Arc Week Episode 2: Arc Bites – Inside an Arc Rating

Tyndale presents Arc Week: a unique, week-long educational look at the world of arc flash hazards through the lens of Shark Week. Join Scott Margolin – our dedicated technical expert by day and passionate shark enthusiast in his free time – for engaging, memorable parallels that bring important lessons about risk protection and PPE to life. Follow along at TyndaleUSA.com/blog.

When planning to dive with sharks, the size, species, and number of sharks – as well as the possible dive conditions – determine the type and amount of PPE you’ll need to wear. The higher the risk of the dive, the more PPE you need to wear. The same is true of arc flash PPE when preparing to work in energized, arc-infested work zones: it all depends on the size of the possible arc.

Join Scott Margolin for a behind-the-scenes look at the science behind arc ratings, types of arc ratings, and how to read an arc rating report:

  • The level of protection of an arc-rated (AR) garment is measured by its arc rating, which tells us how much energy that fabric or garment can block without injury to the wearer.
  • To avoid an “arc bite,” you must always ensure the arc rating for the AR clothing you’re wearing – either a single layer or multiple AR garments layered together – exceeds the incident energy potential for the task at hand.
  • There are two ways to get an arc rating: Arc Thermal Performance Value (ATPV), or Energy to Break Open Threshold (EBT). In both cases, you are protected from second-degree burns at or below the arc rating of that fabric.
  • In the arc rating process for AR fabrics, a computer analyzes 21 data points indicating the absence – or presence – of a burn through the fabric or a hole in the fabric at increasing incident energies. The arc rating for that AR fabric and any garments ever made from it is identified at the point in the data curve where there is a 50% probability of receiving a burn through – or hole developing in – the fabric.

Remember: Whether you’re talking about sharks or arcs, size matters. The larger the shark, the more damage it can do. The same is true of arcs: larger arcs pack more energy and require higher rated AR clothing/PPE.

Need to layer AR garments to ensure your clothing system exceeds the incident energy potential?

It’s not as simple as adding the arc ratings together. The only way to know the true level of protection is to arc flash test that specific combination of garments. Luckily, there’s an app for that!

  • The first and most comprehensive database of its kind, Tyndale’s Layering Tool places our industry-leading database of layered arc flash testing data in the palm of your hand.
  • Simply select a desired level of arc protection, and the tool will show you what to layer – using items you already own, items available in your company’s catalog, or both.

Do you have a flash fire – rather than an arc flash – hazard?

We’ve got you covered, too. Learn more about:

Are your workers equipped to avoid arc bites?

Look out for Arc Week Episode 3 Arc Infested Work Zones, premiering tomorrow, and find out how NFPA 70E serves as your lifeguard.

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