Our Dangers of Improper Wear series examines many of the common mistakes people make when wearing arc-rated and flame resistant (AR / FR) clothing, with real-world arc flash video footage that shows just how substantial each mistake can be. In each episode, you’ll find powerful examples of why wearing the right PPE, and wearing it properly, makes all the difference – with expert commentary from Scott Margolin, Vice President of Technical.
As part of our Dangers of Improper Wear series, we're looking at meltable base layers – which includes non-fr under shirts and anything else you might wear under your arc rated and flame resistant (AR / FR) shirt(s), such as a bra. The manikin shown in the video below is wearing a 7oz. FRMC outer layer with an arc rating of 9.1 calories and a 4.6oz. FRMC base layer with an arc rating of 4.6 calories. This makes the combined system arc rating for these two garments 20 calories. Under the base layer, the manikin is wearing a non-FR, meltable bra. At an independent testing facility, we’ve intentionally subjected this manikin to an arc incident energy above the break open point of the outer layer but below the system arc rating of the two shirts. Watch what happens:
With an 18 calorie arc and a system arc rating of 20 calories, you wouldn’t expect injury. Once the arc-rated outer layer is broken open, typically, we’d expect the AR base layer to protect the wearer from injury but because the manikin was wearing a meltable bra, the bra briefly caught fire, demonstrating how severely someone wearing a meltable bra could be injured.
The mistake in this manikin’s protective outfit is wearing the meltable bra underneath what otherwise would be an adequately protective outfit. Just like meltable base layers, even if you’re wearing an arc-rated outer layer that does its job, there can still be serious consequences.
What should you wear instead?