New Fixed Gas Detection System launching soon


We can repair SF6 leaks
and top up leaking SF6 assets

EMT can provide both the test equipment and certified technicians for SF6 leak surveillance, SF6 leak repair and the safe filling and topping up of SF6 insulating gas compartments. Performing these essential maintenance tasks, our Site Services team can provide 24/7 coverage across the network. Our work delivers key environmental and financial benefits to utilities including: asset reliability, long term compliance and performance, maximum up-time and security of critical infrastructure. Read on to learn more about projects completed for our clients …

SF6 Gas Filling of Newly Installed GIS

EMT Site Services were contracted to undertake SF6 gas filling of newly installed GIS, which was not in service pending final commissioning.


Procedural leak test protocols were carried out using EMT Leak Hunter technology, with no leaks detected during survey.


Existing GIS gas was analysed using EMT Zerowaste Rapide+ technology, also prior to top up.


Based on results, testing concluded that the SF6 gas was of sufficient purity to continue topping up procedure without gas removal, to bring the asset to full working order.

Sulphur Hexafluoride (SF6) survey and top-up UK Solar Farm

#EMTLeakHunter identified an SF6 leak from a plastic valve on the pressure gauge. Findings suggested a gauge replacement was needed, with recommendations for a full de-gas prior, followed by vacuum and re-gas to full working pressure, in order to return the asset to optimal working service.


Why choose #EMTsiteservices for #onsiteleakdetection and #SF6toppingup


  • Thorough analysis, methodologies and reporting
  • Dedicated SF6 service team with point of contact and on-going support
  • SF6 leak detection, handling and topping up
  • Certified, trained and experienced engineers
  • Delivering reliability, quality and assurance to Transmission and Distribution maintenance personnel
  • Ensuring optimum performance, continued compliance and business continuity

SF6 Leak Survey for UK DNO

  • Identified a fittings connection leak on the ball isolation valve and through the plug
  • The valve was closed off but still leaked when in the off position
  • Recommendation for de-gas and replacement
  • Second leakage point located in the manifold behind the pressure gauge; via the small-bore fittings leading into the back of the pressure gauge
  • Recommendation to remove the manifold, further leak test the area, de-gas and change out the existing pressure gauge, pipework and fittings leading to the gauge
  • Leak identified on the top plate at the joint between the plate and the housing
  • Recommendation to remove the plate and replace the seal via a composite fix, which could be achieved as the plate is sitting flat against the surface. A de-gas and re-gas would be required
  • Further recommendation to carry out preventative maintenance on all flange joins to avoid further leaks 

Solar Park SF6 Leak Survey

The asset was leak tested to identify the leak source using EMT Leak Hunter.  SF6 gas content was analysed with Zerowaste Rapide+ technology and the asset was topped up with new gas to meet the required working pressure. 

The asset will continue to be monitored for top up requirements. The team have recommended that prior to future topping up, a full vacuum is applied to the asset to remove any moisture content before SF6 is replaced.

GIS Substation SF6 Re-Gas

The system was checked for SF6 leakage to confirm leak points prior to removal. SF6 was removed from GIS down to zero working pressure.  The leak was repaired and GIS was re-gassed to required pressure.


Our Site Services Team utilised EMT Leak Hunter, Zerowaste Rapide+ and EMT Pressure Validation Kit on this project. 

The team plan to return to site to remove the leak repair kit when GIS is stripped down at a later date.

Electric Utility Substation_SF6 Leak Detection_SF6 Leak Repair_SF6 Regassing of Asset

SF6 Leak Remediation and Preventative Repairs

SF6 leak surveillance on three GIB bushings determined leaks on two areas; identified and verified via IR hand held leak detector and leak detecting fluid. The asset was de-gassed and vacuum pulled before repairs were made to the joints. All other seals were repaired as a preventative measure.


The asset was returned to full pressure and final leak tests were completed. A final test on the condition of SF6 gas was carried out via Zerowaste Rapide+ Analyser. All repairs were successful – pressure and gas quality within required operational conditions. 

Substation_SF6 Leak Remediation Repairs and Preventative Repairs Montage

Norwegian Utility SF6 Leak Detection

A Norwegian utility contracted EMT Site Services to run a series of leak surveys to detect and confirm the presence of SF6 leakage within the work area. Using EMT best practice leak survey methodology and EMT advanced leak detection technology, our team identified and located several SF6 leaks within their installed assets including GIB, HV bushings and interconnecting supply pipework.


