• • • HAZARDOUS AREA EQUIPMENT • • •


Ensuring safety in an explosive environment


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


I


n many industrial environments, gases, dusts or vapours can be found in the air, and if these materials ignite, an explosion could cause


damage and injury. Specific certification of equipment used in such environments is designed to minimise or prevent the potential risk of explosion. Therefore, if your production processes involve flammable liquids, gases, vapours or combustible dusts, or you provide equipment that’s used in such places, you may require expert guidance or product/system certification. For some modern industrial environments which


pose an increased risk of fire and explosion, equipment must meet the enhanced requirements of applicable regulations and standards. Within the European union (EU), compliance with the ATEX Directive (2014/34/EU) is required as it describes the minimum safety requirements of the workplace and equipment used in explosive atmosphere. The ATEX Directive is enacted in the UK as the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016 (UKEX). 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).


Potential ignition sources Increasingly, equipment is being used in potentially hazardous environments to automate or control certain production processes, but the normal operation of equipment often involves actions or reactions that are a potential ignition source, such as:


• Electric sparks – A poor quality component or electrical connection can fail, inadvertently producing an electric spark that can ignite gases or nearby materials.


• High operating temperature – Depending upon the particular hazardous atmosphere present, hot surfaces of equipment could cause an auto- ignition. Process system heating effects by ‘work done’ i.e. pumping systems, must also be considered as these can elevate the ‘product’ above its flashpoint.


• Electrostatic discharge – Some normal equipment operations can generate static electricity, which can serve as an ignition source at certain levels.


• Friction sparks – Equipment operation may also involve repeated contact between materials, resulting in friction that can produce heated sparks and material contents must be considered as a potential ignition source


14 ELECTRICAL ENGINEERING • OCTOBER 2021 electricalengineeringmagazine.co.uk To be able to eliminate the potential ignition


sources, which can include considered faults, prior to manufacture and installation, a pre-assessment is recommended to understand the equipment design, operation and desired location and environment. This can also be carried out for existing non-electrical equipment which was manufactured and installed prior to July 2003.


Tackling hazardous


environments The UKCA Ex Regulation provides a detailed overview of the essential health and safety requirements applicable to equipment used in hazardous environments. However, the specific technical requirements to demonstrate compliance for various types of equipment and operating environments are found in nearly 100 individual harmonised standards. Depending on the equipment and its intended use, this means that more than one harmonised standard may be applicable to the evaluation and certification process. Under the provisions of the UKCA Ex Regulation,


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, and special requirements apply to products intended for use in high risk areas. The task of demonstrating compliance rests with the party responsible for introducing a product into the marketplace. This is typically the product manufacturer, but it may also be an importer or wholesaler. 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. Testing and assessment activities are carried out


by IECEx-approved Testing Laboratories, with certifications issued by IECEx- approved Certification Bodies. Self-certification of products is not accepted under the IECEx scheme as equipment certification 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 into IEC 80079-34 specifically.


Confirming compliance The UKCA Ex Regulation’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. Equipment used in hazardous environments


must be expressly designed to minimise risks, and manufacturers of electrical, non-electrical, electronic, mechanical equipment and systems must ensure that their products meet the requirements of applicable regulations and standards. Although similar in scope and intent, it is clear that the UKCA Ex Regulation and the IECEx Scheme encompass different requirements and utilise different assessment approaches, complicating the regulatory approval process for equipment manufacturers supplying multiple regions.


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