How to Repair an SF₆ Leak with Belzona SF6-FIX

SF₆ leakage in high-voltage switchgear can be repaired quickly and safely using Belzona SF6-FIX, a fast, in-situ sealing solution designed for gas insulated equipment. Commonly used in gas circuit breakers for its excellent insulating properties, SF₆ is now under increasing regulatory pressure due to its high global warming potential. Belzona SF6-FIX enables maintenance teams to stop leaks efficiently without extensive downtime, helping operators maintain equipment reliability while reducing environmental impact.

SF6 leak sealed with Belzona SF6 FIX

How to Stop SF₆ Leakage: a Step-by-Step Guide Using Belzona SF6-FIX

STEP ONE:

Surface Preparation

First, ensure the area is degreased and mechanically roughened for optimal adhesion. The area should be prepared with a suitable power tool to achieve an SSPC-SP 11 bare metal power tool cleaned surface with a minimum profile of 25 µm (1 mil).

Roughen and prepare surface with a suitable power tool

Install the Belzona SF6-FIX breather system

STEP TWO:

Step 2: Install Belzona’s Breather System

This allows gas movement during the cure phase and ensures internal pressure equalisation. This will then be capped off once the leaking flange repair is complete.

STEP THREE:

Apply Belzona 7311 with Belzona 9341 Reinforcement Tape

Apply the first layer of Belzona 7311 to the breather system and prepared bond area using a brush. Once fully encapsulated, wet out and add the reinforcement tape.

First encapsulate the repair (left), then add reinforcement tape (right)

STEP FOUR:

Apply Belzona SuperWrap II with Belzona 9371 Reinforcement Sheet

This composite layer enhances pressure retention and creates a strong and durable wrap.

Belzona 9371 Reinforcement Sheet and Belzona SuperWrap II being applied to a repair

First encapsulate the repair (left), then add reinforcement tape (right)

STEP FIVE:

Second Coat of Belzona 7311

An additional coat of Belzona 7311 ensures full encapsulation of the reinforcement system.

Second coat of Belzona 7311 applied to SF6 leak fix

Roughen and prepare surface with a suitable power tool

STEP SIX:

Cap the Repair & Overcoat with Belzona 5721 (if required)

Cap off the breather system and add UV protection with Belzona 5721 if required.

For repairs that require UV resistance, add a layer of Belzona 5721

Belzona 7311
Belzona 5721

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Frequently asked questions

SF₆ (Sulphur Hexafluoride) is a synthetic insulating gas widely used in the power industry in equipment such as gas insulated switchgear (GIS) and circuit breakers. Its excellent dielectric and arc-quenching properties allow electrical systems to operate safely and efficiently at high voltages.

SF₆ is used in circuit breakers because it has a dielectric strength approximately three times greater than air, enabling it to withstand high voltages and safely interrupt electrical currents. This allows switchgear and substations to be designed in a more compact and efficient manner.

Although highly effective as an insulating gas, SF₆ has a global warming potential (GWP) more than 23,500 times greater than CO₂. Even small leaks can have a significant environmental impact, which is why leak prevention and switchgear maintenance are increasingly important.

Belzona SF6-FIX can be used on a wide range of high-voltage equipment, including gas insulated switchgear (GIS), circuit breakers, disconnectors and other pressurised SF₆ systems where gas leakage is affecting performance or compliance.

Belzona SF6-FIX is a solvent-free, cold-applied repair solution designed to safely seal SF₆ leaks without hot work or extended shutdowns. Repairs can often be completed within a single day, helping reduce gas loss, minimise downtime and provide long-term leak sealing performance.