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Belzona® Elastomers Seal Sf6 Gas Leak



Power (POWR)



Valves, Pipes and Fittings (VPF)


Customer Location:

Electricity Substation, UK


Application Date:

October 2012


Application Situation:

Six capacitor current transformers leaking SF6 gas to Low Voltage side  between bus bar and flange. The operating pressure was 45psi.



Each joint/flange was suffering from leaks requiring sealing as opposed to fully stripping back each joint and replacing with new gaskets which degrade quickly. A solution was required to minimise the uncontrolled release of SF6 gas into atmosphere. The solution must be flexible, and provide in excess of 3kV insulation properties under 0.5bar pressure.



Belzona® 2111 (D&A Hi-Build Elastomer)

Belzona® 2311 (SR Elastomer)



Steel and Rubber


Application Method:

The application was cvarried out in accordance with modified versions of Belzona Know-How System Leaflets VPF-5 & VPF-11. after preparing the substrate and conditioning with Belzona® 2911, a fillet was created using Belzona® 2311 to the circumference of the bus bar, flange and rubber gasket joint. After allowing to cure, a gas test was undertaken to establish that the initial leak sealing system was successful. A coat of Belzona® 2111 was then applied to all of the areas of substrate incorporating Belzona® 9341 (Reinforcing Tape). A second coat was then applied to an approximate thickness of 5mm encapsulating the bus bar, all flange surfaces and the branch joint behind the flange.


Belzona Facts:

Upon completion of each of the six applications, gas testing proved zero emission and in turn, the competency of the repairs with a six month review scheduled.


Photographs Description

  1. Visual view of equipment – horizontal bus bar 
  2. Substrate preparation completed
  3. Conditioned and first Elastomer coat/joint sealing
  4. Completed application with full encapsulation
Case study pic one


 Case study pic two


 Case study pic three


 Case study pic four


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