Guidance

MCERTS for stack emissions monitoring equipment at industrial installations

Published 20 October 2020

Applies to England

This guidance is for:

  • manufacturers of monitoring equipment who need to know what standards to meet in order to be able to sell their equipment in the UK
  • test laboratories who carry out testing of equipment on behalf of manufacturers to see if it meets the required standard

The Environment Agency set up our monitoring certification scheme (MCERTS) to provide guidelines on the standards you need to meet to monitor emissions that affect the environment.

1. Overview

Here we describe the certification process for:

  • continuous emission monitoring systems (CEMS)
  • transportable-CEMS (T-CEMS)
  • dust arrestment plant monitors

These systems measure the gases and particles in industrial chimney stacks, flues and ducts.

MCERTS for CEMS, T-CEMS and dust arrestment plant monitors is an official certification scheme that complies with EN ISO/IEC 17065 Conformity assessment – Requirements for bodies certifying products, processes and services.

Sira Certification Service (part of CSA Group) are a certification body appointed to run this scheme for us.

You can find the requirements for certification and for the manufacturer’s quality management system for manufacturing and design control of monitoring systems in:

  • EN 15267-1 Air quality - Certification of automated measuring systems - Part 1: General aspects
  • EN 15267-2 Air quality - Certification of automated measuring systems - Part 2: Minimum requirements for product quality assurance, initial assessment and on-going surveillance

2. Phases of product certification

Product certification comprises 3 phases.

  1. Laboratory testing – used to determine performance characteristics, where testing requires a highly controlled environment.

  2. Field testing – which must be at least 3 months long. The field test is carried out on processes representative of the intended industrial sectors and applications.

  3. Surveillance – initial and continuing – which comprises an audit of the manufacturing process to confirm that the manufacturer has provisions to ensure manufacturing reproducibility and to control any design changes to ensure that they do not degrade performance below the required standards.

The laboratory and field testing must be carried out by a test laboratory that has accredited procedures:

  • that comply with the requirements of EN ISO/IEC 17025 – General requirement for the competence of testing and calibration laboratories
  • for the performance characteristic tests that they need to carry out on the monitoring systems

The certification body examines the results of the laboratory tests and field tests using a group of independent experts known as the certification committee.

EN 15267-1 describes the roles and responsibilities of all parties involved in testing and certification. EN 15267-2 describes the quality assurance requirements of the manufacturing and design processes. Therefore EN 15267-2 applies primarily to manufacturers of CEMS and T-CEMS.

3. Manufacturing, repairs, maintenance and modifications to certified monitoring systems

Any spares or replacement parts for certified monitoring systems must meet the same performance standards as the original parts. Operators and equipment suppliers must be able to provide evidence that the replacement parts meet the required performance standards of the original equipment as specified by the manufacturer.

Manufacturers can modify certified monitoring systems, provided they can demonstrate that these design changes do not degrade the performance of the monitoring system below the required performance standards.

Manufacturers must have a management system which meets the requirements of EN 15267-2. This standard requires them to keep detailed records and drawings of all design changes to monitoring systems. To make sure the monitoring systems still meet the required performance standards the management system must also include a process for:

  • design verification
  • inspection
  • testing

The certification body will audit the design changes to monitoring systems to make sure they meet the requirements of product certification.

Manufacturers must notify the certification body of any modifications to equipment that may have a significant effect on the performance of the monitoring system. EN 15267-2 provides details of the audit and certification requirements for the manufacturer’s management system.

Design modifications or extensions to the range of application of the monitoring system may require renewed testing. The extent of this renewed testing will depend upon the nature of the modifications to the monitoring system.

If there is evidence that a modification has only limited effects on the performance of the monitoring system, then it would not be necessary to retest the monitoring system completely. In such cases, only a supplementary test would be required to the applicable performance standards.

For software modifications – particularly in measuring instruments – the manufacturer must provide the certification body with documentation that shows the nature of the modification and its effects on operation and functionality. The certification body will then decide if further testing is required.

A monitoring system is certified with a specified type of sampling system. If the analyser is used with different sampling system components from those originally tested, a suitable third party test laboratory must provide evidence to prove the monitoring system still meets the performance requirements with the alternative sampling system.