The team are scheduled to undertake three leak repairs with composite sealant filler and bonding technique, which will require SF6 gas handling and removal of the gas during repair. In addition to EMT site services, this customer has also expressed an interest in EMT fixed point detection systems and our Zerowaste analysis technologies.

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Wind Farm SF6 Gas Handling

EMT customers can choose from a range of innovative packaged solutions, with products and services which support the productivity, efficiency and profitability of their utility operations.


Whatever the requirement or budget, whether the need is for technology, expertise or both, best practice SF6 gas handling with EMT delivers zero emissions, zero waste, compliance and protection of assets, personnel and the environment. The team have completed a project for a UK wind farm, degassing and refilling SF6 Switchgear on a turbine.

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T&D SF6 Leak Repair

Project completed for a large electricity transmission and distribution business in the UK


  • LOCATED SF6 gas leaks on flanges with the EMT Leak Hunter portable gas leak detector
  • APPLIED best practice SF6 gas handling with EMT Smartfill filling and top-up technologies

Middle Eastern Utility Smartfill CTU Installation

On site installation of four Smartfill Continuous Topping Up Systems, for a leading Electricity Transmission and Distribution Network Operator in the Middle East.


The Smartfill CTU delivers live, automated, on-demand top-up in the event of an SF6 leak; and is designed to manage leak operations where regular, controlled top-ups are required. Using this zero-waste approach to replenish the gas results in reduced SF6 usage, inventory and costs.


Smartfill technology ensures assets remain operational and at peak performance, securing continuity for EMT customers. The installation was a success, as was the training which followed, and discussions are underway for further installations on other sites.

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SF6 Leak Management

Following a site survey, the team confirmed SF6 leaks on all phases of the asset, which required immediate repair and preventative maintenance. The project was for six flange repairs; three upper flange and three lower cover plate with sensor.


All repairs were carried out under live conditions and full pressure. From surface preparations; to soft shell mounting and reinforcement; through to hard shell, resin application, final seal and post repair testing – our expert engineers followed proven and rigorous EMT protocols using trusted and reliable EMT technologies and solutions, to ensure compliance at every stage of the project.

Solar Farm SF6 Gas Analysis and Top Up

Issue:  Leaking GIS asset


  • Site survey detected and located switchgear leak using EMT Handheld SF6 Leak Detector
  • Gas analysis carried out by EMT Site Service Engineers using Zerowaste Rapide+ Analyser
  • Tests prior to gas top up indicated SF6 gas required
  • Tests after the asset was re-gassed confirmed SF6 gas usage
  • Asset checked for leaks following gas top up and minor repairs

Result: Leak detected at another location; further works required.

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Survey and Repair of Leaking SF6 Assets

Industry: Power T&D

Application: SF6 leak repair, gas inspection cover plates (non-pressurised) 

Customer: UK electric utility substation


  • Leak surveyed using Handheld SF6 Leak Detector
  • Existing gas purity analysed with EMT Zerowaste Rapide+ Analyser
  • Asset de-gassed using EMT Gas Cart
  • Surface preparation and cleaning works undertaken
  • Nine specialist repair works completed
  • Asset re-gassed, gas purity checked, and post repair testing completed
  • Further scheduled preventative maintenance work has been recommended due to high H20 ppm readings recorded in the SF6 gas
  • EMT delivered the technology and expertise to survey and repair leaking SF6 assets with a cost-effective solution and minimal disruption to operations, which was welcomed by the customer, whose alternative would have been to replace the asset at considerable cost and with significant disruption to the substation.
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Field Based SF6 Gas Top Up

Industry: Solar power generation

Application: SF6 gas topping up at two sites

Customer: UK solar farm

Problem: Low gas pressure reported


Solution: Field based SF6 gas top up utilising EMT Site Services and patented EMT Smartfill technology

  • Leak survey completed using SF6 leak detector
  • Pressure survey completed
  • SF6 gas top up completed
  • Continued pressure monitoring advised
  • Future repair, de-gassing and re-gassing works discussed

Deliverables: SF6 gas top up restored pressure to normal operating conditions. The client was satisfied, particularly given there were challenges sourcing the correct fittings to carry out the works – EMT took care of all requirements from initial surveillance, to sourcing bespoke fittings for connection, and topping up of SF6 compartments.

