ATEX, UKEX and IECEx scheme confusion

By Rhodri Morgan ex-protection UK technical lead at TÜV SÜD, a global product testing and certification organisation


he ATEX directive consists of two EU directives which describe the minimum safety requirements of the workplace and equipment used in explosive atmosphere. Following Brexit, the ATEX Directive is enacted in the UK as the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016 (UKEX). Under the provisions of the ATEX Directive, evidence of compliance is generally demonstrated by the issuance of a manufacturer’s, or supplier’s, Declaration of Conformity which is based on an independent technical assessment of documentation and testing where required. The task of demonstrating compliance with the ATEX Directive rests with the party responsible for introducing a product into the EU and now also the UK marketplace, such as the product manufacturer, importer or wholesaler. Annex II of the ATEX directive for Europe, or the UKSI 2019:696 schedule 25 for the UK, addresses design and construction requirements for equipment and protective systems. However, the specific technical requirements to demonstrate compliance for various types of equipment and operating environments are found in nearly 100 individual harmonised standards for Europe, and now the designated standards list for UK, which may be applicable to the evaluation and certification process.

Annex I identifies three equipment categories, which depend on the environment in which the equipment is to be used. Category 1 and 2 electrical equipment must be tested and certified by an EU Notified Body (NB) or UK Authorised body (AB), and a certified quality system must also be maintained. Category 2 and 3 non-electrical equipment does not require NB or AB involvement, but technical documentation must be stored with an ATEX NB or UKEX AB, depending on which country the equipment will ultimately be located in.


Outside of the EU or the UK, equipment certified in connection with the voluntary IECEx Certified Equipment Scheme meets the regulatory requirements of more than 30 countries. In addition, the IECEx System has been endorsed by the United Nations Economic Commission for Europe (UNECE). As a result, non-IECEx member countries can implement legal frameworks into their respective national legislation, simply by adopting the IECEx System and Schemes. The IECEx conformity mark is evidence that a manufacturer’s products have been independently assessed against the additional requirements of the IECEx conformity mark licensing system.

The primary goals of the IECEx Scheme are to reduce testing and certification cost, speed up market access for new products and equipment, and increase international acceptance of product assessment results. The Scheme achieves these goals through the issuance of an International Certificate of Conformity.

Under the IECEx Scheme, testing and assessment activities are carried out by IECEx- approved Testing Laboratories, with certifications issued by IECEx- approved Certification Bodies. Assessment is based exclusively on compliance with standards issued by Technical Committee (TC) 31 of the International Electrotechnical Commission (IEC). Self- certification of products is not accepted under the IECEx scheme.

The IECEx Scheme classifies equipment according to the hazardous environment areas where specific equipment can be used. Equipment Protection Level (EPL) Ga/Da and Gb/Db corresponds with the ATEX Categories 1 and 2 respectively, while Gc/Dc corresponds with the requirements of ATEX Cat 3.

The use of IEC standards and independent third- parties for testing, assessment and certification are essential elements in the widespread acceptance of IECEx- certified equipment. Indeed, in countries that do not participate in the IECEx System, or which still require separate national testing and certification, IECEx equipment tests and assessment reports are widely accepted by regulatory officials, which may eliminate the need for duplicate testing.

The ATEX Directive’s conformity assessment process provides a certification route for a broad range of electrical and non-electrical equipment. It also offers significant latitude in the technical assessment of non-conventional equipment through the use of a technical construction file. This can be especially important to manufacturers of customised equipment, or equipment specifically designed for unique applications. Other considerations include restrictions on the use and acceptance of previously generated ATEX test data. Under the IECEx Scheme, equipment must be tested and certified by IECEx-approved Testing Laboratories and Certification Bodies, and evidence of prior testing conducted by an EU Notified Body is not acceptable. However, EU NBs or UK ABs located in IECEx member countries are required to accept test reports generated by IECEx- approved Testing Laboratories in support of an ATEX and UKEX certification submittal. Given these considerations, the preferred conformity assessment path for many manufacturers has traditionally involved first obtaining equipment certification under the IECEx Certified Equipment Scheme. The IECEx testing data is then be submitted to an EU NB for ATEX or UK AB as part of the certification process. This path would still require that certain ATEX and UKEX specific requirements are met, such as those related to equipment marking and documentation. However, the effort involved is relatively small compared with other alternatives.


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