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What does the Energy-related Product Directive mean for NOx in Boilers?


The Energy-related Product Directive (ErP) is a wide ranging piece of EU legislation that aims to reduce emissions in Europe through improving the labelling and efficiency of a wide range of appliances from lighting to refrigerators. It has now been in force for a number of years having first been passed in 2009 but various provisions have come into force at later dates. These include Regulation 813/2013 that sets out requirements for the eco design of space heaters and combination heaters.

What Changes Came in September 2018?

As per the phased introduction of ErP, new rules came in on 26th September 2018 covering the emission of nitrogen oxides from space heaters and combi boilers with overall power output of <400kW.

The pertinent information can be found in section 4(a) of Annex II of Regulation No 813/2013 which sets out NOx limits of 56mg/kWh for gas-fired systems and 120mg/kWh for oil-fired boilers. For the last five months, these limits have sat alongside requirements for efficiency and sound power level that have been in place since 2015.

How do I Measure NOx?

The advent of European regulations relating to nitrogen oxides obviously requires boiler technicians to measure these emissions. Several flue gas analysers provide options for measuring NOx including the Anton Sprint Pro5 and Pro6, Kane 905 and 945, and Testo 300 NOx. With measurement ranges going up to 3000ppm or even 5000ppm, these instruments are more than capable of measuring the typical 50 to 100ppm produced by gas- or oil-fired boilers.

Converting NOx ppm to mg/kWh

As noted above, most of our analysers provide measurements in ppm whereas the ErP regulations are expressed in mg/kWh. Converting the values is notoriously tricky as they measure different things: ppm is an expression of the percentage volume whilst mg/kWh is measuring emissions as energy is produced.

A complicated mathematical conversion is required, taking into account the rated power output of the boiler, the molecular mass of NOx and concentration in the total exhaust mass. BREEAM suggests multiplying parts per million by 1.76 to achieve mg/kWh so that a boiler running at 50ppm NOx would return a figure of 88mg/kWh however this is a very rough estimate.

To save time and avoid mistakes during conversion, the Testo 300 NOx comes into its own as the onboard software on the analyser will automatically calculate values in mg/kWh, immediately allowing the user to check heaters against the ErP limits.

Changes for Solid Fuel Boilers

In terms of nitrogen oxide emissions, the next big date to look out for in boilers is 1st January 2020 when standards set out in Section 1(f) of Annex II in Regulation 2015/1189 come into force. This regulation applies to boilers and heaters running from solid fuels including non-woody biomass, peat, coke, and coal with a rated output of <500kW.

The NOx limits imposed are as follows: 200mg/m3 for biomass-fuelled boilers and 350mg/m3 boilers supplied by fossil fuels. It will therefore be important to consider the fuel of the boiler as this can be a major contributor to nitrogen oxide emissions. Any one of the flue gas analysers mentioned above will be equally adept at ensuring compliance to these standards, allowing users to future-proof their toolbox.

To take a look at our entire flue gas analyser range visit this page or contact us on 0113 248 9966 for more information.