Man with brown hair in checked shirt

Accessing new markets with ATEX certification

Stop me if you’ve heard this one before: a potential customer gets in touch about one of your products, they're interested but want to use it in a different environment from that of your other customers. Is this possible?

For example if your product could operate in transportation hubs, alongside manufacturing processes or even in a seemingly benign presence of cleaning solvents, these may all be considered as explosive environments.

To many of our clients, KD is the next port of call. With extensive experience of designing products to safely operate in homes, businesses, and a wide variety of medical and industrial settings, it’s a safe bet that we can help. Interestingly, one of the most common requests recently has been from clients looking to operate their product in explosive environments. This is because potentially explosive environments are more common that we might initially think.

Our Principal Engineer, Dave Baker, explores ATEX certification in finer detail, presenting the method behind the certification and why this could well be relevant for your product:

ATEX certification symbol in yellow and black

What should I consider when developing products for explosive environments?

Global governments are gradually converging on common standards for equipment in explosive (Ex) environments to protect both workers and the wider public. At first, the various permutations can seem complex; in the United States and Canada, electrical equipment must be certified by an accredited test laboratory or certification body.

In Europe, and in the UK at present, we have two EU ATEX (ATmosphères EXplosives) directives. For the rest of the world, there is the IECEx system of standards. However, beneath these multiple systems, there is commonality in the requirements, so it is possible to plot a streamlined approach to approval across multiple regions.

Not all explosive environments are equal, so in practice locations are classified as zones according to the frequency and duration of the occurrence of the explosive atmosphere. For example, the petrol station forecourt, where the underground fuel tanks may be classified Zone 0 on account of the continuous presence of petrol vapour. The region surrounding the filling nozzle may be Zone 1, as an explosive atmosphere is likely to occur regularly in normal operation. The wider forecourt region may be classified zone 2, here flammable substances are infrequent and expected to be for a short period only.

An illustration of a petrol forecourt with a lorry, car and petrol station and ATEX classified zones
Flammable vapour zone classification for ATEX certification

Therefore, all products labelled as suitable for ATEX will have the appropriate zone classification, which in turn denotes the specific measures that may be applied to control an ignition source. Further classification of the environment is also made in terms of characteristics specific to the environment, for example the gas ignition temperature, dust conductivity and vapour ignition energy.

With the classification of the hazard made, the response of the equipment follows. There are numerous protection concepts that are available to the developer, here we consider just a few of the more common strategies:

Intrinsic safety

Intrinsically safe electrical equipment does not create a spark or thermal effect under testing that is sufficient to cause an explosion, although the scope of testing covers not only normal operation but potential fault conditions like short circuits. In practice this means that the level of stored energy within the system must be kept sufficiently low through careful design optimisation, however this may not be an option for many electrical devices.

Flameproof enclosure

This is a method based on containing the explosion within an enclosure, therefore preventing transmission to the surrounding atmosphere. For this design the enclosure must be sufficiently strong to contain the explosion pressure. If there are gaps within the enclosure then they must have a size and geometry that limits the power of any jetting gasses during explosion.

Increased safety

Here the electrical equipment is designed so that in normal operation there is no source of ignition without any sparking components. In practice this translates to limits on creepage and clearances, careful design of thermal management and extra requirements on the enclosure.

Encapsulation

Where ignition sources are potted to prevent access of the explosive environment. Consideration of the potting thickness and through-life effects on the material are considered during assessment of the afforded protection.

What’s next?

If you’re missing out on the Ex market, then it is important to identify the right partners to get a product certified. For ATEX, a notified body must be used issue a certificate and to possibly conduct periodic assessment of the manufacturer’s quality processes. However, the role of a notified body is similar to an independent assessment and cannot steer the development of a product to meet the requirements.

To do this requires expert guidance in product development to ensure that the product not only meets Ex requirements but also the needs of the user. At Kinneir Dufort, our approach to product development means that we can assist the manufacturer through the entire process of getting a product into the Ex marketplace. This process starts with setting the right requirements. Here we work with the manufacturer and the notified body to establish how the product will be used, its environment and the critical Ex constraints. To ensure that the vision for the final product is met we apply our expertise across product insight, design, engineering and human factors to ensure all aspects of the product are considered from the start.

Once the requirements are in place the development of the product can progress. This may be limited to minor adjustments to an existing product or ground up development of something entirely new. At KD our engineers have the experience to blend innovative solutions in design and materials, through to the development of ultra-low power electronic systems. At all stages of this development, KD work with the notified body so that requirements specific to certification are tracked and maintained.

As the design matures KD can work with the manufacturer to assemble the evidence and technical file required for submission to the notified body. This may include existing design documentation or the creation of new test and analysis data to verify the claimed performance.

Finally, there is the manufacture of the product itself, both for compliance testing and market release. At KD we’re practiced in the delivery of batch assemblies to stringent quality and regulatory requirements and can therefore assist with this final step of ensuring the build process meets the design intent and allows the product to deliver the necessary safety and performance requirements.

If you want to learn more about ensuring your product is safe and ATEX certified, please get in touch with our Industrial Portfolio Manager, James Sutherland: [email protected]

Find out more?

Get in touch with our Industrial Portfolio Manager, James Sutherland.