Gas in the Channel Islands

Working on gas in Guernsey and Jersey is not the same as in the UK. The supplied gas is an LPG/air mixture that has different characteristics to natural gas.

Gas engineers who go to Guernsey and Jersey to work need to know the difference between the type of gas supply on the islands and the rest of the UK. You’ll need to undertake a competency test with the islands’ own HSEs before starting work.

While the UK and Northern Ireland use natural gas (methane) in the network, the gas supplied in Guernsey and Jersey is different, and is a mix of LPG and air known as mains gas. It’s piped through the gas network and combines air with butane or propane, or a mixture of both.

There are other differences too, such as the operating pressure for mains gas which is 14 mbar (+/-2) at the meter. Gas appliances shall be designed to work at this gas pressure and you must check this compatibility when you work on the appliance.

The use of butane, propane or a mixture of both in the network can vary and affect the ignition temperature of the gas at the appliance. So can the specific calorific value of the gas: so the stated calorific value is an average of the gas supplied. Specific details of the supply can be provided by the local gas supplier.

An LPG/air mixture gives a different flame picture, which shows a yellow-tipped blue flame when combusted instead of the all-blue flame of a natural gas flame picture.

Domestic gas pipework design can be followed from BS 68911, which guides on the correct pipe sizing and pressure absorption across the pipework. IGEM UP/1B Edition 32 guides on the procedures of purging and tightness testing of LPG/air mixtures.

Working safely, competently and within the regulations in the Channel Islands is not as simple as packing your tools and getting a ferry to these beautiful Islands: it will need some preparation and consideration before taking on that gas work. You need to be Gas Safe registered and the Register does inspect gas engineers and businesses as part of its work there to ensure safe working practices and public safety. ■

Bibliography

1 BS 6891:2015 – Specification for the installation and maintenance of low-pressure gas installation pipework of up to 35mm (R1¼) on premises

2 IGEM/UP/1B Edition 3 +A: 2012 –Tightness testing/direct purging of small Liquefied Petroleum Gas/Air, NG/ LPG installations

Part of competency is the knowledge of local requirements. The required legislative documents for Jersey and Guernsey are included in the collection of Legislative, Normative and Informative Document List (LNIDL), which includes all the relevant gas documents for Guernsey and Jersey.

The LNIDL is updated every three months and the most recent version is on pages 32-37 of this issue.

You can also view and download an online version of the document with online links to the required documents by signing into your Gas Safe Register online account at www.GasSafeRegister.co.uk/sign-in

The online version includes an easy search for information such as Jersey’s Approved Code of Practice 13, Safe work with Gas Systems and Appliances, and Guernsey’s Approved Code of Practice Ordinance 2006, updated 2010.

Guidance on gas work is provided in the appropriate British Standards, IGEM documents and Liquid Gas UK Codes of Practice, when they are recognised in the Codes of Practice for each island. Local Building Regulations and the Health and Safety at Work regulations shall be also followed. Reminder: you are expected to have gas safety and local knowledge/competence of the gas systems you are working on.

(mbar) (+/-2) 21 14

Ignition temperature (°C) 704 530 (propane) 408 (butane)

Note: These figures are approximate and given as an indication of the differences that can be experienced when working in the Channel Islands and the UK. Some are not exact because gas calorific value and the mixtures will vary.