Isolation & Insulation
Isolation Sleeves
Bolt Insulating Sleeves & Washers
Insulating bolt sleeves and washers break the electrical path through individual bolts in flanged connections. Used alongside isolation gaskets, or on their own where a full kit isn't needed, to keep cathodic protection systems working as intended. Mylar handles most temperatures; switch to Nomex above 150 °C.
Types & Variants
Mylar (PET) Sleeves
Standard insulating sleeves for general pipeline isolation. Thin-wall design fits standard bolt clearances on ASME flanges.
HDPE Sleeves
Thicker-wall polyethylene sleeves for larger clearance bolt holes and applications requiring higher mechanical strength.
Nomex Sleeves
High-temperature insulating sleeves rated to 220 °C for hot service flange isolation.
Insulating Washers
Flat insulating washers in Mylar, G10, and PTFE fitted under nuts and bolt heads to break the electrical path.
Common Applications
Pipeline Cathodic Protection
Breaking the bolt electrical path at isolation flanges to maintain cathodic protection system integrity.
Dissimilar Metal Joints
Preventing galvanic corrosion where carbon steel flanges bolt to stainless steel or other alloy flanges.
Electrical Isolation Testing
Used with flange isolation kits and verified using a flange isolation tester to confirm isolation resistance.
Materials & Standards
Materials
- Mylar (PET) for standard duty
- HDPE for heavy duty
- Nomex for high temperature
- PTFE for chemical resistant service
- G10 fibreglass laminate (insulating washers)
Standards
- AS 2832 — Cathodic protection of metals
- NACE SP0286 — Electrical isolation of cathodically protected pipelines
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Raw Materials
Sheet, Roll & Bulk Stock
Compressed fibre, rubber sheet, PTFE, flexible graphite, engineering plastics, foams, and metal shim, supplied as raw stock for in-house cutting, fabrication, or repair.
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Studs, Bolts & Washers
High-Tensile Flange Fasteners
Stud bolts, hex bolts, washers, and nuts in carbon steel, stainless steel, and exotic alloys to ASTM and ISO standards.
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Flange Isolation Kits
Electrical Isolation for Cathodic Protection
Complete flange isolation gasket sets with insulating sleeves and washers to prevent galvanic corrosion in pipeline systems.
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Bolt size, flange standard, and service temperature: we supply sleeves and washers individually or bundled into complete isolation kits. Your call.
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This page is provided for general engineering reference only and does not constitute professional advice, specification, or guarantee of performance. Actual results depend on specific application conditions. Universal Gaskets Pty Ltd accepts no responsibility or liability for decisions made based on this information. For full terms, see our Terms & Conditions.