DSS262: What Are Welding Fumes And Are They Explosible With Jeremiah Wann

In today’s episode of the Dust Safety Science podcast, Jeremiah Wann, CEO and President of Imperial Systems Inc., talks about welding fumes and their risk of explosibility in industrial applications.

Jeremiah acknowledged that at one time, the topic of welding fumes was largely ignored in industry conversations. He credited an unnamed customer for initially bringing the issue to the attention of Imperial Systems Inc. He also mentioned writing an article The Fabricator, addressing the combustibility of weld dust.

Following the publication and promotion of these insights, Imperial Systems received multiple inquiries seeking his knowledge and the findings his company had gathered on the subject. While he expressed a hesitancy to claim full credit for raising awareness about the dangers of welding fumes, he acknowledged that the timing of his article and subsequent educational efforts seemed to coincide with a growing interest in welding safety. He concluded by emphasizing the critical role of marketing and awareness in fostering safe work environments, particularly in industries prone to overlooking such hazards.

Hazard Awareness is Growing

Jeremiah explained that everyone in the metalworking industry now seeks to create a safer, cleaner environment. This shift in priority is significant compared to 20 to 35 years ago when safety and cleanliness were less of a concern. Nowadays, workers expect and demand such conditions, aware that they have numerous employment options elsewhere. Therefore, maintaining a good safety record has become essential, not only for employee satisfaction but also as a fundamental operational standard.

What Applications Generate Weld Fumes?

The scope of environments in the metalworking industry is quite broad. There are typical fabrication shops where individuals work with MiG welders on benches, handling relatively small welding tasks. In these job shops, welding activities can occur throughout the shop, with workers either moving to the products or the products being brought to their workstations. For such settings, an ambient ventilation system, which involves placing ventilation directly above the work areas to circulate air without the use of hooded vents, is most suited.

Another scenario involves the use of robotic welders, which are gaining popularity due to the current worker shortage. At the last Fabtech event attended, the presence of robotic welding units was notable, indicating a trend towards automation. These robots are typically easier to manage in terms of smoke capture, as a hood can be placed directly above the welding cell to efficiently capture emissions.

There are also specialized cases, such as welding inside a vessel, where additional suction or ventilation is necessary due to the confined space. Besides welding, other processes in fabrication shops, including grinding and heavy torch or plasma cutting, require consideration for effective smoke and fume management. This overview encompasses the primary applications and environments within the metalworking industry, highlighting the diverse needs for ventilation and safety measures.

How Are Weld Fumes Tested?

Imperial Systems requests their customers to conduct testing on dust samples and provides them with necessary information for testing, which can be done either by sending samples directly to them for forwarding or by the customers arranging testing themselves. While Jeremiah doesn’t always receive the test results, he does get feedback regarding the combustibility of the dust (KST value) to determine appropriate safety measures. He then educates customers in the metalworking industry about the potential combustibility of weld fumes and dust and recommends testing for safety.

In its own plant, Imperial Systems has implemented dust collectors for various equipment, including lasers, plasmas, and ambient systems, to maintain safety and compliance with NFPA standards.The company recently realized that their ambient units hadn’t been tested for combustible dust. Upon testing, they were surprised to find a KST value of 58, significantly higher than anticipated, prompting immediate steps to address safety concerns.

They are now in the process of enhancing safety measures, including proper dust management, ventilation, and explosion mitigation systems, in line with NFPA 652 and NFPA 484 guidelines. They differentiate between metal and non-metal dust, noting that their ambient collection system, which is positioned 30 feet from the source, primarily gathers smoke and fumes that rise to the ceiling, unlike close capture systems that directly collect metal dust and require different handling due to the risks associated with metal dust explosions.

What Do Weld Fumes Become Once They Condense Into a Dust?

There are significant challenges associated with identifying the exact nature of fumes and smoke in the workplace, particularly what elements or physical materials they condense into once they become dust. This question has often gone unanswered, leaving many to speculate about the composition of the condensed smoke.

In an effort to address this uncertainty, a dust analysis will be done using a Scanning Electron Microscope (SEM) to determine its composition. The expectation is that this analysis will provide clear insights into what the smoke condenses into after welding and grinding activities. Given the lightweight nature of the substances that rise to become airborne dust, it is anticipated that the dust primarily consists of particles from grinding activities, such as those from flap disks.

