DSS179: Explosion Test Data For Artificial Sweeteners

In today’s episode of the Dust Safety Science, we talk about explosion test data for artificial sweeteners. The subject was inspired by a question that Mike Rice, an active member of the Dust Safety Academy, submitted. He wrote:

“Can anyone share or tell me where I can find publicly available explosion test data for artificial sweeteners – specifically stevia, maltitol and erythritol? I’m mostly interested in knowing indicative MEC, MIT and MIE data to understand how they might compare to sugar and other food dust.” GESTIS database

Mike mentioned that he tried the GESTIS Substance Database but found no entries for these materials, so this episode takes a closer look at explosions and artificial sweeteners, along with some challenges involved in testing. They include:

Using textbook or historical data
Mixed materials
Lack of combustible dust information in material safety data sheets

Using Textbook or Historical Data

When you test something moist vs. something dry, or with fine vs. large particles, it can have a major impact on its minimum explosible concentration, minimum ignition energy, propagation rates, and maximum pressures of that material. Processing operations and even humidity changes can also have an effect, so it’s not a good idea to use textbook or historical data when coming up with engineering and explosion designs.

Challenge number two is what do you do when you have many different mixes? And in this case, Mike had mentioned in the LinkedIn post that he’s working with a company that might have a dozen or dozens of different mixes of materials, and he’s trying to give them some guidance on how to approach that.

Mixing Materials

Mixing materials can present a challenging situation for testing. We’ve discussed this issue with Dr. Ashok Dastidar on the podcast before, in Episodes #50 and #54. He talked about developing an “envelope of safety,” or this envelope concept for your testing parameters throughout all the different mixes. ‌Once‌ ‌you‌ ‌have‌ ‌this‌ ‌envelope,‌ ‌you can then test any new mixes or parameters against it.

When you have a lot of different mixes, it’s probably a good time to reach out to a consultant or testing lab and say, “Hey, how do we evaluate our sampling approach here? And how do we use that to best manage and impact the hazard analysis and hazard assessment that we’re doing?

Lack of Combustible Dust Information in Material Safety Data Sheets

Why is combustible dust information not provided in material safety data sheets? This is a great question. We tackled it back in Episode #169 with Keith Plumb about how we might go about adding combustible dust information to material safety data sheets.

There is no solution yet. ‌Some‌ ‌companies‌ ‌do this on their own, and the fact that they highlight the hazards of combustible dust on their safety data sheets is really encouraging. Although there is some data there, you run into the same problem encountered with textbooks and historical data – it’s only relevant at the conditions in which it was tested and you need to be wary about using that in your facility.

On the flip side, it can be a great option if you have a relatively stable material. If you’re buying metal aluminum flakes from a provider, they give you an MDS sheet, and you’re using those same flakes in your operation without any modifications, the data from the safety data sheet may be valid to use. However, it takes a trained eye to be able to evaluate whether it is an appropriate use of these material parameters.

One thing you can do is go to your provider and say, “Hey, would you be interested in doing this type of testing?” It may be more cost-effective for them to do the testing and send out those parameters instead of all the end-users testing the materials individually. On the flip side, you run the same challenges with the test book and historical data: making sure that’s representative of the hazards that are in place at your facility when you’re using and processing those powders.

LinkedIn Responses

When we posted Mike’s question on LinkedIn, one individual reported that they were able to find some sweetener data on the Gestis database, which was really helpful. In this case, two samples came up.

One was a sweetener mixture for tablet pressing. This was reported as ST1 dust with a median particle size of 180 micron with 11% less than 64 micron, 2% less than 32 microns. A material with a mean size of 180 micron with 20% less than 32 micron has a totally different particle size distribution than one that has 2% less than 32 micron but still a mean particle size of 180. The fines are going to do the most work in that sample in terms of propagating that explosion, so it’s not just the mean particle size you can look at.

The second one reported was a sweetener tablet mixture. This is 40% saccharine, which was ST1, and the reported Kst was 98 bar meter per second (98 bar-m/s), 6.3 bar over pressure, and medium particle size of 78 micron with 35% less than 32 micron. MIE was very large, greater than 10 joules and MEC was 500 grams per meter cubed (500 g/m3). With this data set, we’re not seeing tremendously high ST1 class instead of ST2, which would be 200 to 300 bar meter per second rate of Kst values, or ST3 that is 300 and above bar meter per second. We’re seeing a lower classification of material reactivity of the materials and large minimum explosible concentrations and large minimum ignition energies for these materials from the historical data.

Others reached out on the LinkedIn post and shared their experience with these same types of materials. Tim Heneks at DustCon Solutions said that he had a client that often performed dust testing on several samples of sweeteners and found that it had a much higher Kst than he expected. It was in the ST2 class, so 200 to 300 bar meter per second, and had very low MIE values. Tim mentioned that this helped them get the right solution in place as part of their dust hazard analysis.

Brian Edwards from Fike said that he has personally seen tests of fine stevia powder that placed it in ST3 category with an MIE less than 3 millijoules. So again, very minimum ignition energy. In this case, the material test set a mean diameter of less than 10 micron, which had a big impact on the results. Brian noted that people handling artificial sweeteners should definitely consider testing the material.

Conclusion

This discussion confirms that the best solution is to get your material tested until you can prove that it is representative of the historical values that you’re looking at or the literature values are representative of materials that you’re testing. In the latter case, you need to look at particle size and make a strong argument on whether or not you can use that literature data.

At the end of the day, it’s probably better to get material tested because the literature data might not be representative. It’s the safer option, and that’s what truly counts.

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.