What is a CAT Rating? | What Level do you Need?
WHAT IS A CAT RATING?
A CAT rating (short for PPE Category rating) is a way to quickly identify the level of protection that a FR/AR garment offers in the event of an arc flash.
*An arc flash occurs when an electrical current leaves its path, traveling through the air. This results in an electrical explosion where temperatures can reach upward of 35,000° F. Often times a worker can be within close proximity to an arc flash and without proper PPE, it can result in severe burns/injury.
The categories themselves correlate to a more specific measurement of protection known as the Arc rating. The Arc rating is measured in calories/cm² and determines how many calories of energy the garment can withstand from an arc flash. Safety and Health Magazine explains that an "Arc rating is defined as the amount of energy a given fabric can withstand before a 50 percent likelihood of the onset of second-degree burn through the fabric. In other words, what we are really measuring is insulation."
CAT RATINGS 1-4
Most NFPA 70E certified workwear will fall within a CAT rating of either 1, 2, 3 or 4. Each of these ratings correlates with a specific minimum Arc rating so that the wearer or employer can quickly determine if the PPE is sufficient for the job.
| CAT rating | Minimum Arc Rating (calories/cm²) |
| 1 | 4.0 cal/cm² |
| 2 | 8.0 cal/cm² |
| 3 | 25 cal/cm² |
| 4 | 40 cal/cm² |
What this means is that any garment that displays it has a CAT rating of 2 will have a minimum Arc rating of 8.0 cal/cm², 3 will be 25.0 cal/cm², so on and so forth.
DID YOU KNOW?
Before revisions to the NFPA 70E standard in 2015 that altered the terminology, CAT ratings were known as HRC, or Hazard Risk Category. HRC levels were also on a scale of 1-4 and were correlated with identical minimum Arc ratings (the same as on the chart above).
DO GARMENTS HAVE TO DISPLAY A CAT RATING?
The short answer is yes, FR/Arc rated garments are required to display the level of protection that they provide. However, the way in which garments display this information can be nuanced.
For instance, on DragonWear FR clothing, both the CAT and Arc ratings are displayed within the "badge" on the right arm.
*The CAT and Arc rating displayed on the right arm of an Alpha™ Jacket
Other garments, like the DragonWear FR T-shirt display only the CAT rating underneath the logo by the front collar.
*DragonWear FR T-Shirt displaying its CAT 1 rating
Some garments may not display both the CAT and Arc rating, but are required to display a CAT rating — this is where the minimum Arc ratings come in handy. Since we can see that this t-shirt is labeled as CAT 1, we know that it will have a minimum Arc rating of 4.0 cal/cm², but no more than 8.0 cal/cm² since that would bump it up into a CAT 2 rating.
WHAT IS A CAT RATING? IN SUMMARY
The important aspects to remember when it comes to CAT ratings are:
- A CAT rating is a reference to how much protection a specific garment offers in the event of an arc flash
- CAT 1-4 all correlate to a minimum Arc rating, ranging from 4-40 cal/cm² (See the chart above for reference)
- FR/AR garments are required to display its CAT rating (either on the garment or a tag) as a quick reference to the wearer to ensure they're in compliance of safety standards for their job
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