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Ex Certification Schemes

Author : Ron Sinclair MBE, SGS Baseefa

22 November 2021

This briefing note provides a concise guide to the various certification schemes (and related standards and bodies) for equipment offered for use in potentially explosive atmospheres.

ATEX, etc.

The European ATEX Directive has been around since its first publication in 1994. The current version is 2014/34/EU.  The directive is not itself law but requires adoption in each individual country within the European Economic Area (EEA). The UK adopted the 2014 ATEX Directive in 2016 as The Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016, UKSI 2016:1107. For most people, the UK Regulations did not figure in any specific documentation and the common parlance is just ATEX.


In preparation for Brexit, the UK Government issued a very large amending Statutory Instrument, applying to a whole raft of legislation: UKSI 2019:696. This included several pages converting the existing ATEX SI to be fit for purpose after Brexit. There have been several other amending SIs since then, so the correct reference for the UK law, as now applicable, is UKSI 2016:1107 (as amended).

Because the full statutory instrument title is a mouthful, the UK based certification bodies agreed to use the term “UKEX” as the nearest parallel to the European term “ATEX”. Therefore, UKEX replaces ATEX as part of the certificate number, as well as being a generic reference in the UK as a substitute for ATEX.

All the UK bodies that had previously been EU Notified Bodies became UK Approved Bodies. However, because of the Northern Ireland Protocol, they also became Notified to the European Commission, solely for issuing certificates that would be valid in Northern Ireland.  None of the UK Approved Bodies believe this additional notification will be of much use to manufacturers, as all such bodies in the Ex field are partnered with a continuing EU Notified Body who can issue ATEX certificates valid in the whole of the EEA as well as Northern Ireland.


Where the legislation requires the issue of a Notified Body EU-Type Examination Certificate for ATEX, the same requirements apply requiring the issue of an Approved Body UK-Type Examination Certificate for UKEX. For both schemes, the bodies can continue to offer voluntary Type Examination Certificates in their role as an accredited Certification Body, rather than as a Notified Body or an Approved Body. The purpose of such certificates is to satisfy the requirements of the final purchasers of equipment, who want the confidence of buying equipment that has been reviewed by a third party, rather than just self-declaration by the manufacturer. Such certificates have no legal status and normally only apply to non-electrical Category 2 equipment or any Category 3 equipment.

Everyone is familiar with the stylised Ex within a hexagon. This symbol is given in the standards that support both ATEX and UKEX, so does not change. The single coding on a label (familiar from ATEX) applies equally to ATEX and UKEX equipment.


All the standards that were on the EU Commission list of Harmonised Standards for ATEX were transposed and became Designated Standards for the UK legislation. Use of such a standard gives a presumption of conformity with the Directive/Statutory Instrument for those requirements covered by the standards. The Designated Standards list continues to refer to standards by their EN number, rather than their BS number. The coverage of each standard, in respect of the directive/SI requirements, is given in a specific European Annex to the standard.

Not every Essential Health and Safety Requirement given in the directive and SI can be the subject of certification prior to sale. For example, a certificate cannot confirm that, in say three years’ time, an intending purchaser will tell the manufacturer about exposure to a particular hazard beyond those listed in the standards. Therefore, this becomes covered by the manufacturer’s instructions, requiring the purchaser to advise the manufacturer.

CE and UKCA marking

The required EU CE Marking is supported by ATEX documentation; UKCA marking is supported by UKEX documentation. The UKEX Certificate number and UKCA marking can be applied either additionally to the ATEX marking, or as an alternative. Most manufacturers seem to have elected to show both sets of marking at the same time. The relevant number of the Notified Body and Approved Body, responsible for supervision of manufacture, must be marked adjacent to the CE and UKCA marking.

For components, where the CE and UKCA marking are not applied, both numbers should still be shown, if relevant.


Alongside the legal certification schemes, IECEx is a voluntary certification system that can support both ATEX and UKEX, as well as providing a direct passport to many other markets. The IECEx Report can form the technical basis of both ATEX and UKEX certification, and is transferrable between certification bodies in the system.

IECEx is international and, because of its nature, voluntary in application ( legal requirement) but it should be noted the United Nations, through UNECE, has published a document recommending that any new certification schemes developed anywhere in the world should be designed to be compatible with IECEx. Certain countries, notably Australia, New Zealand, India, and Israel have given legal recognition to IECEx, alongside their own national schemes.

Where there is no formal legally recognised scheme in a country, IECEx is usually the preferred form of certification. Certain countries, such as Brazil, make special legal provision for the conversion of IECEx certification into their national scheme. Certification bodies are only accepted into IECEx if they can supply legally recognised certificates in their own country and they undertake to use IECEx reports from elsewhere as the basis of local certification.

Quality Control of manufacture

The QA schemes for both ATEX and UKEX have virtually identical requirements to IECEx. Although ATEX and UKEX can be dealt with separately, it is common practice for the initial assessment and audit of production facilities to follow IECEx practice, resulting in an IECEx QAR (Quality Assessment Report).  From this the QAN (Quality Assessment Notification) for ATEX and the UKQAN for UKEX can be drafted.


Although there are differences in the schemes, there is sufficient commonality that the technical work need only be done once.  It can then form the basis for all three schemes. All the current UK Approved Bodies are also members of the IECEx scheme and have EU based partners for issuing the ATEX documentation, thus effectively providing a one-stop-shop.

This document is distributed by the Ex-SIG as an information service to the SIG membership. No guarantee is made by the institute or the author(s) concerning the accuracy, reliability or completeness of the information provided. This document should not be construed as providing advice.  Readers should satisfy themselves of the applicability of the information provided.  Readers make use of the information provided at their own risk. 

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