Flue Gas Analysers (FGAs) are also known as Electronic Portable Combustion Gas Analysers (EPCGAs) and have been in widespread use for over 30 years.

These battery powered electronic instruments contain sensors measuring various gases found within flues of combustion appliances, whether fired by gas, oil or solid fuels.

A hand-held probe is used to extract combustion gas from the flue of an appliance via a water and dust filter into the analyser with help from the analyser’s internal pump. The analyser’s sensors then calculate and display readings of oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2) and the ratio of CO to CO2. Some models offer additional features, such as temperature, humidity, pressure or gas leak detection.

The European Standard BS EN 50379, governs the performance and accuracy of these analysers - check with the manufacturer to confirm your analyser meets or has been tested to this standard.

In the UK, using analysers to test domestic gas appliances is governed by British Standard Guidance Document BS 7967. Gas Safe Registered engineers must prove their competency to meet this requirement by completing ACS assessment CPA1 or equivalent and, if they wish, they can also meet the requirements of ACS assessment CMDDA1, which includes all requirements of CPA1.

Across Europe, if local “use” regulations do not exist, users can refer to European Normative Guidance Document TS 50612.

Analysers generally require annual calibration and may require their sensors to be periodically replaced. In the UK, Gas Safe Registered engineers are also required to ensure their analyser has a valid calibration certificate which is good practice anyway - when in doubt, contact the analyser’s manufacturer for more information (see below).

An investigation by the UK’s Health & Safety Executive (HSE) uncovered an issue with potentially dangerous levels of carbon monoxide being emitted from the new generation of gas-fired condensing boilers.

Gas Safe Register worked with HHIC, the UK’s boiler manufacturer trade association, to produce Technical Bulletin TB 143 covering a mandatory requirement to check combustion gases within flues of condensing boilers, to be performed during installation and maintenance procedures.

HHIC require their members’ appliances to be installed and serviced with information recorded in Benchmark logbooks.

For more information go to :http://www.centralheating.co.uk/system/uploads/attachments/0000/5417/TB_143_-_CO_and_Combustion_Ratio_Checks_-_Boiler_commissioning.pdf  

The HHIC require a flue gas analyser meeting BS EN 50379 to complete boiler Benchmark commissioning checklists during installation and annual service.

Consequently, your analyser’s accuracy is extremely important, requiring annual calibration & service

BS EN 50379 specifies analysers must be calibrated according to manufacturer’s recommendations. In addition, Section 5.2.1, of BS 7967: 2014 states: “Analysers should be treated with care, and used and maintained with the analyser’s instructions. Before using an analyser it is essential to read operator manuals and ensure that the analyser has a current proof of calibration.”

Flue Gas Analyser manufacturers may have their own service centres for this work and may have authorised support service centres. Only the manufacturer’s own service centres or those service centres authorised by the original manufacturers can service & calibrate these analysers to ensure the requirements of these standards are maintained.

A calibration certificate may vary between different manufacturers but, as a minimum, should include:

• The serial number of the analyser and its type
• Date of calibration
• The next recommended calibration due date or certificate expiry date
• Reference to the test gases and instruments used during the calibration process
• The ambient conditions at time of test
• The calibration results of the parameters calibrated
• The measurement of any uncertainty

All calibrated analysers should have a label or sticker applied including the name of the company who carried out the work and the analyser’s next service date. The label should have a reference to the analyser such as a serial number or certificate number and should be tamperproof and placed where it can easily be seen.

Many analysers rely on service software to calibrate them and only the original equipment manufacturers and their approved service centre partners can provide a full service and calibration.

Using non-authorised calibration companies invalidates an analyser’s warranty. As it is difficult for a non-approved service centre to obtain calibration software and approved spare parts, it’s highly likely any service or calibration they perform will be inaccurate and may involve using incorrect parts.

Generally if the analyser’s laboratory or workshop is accredited to ISO 17025 or has ISO 9001 registration, all necessary procedures will be in place. But if not, to prove competence of your chosen service centre, the following items must be assessed, including but not limited to:

• Written workshop procedures following the manufacturer’s service and calibration instructions
• Traceable UKAS calibrated test and measurement instruments for temperature and pressure
• Test gases of a laboratory grade and supplied with a certification of analysis
• Training records and competency checks for calibration staff
• Control of documents to ensure current procedures are followed
• Documented customer complaints procedure
• Supplied with approved spare parts and a documented process for stock control & non-conformances