An arc flash is one of the most dangerous events that can occur in the workplace. It occurs when electricity has a path of reduced resistance outside of the cables or systems where it is intended to be to another location. The electricity ‘jumps’ from the wiring to another object through the air. This generates a massive amount of heat and can also cause serious damage or injury to anything in its path. Arc flashes are often accompanied by explosions due to the high amount of energy that is being released.
In most situations it is not possible to predict when an arc flash is going to occur since it is not an intended result of a normally operating system. For this reason, anywhere that has high voltage systems in operation should be considered high risk for an arc flash. While these areas should generally be avoided by workers, sometimes it is necessary that they enter them. When this is the case, those entering the area need to be using the proper personal protection equipment (PPE).
Types of PPE for Arc Flash Protection
There are many different types of personal protection equipment that can be used in the workplace. Choosing the right types of PPE to provide protection against an arc flash is very important. The specific things that are necessary will depend on a number of factors including how high the voltage in the area is, the risk of an arc flash, and more. The following are some of the types of PPE to consider:
- Face Protection – A face shield that is rated for arc flash protection will help to avoid burns as well as injury from flying debris.
- Head Protection – A safety helmet or other type of head protection is critical for avoiding injury from the flying debris. This piece should also help ensure the electricity is not able to travel through the helmet into the person wearing it.
- Hearing Protection – Arc flashes can be extremely loud. The fact that they occur suddenly makes the risk to hearing even more pronounced. Wearing strong hearing protection is essential in any area where an arc flash could occur.
- PPE Clothing – The pants, shirt, and other clothing being worn should be rated for arc flash protection. If it not, the person entering the area should put on protective clothing over their other clothes or change into something that will keep them safe.
- Eye Protection – If a situation does not need full face protection, wearing eye protection is still a good idea. Eyes can be especially vulnerable to electricity and flying debris can cause serious damage.
In high risk areas it is recommended to wear a fully body protection suit. This will provide as much protection as possible to anyone who is entering an area where an arc flash can occur.
Arc Flash PPE Categories
It is not enough to just look at the types of personal protection equipment and choose the items that are needed in a given situation. Each piece of PPE also must meet the needed protection levels based on the risks associated with an area. PPE that is used for arc flash hazards are broken down into four categories based on the level of protection that it provides. The four PPE categories are:
- Category 1 – Equipment that has a minimum arc-rating of 4 cal/cm2
- Category 2 – Equipment that has a minimum arc-rating of 8 cal/cm2
- Category 3 – Equipment that has a minimum arc-rating of 25 cal/cm2
- Category 4 – Equipment that has a minimum arc-rating of 40 cal/cm2
The higher the category, the greater the protection that it is able to provide. In most cases, this means that the material used in the PPE will be thicker so that it provides additional levels of protection. Along with the higher category level, additional types of protection are needed as the hazard level increases. For example, when using category 1 PPE there is generally no need to wear a protective hood that covers the neck and back of the head. When moving into category 3 and above, it is typically necessary to have the whole body covered because of the higher level of danger.
Personal Protection Equipment is a Last Line of Defense
Whenever discussing workplace safety, and especially safety with regards to arc flashes, it is important to remember that PPE is a last line of defense. In an ideal world, the PPE would never actually need to be used because the other steps used for workplace safety would be effective. For example, if someone needs to enter an area where there is high voltage equipment, the first option should always be to turn off the electricity at the source and use a lockout tag-out procedure to ensure there is no risk of electrocution.
In many situations, however, the other steps associated with increasing the safety of an area are either not possible, or not entirely effective. Having the right personal protection equipment will help to minimize the danger should all else fail.