In today’s episode of the Dust Safety Science podcast, Matt Williamson, Director of Engineering at ADF Engineering, shares strategies for testing multiple mixes of materials.
Sites in industries like food, feed, flavoring, and pharmaceuticals often deal with numerous materials, which makes testing for combustible dust hazards more difficult and expensive. To kick off, what kind of sites are we talking about here, and why does testing become such a challenge in these environments?
The Challenge of Testing Multiple Materials in Various Industries
Matt explained that in the animal feed and pet food industries, facilities handle hundreds of different raw materials. Similarly, in the flavouring industry, materials like tea leaves and other organic substances are blended together to create food flavourings. The sheer volume of these materials makes it nearly impossible for industries to gather all the data they need to fully understand their safety envelope.
These facilities need to know which material has the lowest minimum ignition energy (MIE) or which poses the highest risk in terms of dust explosions. Without this critical data, it becomes very difficult to design and implement effective safety measures. Testing all 200 or more raw materials used in these facilities would be cost-prohibitive, so the challenge becomes how to effectively narrow down which materials to test.
Common Scenarios Where Testing Becomes Complicated
According to Matt, in pre-blend and post-blend situations, multiple ingredients are typically handled at different stages of processing. For example, materials might be dropped into the system, milled, dried, and then blended before being processed further. This introduces multiple variables into the system – each handling step can create dust, and each material can react differently to these processes.
He pointed out that even with just 12 ingredients, the number of possible material combinations can quickly run into the hundreds. In these scenarios, testing all possible mixtures becomes incredibly costly. However, testing is critical because it helps identify the materials most at risk of generating combustible dust during the handling process.
How Do You Typically Approach This Problem with Your Clients?
Matt emphasized that his first approach is always to gather a detailed list of all the materials being used on-site. This list is typically available through inventory management systems like SAP, which track the facility’s raw material usage.
Once they have this list, the team begins by eliminating materials that are clearly non-combustible, such as minerals and salts. After that, they focus on the materials being handled in the largest quantities. Matt noted that materials which are only used rarely or in very small quantities (e.g., less than 1% of the total material handled) are deprioritized. This allows the team to focus on the materials that are most likely to create a significant dust hazard.
However, even after narrowing the list down to the largest-volume materials, the cost of testing remains a key concern. Sending samples to a lab for testing can easily cost thousands of dollars per sample, so further prioritization is necessary. This is where the method of handling materials becomes an important factor.
Narrowing Down the List Through Material Handling Insights
To further refine the list of materials for testing, Matt and his team assess how each material is handled. Operators are often able to identify which ones create the most dust, and those materials become high-priority candidates for testing. For example, if a facility handles a substance that creates a large dust cloud every time it is transferred, it will likely be prioritized for testing.
On the other hand, materials that are handled in a way that minimizes dust (such as those with larger particle sizes or those fed into the system via gentle processes) are deprioritized. The goal is to identify 2-4 key materials that are most likely to pose a dust explosion hazard, allowing the facility to focus its testing resources on those materials.
Can Testing Blended Materials Reduce Costs?
In situations where testing costs are prohibitive, Matt noted that blended materials are often less hazardous than the individual raw ones. This provides an opportunity to test the blended materials rather than each raw one individually, which can help reduce overall testing costs. However, he stressed that testing the most hazardous raw materials is still essential to accurately assess the risk.
When dealing with blended materials, facilities can focus on testing the blend itself to assess the general risk profile. This is especially helpful when it handles a consistent blend of ingredients. However, it’s important to note that the risk of dust explosions is typically determined by the raw materials with the lowest minimum ignition energy. Therefore, focusing on the worst-case raw materials remains a crucial part of the hazard assessment process.
Using Dust Collection Samples to Improve Testing Efficiency
Another strategy Matt discussed involves using dust samples from the facility’s dust collectors. If a facility processes materials consistently over time, the dust collected can provide a reliable sample for testing. This method can significantly reduce the number of raw materials that need to be individually tested because the dust collected represents the most hazardous particles from the entire process.
However, this approach works best when the dust collected is representative of the materials being handled on-site. In facilities where the blend of materials changes frequently, such as flavouring facilities where the blend might differ from day to day, this approach may not be as effective.
What Role Does Material Handling Play in Dust Hazards?
One of the most critical factors in determining dust hazards is how materials are handled. Matt explained that unloading materials, particularly from bags, is often one of the dustiest parts of the process. When workers cut open a 25-kilogram bag and pour its contents into a mixer or hopper, it creates a large dust cloud that can lead to hazardous conditions.
He recommended that facilities look into handling these materials more gently or switching to bulk bags (super sacks) for high-volume materials. Bulk bags allow for the material to be transferred into the system with minimal dust generation, reducing the overall risk. Not only does this make the process safer, but it can also lower labor costs and improve efficiency.
Matt further explained that materials with larger particle sizes tend to create less dust and are therefore less likely to pose an explosion hazard. However, materials in powder form, particularly organic powders, should be treated with caution. Even if these materials haven’t been fully tested, their characteristics suggest that they are more likely to create dust clouds and therefore should be prioritized for testing.
Avoiding the Pitfalls of Ignoring Dust Hazards
A key point Matt made was the potential danger of ignoring dust hazards simply because a facility hasn’t experienced an issue in the past. For example, a worker may handle a dusty material for years without incident, but that doesn’t mean the material isn’t hazardous. Dust explosions can be rare events, but when they occur, the results can be devastating.
Matt shared an example from another industry where a dust explosion occurred at a bag dump station. The facility had been using the same process for years without incident, but a single day of dry weather and a small change in particle size led to an ignition that injured a worker. This highlights the importance of being proactive in assessing dust hazards, even for processes that seem routine.
Final Thoughts on Testing Multiple Materials
Matt wrapped up the discussion by emphasizing the importance of collaboration between the facility and the dust hazard professional. The facility’s operators have firsthand knowledge of how materials are handled, which ones create the most dust, and how often each material is used. On the other hand, the dust hazard professional brings the technical expertise to assess which materials are likely to pose the highest risks based on their chemical properties and how they are processed.
By working together, they can narrow down the list of materials for testing, focusing on those most likely to create dust hazards. This collaborative approach helps ensure that resources are spent effectively on testing the most critical materials, leading to a safer and more efficient operation.
Matt also reiterated the importance of ongoing testing and monitoring. Even after the initial testing is completed, conditions at the facility may change, or new materials may be introduced. Regularly reviewing and updating the dust hazard assessment helps ensure that the facility remains safe over the long term.
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Matt Williamson directly:
Website: http://adfengineering.com/
LinkedIn: https://www.linkedin.com/in/matthew-williamson-760111215/
Email: [email protected]
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.
Resources mentioned
The resources mentioned in this episode are listed below.
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Companies
ADF Engineering
Standards
NFPA 654
Download the episode
DSS284: A Strategy For Testing Multiple Mixes of Materials With Matthew Williamson
