Demystifying Safety Clothing: Proper protection against arc and flame on the job

By Jeff Gavin | Jun 15, 2023
clothing on fire

Who is responsible for ensuring workers return home at the end of the day?

Who is responsible for ensuring workers return home at the end of the day? It is not the workers alone. This duty falls on managers that familiarize themselves with what their workers face, well-informed safety teams and purchasing departments, standards bodies and safety clothing manufacturers. Yet, mandatory safety dress for workers may still require a widespread culture shift.


In the “Arc Flash Research Project,” IEEE and NFPA share that, annually, 2,000 workers are admitted to burn centers for extended treatment of injury caused by arc flash. Beyond burns, these explosions have caused shock, blindness, memory loss and even death.

OSHA describes arc temperatures as hotter than the sun’s surface and the flash as quick as a fraction of a second. Added to that, they can also involve hot gases, metal shrapnel and a pressure wave akin to “a hand grenade.”

How you dress affects the severity of your injuries, so proper protective gear may allow you to walk away in one piece (although shaken). Protection for electrical workers includes arc-rated (AR) clothing that is flame-resistant (FR). Though not all FR clothing is AR, if FR clothing has an arc rating, it is AR. You should dress based on your surroundings and assignment. 

“Protective clothing [AR workwear and AR flash suits] must be flame-resistant in the arc rating test (ASTM F1959),” said Scott Margolin, vice president of corporate strategy and technical for Pipersville, Pa.-Tyndale Co. Inc., a manufacturer and supplier of arc-rated, flame-resistant clothing. “I chair that ASTM standard”. 

Testing requires an FR vertical flame test (ASTM D6413). A fabric sample is put over a Bunsen burner for 12 seconds. If it burns, it is not flame-resistant. If it resists burning, you measure the char damage. 

“All AR clothing must pass this FR test before it is ever arc-rated,” Margolin said.

If the preconditioned fabrics (that have gone through multiple cycles of washing and drying) pass the vertical flame test, they are then exposed to an open-air arc. This repeated test (ASTM F1959) gleans a representative rating of the fabric. Ratings (ATPV, EBT and ELIM) indicate diverse types of fabrics including knits, weaves and specialty fabrics. Common AR fabric types include cotton blends and soft but strong synthetics called modacrylic and aramid (a heat-resistant cousin to nylon).

“In the old days, an arc-rated base layer was probably 6 ounces [about 170.1 g] and it shrunk like crazy,” Margolin said. “They were expensive and uncomfortable. Today, they can be lighter than a cotton T-shirt (less than 4½ ounces) and every bit as soft. They dry quicker, too. So, if I am doing work where arc flash is possible, I’m wearing an arc-rated base layer and a button-up. I’m not wearing a standard cotton T-shirt under it, ever.”

Avoid 100% cotton 

Although OSHA’s apparel guidance allows 100% cotton and wool as a base layer dependent on weight, Margolin sees a problem. 

“Say a little triangle of your cotton undershirt is exposed at the neck. If there is an arc flash, it will ignite. The flames go to your mouth and nostrils. You are now breathing fire,” he said. “Even if you’re wearing a face shield, if the T-shirt is what’s on fire, the heat’s going to come up under that shield, as is the smoke. A cotton T-shirt cannot be exposed. That’s why your shirt’s supposed to be buttoned all the way up.”

Margolin asks, why gamble?

“No one is using a water extinguisher around electrical,” he said. “You use a foam extinguisher. Put out combusted cotton fabric with a foam extinguisher and it will reignite every time the wind blows, the victim moves, or heaven forbid, the medics come and you’re on oxygen. The medic goes to take off your shirt and it reignites around oxygen. I like the backstop of an arc-rated base layer.” 

For the record, a majority of meltable fabric is not allowed, which rules out quick-dry athletic wear. NFPA 70E defines arc flash clothing in four categories (lowest to highest) based on an incident energy analysis (4, 8, 24 and 40 calories/cm2).

Safety parallels

Now retired, ArcWear founder Hugh Hoagland sold his Louisville, Ky.-based company to Kinectrics, Toronto. ArcWear offers arc, flame and thermal testing and certification. 

“Industrial electricians also need flame-resistant clothing, maybe flash suits on a periodic basis, too,” Hoagland said. “So do commercial workers if they work in three-phase systems. When you’re around switchgear transformers, even the commercial system elevators, you are dealing with much more current and getting into arc flash potential.”

