Arc Week Season 2, Ep. 2: Hidden Dangers – 3 Things to Know About Layering Above CAT 2

In both shark diving and industrial electrical work, risks exist on a scale. As we learned in Episode 1, when we recognize a greater hazard, we must increase our personal protective equipment (PPE) – including our arc-rated (AR) clothing system and other PPE – accordingly. For hazards above CAT 2 (from 8-20 cal/cm²), this is typically achieved through layering.

However, the natural human tendency is to focus on the most obvious hazard, and this can lead us to overlook potentially-hidden dangers or allow gaps in our protection strategies. Scott Margolin, Vice President of Technical, walks us through some of these layering gaps, and how to address them with behavioral safety and PPE:

When you’re about to jump into the water with sharks, it’s easy to perceive that the primary (or only) hazard is the sharks themselves. However, all of the basic diving safety considerations exist and can be easy to overlook, though they are all more likely to injure the diver than the sharks are: 

• If you’re diving with scuba gear, there’s sometimes a tendency to overlook potential hazards like depth, duration, buoyancy control, bottom time, air levels, and other factors.
• If you’re snorkeling, as our Arc Week team will be later this week, it’s easy to overlook hazards like sunburn, jellyfish, Portuguese man of war, abrasion from the skin of a shark, or drifting too far from the boat.

Like a safe dive, a safe electrical task includes factoring in all of the foreseeable hazards. And, when you increase PPE, doing so properly means considering all of the components of your protective system.  

Layering for Hazards 8-20 cal/cm²

Most people rely on 8 cal/cm² (CAT 2) dailywear (arc-rated shirt and pants or coverall) as the cornerstone of their program, and complete the PPE with voltage-rated gloves, leather keepers, a hard hat, face shield, and balaclava to cover the whole body.

When the possible incident energy exceeds 8 cal/cm², most electricians and safety directors don’t want to leap right to a 40 cal/cm² suit for tasks in the 8-20 cal/cm² range, so they layer up with either:

• A coverall over the dailywear, or
• An extra layer on the torso if the rating of the pants – which are generally made from heavier, more protective fabrics than shirts – is sufficient to meet the incident energy hazard they face

However, like with shark diving, there can be a dangerous gap(s) in your protection strategy. Watch out for these three common pitfalls:

Gap #1: Face and Head Protection

In shark feeding dives, where divers lure large sharks close enough to hand feed, divers often wear chain mail. This approach is appropriate for feeding most species where there’s a clear pecking order among the sharks and they approach the feeder one at a time. However, with species like Caribbean Reef sharks, which feed competitively and tend to form a “sharknado” around the feeding diver, we supplement standard chain mail with a helmet to further protect the head.

Similarly, when you layer for an electrical task with incident energy potential in excess of 8 cal/cm², the focus is often on the clothing. However, it’s very important to understand that most face shields and balaclavas or shrouds that are paired with CAT 2 AR clothing are often rated for 11-12 cal/cm². What happens if you have an incident energy potential above 12, and layered up to protect torso, legs, and hands, but didn’t upgrade the PPE for your face and head? It’s vitally important to be aware and properly protect these areas as well. There are face shields and shrouds rated for 20 cal/cm². 

Gap #2: Effective Layering

Layering is a powerful and effective tool, but it’s very important to remember that you can’t simply add the arc ratings of the layers. The only way to know the true level of protection provided by a layering system is to arc flash test that specific combination of fabrics together.

Good news: the protective level of two garments layered together often exceeds the rating you would get by simply adding the arc ratings together, thanks to the insulative air gap between the layers. Nonetheless, test data is an essential piece of the layering equation.

Gap #3: Lack of Layering Data (or Inadequate Access to Layering Data)

Arc ratings are specific to each AR fabric. So you have to know exactly what fabric and weight of fabric each garment is made from, then find the system arc rating for those fabrics together (if it exists) and make it available to each worker in the field.

Up until recently this was a major problem that either limited layering or limited garment choice – the #1 driver of comfort and satisfaction – within a clothing program. Luckily, there’s now 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.

Download the app today, and don’t forget to increase your face, head, and neck protection to match your hazard.

Hungry for more? Learn about the science behind arc ratings and other important tests that go into the AR clothing you trust with your life.

Do you have a flash fire – rather than an arc flash – hazard? The hazards may differ, but the lessons ring true: consider all foreseeable hazards in your risk assessment. And, when you increase PPE, consider all of the components of your protective system. Learn more about the testing that goes into your flame resistant clothing to ensure it’s sufficient to protect you in an incident.

Check out Episode 3: “You’re Gonna Need a Bigger Boat”. Guest expert Rich Gojdics, Vice President of Business Development at Enespro PPE, joins Scott to take us through PPE for CAT 3 & CAT 4 hazards – using the plot of a famous shark movie to help explore matching PPE to the hazard.