Choose by bolt diameter, temperature and dielectric requirement
An insulation sleeve tube is a hollow dielectric tube that slips over each flange bolt to electrically isolate it from the flange and prevent metal-to-metal contact. In a flange insulation gasket kit, the sleeve works together with the insulating gasket, insulating washers and steel washers to completely break the electrical continuity across the joint — this is what enables cathodic protection systems to work and stops galvanic corrosion from eating away at the pipework.
As an experienced insulation sleeve tube manufacturer in China, Kaxite Sealing supplies two sleeve materials — thin-wall Mylar polyester sleeve for economical general service and NEMA G10 epoxy fiberglass tube for high-strength standard service — in diameters from 0.66 mm to 810 mm. Both materials are compatible with all our Flange Insulation Gasket Kits.
From small instrument bolts to large pipeline flanges — a sleeve for every bolt size
Custom diameters and wall thicknesses available at no extra tooling cost — send your requirement for a quote
Four parts working together to break electrical continuity across the flange joint
Dielectric gasket breaks the metal-to-metal contact between the two flange faces
This sleeve — Mylar or G10 — isolates the bolt shank from the flange bolt hole
G10/G11 or phenolic washer isolates the nut and bolt head from the flange face
Zinc-plated steel washer distributes bolt load without breaking the electrical isolation
All four parts are shipped together in our complete Flange Insulating Gasket Sets — order the sleeve separately when you need replacements.
Transparent or striped PET polyester sleeve, 2 m per piece, ID 0.66-70 mm
Heat-rolled epoxy fiberglass tube, diameter 8-810 mm, max length 10 m
Wherever flange bolts must be electrically isolated from the pipework
Cathodic protection & stray current control
Galvanic corrosion prevention
Buried pipeline isolation
Dissimilar metal flange joints
Turbine & generator piping
Seawater & platform piping
China has become a global leader in manufacturing excellence, particularly in advanced materials and industrial components. Our manufacturers combine cutting-edge technology, rigorous quality control and decades of experience to produce insulation sleeve tubes that meet international standards and exceed customer expectations.
By sourcing from China you gain access to 30-50% cost savings compared to Western suppliers, a vast supply chain network, and factory-direct engineering support for custom sizes. Every shipment includes Mill Test Certificate, dimensional inspection record and material composition report. See our About Us page or Contact Us to arrange a factory audit.
We supply two main materials — thin-wall Mylar (PET polyester) sleeve for economical general service, and NEMA G10 epoxy fiberglass tube for high-strength standard service. Mylar is transparent or striped and is used with G10/G11 or phenolic insulating washers. G10 tube complies with EN60893, DIN7735, NEMA LI-1 G10 and IS10192 standards. See our Mylar Isolating Sleeve and NEMA G10 Tube product pages.
Choose Mylar when you need a low-cost thin-wall sleeve for standard bolt isolation, especially for small-to-medium flanges and moderate temperatures. Choose NEMA G10 when you need higher mechanical strength, thicker wall, larger diameters (up to 810 mm) or higher continuous temperature up to 130°C. Contact us with your bolt size and service conditions for a recommendation.
Absolutely. Mylar sleeve is available in custom inside diameter (0.66-70 mm), wall thickness (0.03-1 mm), length (cut to order from 2 m stock) and finish (transparent or striped). G10 tube is available in custom diameter (8-810 mm), wall thickness (from 0.5 mm) and length (up to 10 m). Please send your inquiry with a drawing for a fast quotation.
Both options are available. Complete Flange Insulating Gasket Sets already include the sleeves, insulating washers and steel washers. You only need to buy the sleeve separately when you need replacement sleeves, a non-standard size, or a specific sleeve material that isn't part of a standard kit.
Yes. Every shipment includes Mill Test Certificate, dimensional inspection record and material composition report. G10 tube standard compliance (EN60893, DIN7735, NEMA LI-1 G10, IS10192) is documented, and third-party inspection (SGS, BV, TUV) is available on request. Contact us to discuss specific documentation requirements.
MOQ is 10 pcs for standard sizes. Lead time is 7-15 days after order confirmation. Payment terms are T/T or L/C. Free samples are available — you only cover the courier cost. Send your inquiry for a fast quotation.
Send us your required ID, wall thickness and length — we machine or slit to your exact specification. No extra tooling charge for standard materials.
Get Custom QuoteVerify material, dielectric strength and dimensional tolerance against your own specification before placing a bulk order. Mylar and G10 samples both available.
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