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This question relates to the ATEX directive, which is the European regulation governing the design of products to be used in explosive atmospheres. In particular, I am asking about the part relating to non-electrical (i.e. mechanical) devices.

Does anyone have experience in applying non-electrical ATEX to products containing springs? If so, do you know of any good guidelines as to how to conduct the assessment?

I'm thinking that the main potential ignition source would be a mechanical spark, which could conceivably be generated if the spring was to fail. So, the question boils down to: how to assess whether this is a genuine concern or not?

One possible option would be to assume as a worst-case that all the stored energy in the spring is converted into heat in the spark, and compare that to the minimum energy needed to ignite the explosive mixture; however, my gut feeling is that would be very conservative.

Chris Mueller
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Time4Tea
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1 Answers1

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This is not an authoritative answer as I don't know the ATEX regulation that well.

You have it however right that the ability to form a spark is relevant here. So your next step would be to look at the materials you use. Steel gives sparks on occassion. Most ATEX mechanical tools (hammers, wrenches) are from Bronze or Beryllium, so I would research in that direction.

Another avenue of research: Some pneumatic ATEX tools do use steel components, here the moving parts are in an oil bath.

mart
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  • Thanks for your input. I wasn't aware that materials can have different levels of risk for mechanical sparks (although, it makes sense). Do you know of any good references for information on this? Thing is, we have an existing product that we want to sell into the EU, so we need to assess what we currently have. – Time4Tea Oct 12 '15 at 15:28
  • No, I no good source. google Atex tools to see what others are using. I only know atex from a plant design perspective. – mart Oct 12 '15 at 19:35