The speculation is that the dust may contain binders from the flap discs, nylon, paper, and other combustible materials, considering the extensive grinding that takes place to ensure a smooth finish on welded products. The results of the SEM analysis are eagerly awaited to confirm the exact composition of the dust collected during these processes.

Sandard testing services like those provided by companies such as Fike or Baker primarily offer results on the explosiveness of the dust, like the maximum explosion pressure (KSt) and other related metrics, without delving into the specifics of dust composition. From an industry perspective, understanding the detailed composition of the dust could be invaluable. If, for instance, it’s found that a significant portion of the combustible dust originates from specific types of grinding or polishing, there might be opportunities to modify processes to reduce the presence of combustible materials.

Sharing these findings with the wider industry could lead to enhanced safety measures and potentially innovative engineering solutions to minimize combustible dust at its source. Considering the considerable expenses associated with mitigating the risks of combustible dust and weld fumes, identifying ways to engineer out these hazards could result in cost savings while maintaining a safe working environment. This approach suggests a proactive strategy to not only comply with safety standards but also contribute to the broader goal of workplace safety and efficiency.

How Much Material Collects in the Ducting and System?

In close capture situations, such as robotic weld cells, a higher concentration of fumes and smoke is collected, filling up receptacles more quickly. However, the experience with ambient systems has been notably different. Customers often question the whereabouts of the dust due to its minimal visible accumulation.

For example, in most places, the 55-gallon drums used to collect dust underneath the dust collectors have been emptied very infrequently. The dust collected is extremely fine, resembling liquid when touched, which suggests the fume nature of the substance and its low bulk density. Despite the seeming scarcity of dust, the effectiveness of the ambient systems is immediately noticeable; the absence of just one system can be detected almost instantly, highlighting their importance in maintaining a clean work environment.

On the other hand, heavy-duty applications, such as those involving coal mining equipment manufacturing, generate significantly more weld fumes. In one extreme case, a customer using robotic welders to apply a chrome laminate on steel sheets for heavy machinery accumulated enough fumes to fill large hoppers within days, requiring frequent emptying. This scenario contrasts sharply with the slow accumulation observed in ambient systems, demonstrating the wide range of dust and fume generation across different welding activities and the tailored solutions required to manage them effectively.

What Are Some Recommendations on the Protection Side?

The cost of implementing safety measures for combustible dust in welding facilities has become more manageable over time, despite overall price increases. Nowadays, there are both active and passive systems available for mitigating risks associated with combustible dust. Active systems, which involve chemical suppression, are often necessary in large, automated welding facilities. These systems can include canisters placed at various points of the dust collector to prevent explosions from spreading.

Imperial Systems has invested in ensuring their equipment, such as the Cmax collector, is certified to block explosions up to 200 KST from reaching return areas, using primary filters tested by third parties. When this method is insufficient due to higher KST levels or unsuitable applications, canisters are added to the outlet side, along with options for flameless vents to safely release pressure without needing extensive space.

In addition to these measures, backdraft dampers and fast-acting slide gates are employed to protect both the inlet and outlet of systems. The company utilizes IDA primary filters for return air in ambient systems and EIV valves as flap-style valves on the inlet, ensuring protection across their units.

Significant investment has been made in third-party testing, including destructive testing, to validate the safety and efficacy of their equipment. This rigorous testing process not only ensures compliance with safety standards but also provides invaluable insights into the durability and reliability of their products. Such thorough testing enables precise sizing of safety features like vents, based on real-world performance rather than theoretical calculations. This commitment to comprehensive testing and quality assurance underpins the company’s dedication to producing safe, reliable equipment for handling combustible dust in the metalworking industry.

Conclusion

This discussion reaffirms the evolving priority of workplace safety in the metalworking industry. Jeremiah’s insights offer valuable perspectives on dust management and explosion mitigation, emphasizing continuous improvement and industry collaboration to safeguard workers and facilities.

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

Website: https://www.isystemsweb.com/

LinkedIn: https://www.linkedin.com/company/imperial-systems-inc-/

Email: [email protected]
Phone: 724.300.8146

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.