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IECEx: a view from the chair (7)

03 August 2015

Prof. Dr. Thorsten Arnhold, the chairman of IECEx, gives his insight on developments within the organisation and the wider world of explosion protection. This month, he discusses what is for him the greatest challenge and opportunity over the next two years inside the IECEx system: the implementation of non-electrical explosion protection into the conformity assessment practice.

Prof. Dr. Thorsten Arnhold, IECEx chairman and VP Technology at R.STAHL
Prof. Dr. Thorsten Arnhold, IECEx chairman and VP Technology at R.STAHL

We are expecting the new standards IEC 80079-36 and 80079-37 to be published in 2016. According to the IECEx rules of procedure, a manufacturer’s self-declaration will not be an option to get a Certificate of Conformity. That means all nonelectrical equipment for use in hazardous areas needs a third party conformity assessment.

Some may shrug the shoulders and say: “So what, we have more than 50 IECEx - Certification Bodies (CB) in the world. Let`s pile up their capacity and extend the business.”

Unfortunately there is no such easy solution. Non-electrical is not as easily evaluated, tested and certified as electrical. If a manufacturer today wants to get an IECEx certificate for a light fitting, he can send the product to the IECEx-CB. The CB gives an order to an Ex-test laboratory (TL) to carry out exactly defined type tests according to the relevant IEC standards.

If everything is OK, the Ex-TL issues a test report which together with the Assessment Report of the manufacturer`s quality management system (QAR), is the basis for the IECEx Certificate of Conformity (CoC).

For non-electrical equipment, the heart of the test procedure is the ‘Ignition hazard assessment’, a systematic and structured analysis of the product to see if there are elements which can cause the ignition of an explosive media under normal operation conditions (EPL a), plus expected malfunctions (EPL b), plus rare malfunctions (EPL c). There are 13 possible ignition sources listed in IEC 80079-36 (3.1.1):
•  Hot surfaces
•  Flames and hot gases
•  Mechanically generated sparks
•  Electrical sources
•  Stray electric currents, cathodic corrosion protection
•  Static electricity
•  Lightning
•  Radio frequency electromagnetic waves
•  Electromagnetic waves including optical radiation
•  Ionizing radiation
•  Ultrasonics
•  Adiabatic compression and shock waves
•  Exothermic reactions, including self-ignition of dusts.

All these ignition sources have to be considered when somebody is dealing with electrical explosion protection. But, for non-electrical equipment, these sources will no longer be hidden in obvious electrical contacts, lamp holders, motors or resistors. Now we have to search for them in couplings, gearboxes, brakes, hydraulic and pneumatic motors. To find them and to develop efficient protection concepts needs a completely different kind of competence than that for electrical equipment. This is also true for the test and certification process!

The latter will change significantly. It will be not sufficient for the manufacturer to send the test sample together with a written description to the Ex-CB and Ex-TL and to wait for the certificate.

For complex products (and most of the machines used in hazardous areas are pretty complex) it will be necessary for the manufacturer’s experts to carry out the ignition hazard assessment close together with the experts of the Ex-TL. They have to explain the protection concept and the TL has to find out if it is appropriate.

This new procedure will establish a lot of new requirement for the Ex-CBs. They will need many experts who are able to do complex evaluations, as well as new logistic concepts to carry out evaluation activities outside the laboratories, i.e. at the manufacturer’s facility or at the end customer`s site. Similar requirements will be needed for the manufacturers of non–electrical equipment.

At IECEx we are preparing the appropriate documents and procedures in a special working group (WG 15). For manufacturers of non-electrical equipment intended for use in hazardous areas, it would be wise to use the time until the standards are published to also give this serious consideration.

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