommended for all environments. The encapsulation of PTFE in the seal groove eliminates creep or cold flow, and the spring keeps radial load on the seal even under pressure cycling.
Viton Sealing Ring
Viton is a general-purpose oilfield elastomer. Viton sealing ring has excellent resistance to aliphatic hydrocarbons, glycols and H2S, and good resistance to aromatic hydrocarbons. Selected where the process fluid is not compatible with PTFE.
GRE Standard — G10 / G11
GRE (glass-reinforced epoxy) tubing mainly refers to G10 and G11. Suitable for continuous exposure to 150 °C. This material is an epoxy laminate that offers excellent resistance to crushing, cracking, breaking and thread pinch.
NOMEX High Temperature Sleeve
Nomex is a high-temperature sleeve material manufactured from solid organic polymer. Suitable for temperatures up to 230 °C — used where GRE sleeves would exceed their continuous temperature limit.
Mylar® Spiral Wound Sleeve
Spiral wound Mylar® is a general-purpose sleeve material recommended for bolting applications with flange temperatures below 150 °C. Low cost, high dielectric strength, easy to install.
Isolating Steel Washers
The FIK 600-VCS kit is specified where a bolted flange joint must be sealed and electrically isolated at the same time, and where the cost of gasket malfunction cannot be accepted. The VCS kit covers more applications than a standard isolation gasket because it fits raised face, full face and RTJ flanges with the same construction.
Typical applications include cathodic protection, insulation between dissimilar metals to prevent galvanic corrosion, and wellhead isolation from interconnected flow lines. The kit is also used to seal and isolate valve assemblies, Christmas tree connections, pump connections, compressor connections, tanks and heat exchangers with sacrificial anodes.
The VCS very critical service flange insulation gasket kit offers very high reliability sealing and insulation for all critical services. It seals and insulates at all pressures up through ANSI 2500# and API 15,000 PSI, and tolerates severe service conditions including large bending moments, vibration, temperature and pressure cycling.
The FIK 600-VCS kit is available in ASME B16.5 dimensions from Class 150 through Class 2500. Each pressure class has its own bolt pattern, flange OD and gasket bore. Confirm the exact dimensions against your flange drawing before ordering.
Dimensions of Class 150 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 150.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 89 | 60.5 | 4 | 15.9 | Matched to bore |
| 1" | 108 | 79.2 | 4 | 15.9 | Matched to bore |
| 2" | 152 | 120.7 | 4 | 19.1 | Matched to bore |
| 3" | 190 | 152.4 | 4 | 19.1 | Matched to bore |
| 4" | 229 | 190.5 | 8 | 19.1 | Matched to bore |
| 6" | 279 | 241.3 | 8 | 22.2 | Matched to bore |
| 8" | 343 | 298.5 | 8 | 22.2 | Matched to bore |
| 10" | 406 | 362.0 | 12 | 25.4 | Matched to bore |
| 12" | 483 | 431.8 | 12 | 25.4 | Matched to bore |
| 14" – 24" | Full range available — confirm on enquiry | ||||
Dimensions of Class 300 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 300.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 95 | 66.7 | 4 | 15.9 | Matched to bore |
| 1" | 124 | 88.9 | 4 | 19.1 | Matched to bore |
| 2" | 165 | 127.0 | 8 | 19.1 | Matched to bore |
| 3" | 210 | 168.3 | 8 | 22.2 | Matched to bore |
