Most commonly, the hazards we associate with electricity and exposed electrical equipment are those due to direct contact. In these cases, a worker might accidentally touch an uninsulated wire or piece of electrical equipment, and momentarily become a conductor themselves. Severe burns and arrhythmia or stoppage of the heart can occur. What most people don’t know, however, is that another type of fairly common electrical hazard exists, known as an “arc flash.” In short, arc flashes are exposed flashes or “bolts” of electricity that occur when two energized systems overcome the resistance between them; electricity then visibly arcs between the two components, not only burning the air between them but causing an electrical explosion upon termination of the arc (which happens extremely quickly). These explosions can cause heats burns, lob dangerous molten droplets a considerable distance, and damage equipment beyond the point of no repair.
Startlingly, these arc flash explosions occur a reported five to ten times each and every day in the U.S. Unfortunately, these numbers mask the real risk factor of such conditions, as they are reported via special burn unit hospitals when an electrical arc explosion is the cause of injury or death. Other incidents, where injuries are less severe, where only equipment is damaged, or where a close-call/near miss occurs, are not even reported. This is all to say that arc flash explosions are a very real and very serious problem; they can result in lost time and wages (only partially covered by worker’s compensation), disability and inability to reintegrate into the workforce, as well as exorbitant costs on the part of the employer during lawsuits, for lost productivity, and during the rehiring and retraining of new employees. So, how can you keep your employees safe? Let’s take a look at a few different methods for doing just that.
Arc Flash Safety and Prevention
Elimination/Substitution: One one of the best ways of tackling electrical risks is by removing them altogether. This can seem tricky, but, given some thought, you may be able to use it in your own business. Elimination involves finding places in your operations where workers are unnecessarily exposed to risk. For example, look at the time of day that certain energized electrical systems need to be running, can they be turned off during worker shifts? Can processes be conducted in cycles so that workers don’t need to be around when components are on/running? Perhaps a risk is created by an old piece of equipment. In this case, upgrading it to a newer, safer model might be expensive in the short term, but an extremely smart long term investment. Taking a current system and ensuring that it has proper grounding can also help to make sure it won’t arc and become a safety a hazard.
Testing/Inspection: Of course, even knowing which components present arcing risks in the first place can be a challenge on its own. Luckily, the NFPA, or National Fire Protection Association, provides guidelines on exactly how one can go about assessing the risk associated with any piece of energized equipment. Not-so-luckily, the process involves some semi-complex equation work that could potentially be intimidating to the layperson. If you’re not confident in your ability to accurately conduct this assessment, you need to hire a risk assessment organization who can do it for you (many of them exist and even specialize in electrical hazards). The results of this analysis will give your various systems a category number, each of which has different requirements (usually dictating a certain associated PPE outfit).
In addition to initial assessment, regular inspections of your systems are vital. Worn insulation and parts are a leading cause of arc flash explosions and fires, so make sure that all parts are up to their respective tasks. Additionally, your maintenance workers should be specifically trained to inspect energized electrical equipment, and all such systems should be completely powered down and grounded before inspection, or the inspectors themselves may be put at risk.
Personal Protection Equipment
According to OSHA’s document on Understanding “Arc Flash”:
Employees must follow the requirements of the Arc Flash Hazard label by wearing the proper personal protective equipment (PPE), use of insulated tools and other safety related precautions. This includes not working on or near the circuit unless you are a “qualified” worker.
www.osha.gov - Understanding Arc Flash
“But wait! What if an employee isn’t wearing his or her PPE?!” you might protest. This happens all the time, and is still, ultimately, your responsibility. While you can’t control individual behavior in the moment, properly encouraging compliance and working around any mental or physical hangups that are causing employees to not wear their PPE falls on you. Your training programs need to make the importance of safety with regards to arc flash explosions clear to your employees. Additionally, if gear is not being worn, you should engage employees as to why it’s happening. “I forgot,” is only an acceptable excuse a few times before managers should take punitive action – this keeps the situation in your control. When other answers arise, you might find underlying problems (like gear not fitting right, or gloves inhibiting a worker’s ability to perform a task), in which case, again, you’re responsible for addressing these in a timely and effective manner. Even tasks which workers are the ones conducting on the ground level, inspecting their own PPE for defects, for example, should be double-checked at regular intervals by management to ensure you maintain control of the process and that no corners are being cut.
As a brief guide, arc flash PPE equipment for various NFPA arc flash electrical risk levels are fairly straight forward. Lower risk categories simply require a full body buffer of cotton clothing, while higher risk categories require users to wear rubber insulated clothing and fire-resistant pants, shirts, overalls, and face masks.
One of the best ways to keep workers out of harm’s way is to keep workers out of harm’s way… literally. Electrical panels and equipment that are exposed should be housed behind locked frames. Larger transformers that don’t necessitate regular worker access should be locked behind chain link fences to ensure employees don’t accidentally get too close. Work tasks should be structured in such a way that workers are at risk or near energized equipment for as little time as possible, if at all. Make sure you label all of these panels, gates/fences, and any arc flash risks with proper warning signs and labels that identify them and advise workers to keep their distance.
After you’ve taken these “action” steps, look to training and employee education to further your electrical safety program. Even when it’s your responsibility, the success of any safety program or element thereof comes down to your employees and how responsive they are to what you teach and ask of them. Keep that in mind, and you won’t ever find your business or your workers represented on a chart of arc flash explosion statistics!
10 Astonishing Facts about Arc Flash
- Arc Flash Requirements : What PPE Is Needed for Each Rating?
- NFPA 70e Arc Flash Labels
- Easy Power, Arc Flash Analysis, Power System Software
- Workplace Safety and Arc Flash Labels
- Arc Flash Boundaries