Unravelling ATEX - A Guide for Everyone

Unravelling ATEX - a guide for everyone


Because several standardisation bodies have input into the ATEX regulatory standard, the descriptive markings used by these multiple bodies can be a point of confusion, as often the markings are similar. For example, markings like II and IIG can prove perplexing. “II” indicates non-mining applications, whereas “IIG” is a gas safety marking from CENELEC.

Our first blog of a two-part series will demystify the basic principles and markings of ATEX while using the example of our particle size analyser Eyecon2 to demonstrate ATEX compliance.

ATEX background and history

The industrial revolution made it possible for the advancement in technology and manufacturing we see today, but I doubt many of us would switch places with those working in the dangerous conditions our ancestors were subjected to. Thankfully, regulations developed to ensure that the workplace and the equipment in it are designed with our safety in mind. One such necessary regulation is ATEX.  This regulation is designed for the safety considerations of potentially hazardous explosive environments throughout the European Union (EU) but is also accepted by many organisations working in countries outside the EU. 

The ATEX Directive describes a hazardous area as any location where there is a risk of an explosion due to the presence of flammable gas and vapours.

ATEX (equipment intended for use in ATmosphere EXplosible)  is the combination of two EU directives to meet the minimum safety requirements for an explosive risk.

  1. Workplace - ATEX 137  Directive 1999/92/EC
  2. Equipment - ATEX 214  Directive 2014/34/EU

These directives began as French legislation that was adopted for use by the EU and which also forms the basis of IECEx -the international system for certification of equipment for use in explosive atmospheres. 



A series of unfortunate events prompted the formation and the subsequent enforcement of the ATEX regulation.

One of the earliest recorded dust explosions was in 1785 at Giacomelli’s Bakery, Italy. A baker’s boy was shovelling flour under an open flame, an action which caused the resulting flour cloud to ignite with a ferocity to blow the windows and their frames out into the street. The boy suffered scorches to his arms and face.

In 1983, The Aluminium Powder Co-operate, a plant situated in Anglesey, North Wales, was atomising molten aluminium into a stream of compressed air. The mixture resulted in an explosion that injured two people. This incident received notoriety due to the pictures showing the extensive plant-wide damage.

Sadly, time and again, we have been shown the importance of why potentially explosive environments have to be treated with due care. ATEX imposes requirements for companies to protect their employees from the risk of explosion. It is important to remember that every environment is different, and each has specific requirements depending on the nature of the atmosphere and the elements that are present within it.


Unravelling ATEX - a guide for everyone


Explosive Environments Ex

Potentially explosive environments, or ‘Ex’ areas, have different levels of risk and are categorised into zones in the workplace where equipment is operated. The classification is based on the explosive risk being either gas, or dust, or both.  ATEX certified equipment will state the environments they can safely operate within.

ATEX zones and protection classifications

There are zones categorised separately for dust and gas, where gas zones are identified as being one numeric character long, i.e. 0,1,2 and dust zones are identified by the addition of a ‘2’ character, i.e. 20,21, 22.  In both cases, the last digits 0,1,2 identify the type of zone.


Gas Zones Dust Zones Meaning
0 20 Continually present
1 21 Likely to occur in normal operation
2 2 Not likely or occur in normal operation and only for short durations.


For instance, 2, 21 indicates that a combustible gas is not likely to be present in normal operation, but a combustible dust is likely to be present in normal operation.  

So, what exactly is not likely when considering the presence of gas or dust in normal operation? These are not terms engineers and scientists are comfortable with, but thankfully, the ATEX directive has quantified ‘not likely’ to be less than 10 hours a year.

In part 2 of our ATEX blog series explores equipment classification and breaks down the exact meaning of the ATEX labels. 

If you require more information on ATEX to further demystify the subject, get in touch!


Chris O’Callaghan

Chris O’Callaghan is Head of Engineering within Innopharma Technology and is responsible for process analytical technologies and control products, applications development, and customer project delivery. He and his team manage the custom engineering projects required to successfully interface control systems with new and existing product lines in the continuous and batch manufacturing spaces, as well as control strategy development and deployment.

Darren McHugh

Darren McHugh is a Senior Product Manager at Innopharma Technology, with over 18 years of experience in the field of Manufacturing. He holds separate degrees in: Mechanical Engineering, Manufacturing Engineering, Pharmaceutical and Medical Device Manufacturing, and a Master’s in Product Management. He has worked with several companies in the manufacturing industry to help them implement smart manufacturing solutions into their processes. Darren is an expert in Industry 4.0 and 5.0 solutions, where he has used IIoT, image analysis and machine learning (ML) technologies to help companies capture the full potential of their digital transformation efforts and deliver a satisfactory return on investment.

Laryssa Gorato

Laryssa Gorato is an Associate Product Manager at Innopharma Technology with a proven track record of success in developing and launching innovative products. Laryssa is a PAT specialist and the lead point of contact for the Eyecon 2 particle size and shape analyser. Responsibilities include installing, training, and supporting customer success. Laryssa is passionate about converting the needs of Innopharma customers into product features, the implementation of which has improved the product functionality and delighted customers.

Eyecon₂ Direct Imaging Particle Analyser 

Uses direct imaging processed in real-time, with ellipses fitted to each particles boundary, shape and size reported back, highlighting variations


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