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The application of Intrinsic Safety in 2020

Author : Sean L Clarke, Managing Director, ExVeritas

15 October 2019

This presentation looks at why intrinsic safety has always been ‘evolving’ and adapting, the problems that can give rise to and the potential benefits to designers in the future, as together with the protection concept, electronic technologies has been evolving faster than any other technology we know.

Certification can always change through official standards interpretations, clarifications, interlaboratory test programs and of course a ‘new’ standard (such as the pending Edition 7 of the intrinsic safety standard), but how do we communicate what is considered to be the ‘correct’ methodology and interpretations to designers and how do these standards follow evolutions on components that can be used on limiting circuits? Does there really have to be ‘moving goalposts’ in such a dynamic and progressive subject, or can we finally say that we now know the definitive methodology to make a circuit intrinsically safe?

This presentation considers ‘why’ we assess the way we do (such as historical limitations on data), why there may be variability in assessment techniques between bodies and what we are doing collectively (such as interlaboratory testing programs for IECEx) or as individual Certification Bodies to overcome that. The presentation will also consider the new emphasis put on specific technical issues such as the limitations of the ‘design curves’, transients, service temperatures and safety factors, as well as new methodologies and possibilities related to the kind of methods used on intrinsically safe and why that is turning what was once ‘certification by theoretical analysis’ in to ‘certification by testing’.

Sean Clarke MSc CEng FIET

Sean Clarke is a Chartered Electrical Engineer and a Fellow of the Institute of Engineering and Technology and has 30 years’ experience in electronics, safety systems and Ex Certification. Sean is currently the Managing Director of ExVeritas, an ATEX Notified Body in the UK and EU and an IECEX Certification Body. ExVeritas Inc is also currently completing NRTL accreditation for North American Listing.

Sean Clarke MSc CEng FIET
Sean Clarke MSc CEng FIET

Sean has been involved in Notified Body intrinsic safety certification for over 20 years and has been involved with intrinsic safety as a design consultant and as an ATEX Notified Body and IECEx CB Certificate issuer (but never at the same time!) Sean also presents training for intrinsically safe circuit designers worldwide with both introductory and advanced workshop classes.

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