“Most of the time, contractors [shy of line contractors] are bending conduit and running wires before connection, so they aren’t in flame-resistant uniforms, but here’s the thing—know your surroundings. There were electricians working in an office building one day, not working on anything energized. Safe, right? But there was an installed cabinet in the next room that faulted, sending a fireball into their room,” he said. “The electricians’ clothing caught on fire. One of them died and the other was burned beyond recognition to never work again. 

"As an electrician, if you know you’re going into something that might have a higher danger exposure, put on the arc flash suit. I’ve probably seen two people dying out of 130 because they weren’t wearing arc flash protection. There are no standard work practices that prevent arc flashes. There’s some new equipment designs that prevent them, but they are few and far between. Regular equipment maintenance can be lax as well,” he said.

Standards that recommend regular equipment maintenance are helpful if followed. They include NFPA 70B, Standard for Electrical Equipment Maintenance, which is geared for commercial and industrial applications, and ANSI/NETA MTS-2023, Standard for Maintenance Testing Specifications for Electrical Power Equipment and Systems. Hoagland suggested the best way to put them into practice is to make them a requirement in the project bid.

One of the downfalls Hoagland sees is a lack of safety knowledge in company managers. He has served as an expert witness in multiple lawsuits, and often discovered that company managers refused to be trained in safety. 

“Not having the right PPE, if any, is alarming,” he said. “In a crisis, the top motivation is often, ‘Let’s get this thing back up,’ skirting safety. I believe not just electricians, but every manager that directly supervises should have NFPA 70E training. You cannot ask your workers for the sake of production or for the sake of convenience to break the rules.”

Learning from mistakes

Brandon Schroeder is a motivational safety speaker based outside Cedar Rapids, Iowa, and a journeyman for Tri-City Electric Co. of Iowa in Davenport. He created “Believe in Safety” as the result of his arc flash accident a decade ago. That day, the general contractor on a rehab office project asked Schroeder to relocate a temporary power feed. Though he usually had his 12-calorie arc suit in his truck, he had lent it out. He proceeded with the job confident in his abilities and in avoiding an accident.

“A risky attitude for sure,” Schroeder said. 

Working with a 750 KPH transformer, 13,800V primary, Schroeder needed to step down voltage to 480V. The panel was fed directly from the utility transformer and the only way to shut it off was to call and have the utility pull the primary fuses. 

“I had 30 minutes to get this done. If I called the power company, I would never get anyone out in the next 30 minutes to help me,” he said.

What happened next would be anyone’s nightmare.

“I unhooked the temporary power feed, but the cord fell. The ground wire flopped in the panel, hitting the bus bar,” Schroeder said. 

A 480V arc flash ignited a ground fire around him and blew off the palm of his hand. He had to be airlifted to a hospital. Though his clothes did not ignite, he suffered third-degree burns on his hands and arms. The flash melted the top of his hard hat, but with his head facing down, the brim of the hat deflected enough heat, inflicting lesser but serious second-degree burns to his face and ears. Skin grafts were used for his palm, all five fingers and left and right arms. His 18-month recovery included battles with deep depression and painkillers.

As a public speaker, Schroeder shares his experience so it serves as an education and motivator for better safety practices. 

“While equipment subject to arc flash is now more clearly marked with a sticker, if you’re not properly training your employees on what those stickers mean and how to avoid the hazards, you aren’t really alleviating the risk,” he said. “You want to see someone dressed properly. That could be everything from an arc-rated shirt, pants, a face mask and a face shield, and voltage-rated gloves, to a 40-calorie arc suit.”

Read more about Schroeder in “Making Safety Personal,“ Safety Leader, May 2020.

Layering for protection

Hoagland and Margolin agree that layering PPE clothing benefits a worker. There are some intricacies. 

“As soon as you layer, you have an air gap, dead air trapped between two layers that serves as insulation,” Margolin said. “So layering is your friend. Your 4-calorie base layer and an 8-calorie outer layer doesn’t add up 12 calories, but likely 15–20 calories. All those layers all must be arc-rated to count toward a system arc rating.”

Companies such as Tyndale and others will help contractors figure out their clothing’s arc-rating system. 

“Electrically savvy safety managers who are 70E-versant can make such determinations, too,” Hoagland said. “Make sure your arc-rated clothing meets or exceeds the hazard you face.”

Header image caption: Arc temperatures can be hotter than the sun’s surface, and the flash quicker than a fraction of a second.

Image courtesy of Tyndale Company Inc.

About The Author

GAVIN, Gavo Communications, is a LEED Green Associate providing marketing services for the energy, construction and urban planning industries. He can be reached at [email protected].





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