Understanding ATEX and IECEx schemes

The ATEX and IECEx directives are standards that need to be adhered to in relation to environments which pose a risk of fire or explosion.

By Lee Ray January 30, 2021

Due to the use of flammable gases, vapors or combustible dusts, some modern industrial environments pose an increased risk of fire and explosion. Within the EU, compliance with the ATEX Directive (2014/34/EU) is required, and in other markets the IECEx Equipment Certification Scheme applies.

Like all EU Directives, the ATEX Directive generally relies on the application of relevant standards to assess technical compliance. Compliance with the technical requirements of EU harmonized standards provides a presumption of conformity with the Directive’s essential requirements. As EU Directives are transposed into National Law, the UK already has a legal system in place that applies. The actual standards will remain the same as EU harmonized standards and will be carried across as UK designated standards to maintain a single standards model.

In cases where relevant harmonized standards do not exist, manufacturers are required to apply other EU standards, or applicable national or international standards. In rare cases, where a particular product is not covered by any existing standard, a manufacturer is required to complete a thorough evaluation of the product to demonstrate compliance.

Under the provisions of the ATEX Directive, evidence of compliance is generally demonstrated by the issuance of a Declaration of Conformity, from the manufacturer or supplier, based on an independent technical assessment. Special requirements apply to electrical products intended for use in high risk areas. The task of demonstrating compliance with the ATEX Directive rests with the party responsible for introducing a product into the EU marketplace. This is typically the product manufacturer, but it may also be an importer or wholesaler.

Annex II of the ATEX directive 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 harmonized standards. Depending on the equipment and its intended use, this means that more than one harmonized standard may be applicable to the evaluation and certification process. Updated harmonized standards lists are published periodically in the Official Journal of the European Union.

Annex I identifies three equipment categories, which depend on the environment in which the equipment is to be used. Cat 1 and 2 electrical equipment must be tested and certified by an EU Notified Body (NB), and an NB-certified quality system must also be maintained. Cat 2 and 3 non-electrical equipment does not require NB involvement, but technical documentation must be stored with an ATEX NB.

The IECEx scheme

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. Under the System, regulatory authorities in member countries accept certifications issued by IECEx-recognized Certification Bodies, regardless of their location.

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. Equipment certification under the IECEx Certified Equipment Scheme is based on a compliance assessment with the technical requirements found in the IEC 60079 series of standards (electrical products); the IEC 80079 series of standards for non-electrical products; and the application of quality systems which have been developed by TC 31. However, the IECEx scheme only assesses electrical equipment against the technical requirements of IEC standards issued by TC 31. This restriction can present an insurmountable hurdle for manufacturers of highly specialized electrical equipment, for which a relevant standard does not yet exist.

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 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 mark license number is issued to a manufacturer by an accepted IECEx certification body (ExCB) that has entered into a mark license agreement with the IEC.

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.

Conformity route

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 customized 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 located in IECEx member countries are required to accept test reports generated by IECEx-approved Testing Laboratories in support of an ATEX 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 as part of the ATEX certification process. This path would still require that certain ATEX- specific requirements are met, such as those related to equipment marking and documentation. However, the effort involved is relatively small compared with other alternatives.

This article originally appeared on Control Engineering Europe’s website.

Author Bio: Lee Ray is operations manager for Industrial Products (UK) at TÜV SÜD.