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Practice safety first because arc flash has officially become ubiquitous

By Jim Neumann

The unpredictability of arc flash incidents make them difficult to prevent.

It’s been facebooked, tweeted, youtubed, linked in and wikipediaed. And yet, despite its global name recognition, an electrical accident in the workplace kills a worker every 28 hours. According to an IEEE study involving more than 120,000 workers, arc flash was the culprit in more than 75% of those accidents.

Electrical accidents represent a statistically small percentage of work-related incidents, often occurring even in facilities that have passed formal inspections within recent months, but they’re disproportionately fatal. In a seven-year study conducted by the U.S. Department of Labor’s Bureau of Labor Statistics, 2,576 U.S. workers died and another 32,807 sustained lost-time injuries, losing an average of 13 days away from work, because of electrical shock or burn injuries.

The Internet is brimming with information about arc flash: 364,000 hits on Google, 11.2 million hits on usa.gov and even 445 chilling videos on YouTube. So, why are U.S. workers still getting killed on an almost-daily basis?

Arc flash: The element of surprise

The problem is that an arc flash incident can occur, without warning, nearly anywhere high voltage is used. Incidents can even occur in facilities that have been rigorously inspected, like data centers, manufacturing plants, commercial buildings, convention and hospitality centers, power generation and distribution infrastructure, retail space or other facilities where high levels of electrical power are needed.

But just as law enforcement officials can only attempt to preempt terrorist attacks by increasing surveillance, training those on the front lines on what to look for, investing in protective infrastructure and so on — facility operators haven’t historically been able to overcome the core problem: predicting when and where incidents will occur.

A half-dozen basic obstacles, until very recently, have kept organizations from accurately determining the potential for arc flash exposure within their facilities and educating workers about threats within their work environments.

Now you see it, now you don’t: In a typical facility, day-to-day operating conditions are too dynamic to allow for the accurate prediction of arc flash threats. People joke about trying to service an aircraft’s engines while it’s still in flight, but eventually an aircraft lands. In a mission-critical facility, there’s never a risk-free time to conduct service, maintenance or technology upgrade procedures. Because these procedures have to be done on “live” equipment, errors become more likely.

While you were reading this, the threat escalated: The gradual aging and deterioration of power cabling, connectors and other components produce a corresponding increase in the potential for arc flash threats. Unfortunately, the rate at which this deterioration can cause arc flash problems is completely unrelated to the timetable that arc flash studies are scheduled to be conducted, just as few people arrange to have their heart attacks during the same 30-minute window that they are in their physician’s office for an annual checkup.

Need to have vs. nice to have: NFPA 70E Article 130.3 requires that an arc flash study be conducted at least every five years or whenever a major modification occurs. These studies are typically complex and usually require that an outside expert be retained. These studies, which increase in cost with the size of the facility include data collection, revision of one-line drawings, short circuit and protective device coordination studies, warning label installation and arc flash training. For all of their good intentions, companies can be slower to spend money on things like inspections until the need for them is plainly evident.

It’s an arduous undertaking that never really ends: Greek mythology speaks of Sisyphus, who angered the gods and was given the punishment of spending eternity rolling a boulder to the top of a tall peak, only to have it roll down the other side of the peak each time. Though that’s a little more grueling than conducting an arc flash study, there are similarities: an arc flash study is a painstaking, labor-intensive undertaking and one that’s outdated almost as soon as it’s completed, because of equipment changes, components being handled during maintenance procedures or just plain aging.

A false sense of security: In a freshly inspected facility, workers assume that arc flash safety levels are at their highest, which can lull them into believing that it’s safe to lower their guard in terms of safety precautions. This is particularly true in facilities that are “self-inspected.” Self-conducted inspections seldom do the thorough job of experienced experts, setting the stage for potentially catastrophic problems down the road.

NIMBY becomes NIMMCF (not in my mission-critical facility): When many people hear a dangerous term such as “arc flash,” some have a difficult time envisioning that their air-conditioned data center or pristine mission-critical facility poses a safety threat. But the threat of arc flash is present anywhere there are high levels of electrical power: workers have been injured and killed using ladders and power-washing equipment, and a frightening story in the medical publication, Anesthesia & Analgesia, describes a nurse electrocuted in an operating room that was fully compliant with current National Fire Protection Association (NFPA) electrical codes.

Next-generation assessment

But within the past 18 months, a new software technology called “power analytics” has emerged that, though developed primarily to ensure power reliability and energy efficiency, has also been proven to provide real-time arc flash assessments.

The term “power analytics” refers to integrated software technologies that help organizations ensure their electrical power infrastructure is optimally designed at the CAD stage, performs precisely as intended in terms of reliability and energy efficiency once in the deployment/diagnostics stage, and operates flawlessly as organizations make real-time transitions between public and on-premise power sources in the grid management stages.

Once in the deployment/diagnostics stage, the diagnostics software maintains an uninterrupted watch over site operations, continually checking components, equipment, and systems and comparing their real-world status to the original CAD model. When deviations are detected, the system performs the calculations necessary to make intelligent recommendations about where arc flash hazards have the potential to emerge and gauges their severity.

Before entering an energized area and beginning work, site personnel simply query the system for a real-time arc flash status. It then responds with an up-to-date recommendation on the appropriate safety procedures and PPE necessary to work in the vicinity. Recommendations are based upon IEEE 1584 and the NFPA 70E standards titled, ”IEEE Guide for Performing Arc-Flash Hazard Calculations” and “Standard for Electrical Safety Requirements for Employee Workplaces,” respectively.

For example, when performing repairs to equipment on which a worker could accidentally be exposed to an electrical hazard, power analytics systems can provide specific guidance on gloves, clothing, goggles and helmet the worker should wear to increase safety in the event of an accident. Forewarned about the nature of the threat, workers will be able to proceed with a greater knowledge about specific safety risks they might encounter.

There are no crystal balls that are 100% foolproof when it comes to detecting arc flash hazards. But the new generation of power analytics technologies are the most promising development yet for ensuring that workers are forewarned to the greatest extent possible about how to protect themselves from this all-too-common threat.


See the original article at http://www.plantservices.com/articles/2010/10YourSpace.html.