This post is by Simon Barrowcliff, Safety Director, TRaC
Few people know that the UK pioneered ensuring the safety of equipment in potentially explosive atmospheres. In fact, much of the basis data for all Ex standards throughout the world was obtained by the Health & Safety Labs in Buxton in the late 1940s.
Hazardous atmospheres occur when there are flammable gases (including vapours and mists) or dusts present. The flammable material is the fuel that, when combined with oxygen from the atmosphere and an ignition source, can cause a dangerous explosion. This can happen in a wide variety of locations, such as oil refineries, chemical plants, saw mills, paint spray shops, mines and even custard power factories!
Due to the common heritage of the research at Buxton, standards around the world have many similarities. The UK's ATEX certification and the international IECEx standards are very similar, with only minor points of difference.
Few people know that the UK pioneered ensuring the safety of equipment in potentially explosive atmospheres. In fact, much of the basis data for all Ex standards throughout the world was obtained by the Health & Safety Labs in Buxton in the late 1940s.
Hazardous atmospheres occur when there are flammable gases (including vapours and mists) or dusts present. The flammable material is the fuel that, when combined with oxygen from the atmosphere and an ignition source, can cause a dangerous explosion. This can happen in a wide variety of locations, such as oil refineries, chemical plants, saw mills, paint spray shops, mines and even custard power factories!
Due to the common heritage of the research at Buxton, standards around the world have many similarities. The UK's ATEX certification and the international IECEx standards are very similar, with only minor points of difference.
Ex standards use a concept of zoning, where the atmosphere is classified based on the likelihood of an explosive atmosphere being present. ATEX and IECEx use 3 zones, with zones 0, 1 and 2 representing the presence of gas and zones 20, 21 and 22 covering dust. These zones are defined as:
• Zone 0/20: Flammable atmosphere is present continuously, or for a long period of time (typically >1000 hrs/yr)
• Zone 1/21: Flammable atmosphere is likely to be present during normal operation (10 to 1000 hrs/yr)
• Zone 2/22: Flammable atmosphere is not likely to occur during normal operation, and will exist for only a short time if it occurs (<10 hrs/yr)
The most commonly used standard in the US, however, the NEC article 500 system, only defines two zones. Even so, they map conveniently to the zones used in the ATEX standard, as the US Div 2 corresponds directly to Zone 2/22. Div 1 corresponds to Zone 1/21 and, as there is no direct equivalent for Zone 0,20 in the US standard, they are also included in Div 1.
It's great to see that the UK's lead in the important area of ensuring the safety of electrical equipment in potentially explosive atmospheres has not only put us at the forefront of preventing explosions, but has also resulted in similar standards across the globe. The level of consistency has made compliance easier for companies wishing to sell products world-wide, ensuring safe products are available in all countries.
Some previous Certification & Test entries:
* Why some certifications need factory inspections
* Can Standards really be improved?
* What does a UKAS schedule mean?
* Improve temperature testing by optimising chamber airflow and distribution
* Which standard should I apply?
* Are EMC Standards Really Necessary?
* Standards really do help the economy
* Spot the difference - Why military products need CE marking
* Safety Standards for Military applications
* 9 months to go until testing above 1GHz is a reality - are you ready?
* EMC - It's all in the cables!
* Which CE badge have you got?
• Zone 0/20: Flammable atmosphere is present continuously, or for a long period of time (typically >1000 hrs/yr)
• Zone 1/21: Flammable atmosphere is likely to be present during normal operation (10 to 1000 hrs/yr)
• Zone 2/22: Flammable atmosphere is not likely to occur during normal operation, and will exist for only a short time if it occurs (<10 hrs/yr)
The most commonly used standard in the US, however, the NEC article 500 system, only defines two zones. Even so, they map conveniently to the zones used in the ATEX standard, as the US Div 2 corresponds directly to Zone 2/22. Div 1 corresponds to Zone 1/21 and, as there is no direct equivalent for Zone 0,20 in the US standard, they are also included in Div 1.
