Understanding European (CEN) and International (ISO) standards

Standards are developed in Europe by Comité European de Normalization (CEN) and internationally by International Standardization Organization (ISO).

European Standards (ENs) are based on a consensus, which reflects the economic and social interests of 33 CEN Member countries channelled through their National Standardization Organizations. Most standards are initiated by industry. Other standardisation projects can come from consumers, Small and Medium-sized Enterprises (SMEs) or associations, or even European legislators.

ISO International Standards ensure that products and services are safe, reliable and of good quality. For business, they are strategic tools that reduce costs by minimising waste and errors, and increasing productivity. They help companies to access new markets, level the playing field for developing countries and facilitate free and fair global trade.

Selection of standards for emission monitoring

With the increasing requirement for the installation of continuous emission monitoring systems (CEMS) it is important that capital investment is protected and that instrumentation gives reliable, meaningful and repeatable data. Fitting EN15267, Air quality. Certification of automated measuring systems, approved equipment is one element but it is extremely important that the system is verified. The verification process requires the use of standard reference methods to underpin the data. 

Standard reference methods are essential for the effective measurement and control of air pollution. Such standards are developed at National, European and world-wide level.  The robustness and fitness for purpose of these standards is a function of the accumulated expertise and experience of the people who work together in committee to produce them. 

ISO standards are accepted on a case by case principle, it is not mandatory for a member country in the European Union (EU) to adopt a standard.

CEN standards must be implemented by member states of the EU. If a conflicting standard is in existence then this must be withdrawn.


Understanding how standards numbers work

Figure 1 shows how standards are adopted in the UK and published by British Standards Institution (BSI).

1. Should a standard be developed for example in the UK by BSI it will be prefixed by “BS” e.g. BS 3841-1:1994 Determination of smoke emission from manufactured solid fuels for domestic use.

2. When a standard is developed and published by CEN it is prefixed with “EN” and when introduced in the UK it will become a “BS EN” document e.g. BS EN 1911:2010 Stationary source emissions – Determination of mass concentration of gaseous chlorides expressed as HCl and as stated above any conflicting standard must be removed. A standard can be developed by CEN or ISO under a joint agreement and then it is published by CEN and ISO with a prefix “EN ISO” and in the UK it then becomes an “BS EN ISO” document e.g. BS EN ISO 23210:2009 Stationary source emissions – Determination of PM10/PM2.5 mass concentration in flue gas.

3.  When a standard is developed by ISO it is prefixed “ISO” and should this be adopted in the UK it becomes a “BS ISO” document e.g. BS ISO 25597:2015 Stationary source emissions – Test method for determining PM10/PM2.5 mass in stack gases using cyclone samplers and sample dilution.

 Standards developed and published by CEN are generally accepted as being the most robust. However, other standards are still important, as there are substances that are not, as yet, covered by CEN Standards. The choice of the method is often dictated by the requirements of EU Directives, i.e. Industrial Emission Directive (IED), where, for example, the use of CEN standards is mandatory. If the standard is not dictated by mandatory requirements then monitoring standards should be used in the following order of priority as given in the European IPPC Bureau’s Reference Document (http://eippcb.jrc.ec.europa.eu/) on the General Principles of Monitoring:

1. EN standards

2. ISO standards, other international standards, national standards

3. Validated laboratory-developed and non-standard methods

The intended application of the standard method must always be taken into account; for example, a CEN method may be less suitable than another less-rigorously validated standard method if the application is not one for which the CEN method was developed. 

The standards bodies have various technical committees that are responsible for the development of the standards. For emission to air the CEN committee is CEN/TC 264 Air Quality and for ISO is ISO/TC 146/SC 1 Air Quality – Stationary Source Emissions.

Scope CEN technical committee 264 (CEN/TC 264)

Standardisation of methods for air quality characterisation of emissions, ambient air, indoor air, gases in and from the ground and deposition, in particular measurement methods for air pollutants (for example particles, gases, odours, micro organisms) and methods for the determination of the efficiency of gas cleaning systems. Excluded are: - the determination of limit values for air pollutants; - workplaces and clean rooms; - radioactive substances

Scope of ISO technical committee ISO/TC 146

Standardisation of tools for air quality characterisation of emissions, workspace air, ambient air, indoor air, in particular measurement methods for air pollutants (particles, gases, odours, micro-organisms) and for meteorological parameters, measurement planning, procedures for Quality Assurance/Quality Control (QA/QC) and methods for the evaluation of results including the determination of uncertainty.

ISO/TC 146 structure

The Technical committee has various subcommittee / working groups

The following is a list of standards under the control of ISO/TC 146/SC 1

Further guidance and advice.

The Source Testing Association provides guidance to its membership and their clients. This includes methodology advice, guidance on equipment selection and training. Visit the STA web site for details www.s-t-a.org or for any technical question contact airanswers@s-t-a.org or telephone +44(0) 1462 457535.