ISOMAX HPS Flange Insulation Sets

The HPS is a high strength and high reliability flange gasket designed for electrical insulation and sealing in very critical service applications. The gasket is manufactured using a composite seal retainer material bonded to a high integrity metal core, 316 Stainless Steel is standard. The spring energized PTFE seal offers excellent sealability even at low loads.

  • The HPS gasket is a high reliability gasket used for both insulating and general sealing applications
  • The HPS is suitable in all services up to and including ANSI 2500# and API 15,000# classes.
  • Each HPS insulation set comprises one central insulating gasket, one insulation sleeve per bolt and two insulating and two plated steel washers per bolt.





  • Metallic Core: 316 Stainless Steel
  • (Duplex & Inconel available)
  • Gasket Insulating Material: G-10 Glass Reinforced Epoxy (GRE) as standard (G-11 available)
  • Seal Material: Spring-energized PTFE as standard
  • (Viton available)
  • Insulating Sleeve Material: GRE as standard
  • (Mylar available)
  • Insulating Washers Material GRE (standard)
  • Steel Washer Material Zinc Plated Steel as standard
  • (Stainless steel available)

General Characteristics

  • Flange insulation as well as cathodic protection
  • Reduces galvanic corrosion in dissimilar metal materials used in flange joints
  • Allows mismatched ring-joint to raised-face flanges to be effectively sealed. HPS will seal in ring joint, raised-face and flat face/slip-on flange applications.
  • Will withstand corrosive environments including high CO2, H2S and processed water
  • The bore construction protects flange faces from media-induced corrosion and flow-induced erosion.
  • The pressure energised seal allows for reduced flange assembly stress
  • Easy to install and remove
  • Reusable seal retainer and seals
  • Suitable for all ANSI and API rated flanges
  • High strength laminate material reduces failure due to over compression

HPS Design

The design of the HPS gaskets incorporates a high-strength reinforced epoxy laminate bonded to a 316 stainless steel core as standard (other core materials available). This design results in the gasket having the strength of a traditional metallic gasket while at the same time allowing complete electrical insulation between the flange faces.

PTFE Spring-energised seals are installed into machined grooves to provide a pressure-activated sealing system that allows the HPS to be used as a high pressure insulating gasket. (Viton o-rings also available if specified)

Electrical Insulation

The HPS distinguishes itself by providing electrical flange insulation in a high-strength gasket. The HPS significantly reduces the potential for electrical conductivity between two flange faces by providing a non-conducting, non-metallic interface.

This eliminates potential corrosion resulting from dissimilar metals making contact or from ground induced current corrosion of metal components in pipeline systems. The HPS is an effective sealing system used in breaking electrical conductivity in piping systems with cathodic protection.

The HPS’s steel core and construction enables the gasket to withstand higher system pressure, pressure cycling, over torquing than conventional insulating gaskets.

Sealing raised face to Ring Joint flanges’


The positioning of the sealing elements of the HPS gasket are designed to fit Raised Face, Flat Face and Ring Type Joint flanges.

Because of this design we are able to replace the old design of Phenolic RTJ gaskets commonly designated Type “D-Ring Joint Gasket” which were limited in their ability to take high stresses or excessive bolt loads which often resulted in gasket fracture, damage or failure in service.

Because the HPS uses pressure-activated sealing elements which are designed to sit inside the ring groove on RTJ flanges it has the additional advantage of allowing the HPS to seal mismatched RTJ to raised face or flat faced flanges. This can be of great benefit to the customer when replacing flanges or valves using current stock inventory that may have a different flange face(than the mating flanges in situ).

HPS Flange Insulation Sets

HPS Flange Insulation Kit Components

The gasket set comprises the following as listed below:

  • Insulating facing: G-10 glass reinforced epoxy resin standard. G11 also available on request.
  • Seal: Spring energised PTFE (Viton also available)
  • Core: Stainless steel 316
  • Standard Thickness: 7.0 mm.
  • Insulating Washers: G-10 glass reinforced epoxy resin (other materials are available) 3.2mm thickness 2 washers per bolt
  • Steel Washers: Zinc-Plated steel, 3.2mm thickness (stainless steel washers also available) 2 washers per bolt.
  • Insulating Sleeves: G10 glass reinforced epoxy resin. (Mylar and Nomex also available) 1 insulating sleeve per bolt.

Insulation Kit Properties

Material type: G-10 Glass-reinforced epoxy resin  G-11 High temperature resin
Compressive strength: 50,000psi – minimum 50,000psi – minimum
Dielectric strength: 24.1-31.5 kV/mm 24.0 kV/mm
Maximum temp: 150°C 200°C
Water absorption: 0.1% – maximum 0.1% – maximum
Flexural strength:  65,000psi 57,700psi
Tensile strength: 50,000psi  41,000psi
Temperature range: – 130°C to 150°C  (limited by gasket material)  – 46°C to 200°C  (limited by gasket material)
Seal: Spring-energised PTFE (Viton rubber also available)



Open chat