When it comes to protecting workers from arc flash hazards, not all flame-resistant (FR) clothing delivers the same level of safety. It’s not just about whether the fabric resists ignition it’s about whether the garment has been tested and rated to handle real-world arc flash exposure. That’s where Arc Ratings and PPE Categories (CAT 1–4) come in.
At Dukel, we break down these standards so crews in construction, utilities, and heavy industry can make informed choices and stay safe on the job.
What Is an Arc Rating?
Arc ratings measure how much thermal energy a fabric can withstand before the wearer risks a second-degree burn. The value is expressed in calories per square centimeter (cal/cm²).
- The higher the arc rating, the greater the protection.
- Ratings are determined through rigorous testing under ASTM F1506 and NFPA 70E standards.
Think of it as a performance score that tells you exactly what level of arc flash a garment can handle.
Breaking Down CAT Levels
NFPA 70E groups FR clothing into four PPE Categories (CAT 1–4) based on arc rating ranges. Here’s what that looks like in practice, with gear you can find at Dukel Safety:
- CAT 1: Basic Protection (4–7 cal/cm²)
- Example: Lightweight FR work shirts and jeans
- Best for low-risk environments like control rooms or routine breaker operations.
- CAT 2: Moderate Protection (8–24 cal/cm²)
- Example: FR work shirts and pants from brands like Drifire
- Common for construction electrical work, utility maintenance, and general field tasks.
- CAT 3: High Protection (25–39 cal/cm²)
- Example: 25 Cal Arc Flash Kits with shrouds or hoods
- Required in higher-risk zones like switchgear rooms.
- CAT 4: Maximum Protection (40+ cal/cm²)
- Example: 40 Cal Arc Flash Suits with lift-front hoods.
- Designed for extreme conditions with the highest levels of incident energy.
Why OSHA Guidance Is Essential
It’s not enough to just grab a garment with a higher CAT rating. OSHA requires employers to conduct an incident energy or hazard assessment to determine:
- Arc flash boundaries
- Minimum PPE category requirements
- Safe working distances
For reference, OSHA’s publication Protecting Employees from Electric-Arc Flash Hazards (4472) is an excellent resource for compliance
Choosing the Right Category
When selecting FR apparel for your crew:
- Start with the assessment. Confirm your site’s expected incident energy.
- Match gear to the hazard. For example, an 18 cal/cm² exposure means CAT 2 apparel at minimum.
- Consider layering. Multiple compliant garments can increase overall arc protection if tested as a system.
Why It Matters
Selecting the wrong PPE category can mean the difference between minor injuries and life-altering burns. CAT levels aren’t just technical jargon they’re lifesaving standards.
At Dukel Safety, we carry a full range of FR gear from CAT 1 shirts and jeans to CAT 4 arc flash suits backed bt trusted brands and ready-to-ship inventory. Our mission is simple: keep your team compliant, safe, and on the job with the protection they need.
Stay Safe with Dukel
Arc flash doesn’t give second chances. By understanding CAT 1–4 apparel, you can confidently protect your crew against electrical hazards.
Explore Dukel FR Apparel Collection and equip your workforce with the right gear today.
