DSS025: The History of Arc Flash Safety and Application to Combustible Dust with Dan Laird

In this episode of the DustSafetyScience Podcast, we interview Dan Laird, Director of Engineering at Hallam ICS in Raleigh, North Carolina, about arc flash safety and how some of its components can apply to combustible dust safety as well.

We were introduced to Dan through Chris Giusto, Director of Industrial Projects at Hallam, who was interviewed on Episode 22 of the podcast, Dan has an electrical engineering degree and a strong background in the field, having worked with electrical systems for 25 years. He has been involved in arc flash safety since 2006 and says that in his opinion, combustible dust safety is still in the educational phase that arc flash safety went through over a decade ago.

During this interview, Dan shares some of the lessons learned in that process to see how they can be applied to combustible dust today. He also discusses topics like:

Different types of gap analysis, including requirements for PPE work procedures, engineering changes, or engineering implementations of safety systems
Inherent safety and how principles like minimization and substitution can be applied to combustible dust as well
How arc flash studies are completed
How the different groups involved, like the EHS health and safety managers, plant management, and the engineering team all need to really be on the same page to make arc flash safety work.

What is Arc Flash Safety?

The U.S. Navy was one of the pioneers in arc flash safety. They were investigating electrical accidents and found that most incidents weren’t cases of an electrician bumping into something energized. They were burn injuries that resulted due to an arc fault, a type of electrical explosion that occurs results from a low-impedance connection through air to ground or another voltage phase in an electrical system.

Dan shared a video about an arc flash accident, which is linked in the resources list below. An arc of electricity flashed from one volt meter lead to another, causing a large explosion. These types of incidents often cause severe burn injuries to workers in the vicinity.

Gap Analysis of Arc Flash Hazards

The outcome of these studies and incidents was a determination to protect workers. There are three different approaches that a facility can take:

The Personal Protective Equipment route
The work procedures route, such as warning signs and operating procedures
Making some engineering changes, such as guards and gates

In Dan’s opinion, the ideal solution was a combination of all three. EHS health and safety managers, plant management, and an engineering team can work together to implement electrical safety procedures that address gaps or potential hazards. He mentioned that out of the three, the engineering side is the most powerful because as it takes the risk out of the personnel’s hands.

Overview of Arc Flash Studies

When a facility undergoes an arc flash study, its drawings are used to make a computer model of the power system. These drawings are typically only 50 to 75% accurate, so a field survey is needed to capture all required elements, such as trip settings and input parameters.

After the computer model is built, it is easier to recognize danger spots and decide how to mitigate them. Is protective gear sufficient? Can equipment operation methods be improved? What kind of engineering controls can mitigate the hazards?

This is another approach that’s also used in combustible dust safety- understanding the system model, identifying fault points, and determining what should be done first. The PPE, work processes, and engineering changes are also concepts that appear in combustible dust safety.

Changes in Arc Flash Safety

Dan said that arc flash safety has changed significantly over the past 10 years. In the past, it was primarily in an education phase because, outside of the U.S. Navy and some other proactive industries, people didn’t believe the danger existed.

Even when they acknowledged the risk, facility managers were defensive, claiming that their people were careful or that they knew (for example) that wheat dust was explosive, so why did they need a hazard analysis?

Once that resistance was overcome, they would ask if they really had to comply, saying that their state didn’t follow OSHA, etc. So much education was involved that Dan commented, that the NFPA combustible dust guidelines may be 10 years behind where arc flash is today.

Dr. Chris Cloney recently did a presentation at Powder & Bulk Solids about a dust explosion at Giacomelli’s Bakery Warehouse in Italy in 1785. Flour dust came in contact with a mounted lamp and exploded, injuring two workers. When the investigator asked if anything similar had happened in the past, the mill management initially denied it before acknowledging that there had been smaller flash fires and finally admitting that one person had burned their hand. This information only came to light because the investigator persisted.

Dan acknowledged that that arc flash matrixes had become more successful, but it was an uphill battle for a while. In the past, these studies were done by engineering firms, with involvement from the EHS Department. There were some political rivalries, and plant managers weren’t happy about having to pay for changes out of their budget, but over the last 10 to 15 years, these departments have learned to work together.

Dan also noted that more facilities are being designed with safety in mind. When he started over 20 years ago, plants were built with large transformers. Now, being more aware of arc flash, building designers might put in three smaller transformers to reduce the incident energy and make it easier to conduct arc flash studies.

Principles of Inherent Safety

Two of the principles of inherent safety are substitution and elimination, which involved changing or getting rid of the hazard. Another one is minimization, which applies in Dan’s example of substituting three smaller transformers for a large one. It’s an approach that applies to both arc flash and combustible dust safety.

In wood processing industries, we may be able to start getting rid of storage silos if we can improve the raw material delivery and manufacturing processes. This would be an example of elimination of the hazard of storage silo fires or explosions all together.

Arc Flash Safety Groups and Reference Materials

When asked about groups and reference materials that teach arc flash safety, Dan recommended the following:

The Eddie Adams arc flash video, which reveals in compelling detail what a burn victim goes through
The IEEE calculation method on arc flashes
Brain Filler, which is the website of IEEE committee member and independent tester Jim Phillips

Conclusion

At the end of the interview, Dan said, “If you’ve ever seen a victim of a burn injury… it’s almost better to have a fatality then to have the injury. You wouldn’t wish this on your worst enemy. So I would say that if you’re on the fence about (paying for an arc flash study and improvements), just think about what happens to one burn victim.”

It’s a risk that also appears in combustible dust environments. Dr. Chris Cloney mentioned a video about a rubber dust flash fire that left an employee with burns on 75% of his body. If steps can be taken to prevent these incidents completely, they’re worth the effort and price.

If you would like to discuss further, leave your thoughts in the comments section below.

You can also reach Dan Laird directly:
Email: [email protected]
LinkedIn: https://www.linkedin.com/in/dan-laird-28a18b20/

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.