DSS033: Explosion and Fire Safety in 3D Printing Applications with Jason Reason

In this episode of the DustSafetyScience Podcast, we interview Jason Reason, Director of Combustible Dust Services at Seam Group, about explosion and fire safety in 3-D printing and additive manufacturing applications.

Jason appeared on Episode #20 of the podcast, talking about the role of qualified persons in dust hazard analyses. He has extensive experience in combustible dust safety, being a former member of Indiana OSHA and now chairman of the NFPA 664 forum on wood processing industries. He also does a lot of work in 3D printing and additive manufacturing industries related to combustible dust, which gives him unique insights into today’s topic.

Jason said that he became involved in 3D printing over four and a half years ago. Since then, he has done over a hundred DHAs for additive manufacturing companies. Today, he’s a member of the task group rewriting the additive manufacturing chapter for NFPA 484.

What is Additive Manufacturing?

Jason defined additive manufacturing as the process of building things layer by layer. Most people assume that it is synonymous with 3-D printing. The printers, used to quickly prototype items, range in size from a computer screen to larger units that are printing engine blocks.

“I wish I could tell you how NFPA defines it but they don’t define it,” he said. “It’s part of the problem.”

When asked about hazardous materials associated with 3D printers, Jason said that from a combustible dust standpoint, there are two types of powders that merit concern:

Plastic / nylon / polymer, which are all words for plastic powder
Metal powder

The powder can vary in terms of the particle size but most of the powder bed printers go somewhere in the range of 30 to 150 microns.

Jason explained the printing technology is constantly changing. “I recently found out that somebody is apparently 3D printing chocolate now,” he said.

Additive manufacturing is in a Wild West phase, with new concepts that had never been thought possible, so there are safety considerations. What are the combustible dust hazards in 3-D printing and additive industries? What areas are causing a lot of issues?

Combustible Dust Hazards in Additive Industries

According to Jason, a primary concern is that there are not a lot of DHAs being done in these industries.

“I mean, obviously, we (Seam Group) have done hundreds of them,” he said. “But the other ones I’ve seen out there are just horrible. And the reason they’re horrible is because the people doing this don’t understand the hazards of additive manufacturing. I know in the last podcast we talked about qualified persons and everything. This is a level up for a qualified person.”

He warned that safety is not a priority for printer designers and that one of the problems involved with doing a DHA in this environment is that no one looks at the printers because they don’t understand them. They see the device has been certified by a nationally recognized testing laboratory, or NRTL, and don’t investigate further.

Jason provided an example of some printer manufacturers who said that their printer was NRTL’ed. Argon was flowing into it, but it was three to four percent above the limited oxygen concentration, or LOC, making it an explosion hazard.

The industrial printers can be six to seven feet tall and carry up to 2000 pounds of powder. When operating, a laser hits the powder bed and welds the item layer at a time. A build elevator drops after one layer has been done, and then a new colour blade applies a new powder later and the process starts over. Depending on the part that needs to be printed, it could take 24 to 36 hours on a standardized powder bed.

Other 3D printing methods include electron beams and robot arms that can print a part in 15 minutes. Both are examples of how fast the print technology changes, which makes the hazards more difficult to address.

When the powder is being loaded or unloaded in bulk, it can create a dangerous condition in hazard-prone areas. When the powder moves through the machinery, it’s another potential hazard, and when it’s being laid out and exposed to lasers, it can generate dangerous dust clouds.

“There are a lot of things wrong with these things,” Jason said. “I’ve looked at more printers than I can count and I can honestly tell you I’ve never seen a compliant printer. They don’t exist. If anybody says they do, they’re lying. There’s not a printer made right now, whether it be in America or Germany or wherever else they make these printers that comply with the OSHA and EPA standards. Every one of them’s unsafe. But that means that there are potential hazards in every printer that everyone has right now.”

He said that with metals, a condensate called a nano metal is created when the laser interacts with the powder. All nano metal and nanoparticulate go into filters that act as dust collector systems. These filters have to be changed, but if the nano metal on the filter cartridge is jostled in a non-inert environment, it will flash. Jason has seen people receive second and third-degree burns on their forearms, chest, and face after handling a filter.

When Dr. Cloney was doing his Master’s and Ph.D. research in Halifax, a Master’s student was doing investigations on the explosion properties of nano aluminum. There wasn’t a lot of information available on the subject, although some Chinese groups had done a couple of studies.

Pictures of the 20-litre chamber in these studies showed that the tubing leading from the reservoir into the chamber dispersion system was discoloured. At first the Halifax group couldn’t figure out why, but as soon as they started using that nano aluminum, they realized that it couldn’t be dispersed into the 20-litre chamber without igniting.

When dust is placed in the dispersion reservoir, it becomes pressurized before it enters the chamber and creates a dust cloud that later ignites. The nano aluminum couldn’t go through the tubing without igniting, which was why those studies featured discoloured tubing.

Jason said that he has seen some so-called additive manufacturing DHAs that never looked at the printer or mentioned the filter media. The hazard was completely ignored. Doing a DHA while ignoring the black box (printer) is dangerous: the box needs to be included and manufacturers need the training to improve the black box so that it’s not so hazardous in the first place.

How is 3D Printing and Additive Manufacturing Handled in the NFPA and OSHA Frameworks today?

Jason said that OSHA has little understanding of additive manufacturing. The version of NFPA 654 will reference additive manufacturing but not to a great extent. The 2019 version of NFPA 484 includes a Chapter 13 that is actually additive manufacturing, making it the first standard to take a shot at having some requirements.

He stressed that DHAs for additive manufacturing are highly complex. He typically reads about five to ten thousand pages to get the background required to be able to knowledgeably carry out the DHA. This documentation includes:

Equipment manuals
Building codes
Fire codes
OSHA standards
NFPA documentation
F.M. 776, which references 3-D printing and additive manufacturing

There are a lot of open challenges: manufacturers not understanding the hazards and DHA inspectors treating the printer like a black box. In Jason’s opinion, the biggest challenge was the lack of data on the nanoparticle or nano metal.

“I wish someone would actually write a white paper on this,” he said. “Figure out if this stuff is pyrophoric and what makes it go. I’ve dealt with it enough that I like to think I understand it but I’m not taking it to the actual level that you guys would take it in the labs. I really wish someone would do that. I think that it would be one hell of a study, to be honest with you.”

Conclusion

Jason said that there needs to be a better way of dealing with explosion and fire safety in 3D printing and additive industries. He recommended the formation of a committee consisting of printer manufacturers, powder producers, representatives of industries that use 3-D printers, and other concerned parties so that a unified approach can be taken. When standards can’t keep up with the technology, collective action by experts could make a difference.

If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Jason Reason directly:
Email: [email protected]
LinkedIn: https://www.linkedin.com/in/jason-reason-cih-csp-chmm-b561a148/
Website: https://www.seamgroup.com/combustible-dust

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.