In today’s episode of the Dust Safety Science podcast, we feature Part Two of an Ask Me Anything session on operator safety. Last week, David Hakes, President and owner of XP Products, discussed the challenges inherent in handling certain types of dust. Today, he answers questions from attendees.
Q. What Happens to the Dust After Collection?
David said that in most cases, plants don’t have any use for the waste that they generate. They often have a waste firm come in once a week or once a month to take away the dust and other process-related substances collected.
Facilities with large dust collection systems have rotary valves that connect directly to a pneumatic conveyor. From there, it can be carried to a central point for later collection. This setup is especially common in facilities that generate such a high volume of dust that no one has time to move a drum every four or five hours.
Q. How Often Should the Waste Stream or Barrels Be Removed?
As manufacturers start ramping up, especially in the food industry, their dust collection equipment starts to work overtime. Outside dust collectors are typically emptied on a daily or weekly basis, depending on how much dust is being collected. However, as David pointed out, if staff is limited, it’s easy to forget that the drums need to be emptied. Over time, dust can back up into the dust collector and create another slew of problems, which makes sensor installation advisable.
Q. What Sensor Options are Available?
David said that level sensors can be placed on a fixed drum lid or fixed spool. He recommended a device by IFM, which does well with practically all materials except metal.
“We’ve had pretty good luck with two or three sensors,” he said. “[They] should be engineered into your dust collector. You need a fixed point on your dust collector to have that sensor, and then you need to be able to protect the sensor so that when you remove the drum or put the drum back in place, you don’t damage it.”
Q. What is the XP Product Drum Kit?
David explained that the XP Product Drum Kit was designed to eliminate rotary valve injuries while allowing the machine to remain NFPA-compliant. It consists of a fixed spool bolted to the bottom of the dust collector. The drum lid is bolted to that spool, so that the drum base has to index up and down to remove it and seal to the bottom of the lid.
“We use a commercially available hydraulic lift to do that,” he says. “It’s a safe device designed to contain a deflagration. It leads to reduced pressure of the overall dust collector as long as the dust collector is properly vented or properly protected, and the hydraulic lift on the drum allows you to roll the drum out and move it safely up to 800 pounds.”
He acknowledged that the XP Product Drum Kit doesn’t address all rotary valve issues and is not designed for a larger container, being a 55-gallon drum. Its purpose is to replace rotary valves in facilities where they are not a good fit or too dangerous.
“We’ve developed a bag in-bag out option that has been in the field now for the last year, and we’ve developed a pretty good design for having a liner,” David says. “There’s a bag inside the drum, you lower the drum and you can tie off the bag while the bag is still connected to the bottom of the dust collector. That allows the operator to remove himself from the exposure of the dust or contain the dust in a liner. Pull the liner out if it’s not too heavy, and then put the drum back in place with another liner.”
Q. What Should People Know About Changing Filters?
David pointed out that during filter changes, you want to keep any ignition sources away because the dust could be a type with a low MIE. This means using explosion-proof or air-operated tools: anything that won’t create an electric charge or spark.
Q. How Should Dust Spills Be Handled?
Spill containment protocols usually address liquid spills, but they should also plan for dust. The exact steps depend on the type of powder involved.
When there is a spill in a plastics facility or woodshop, employees shovel it into a container and then pull out their vacuums and clean it up. These plants need to have explosion-proof vacuums, because portable vacuum systems can generate a static discharge big enough to exceed the MIE of that dust and potentially create a problem.
Q. What Training Should Operators Receive?
David emphasized the importance of including combustible dust protocols in all plant safety rules. Initial training during the employee orientation process is also important. And I think combustible dust is a different hazard but it needs to be understood in a similar way.
“[Combustible dust] is quite complex,” he says. “That’s why it’s often avoided or ignored. But training is important, especially when it comes to the fire triangle. We need ignition, we need oxygen and we need a dust source before you get into the Pentagon. Start small and let them understand the basics of how a dust explodes and what it takes to get it to explode. That education process is going to make everybody more well-informed.”
Q. How Should Drums Be Safely Handled Once Full?
Drums can hold up to 500 or 600 pounds of a dense powder. When they’re full, removing them safely from the bottom of the dust collector is critical. Some companies use forklifts with an extended ledge, which can be cumbersome. The XP Drum Kit has a hydraulic dolly that lifts the drum so it can be rolled away safely.
“Keep in mind that these things now have a center of gravity that’s about 20 inches off the ground,” David says. “Even when you start rolling them around or moving them, they will tip and then you’ve got other issues, so you want to be able to secure the drum and hold it.”
What are a couple of questions that would ask operators to identify if it’s time to give refreshers? And I’ll add to that. Maybe is it better to focus on a different time scale? Like how do you go about understanding when refresher training is needed?
Q. How Often Should Operators Undergo Training?
“It depends on how quickly people or personnel are turning over,” David says. “Probably every six months if you’ve got somebody new coming in. Companies have always sought to train operators without overwhelming them with information. Retention of that information is pretty minimal unless they’re interacting with the process on a regular basis, so training frequency really depends on how often they come in contact with combustible dust or what area they are working in.”
Conclusion
At the end of the session, David emphasized the importance of making safety a part of company culture.
“Whenever I walk into a plant, they give me a sheet and say, “Here are the areas that you need to be concerned with and here are the hazardous chemicals that we have in the facility. If there’s an alarm, ammonia leak or some other chemical spill, here’s where you need to go or what you need to be aware of.” With dust, they don’t usually have to go to that extent with their outside visitors or contractors or vendors, but internally, their people need to understand what combustible dust is and what their potential hazards are. Weaving it into the culture of the company is really an important part.”
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach David Hakes directly:
Email: [email protected]
LinkedIn: https://www.linkedin.com/in/david-hakes-21a336134/
Tel: 630-464-3800
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
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Dust Safety Academy
Dust Safety Professionals
Companies
XP Products
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