| 4" | 254 | 200.0 | 8 | 22.2 | Matched to bore |
| 6" | 318 | 269.9 | 12 | 22.2 | Matched to bore |
| 8" | 381 | 330.2 | 12 | 25.4 | Matched to bore |
| 10" | 445 | 387.4 | 16 | 28.6 | Matched to bore |
| 12" | 521 | 450.9 | 16 | 31.8 | Matched to bore |
| 14" – 24" | Full range available — confirm on enquiry | ||||
Dimensions of Class 600 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 600.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 95 | 66.7 | 4 | 15.9 | Matched to bore |
| 1" | 124 | 88.9 | 4 | 19.1 | Matched to bore |
| 2" | 165 | 127.0 | 8 | 19.1 | Matched to bore |
| 3" | 210 | 168.3 | 8 | 22.2 | Matched to bore |
| 4" | 273 | 215.9 | 8 | 25.4 | Matched to bore |
| 6" | 356 | 292.1 | 12 | 28.6 | Matched to bore |
| 8" | 419 | 349.3 | 12 | 31.8 | Matched to bore |
| 10" | 508 | 431.8 | 16 | 34.9 | Matched to bore |
| 12" | 559 | 489.0 | 20 | 34.9 | Matched to bore |
| 14" – 24" | Full range available — confirm on enquiry | ||||
Dimensions of Class 900 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 900.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 121 | 82.6 | 4 | 22.2 | Matched to bore |
| 1" | 149 | 101.6 | 4 | 25.4 | Matched to bore |
| 2" | 216 | 165.1 | 8 | 25.4 | Matched to bore |
| 3" | 241 | 190.5 | 8 | 25.4 | Matched to bore |
| 4" | 292 | 235.0 | 8 | 31.8 | Matched to bore |
| 6" | 381 | 317.5 | 12 | 34.9 | Matched to bore |
| 8" | 470 | 393.7 | 12 | 41.3 | Matched to bore |
| 10" | 546 | 469.9 | 16 | 41.3 | Matched to bore |
| 12" | 610 | 533.4 | 20 | 41.3 | Matched to bore |
| 14" – 24" | Full range available — confirm on enquiry | ||||
Dimensions of Class 1500 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 1500.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 121 | 82.6 | 4 | 22.2 | Matched to bore |
| 1" | 149 | 101.6 | 4 | 25.4 | Matched to bore |
| 2" | 216 | 165.1 | 8 | 25.4 | Matched to bore |
| 3" | 267 | 203.2 | 8 | 31.8 | Matched to bore |
| 4" | 311 | 241.3 | 8 | 34.9 | Matched to bore |
| 6" | 394 | 317.5 | 12 | 41.3 | Matched to bore |
| 8" | 483 | 393.7 | 12 | 47.6 | Matched to bore |
| 10" | 584 | 482.6 | 12 | 54.0 | Matched to bore |
| 12" | 673 | 571.5 | 16 | 54.0 | Matched to bore |
| 14" – 24" | Full range available — confirm on enquiry | ||||
Dimensions of Class 2500 VCS flange insulation gasket kit for ASME B16.5 in millimetres. Bolt pattern follows ASME B16.5 Class 2500.
| NPS | Flange OD (mm) | Bolt Circle (mm) | Bolt Holes | Bolt Hole Dia. (mm) | Gasket Bore (mm) |
|---|---|---|---|---|---|
| 1/2" | 133 | 88.9 | 4 | 22.2 | Matched to bore |
| 1" | 159 | 108.0 | 4 | 25.4 | Matched to bore |
| 2" | 235 | 171.5 | 8 | 28.6 | Matched to bore |
| 3" | 305 | 228.6 | 8 | 34.9 | Matched to bore |
| 4" | 356 | 273.1 | 8 | 41.3 | Matched to bore |
| 6" | 483 | 368.3 | 8 | 54.0 | Matched to bore |
| 8" | 552 | 438.2 | 12 | 54.0 | Matched to bore |
| 10" | 673 | 539.8 | 12 | 66.7 | Matched to bore |
| 12" | 762 | 619.1 | 12 | 66.7 | Matched to bore |
| 14" | Confirm on enquiry | ||||
Factory-Direct Supply
Ningbo Kaxite Sealing Materials Co., Ltd produces VCS very critical service flange insulation gasket kits at its own facility in Zhenhai District, Ningbo, Zhejiang, China — factory-direct supply without trading-company mark-up.
SS 316L Core as Standard
SS 316L is standard, with SS 304 and super duplex S31803 available on request. Every metallic core is bonded to the G10 or G11 retainer under controlled pressure.