4. Previous performance tests

Manufacturers that have type approval test reports to demonstrate compliance with the requirements of the German Environment Agency (Umweltbundesamt - UBA) are able to submit these reports along with their application for MCERTS certification.

5. Certificate validity

Certificates are valid indefinitely, subject to:

  • a five-yearly review
  • the satisfactory control of manufacturing processes and design changes
  • compliance with the requirements of EN 15267-1 and EN 15267-2
  • compliance with the applicable performance testing standards

The certification body keeps the validity of the certification of the monitoring system under continuous appraisal. This takes into account:

  • reports from technical changes
  • post-certification surveillance as defined in EN 15267-1
  • any changes in the technical requirements notified by the Environment Agency
  • any complaints from users

6. Testing on a highly demanding process

Monitoring systems will ordinarily be tested on a highly demanding process, such as a large combustion plant, municipal waste incinerator or a gas-fired turbine, depending on the intended application.

If the monitoring system performs acceptably on these applications, then experience has shown that it will generally perform well on the majority of other processes.

There will always be exceptions, and it is the manufacturer’s responsibility, together with the user, to ensure that the monitoring system will perform adequately on a specific process.

7. Fixed and transportable CEMS

Here we describe the certification process for CEMS and T-CEMS. These are systems used to measure the gases and particles in industrial chimney stacks, flues and ducts.

This information does not apply to highly-portable, handheld emissions monitoring systems (HEMS). This type of system includes compact emissions-monitoring systems designed for low risk medium sized combustion plants, landfill-gas monitoring systems, and some types of fugitive emissions monitoring systems. Use the performance standard for handheld emission monitoring systems instead.

7.1 Required standards for CEMS

CEMS are designed for fixed and permanent use at a stack.

The following standards are required for the testing of CEMS under MCERTS:

  • EN 15267-3 Air quality – Certification of automated measuring systems – Part 3: Performance criteria and test procedures for automated measuring systems for monitoring emissions from stationary sources
  • EN 15267-4 Air quality – Certification of automated measuring systems – Part 4: Performance criteria and test procedures for portable automated measuring systems for monitoring emissions from stationary sources
  • EN ISO 16911-2 Stationary source emissions – Manual and automatic determination of velocity and volume flow rate in ducts Part 2: Automated measuring systems

EN16911-2 includes extra requirements to EN 15267-3 and therefore provides additional assurance to users of flow-monitoring CEMS if required.

EN 15267-3 covers the first quality assurance level (QAL1) and third quality assurance level (QAL3) requirements of EN 14181 Stationary source emissions - Quality assurance of automated measuring systems. It provides a way to demonstrate compliance with the uncertainty requirements specified in the Industrial Emissions Directive (IED) (2010/75/EU).

EN 15267-4 provides performance requirements for T-CEMS. Manufacturers have developed these systems for use within standard reference methods (SRMs) for compliance monitoring and for the second quality assurance level (QAL2) requirements of EN 14181.

7.2 Required standards for T-CEMS

T-CEMS are a variant of CEMS which the manufacturer has designed for periodic use at more than one stack and not for permanent use at any given stack.

T-CEMS are used for:

  • regulatory compliance monitoring
  • verifying and calibrating installed CEMS, according to the requirements of BS EN 14181
  • providing temporary back-up systems when permanent CEMS are not operating

The requirements for T-CEMS are specified in EN 15267-4. The tests are either identical or similar to those for CEMS. Therefore, manufacturers submitting a CEMS for certification as a T-CEMS may use existing test data, where applicable. However, there are some additional tests that are specific to systems used for periodic monitoring.

The scope of EN 15267-4 includes T-CEMS for gases, including total organic carbon and particulate matter. The performance requirements for gases are specified in EN 15267-4. The requirements for particulate monitoring T-CEMs are not specified because there are currently no existing T-CEMs available for measuring particulate matter.

T-CEMS, like CEMS, are tested in a laboratory and in the field. The field tests must be on at least 5 installations, which represent the conditions expected for the T-CEMS.