It's great to see that the UK's lead in the important area of ensuring the safety of electrical equipment in potentially explosive atmospheres has not only put us at the forefront of preventing explosions, but has also resulted in similar standards across the globe. The level of consistency has made compliance easier for companies wishing to sell products world-wide, ensuring safe products are available in all countries.
Some previous Certification & Test entries:
* Why some certifications need factory inspections
* Can Standards really be improved?
* What does a UKAS schedule mean?
* Improve temperature testing by optimising chamber airflow and distribution
* Which standard should I apply?
* Are EMC Standards Really Necessary?
* Standards really do help the economy
* Spot the difference - Why military products need CE marking
* Safety Standards for Military applications
* 9 months to go until testing above 1GHz is a reality - are you ready?
* EMC - It's all in the cables!
* Which CE badge have you got?
After obtaining his Bachelor's degree in engineering, Jonathan worked for a number of engineering companies prior to obtaining a teaching role at the University of Hull (England). In 1995 he joined KTL, an internationally renowned test laboratory which then became TRaC, as part of the Digital Group specialising in regulatory requirements for digital telecommunications equipment. During his time at the company he has, among other things, been appointed as Senior Protocol Engineer, and Approvals and Homologation Group Manager. Jonathan has actively participated in various technical working groups for the ZigBee Allianceâ and is currently the ZigBee Qualification Group (ZQG) Lead Technical Editor. 
Steve is Managing Director for the EMC and Safety business of TRaC and has been involved in EMC and product approvals for 19 years. In addition to the day to day running of the business, Steve is actively involved in EMC standardisation both in commercial and defence areas. In addition to being the UK Principal expert on EMC standardisation of Industrial, Scientific and Medical (ISM) products he is also the convenor of CISPR/B/WG1 who has the responsibility of writing the International standard, CISPR 11. Steve wrote the CE marking annex to the UK's defence EMC standard as well as being co-convenor of CENELEC TC210/WG9, responsible for writing a guide on approval of military systems with commercial (CE Marking) requirements.
Joe Lomako MSc is the Business Development Manager of Telecoms and Radio at TRaC. He has been involved in the testing and compliance industry for over 15 years. Prior to joining TRaC Joe specialised in EMC, EMF Exposure and Radio compliance.
Appointed Test Manager in 2007, following three years as Projects Manager at TRaC, having previously worked as Head of Environmental Testing at another UKAS accredited test house. Over 20 years' experience of modelling, testing and measurement in the structural dynamics and seismic fields.
Chris has worked in electrical safety compliance for over 17 years. Having previously worked for BSI, he joined TRaC in 1996, progressing through a number of testing roles before becoming Safety Product Manager in 2006.
Appointed Commercial Manager - Analysis in November 2009. Prior to joining TRaC, he was the Business Development Manager at Onward Technologies, an engineering services company based in India. Graham has spent over 20 years working in the CAD / CAE domain selling both engineering services and engineering systems. 
Stephen Tait joined KTL, an internationally renowned test laboratory which then became TRaC, as part of the Telecom Group specialising in telecommunications product testing for worldwide approvals. Stephen is also responsible for the Telecoms commercial activities within the TRaC group.
Simon Barrowcliff is the Director of the ATEX Notified Body at TRaC. He set up TRaC's Lancashire-based, ATEX business in 2002 and has been heavily involved in EX testing and compliance since then. Simon also runs TRaC's certification schemes for electrical safety under the IECEE CB scheme. He is a chartered electrical engineer with more than 20 years experience of product compliance for electrical and mechanical equipment.
Appointed Managing Director in November 2007. Previously he was Test Facilities Manager for Flight Refuelling, part of the Cobham group, and spent his early career in the Environmental Engineering Department of British Aerospace at Stevenage.
Brendan was appointed Sales Director in August 2009. He joined the group in 2005 as Business Development Manager for environmental test services. Before joining TRaC he spent five years in Application Engineering and Technical Sales roles for automotive test equipment. He studied Mechanical and Manufacturing Engineering at Trinity College Dublin.
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