Q: Our customer is specifying “HRC 2”. What does this mean?
A: Hazard Risk Categories (HRC) was a term coined by NFPA 70E-2000 to “group” levels of PPE with a goal of simplifying PPE programs for end users. The 2018 edition of NFPA 70E replaced the term “HRC” with “PPE Categories” since the risk assessment part of the standard was separated to comply with OSHA requirements and standard requirements such as ISO 45001.
NFPA 70E-2018 PPE Categories:
| PPE Category | Arc Rating (minimum) |
| 1 | 4 cal/cm² |
| 2 | 8 cal/cm² |
| 3 | 25 cal/cm² |
| 4 | 40 cal/cm² |
It’s common to see both “HRC” and “PPE Category” on garment labels to indicate the arc rating of the garment. You might also see “ARC 2” on garment labels–this is a shorthand term for the terms to specify that they are for arc flash.
A common mistake of hazard assessment is to label equipment that has an 8.1 cal/cm² exposure as PPE Category 3. This is incorrect but a misunderstanding of the old HRC levels by the 2002 version of IEEE 1584 which has been corrected in the IEEE 1584-2108 standard. The PPE Categories are technically ONLY applicable when you have done your risk assessment following the NFPA 70E Tables. If you have done incident energy calculations the PPE should MATCH the hazard or be greater. This does not preclude an employer from using 25 cal/cm² PPE Category 3 PPE for all exposures UNDER 25 cal/cm² but they are not required to do so. Many engineering companies who used the common arc flash calculation software packages defaulted to this mistake.
