| Incident Energy (cal/cm2) | Hazard Risk Category | Required PPE |
|---|---|---|
| 1.2 | 0 | |
| 4 | 1 | |
| 8 | 2 | |
| 25 | 3 | |
| 40 | 4 | |
| 100 | 5 |
The amount of thermal energy impressed on a surface, a certain distance from the source, generated during an electrical arc event.
Incident energy is measured in calories/cm2.
1.2 cal/cm2 of heat energy can cause a second-degree burn to unprotected skin.
HRC – Hazard Risk Category is determined by minimum amount of Incident Energy released up to defined boundary from the source of Arc Flash Point. HRC – Hazard Risk Category, 0 to 5, is used to define the required Arc rating of the PPE required to work into that particular Arc Flash Boundary.
The distance from the source of the arc flash blast where the incident energy equals 1.2 cal/cm2
In order to protect workers, one would have to stand outside of this boundary or be dressed in personal protective equipment (PPE) that has a withstand rating exceeding the level of exposure at a given distance (working distance of 18 to 24 inches)
Degree of Burn is the level of depth of Burn effect on the human skin up to bones.
PPE : Personal Protective Equipment.
PPE will protect the user against health or safety risk at work.
PPE potects user against Hazards like, physical, electrical, heat, chemicals, biohazards, and airborne particulate matter.
In context of Electrical Safety at work, PPE includes, Arc Rated Clothing, Helmets, Gloves, Safety Shoes, Safety Glasses, Hearing Protection etc.