In order to protect yourself and workers in your facility, it is important that everyone is aware of how to read arc flash labels. Being able to read arc flash labels is crucial for management in determining PPE requirements, and is crucial for both electrical and non-electrical workers to determine whether or not they currently have appropriate PPE for the task at hand.
Arc Flash Labels
First, let’s take a look at a typical Arc Flash Warning Label.
There are two important pieces of information about arc flash here that determine the PPE requirement. The first is the Flash Hazard Boundary. This is the minimum working distance where appropriate PPE for energized work will effectively protect personnel against arc flash hazards. Working any closer than the minimum distance specified in the Flash Hazard Boundary can result in serious harm in the case of an arc flash incident because the PPE recommended by the label will not protect a worker from the effects of arc flash.
Next, you’ve got the energy level of cal/cm square, with a flash hazard at 18 inches. In this case the energy level is 3 cal/cm square. This is the most important piece of information on the warning label: it tells you how severe a potential arc flash incident could be. This number is determined by an incident energy study.
PPE Selection Using Incident Energy Levels
With these two pieces of information, you can now select your PPE. PPE categories are not rigorously defined by any standards organization: the level of PPE required for a particular job is defined by the facility management. CSA Z462 recommends three different levels of PPE depending on the the incident energy level:
- Incident energy levels less than 1.2 cal/cm square
- Incident energy levels between 1.2 and 12 cal/cm square
- Incident energy levels greater than 12 cal/cm square
Level 1 PPE could be anything that covers exposed skin, hearing protection, insulated gloves and shoes, and eye protection. Level 2 PPE would be similar, except that all of the clothing has to be arc rated. Level 3 generally requires arc flash suits and other bulky PPE.
However, there are no hard and fast rules for determining PPE, just helpful guidelines. PPE categories for your facility should be heavily influenced by your Electrical Safety Program.
PPE is ALWAYS the Last Line of Defence!
Remember than PPE is supposed to be the last line of defence against arc flash and shock hazards. Your electrical safety program should consider the Hierarchy of Hazard Mitigation Controls. They are:
This hierarchy of mitigation controls should always be followed to effectively reduce the risk of an arc flash hazard occuring.
The Ability to Absorb Risk is Important
PPE levels are also determined by the amount of risk that your company is willing to absorb. Statistics gathered by the NFPA show that the average electrical accident costs $80,023.This cost includes both workers’ compensation (medical bills and wages while unable to work) as well as equipment costs.
If it is more expensive to purchase and maintain PPE than it is to allow for electrical accidents, then you need to look in to the other controls that can be used to mitigate arc flash hazards. Your electrical safety program should outline the process to follow if you cannot provide higher levels of PPE (but can use other controls to lower incident energy levels on the work site). Overall, your electrical safety program and your ability to absorb risk will determine how the PPE levels are developed for your company.