Klinger C4400 Insulating Gasket for Premium Oil Chemical and Power Applications

Flange joints in chemical reactors, power-plant steam lines and refinery piping stay tight only when the gasket matches the duty. KLINGERSIL C4400 is an asbestos-free, aramid fibre reinforced gasket sheet on a nitrile rubber (NBR) binder with a 3XA graphite anti-stick coating — the reliable compressed fibre flange gaskets for medium- and high-pressure services up to 100 bar (≈10 MPa).

What KLINGERSIL C4400 Is and Where It Is Used

Klinger developed C4400 as an asbestos-free replacement for traditional compressed fibre sheets. Aramid and synthetic fibres carry the mechanical load, the NBR binder supplies elasticity, and both faces are coated so the sheet releases cleanly after long service. One grade covers water, steam, oils and many chemicals.

• Asbestos-free aramid and synthetic fibre reinforcement with high tensile strength and creep resistance.
• NBR binder that resists oils, aliphatic hydrocarbons and saturated steam.
• 3XA graphite coating on both faces for clean release and secondary sealing.
• Universal sheet for medium- and high-pressure duties up to 100 bar (≈10 MPa).

Where one sheet has to cover mixed media, C4400 is a common specification:

• Oil and petrochemical plants — reactors, heat exchangers, columns and process piping.
• Power generation — steam lines, auxiliary systems, pumps and valves.
• Shipbuilding — engine piping, fuel-oil systems and seawater cooling circuits.
• Water and food duties — DVGW-approved grades for drinking water and certain food-grade fluids.

Material Build and the 3XA Anti-Stick Coating

The fibre skeleton resists crushing and permanent set under high bolt load, while the NBR matrix flows into micro-irregularities on the flange face and keeps the seal through thermal and pressure cycling.

The graphite-based 3XA coating delivers three practical benefits:

• Clean release: the sheet does not bond to the flange, so break-out and face cleaning stay fast and damage-free.
• Secondary sealing: graphite fills micro-gaps and raises overall tightness.
• Lower bolt stress: the low-friction layer builds sealing force more efficiently, so the same tightness needs less bolt preload.

KLINGERSIL C4400 gasket sheet

Performance Envelope

C4400 behaves as an all-rounder, but every duty should still be checked against its limits.

Typical ratings from the C4400 property profile; confirm them against the current manufacturer data sheet for the exact size and medium.

Selection, Installation and Care

Start with the joint: match the sheet to the pipe flanges by size, pressure class and facing (RF or FF), then confirm that temperature, pressure and medium sit inside the C4400 envelope. For strong oxidising acids or solvents, use the manufacturer’s chemical compatibility table.

• Surface preparation: clean, flat, scratch-free faces with all old gasket residue removed.
• Centring: place the sheet concentrically between the flanges.
• Tightening: use a diagonal cross pattern in several passes up to the recommended torque, ideally with a calibrated torque wrench.
• Inspection: check bolt load after the first heat-up and re-tighten only to the recommended torque.

Flange joint with KLINGERSIL C4400 gasket

Frequently Asked Questions

What binder does KLINGERSIL C4400 use?

An NBR (nitrile butadiene rubber) matrix locks the aramid fibres in place and provides elasticity plus resistance to oils and aliphatic hydrocarbons.

What temperature and pressure can C4400 handle?

Continuous service runs from −50 °C to +400 °C with 450 °C short peaks, and the maximum recommended sealing pressure is 100 bar (≈10 MPa).

Can C4400 replace asbestos gaskets?

Yes. It is an asbestos-free fibre-reinforced sheet built as a direct replacement, with better safety and environmental behaviour.

Which media are suitable?

Steam, hot and cold water, seawater, air, industrial and fuel gases, oils, dilute acids and alkalis; strong oxidising acids and some solvents need a compatibility check.

How should the gasket be tightened?

Use a diagonal cross pattern in several passes to the recommended torque with a calibrated torque wrench; over-torquing crushes the fibre sheet.