PTFE or Viton Seal
Spring-energized PTFE seal as standard, with Viton O-ring available for services where the process fluid is not compatible with PTFE. Both seals eliminate cold flow.
One Kit Fits RF, FF and RTJ
Unlike a Type E or Type F gasket, the VCS kit can be supplied for raised face, full face and ring type joint flanges from the same construction — one source for a mixed critical service order.
Up to API 15,000 PSI
Seals and insulates at all pressures up through ANSI 2500# and API 15,000 PSI. Pressure-triggered sealing means less bolt load is needed for the same sealing performance.
Material Certificates on Request
Material certificates can be provided on request so your QA department can verify grade and properties before installation. G10 and G11 laminates meet NEMA grade requirements.
What is a VCS very critical service flange insulation gasket kit?
A VCS very critical service flange insulation gasket kit — FIK 600-VCS — is a high-reliability flange isolation gasket built for services where the cost of gasket failure cannot be accepted. The central gasket retainer is a G10 glass-reinforced epoxy laminate bonded with an SS 316L metallic core, and the seal is a spring-energized PTFE ring seated in the retainer groove. The kit seals and electrically isolates a bolted flange joint at the same time, and is rated up to ANSI 2500# and API 15,000 PSI.
What is the difference between a VCS gasket kit and a standard flange insulation gasket kit?
A VCS kit uses a pressure-triggered sealing system with a G10 retainer bonded to an SS 316L metallic core, plus a spring-energized PTFE seal. This gives it far higher pressure and temperature capability, better resistance to CO2 and H2S, and greater tolerance to bending moments, vibration and pressure cycling than a standard phenolic or neoprene faced isolation gasket. A standard kit is usually sufficient for water, gas and oil service at lower pressures; a VCS kit is specified for wellhead, Christmas tree, compressor and high-pressure RTJ joints.
What pressure rating does the VCS flange insulation gasket kit support?
The VCS very critical service flange insulation gasket kit is suitable for all services up to ANSI 2500# and API 15,000 PSI. Sizes cover ASME B16.5 and AWWA. The kit can be used on raised face, full face and RTJ ring joint flanges.
What materials are used in the VCS flange insulation gasket kit?
The central gasket retainer is G10 glass-reinforced epoxy laminate bonded with an SS 316L metallic core; SS 304 and super duplex S31803 are available on request. The seal is a spring-energized PTFE ring as standard, with Viton O-ring available. Isolation sleeves can be GRE (G10 or G11), Nomex or Mylar. Isolation washers can be G10, G11, Mylar, Nomex or Mica. Metallic washers can be ZPS, HCS, SS 316 or SS 304.
Where is the VCS very critical service flange insulation gasket kit used?
The VCS kit is used for cathodic protection, insulation between dissimilar metals to prevent galvanic corrosion, and wellhead isolation from interconnected flow lines. It is also used to seal and isolate valve assemblies, Christmas tree connections, pump connections, compressor connections, tanks and heat exchangers with sacrificial anodes. It can mate mismatched ring joint to raised face flanges and remove fluid trap corrosion between RTJ flanges where high concentrations of CO2, H2S and other aggressive hydrocarbon media exist.
What standards does the VCS flange insulation gasket kit meet?
The VCS very critical service flange insulation gasket kit is made to ASME B16.5 and AWWA sizes. Custom gaskets to customer drawing and other flange standards such as API, BS, DIN and AS are also available on request.
Send us your specification — we reply within 24 hours
Tell us the flange size, the pressure class (ANSI 150 to 2500, or API 15,000 PSI), the flange type (raised face, full face or RTJ), the retainer material (G10 or G11), the metallic core (SS 316L, SS 304 or super duplex S31803), the seal type (spring-energized PTFE or Viton), the standard (ASME B16.5 or AWWA), and the quantity. If you are not sure whether you need the VCS kit or a standard Type E / Type F / Type D isolation gasket, send us the flange drawing and the process conditions and we will match the correct kit.
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No 432 Zhenhai Middle Road, Luotuo Street, Zhenhai District, Ningbo City, Zhejiang China
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