T-CEMS must also demonstrate equivalence to the applicable SRM, when applying the requirements of EN 14793 – Stationary source emissions – Demonstration of equivalence of an alternative method with a reference method.

7.3 Scope of determinands

The determinands covered by MCERTS for CEMS and T-CEMS include, but are not restricted to:

  • sulphur dioxide
  • oxides of nitrogen (including nitrous oxide)
  • carbon monoxide and carbon dioxide
  • hydrogen chloride
  • hydrogen fluoride
  • methane
  • sulphur hexafluoride
  • hydrofluorocarbons and perfluorocarbons
  • mercury
  • formaldehyde
  • benzene
  • volatile organic compounds, expressed as total organic carbon
  • oxygen
  • water vapour
  • particulate matter, for installations which must comply with the requirements of EN 14181
  • flow rate

7.4 Scope of use

MCERTS for CEMS and T-CEMS can apply to waste incineration and large combustion plants (including gas turbines), as well as some other types of installation specified in the IED.

7.5 CEMS that measure particulates

MCERTS for CEMS only covers the requirements for particulate CEMS that must meet the requirements of EN 14181 (these are referred to as first level). There are also second and third level particulate CEMS – these are covered in the section ‘MCERTS for dust arrestment plant monitors’.

7.6 Main performance characteristics

The main CEMS and T-CEMS performance characteristics are assessed by a combination of laboratory and field tests. The CEMS and T-CEMS performance characteristics are specified in EN 15267-3 and EN 15267-4 respectively.

7.7 Flow monitoring CEMS

In the table below are additional performance criteria that are specified in EN 16911-2 but are not yet included in EN 15267-3.

Additional performance criteria and tests according to EN ISO 16911-2 for CEMS monitoring gas flow in laboratory tests

Performance characteristic Performance criteria Test in clause in EN 15267-3
Repeatability standard deviation at upper reference point Less than 2.0 % 10.11
Influence of vibration Less than 2.0 % 10.18
Assessment of provisions to perform QAL3 checks Pass 10.13
Assessment of provisions to perform lack-of-fit tests Pass 10.12

8. MCERTS for dust arrestment plant monitors

Here we outline the certification process for automated dust arrestment plant monitors installed in industrial chimney stacks, flues and ducts.

There are 3 levels of continuous emissions monitoring systems (CEMS) that monitor particulates, known as first, second and third level.

MCERTS for first level CEMS are tested and certified to the requirements of MCERTS for CEMS and transportable-CEMS. For this guidance, see the section on ‘Fixed and transportable continuous emission monitoring systems’.

MCERTS for second and third level particulate monitoring CEMS apply to dust arrestment plant monitors. The definitions are that:

  • second level are calibrated in mass concentration units (for example mg/m3) and used for dust arrestment control purposes – these are also called filter-dust monitors
  • third level indicate a change in the emissions level or a change in the magnitude of dust pulses created by the cleaning process of dust arrestment plants – these are also called filter-leakage monitors

8.1 Required standards for dust arrestment plant monitors

Use this standard for the testing and certification of dust arrestment plant monitors under MCERTS: EN 15859 Air quality – Certification of automated dust arrestment plant monitors for use on stationary sources – Performance criteria and test procedures.

This tests performance and accuracy of:

  • first level monitors against a standard reference method, under field conditions
  • second level monitors against a MCERTS certified first level particulate CEMS, under field conditions

Measurements made by dust arrestment plant monitors certified to the requirements of this standard do not meet the:

  • uncertainty requirements for large combustion and waste incineration plants
  • third quality assurance level (QAL3) functionality of EN 14181 - Stationary source emissions - Quality assurance of automated measuring systems

9. What to do next

Find out more about MCERTS product certification on the:

You can contact the Environment Agency if you need any help.

General enquiries

National Customer Contact Centre
PO Box 544
Rotherham
S60 1BY

Email enquiries@environment-agency.gov.uk

Telephone 03708 506 506

Telephone from outside the UK (Monday to Friday, 8am to 6pm GMT) +44 (0) 114 282 5312

Monday to Friday, 8am to 6pm.