A Review of EA Guidance Document M22 for the Use of FTIR Analysers in Emissions Monitoring - Andy Tiffen

M22 is an Environment Agency Technical guidance note on measuring stack gas emissions using Fourier Transform Infra Red (FTIR) instruments. FTIR is a powerful analytical technique that is able to identify and quantify a large number of species from the common combustion process pollutants such as CO, NOx and SO2 through to complex organic compounds. Prior to the publication of M22 the internationally recognised standards that were used for the deployment of FTIR in the UK for the purposes of stack emissions testing were issued by the US EPA in the form of Method 320 and ASTM D6348-03. Protea Ltd, with its 15 year history of deploying FTIR in the UK, were the first to gain Mcerts accreditation under ASTM D6348-03 and the process was not an easy one. The ASTM standard includes different levels of validation that can be difficult to apply to specific monitoring projects and as a result many compromises were made during the accreditation process to enable a UK test houses to comply with the requirements. M22 was introduced to overcome these challenges.

History of M22

As a result of the compromises made when operating an FTIR under ASTM in the UK and the need for an in depth knowledge of FTIR operation and spectral analysis it became clear that a UK FTIR standard would be of great benefit. The Environment Agency therefore commissioned the National Physical Laboratory to create a viable standard for FTIR deployment within the emissions monitoring industry in the UK (M22). Many refinements were made to the first draft by NPL by an FTIR working group consisting of FTIR manufacturers, operators and the Source Testing Association (STA).

The final version from the working group was submitted to the Environment Agency for approval, where it had some revision at the request of technical specialists within the EA. These changes have now been a matter of debate amongst the FTIR operators and manufacturers. Protea is a member of the STA’s FTIR working group, which is assisting the EA in finalising Version 1 of M22. The objective is to create a standard that is both viable for users and provides increased assurance in the quality of data reported by test houses using FTIRs.

M22 outlines how an appropriate FTIR should be selected, how it is checked to ensure it is fit for purpose and how it should be operated in the field. Critically, M22 also covers the post-sampling Quality Assurance checks that are needed to confirm reliable results and it has removed many of the ambiguities of the ASTM method. M22 also harmonises with the style used in Europe for CEN standards