Air quality monitoring
In a recent EnviroTech Online webinar hosted in partnership with the Source Testing Association (STA), emissions experts Anthony Sumner and David McGee delivered an overview of EN17255.
Drawing from decades of industry experience and insight, they unpacked the implications of the standard. Including an outline on its structure and key compliance considerations.
Here we take a dive into the main outcomes from the webinar.
As the regulatory landscape around emissions monitoring tightens across Europe, one technical standard is beginning to stand out: EN17255.
With the potential to reshape how environmental data is handled, this standard is poised to become the cornerstone of delivering, operating and ensuring the ongoing compliance of Automated Measuring Systems (AMS).
Understanding EN17255 is no longer optional - it’s essential.
EN17255 is a multi-part European standard focused on Data Acquisition and Handling Systems (DAHS).
These systems are critical for gathering and processing stationary source emissions data from Automated Measuring Systems (AMS) - the backbone of continuous monitoring at industrial sites.
The standard is split into four parts:
EN17255 is a series of standards which, between them, govern the process for the quality assurance of data received by a data acquisition and handling system (DAHS) from automated measuring systems (AMS), being used for monitoring emissions from stationary sources and quality ensured to EN 14181.
As well as being able to provide data for other key legislative drivers, such as the Industrial Emissions Directive (IED) and emissions trading schemes, such as UKETS and EU-ETS.
“EN17255 is not just another standard – it’s one that could change the shape of the emissions monitoring industry,” said Antony, who serves as Joint Equipment Officer for the STA.
“Whether you're a DAHS supplier, plant operator, stack tester or regulator, EN17255 has implications that touch every corner of the sector.”
At its core, EN17255 seeks to harmonise emissions reporting across Europe.
It aims to improve reliability, traceability and uniformity of data. For instance, the standard calls for:
It also introduces clearer mechanisms for managing issues like invalid data days, data capping and the integration of manual inputs – areas previously left open to interpretation.
Part 1 focuses on what needs collecting and how.
It specifies data points such as emissions measurements, peripheral data (like temperature and oxygen levels) and flow data.
It outlines how to calculate short- and long-term averages, and how to deal with exceedances and invalid data, with specific requirements in relation to the QAL 3 and how to deal with flow data EN ISO 16911‑1.
Part 2 turns to system functionality.
It mandates that DAHS must be capable of acquiring both analogue and digital data, process that data accurately, and meet prescribed data integrity requirements, such as data back-ups (at least daily) and data availability requirements (>99%).
Additionally, it puts the onus of the DAHS supplier to provide comprehensive documentation, from configuration files and alarm logs to calculation lists and end user training procedures with every system sold.
Part 3 deals with performance testing.
The only current route for certification under EN17255 Part 3 is currently via TÜV, the German testing, inspection, and certification organisation, which evaluates systems against the specific requirements as stated in Part 3.
By using a TÜV-certified DAHS, companies can demonstrate that their emissions monitoring systems comply with the relevant European regulations.
At TÜV DAHS can be certified not only to meet EN17255, but also localised standards, such as Germany’s VDI 4201 and specific German Environment Agency (UBA) requirements which are only applicable to Germany and do differ in some areas to that required currently in the UK.
Part 4 specifies the requirements for the installation and on-going QA/QC.
Plant operators are responsible for installing and maintaining the DAHS, including daily system checks and prompt action on alarms.
Independent ‘testing laboratories’ must verify that the installation is correct. Along with performing annual functional tests, ideally coordinated to be conducted at the same time as EN14181 QAL2 & AST exercises.
A key takeaway from the webinar was that EN17255 introduces a more complex web of responsibilities – potentially creating some confusion.
Coordinating between AMS and DAHS suppliers, stack testers and testing labs could prove operationally challenging.
“There are situations where four separate entities may need to collaborate to complete compliance testing,” noted David.
“That’s a big coordination exercise and one the industry needs to prepare for.”
Furthermore, EN17255 does not define what constitutes “appropriate accreditation” for testing laboratories.
This leaves some uncertainty in terms of who is qualified to carry out these checks.
Should labs be accredited to ISO/IEC 17025? Is an extension of existing MCERTS EN14181 accreditation sufficient?
Are stack testing laboratories equipped, willing and able to take on more responsibilities, by adding EN17255 to their portfolio services?
These are still open questions.
Although EN17255 is a European standard, its implications are already being felt beyond the EU.
Countries outside Europe, including those issuing international tenders, are increasingly asking for DAHS systems compliant with EN17255.
Suppliers hoping to compete globally will need to adapt to its requirements.
However, implementation remains uneven.
In the UK, the Environment Agency (EA) has yet to confirm how EN17255 will integrate into regulatory guidance.
Working Group 9 of CEN Technical Committee 264 is currently reviewing and revising the EN14181 standard and as part of that process looking at how it fits in with EN17255 and is expected to provide additional clarity soon.
Questions also remain around whether EN17255 certification will replace or coexist with MCERTS, the UK’s monitoring certification scheme.
“There’s a real possibility that multiple certifications will be needed across different countries, depending on their reporting requirements,” said Antony.
“That’s something suppliers need to be aware of.”
For plant operators, the rollout of EN17255 could mean:
For suppliers, it opens opportunities to develop new systems or modules tailored to specific national requirements. Such as biogenic carbon reporting or NOx trading compliance, of which some already exist in the marketplace.
But the transition won’t be seamless.
David pointed out that commissioning a DAHS can already take two days for simple systems, and much longer for more complex ones.
Add to that the new expectations around quality assurance, signal checking and reporting formats, and it’s clear the industry will need time and guidance to fully adapt.
EN17255 is more than a standard – it’s a signal.
It’s a signal that emissions monitoring is entering a new phase where data integrity and standardisation are not just aspirations but requirements.
As regulators look to harmonise reporting across Europe, and as industries face increased scrutiny over environmental performance, this standard will serve as both a guide and a benchmark.
While questions remain about implementation, testing accreditation and overlap with national schemes, one thing is certain: EN17255 will become increasingly central to how emissions data is collected.
For those in the emissions monitoring space, now is the time to get ahead of the curve.
IET 36.3 May
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