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SF6 Flange Repair Live Conditions Pressure/Outage

Industry: Power T&D

Application: SF6 leaking vertical flanges

Customer: UK electric utility

Problem: Three identified leaking flanges on SF6 substation


Solution: Vertical REFLANGEKiT® SF6 leak sealing

  • Leak surveyed/identified using SF6 leak detector
  • Environmental/climatic conditions surveyed and approved
  • Surface preparation works undertaken
  • Cleaning and degreasing of surfaces carried out
  • Phase one flange repair – soft shell mounting completed; the purpose of the soft shell is to protect the functional parts of the flange i.e. bolts and seals, and to concentrate the leaked SF6 gas to a single point of the shell where the valve is located. This was followed by re-enforcement of the soft shell
  • Phase two flange repair – hard shell and resin application completed; resin was injected into the hard shell and left to cure overnight
  • Flanges repaired under live conditions and pressure/outage
  • Sleeve removed, valve sealed, and leak test undertaken using EMT SF6 calibrated leak detector, concluded with final seal and post repair testing

Online Repair SF6 Leaking Flange

Industry: Power T&D

Application: SF6 leaking flange

Customer: UK electric utility

Solution: REFLANGEKiT® SF6 leak sealing technique


Technology: The 3X ReflangeKit® concept is based on a composite double shell system that encapsulates the leaking flange. The first shell covers and protects the flange collecting SF6 leaks. The second shell contains specific resin. An exhaust valve allows the SF6 gas to escape during resin injection. After overnight curing of the resin, the valve is closed and sealed giving a 100% seal and leak free composite repair.


Benefits: The installation was non-invasive and did not require a power outage. Repair was completed online and under pressure. Disassembly was easy, the fix was efficient, and cost effective.


Deliverables: Shunts, bolt heads and flange seals are now protected. The completed repair was tested and successful – further repairs are scheduled

Multi-Site SF6 Maintenance Services

Site 1: SF6 substation 3x leaking flanges

Site 2: SF6 substation 6x leaking GIB/GIB flanges

Site 3: SF6 substation 3x leaking GIB/GIB flanges

Site 4: SF6 substation 1x leaking GIB/tank flange


Repair 1: New cover plate repairs

Repair 2: Composite encapsulated leak repair – GIB/GIB straight, medium resin fill

Repair 3: Composite encapsulated leak repair – large flange, GIB/GIB straight, large resin fill

Repair 4: Composite encapsulated leak repair – large flange, reducing shell, large resin fill



  • Online and under pressure installation
  • Non-invasive system (no risk of resin intrusion into the flange)
  • Bolt and screw protection
  • Easy disassembly
  • Cost effective installation (costly consignation avoided)


  • SF6 leak remediation was a success and the flanges remain in service
  • SF6 savings across multiple sites 1584 Kg/yr, that’s equivalent to 36,115 metric tons of Carbon Dioxide, or 4,393,148,505 smartphones charged (CO2e), or 4,063,824 gallons of car fuel (CO2e)

EMT Site Services + EMT Technologies = SF6 Leak Free

Our technology enables quick and reliable identification of SF6 leaks in order for utilities to: 
  • Reduce the rate of SF6 loss
  • Comply with regulations
  • Reduce costs
  • Reduce risk of fines
  • Reduce CO2 footprint
Our services can be quickly deployed to site, and using our own advanced leak detection systems, analysers and gas carts, we can confirm if a leak is present, identify the location of the leak, and make recommendations for monitoring, management and repair. Our leak monitoring and leak management services provide clients with comprehensive reporting on mass flow measurement and SF6 gas usage. 
Our people are certified SF6 engineers expert in leak detection surveillance and are fully trained and experienced in surveying SF6 filled installations. Our engineers can carry out filling and topping-up procedures on SF6 assets using EMT innovative Smartfill gas handling equipment. The team specialise in flange repairs and corrosion prevention, and also deliver SF6 training to utility companies.

EMT’s products and services deliver a total SF6 management solution to ensure you have everything you need to keep your SF6 operations running smoothly.