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CATHODIC PROTECTION · ELECTRICAL ISOLATION

Flange Isolation Gasket Kits

Flange isolation kits, rubber-steel gaskets, pressure gauges and thermometers built to ASME and EN standards, with documentation your inspectors will accept.

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Protects the CP system

Keeps protection current on the pipeline, so rectifier output is not lost to plant or earth.

Stops galvanic corrosion

Isolates dissimilar metals at the flange, such as carbon steel to stainless or copper alloy.

Seals and isolates in one

Gasket, full-length sleeves and double washers isolate every stud from both flanges.

Installation data included

Each kit ships with torque values, tightening sequence and electrical test procedure.

KIT TYPES

Choose the gasket by flange facing

Type E · Full face

Gasket matches the flange OD with bolt holes. Fits raised-face and flat-face flanges; keeps debris and moisture out of the bore area.

Type F · Raised-face ring

Ring gasket that sits inside the bolt circle on raised-face flanges. Centres on the sleeves during assembly.

Type D · Ring-type joint

Oval or octagonal isolating ring for RTJ grooved flanges in high-pressure service. Sized to ASME B16.20 groove numbers.

MATERIALS

Material selection guide

Select the retainer and seal for the service temperature, pressure and medium. Values are typical; the kit datasheet governs.

Retainer / seal

Typical max. temperature

Recommended for

Neoprene-faced phenolic

−54°C to +79°C

Water, low-pressure utilities, general service

G10 retainer + nitrile O-ring

−54°C to +138°C

Hydrocarbons, natural gas, Class 150–600

G10 retainer + FKM (Viton) O-ring

−30°C to +177°C

Higher temperature and aromatic hydrocarbons

G11 retainer + PTFE spring-energised seal

−45°C to +177°C

High pressure, sour service, Class 900–2500

Sleeves: polyethylene, polyester (Mylar), G10 or Nomex. Isolating washers: phenolic, G10 or G11. Steel washers: zinc-plated carbon steel to ASTM F436.

SPECIFICATIONS

Technical data

Need a size or rating not listed? Send your line data and we will confirm a kit.

Nominal sizes

NPS ½" to 88" (DN 15 to 2200)

Pressure classes

ASME Class 150 ; EN PN 10 to PN 63

Flange standards

ASME B16.5, ASME B16.47 Series A and B, EN 1092-1

Washer configuration

Double washer (standard)

Gasket thickness

3.2 mm / 0.126 in

Dielectric strength (retainer)

550 V/mil, tested to ASTM D149

Insulation resistance (new joint)

≥ 350 MΩ at 500 V DC

Design reference

AMPP SP0286 (electrical isolation of CP pipelines)