The new Fluorinated Greenhouse Gases Regulations 2009 impose specific conditions on operators of high voltage (HV) switchgear assets containing SF6 gas. EA Technology senior consultant Gary Eastwood explains why the new regs are important

The good news about sulphur hexafluoride (SF6) is that it is an exceptionally effective electrical insulator that is widely used to ensure the safe and reliable performance of modern HV switchgear around the world. The bad news is that, for a given mass of gas released into the atmosphere, it has the highest potential to contribute to global warming of any other fluorinated greenhouse gas so far evaluated.

Let's start by examining the global warming potential issue, because that is the driver behind the new regulations, which have come into force across the European Union (EU) and will no doubt influence legislation globally.
 
SF6 molecule
Pure SF6 is a colourless, odourless, non-toxic gas made up of a single sulphur atom, bonded with six fluorine atoms. Under normal conditions it is extremely resistant to reaction with other substances, making it chemically inert: and it is over five times heavier than air. However, if it is allowed to escape to atmosphere, its potential effect on global warming, measured over a 100 year time period, is approximately 22,000 times greater than the equivalent amount of carbon dioxide (CO2). In other words, releasing a single kilo of SF6 gas has the same effect as 22 tonnes of CO2.

The advantages of using SF6 in HV switchgear are considerable, not least because the gas is non-flammable, non-corrosive to internal switchgear components and its thermal properties make it an exceptional arc suppressant: even when SF6 is momentarily broken down during arcing, it largely re-combines back into its original state. In its pure form, it is non-toxic and does not pose a hazard to human health providing switchrooms and storage locations are well ventilated. This combination of properties has enabled designers to develop HV switchgear which is smaller and requires less frequent intrusive maintenance than equivalent types that use air or oil for arc extinguishing and insulation.

The electricity industry is a major user of SF6, accounting for approximately 4,000 tonnes of production each year. Not surprisingly, the European Commission initially considered an outright ban on the use of SF6 in new switchgear, but subsequently stepped back from this position, particularly in the light of voluntary actions already being taken by SF6 producers, switchgear manufacturers and utilities to minimise emissions of the gas. Instead, they have decided to impose new regulations (Regulation EC No. 842/2006) that require SF6 gas, or mixtures of the gas, in high voltage switchgear to be recovered by trained and certificated personnel. This applies to maintenance activities as well as final disposal. Every EU member state is obliged to adopt these regulations. Hence the UK's Fluorinated Greenhouse Gases Regulations 2009.

The new regulations certainly provide for member states to impose fines for non-compliance, but in practice the industry itself is expected to ensure the requirements are being implemented. Minimising the release of SF6 is important in the context of individual companies' environmental and corporate responsibilities: but it is also a challenge collectively for the industry. If SF6 emissions from electrical equipment are seen as not being controlled through compliance with the regulations, then there is a real danger of more regulation or possible restrictions on its use in high voltage equipment, at greater cost and inconvenience to the industry. Compliance is therefore not only the right thing to do environmentally: it is in our own best interests.

Specific provisions relating to handling of SF6 in HV switchgear are laid out in the new UK regulations. These stipulate that anyone who recovers the gas from HV switchgear must have enrolled on an appropriate training course by 3 July 2009, for the purposes of gaining certification in the regulations.

Subsequent to that, personnel will only be allowed to recover the gas if they have passed an assessment, and been issued with a certificate of competence, by an approved evaluation and certification body. It is worth noting operators of HV switchgear are also responsible for ensuring that anyone who carries out gas recovery on their equipment, including contractors' personnel, is suitably qualified and certificated.

Because EA Technology has been running SF6 training courses for several years, it has been relatively straightforward for us to tailor them to meet the specific requirements of the new regulations. We have also been designated as an evaluation and certification body in the UK by the Department for Environment, Food and Rural Affairs (DEFRA) and certification issued by us is valid in all EU member states.

Our two day course comprises one day on the theory and generic practices for handling and testing SF6, using a range of equipment typically used by the industry: the skills and knowledge gained are intended to be readily transferable to other types of switchgear and SF6 handling equipment. Training includes the correct selection and use of Personal Protection Equipment (PPE) for working in open compartments which may contain small quantities of SF6  decomposition products, produced by arcing or abnormal electrical discharges.

On the second day, delegates are assessed and issued with a certificate of competency and a personal ID competency card. Both are valid for four years and are recognised across the EU. Each course is limited to 16 people, split into groups of eight, so tuition and assessment are on a personal level. Each stage of the assessment is fully documented using pre-prepared question papers and checklists. Delegates are issued with digital copies of all course presentations and materials on a memory stick: this also includes our practical guide for storage, transport, handling, testing and disposal of SF6.

We also offer single day courses, without the assessment and certification elements, for managers and supervisors who are responsible for developing SF6 policies and monitoring compliance by staff and contractors: and we provide refresher courses for people who already have SF6 handling experience but need to get up to speed on the latest developments.

In our view, the requirement for training and certification should be seen as a positive step towards minimising emissions of SF6 when carrying out maintenance activities and final disposal of HV switchgear, rather than an additional regulatory burden. Given that restrictions have been placed on the use of SF6 in other industries and the fact EU member states are required to report annual emissions of fluorinated greenhouse gases, it is truly in the best interests of the electricity industry that operators of HV switchgear should take the steps necessary to achieve compliance with the new regulations and build on the voluntary actions already taken to date.

Details on SF6 training courses, assessments and certification are available from Jackie Clarke or Vanessa Revell at events@eatechnology.com  or call 0151 347 2323.