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Flue Gas Analysis Explained: The Importance of Regular Testing

Why is testing Flue Gas so important? Our Guide to the Basics of Flue Gas Analysis

Flue Gas Analysis ensures that vehicle engines, boilers, heaters, and other equipment items containing combustion processes are running efficiently, and the process remains a vital tool for any Gas Safe Registered or qualified engineer. Knowing flue gas composition allows us to ensure that product emissions are optimised to be as near as possible to the minimum emissions regulations required for each applicable industry.

When you burn fuel, such as coal or oil, the resulting gas is called flue gas. Flue gas is the hot air emitted via a building’s chimney or flue during the combustion process; analysing it was once time-consuming and expensive, but modern advancements have made analysing flue gas cheaper and easier. Flue gasses are analysed through the use of a Flue Gas Analyser (FGA).

The composition of flue gas can vary, depending upon a number of factors. But common elements found in flue gasses can include Oxygen, Nitrogen, Carbon Dioxide, Carbon Monoxide, Sulphur, and Water Vapour, alongside other pollutants like dust and soot.

From a standpoint of human life and environmental preservation, Carbon Dioxide and Nitrogen pose the biggest risk, whereas evidence of Oxygen and Carbon suggests inefficiency in the combustion mechanism or process.  

Flue Gas Analysis Process

A Flue Gas Analysis, or Combustion Test, is designed to prove that the appliance or system is working and burning gas efficiently. The Flue Gas probe for the test itself is inserted into the flue of the appliance, where it provides a view for the user inside the appliance via the analysis of the exhaust fumes excreted. This analysis can also tell us the amount of Carbon Dioxide, Carbon Monoxide and Oxygen produced, how much excess air the unit has, and the temperature of the flue gasses being emitted.

Alternatively, if the item of equipment is very large or industrial in size, and readings are more difficult to collect by an in-situ probe, gasses can be directly collected from the system with a tube. This enables the extraction of gasses that may be emitted from a harder-to-reach exhaust.

The Flue Gas Analyser must also ONLY be used with a valid and in-date calibration certificate, as instrument calibration ensures that the Flue Gas Analyser is providing accurate readings.

Prior to carrying out the Flue Gas Analysis, the appliance or system should be switched on and operational, as this enables the most accurate temperature and efficiency calculations. What’s more, the Flue Gas Analyser itself should be initiated in clean air whilst the flue probe is already attached, so the probe and test instrument can be properly purged before use.

Post-Flue Gas Analysis

Once the Flue Gas Analysis has been completed, it’s important for users to follow a standard set of care practices to enable instrument longevity and continued accuracy of readings. This includes:

  • Draining away any condensation build-up from the probe and trap, as excessive water ingress may damage the instrument’s inner workings.  
  • Ensuring the storage of the Flue Gas Analyser in an area with a steady ambient temperature, due to the potential of fluctuating temperatures resulting in an internal condensation build-up which may cause damage if left unchecked.
  • Protecting the unit from extremely cold conditions, as freezing temperatures can prematurely result in the depletion of the battery and sensors.
  • Removing the Flue Gas Probe only once the instrument has completely powered down.

Importance of calibrating your Flue Gas Analyser

Much like a vehicle MOT, an annual Flue Gas Calibration ensures that your test instrument is functioning within standard compliance parameters, as the moving parts and sensors within are prone to wear and tear. Deterioration in this manner can interfere with the accuracy of the readings gathered, and if the Flue Gas Analyser does not have a valid calibration certificate, then any work completed with the unit will fail assessment and may lead to unsafe installations being approved.

Annual calibration reduces the uncertainty associated with instrument measurement processes, ensuring that any and all results are accurate and that the equipment being checked, installed or serviced by the engineer is safe for consumer use. Annual FGA calibration is a legal requirement under British Standards BS7967 and BS EN:50379, and any engineer found to be using an out-of-date analyser could face serious legal penalties. 

To view our entire range of Calibration & Repair services, click here.

For Kane FGA calibration then Kane will need to be contacted directly, as this is not something we can accommodate.