Thank you for taking the time today Debora. To begin, can you tell us a bit about your background in compliance?
Yes. I used to work as an inspector for Notified Bodies but due to the nature of such a position, I was strictly forbidden to provide any advice to manufacturers. That’s why I switched to consultancy; because it is more rewarding as I can advise my clients in the early stages of the project. However, on the other hand, if I had not had experience working for Notified Bodies, then I would not have had such an in-depth background on directives and the responsibility of manufacturers; so it ultimately led me to be in a better position as a consultant.
So, your specialty with Certification Experts is in the ATEX area. Can you elaborate a bit more on the ATEX directive and what it means for manufacturers?
Okay. The ATEX Directive applies when you would like to manufacture equipment that is intended to occur and be installed in a potentially explosive atmosphere. The directive is applied to ensure the product is compliant with the requirements that are active. If you comply with the ATEX directive, your product will be incapable of igniting an explosive atmosphere that might be around it.
In terms of the directive, there is a list of procedures that apply to manufacturers. These procedures explain what manufacturers have to do in order to prove that the product is compliant with the ATEX directive. Sometimes, these procedures also explain whether or not you need to involve a notified body. Equipment that complies with the ATEX Directive is unable to ignite the surrounding atmosphere. The directive clarifies what manufacturers have to do to demonstrate this quality and if they have to involve a Notified Body. An aspect that is unique to the ATEX Directive, compared to other product directives, is that the products are classified into 3 categories. Category 1, Category 2, and Category 3.
Category 3 includes equipment that is quite easy to be designed, because it just has to prove that during normal functioning it won’t be able to ignite an explosive atmosphere. If you have Category 3 you can only install the equipment in an area known as Zone 2. Zone 2 means an explosive atmosphere is not usually present. If it is present, it’s only for a limited amount of time.
On the other end, you have Category 1 which is much more complicated to design. The product has to be able to work in an explosive atmosphere while it is experiencing 2 sources of failures happening at the same time. This is a rare condition. The product must still not be capable of igniting an explosive atmosphere in order to be compliant. So the design is more complex to be achieved and the manufacturer must involve a Notified Body.
How is it possible for product manufacturers to design ATEX compliant products?
Well, the ATEX Directive doesn’t tell you how to design equipment but it refers to a list of technical standards known as ‘harmonised standards.’ These standards contain enough technical advice on how to design the product, the requirements, the tests that are needed in order to satisfy the standards. There is enough technical knowledge available to manufacturers to ensure that the product can satisfy these requirements and will not ignite due to failure or malfunction.
What would you say are three frequent mistakes that might cause an explosion?
Talking to my clients, I often find that hazard zones and equipment categories are mismatched. Another mistake is that Zone 2 is occasionally perceived as ‘non-dangerous,’ and the third one would be that people often talk about the ignition temperature as the temperature class, and use these synonymously.
To elaborate a bit more on the first one; if you consider an industrial site, for example, you will have volumes of the atmosphere that may have potentially flammable gas or flammable dust. You have to imagine volumes where an explosive atmosphere might be present. It may also not always be there. When you do the hazardous area classification, you try to estimate the likelihood that an explosive atmosphere may be present at any time.
If you can make the reasonable assumption that the atmosphere is always there, then that Zone is classified as Zone 0. If you think that it is only there occasionally, for short times, then it is called Zone 2. And in the middle, you have Zone 1. But this is referring to the quality of the site. Then you have the link between the ATEX directive, which states that in Zone 0, you can only put Category 1, in Zone 1, Category 2, and in Zone 2, Category 3.
To further complicate things, when you are talking about dust, not gas then you have different numbers for the zones. So you have Zone 20, Zone 21, and Zone 22. The names are always based on the likelihood of the presence of flammable material.
At least once, everyone (myself and colleagues included) have mistaken the zone and the category. This is okay, as long as this is merely an oversight that is corrected quickly. However, if it is a concrete mistake, this can be very dangerous.
As for Zone 2 occasionally being perceived as ‘non-dangerous,’ people sometimes make the assumption that just because it is ‘Zone 2’ it may not contain an explosive atmosphere. However, you should always be careful because if you have an explosion, which is rare, however, still possible, you won’t know how extreme the explosion may be. It could cause all kinds of damage and pose health and safety and monetary risk. A rare event, however, is still devastating just like any other explosion.
Occasionally it happens that manufacturers and site managers talk about ignition temperature and temperature class as if they are synonymous. However, this is a mistake which is also dangerous. You have to consider that the site manager will explain the explosion problems that he has considering the type of flammable material that is present on-site and the explosion temperature.
So which temperature will be the explosive threshold. If the site manager has, for example, some petrol fuel with an ignition temperature of 300 degrees, then the last thing the manufacturer of equipment should sell to the site manager is equipment with a temperature class of T2 which also means that the maximum temperature is 300 degrees.
People often make the assumption in ATEX that if you have a flammable atmosphere that makes contact with a surface that has a specific ignition temperature, this is the exact level that will cause an explosion. The temperature class of the equipment should always be lower than the ignition temperature of the flammable atmosphere. You also have to consider safety gaps, which exist on most products and depend on many features including the category of the equipment.
Thanks for explaining. So, from all of that, what would you say is the best way to prevent an explosion?
Start by removing the explosive atmosphere. That is the basic principle in safety. It applies to any field, and it is the best way. Sometimes, it is possible to substitute the flammable material with an equivalent. Certain processes are now carried out with other materials. However, I know that when we say ATEX, we almost always think oil and gas, which do not really have substitutes. It is possible though, to install some equipment that is needed on-site in a different zone.
So perhaps in Zone 1, you could decide to install the equipment a little further away in, for example, Zone 2. If you take these measures, you immediately reduce the risk of explosion on site drastically and can be beneficial from the point of view of equipment and installations for your product’s health and safety.
Thank you very much, that was a very interesting and informative interview on the ATEX Directive.
No problem, thank you, Clare.
Debora Greco has been working in the safety and compliance of equipment since 2007 when she joined an ATEX Notified Body in Italy. When she moved to the United Kingdom, she switched to the world of CE marking consultancy, where she has stayed ever since. Here at Certification Experts, we know that each successful compliance project simply requires merging the manufacturers’ knowledge of the equipment with our knowledge about the compliance routes and we look forward to having Debora work with us on future projects.