DSS167: How Small Is Small? Challenges In Applying IEC 60079-10-2 with Keith Plumb

In today’s episode of the Dust Safety Science podcast, we talk to Keith Plumb, process safety and equipment consultant, director and owner at Integral Pharma Services in Cheshire, UK, about challenges in applying IEC 60079-10-2. During this discussion, we answer the following questions:

What are the IEC standards? How are they used?
What is the hazardous area in relation to combustible dust?
What are some of these challenges with small-scale operations? Do they fit underneath the standard, or do they not?

Keith, who appeared on Episode #34 to talk about dust explosion risk reduction toolkits, does a lot of process safety work in the UK and across Europe. While he works mainly in the pharmaceutical industry, he also reviews processes in the food industry.

What are the IEC Standards?

Keith explained that the CEN standards are applied as the norm in Europe. IEC stands for the International Electro-Technical Commission“. This is because, historically, people thought the standards were related to electrical equipment.

“Actually, it’s a bit of a red herring,” he says. “So when it comes to Hazardous Area Classification, it’s about the properties of the material that you’re handling. It hasn’t got anything to do with electricity. Traditionally, the equipment certified for the hazardous area is electrical equipment, but in the IEC/ISO world, that’s essentially disappeared and anything that can cause a spark is covered.”

Every country in the world that is a signatory of ISO can use the IEC standards, which are the same as their CEN counterparts. That includes North America, Japan, China, Australia and other countries.

What is a Hazardous Area Under the Standards?

IEC 60079-10-2 defines a hazardous area as an area where the quantity used is large enough for protective measures to be required. It doesn’t indicate how large “large enough” is, and that’s the fundamental problem.

“There is some point when the quantity is small enough that you can say, ‘I don’t need to apply special protective measures. I don’t need classified electrical equipment.’ But I don’t know where it is,” Keith says.

He illustrated an example using sugar. In Europe, the main types are granulated sugar, caster sugar and icing sugar.

“If everything is the size of caster sugar, you might have a problem. If you’ve got granulated sugar, you probably haven’t. But the reality is that if you’ve got granulated sugar, it’s also mixed up with some stuff that’s the size of icing sugar. So if you’ve got 20 kilograms of a solid that’s reasonably big particle size, there’s a reasonable chance that a fair proportion of it is in the range that you could ignite…. Inevitably, when you pour in the vessel, you create some level of dust cloud. Is that dust cloud in the flammable range or near the flammable range? Should you be making it a hazardous area? It’s a good question.”

He recommended erring on the side of caution. If even 10% of a material’s content is explosive, larger quantities can create a significant explosion. “How small is small” may not always be relevant when the material involved can have explosible content mixed through particles that are otherwise a safer size.

What are the Challenges With Small Scale Operations?

While larger operations can afford to pay for extensive testing and the safety equipment necessary to address hazardous areas, it can be a different matter for smaller operations. For example, a smaller pharmaceutical company may opt to run high-purity water through spray nozzles and wash finer dusts away, but this is not the same as dust extraction. In the end, cost can dictate how extensive safety measures may be.

Keith insisted that combustible dust is a problem that not all facility owners and managers appreciate.

“What I find is the clients argue like mad against me because they say “Oh no, we never had an explosion.” And I say that doesn’t prove a damn thing.”

Conclusion

Combustible dust safety, which includes issues like particle size and quantity of dust, continues to experience challenges despite the presence of standards like IEC60079-10-2. Keith says that he would like to start a project to define the overall problem, which may in turn lead to a project exploring solutions.

“What I really wanted to do was to set up a short project, maybe three months, get a bunch of folks around the table. Can we define the problem in such a way that we could then convert it into some kind of research project or whatever to maybe get some answers? I think that’s quite important. I’m hoping to try and set this project up [in the next few months or so]. Although it would be [at] the Institution of Chemical Engineers, I’m sure the Institution is open enough to get people into it from any background that can help try and define what this problem is.”

If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Keith Plumb directly:

Email: [email protected]
LinkedIn: https://www.linkedin.com/in/eur-ing-keith-plumb-b482797/
Website: https://www.integpharma.com/

If you have questions about the contents of this or any other podcast episode, you can go to our ‘Questions from the Community’ page and submit a text message or video recording. We will then bring someone on to answer these questions in a future episode.