The National Institute for Occupational Safety and Health (NIOSH) defines an arc flash as “the sudden release of electrical energy through the air when a high-voltage gap exists and there is a breakdown between conductors.” The result: an instant release of a tremendous amount of energy.
The often-violent results can produce enormous pressure, sound, light, and heat. Anyone near an arc flash risks serious injury and even death. The heat can reach 35,000 degrees — four times hotter than the sun’s surface. Workers can be thrown about, and objects, often bits of molten metal, are shot about too, at great velocity. Burns can be horrible, and vision and hearing lost. Often, extended, expensive medical care is needed.
The causes of an arc flash, OHSA says, include dust, tools being dropped, accidental touching, condensation, material failure, corrosion, and faulty installation.
NIOSH goes on to say, “The organization has a responsibility in preventing arc flash injuries. It has the ability to provide a safety analysis of the workplace and develop engineering controls to eliminate hazards. It can engineer new or retrofitted facilities, incorporating the latest safety technology. Organizations have the duty to provide appropriate tools, PPE (personal protective equipment), and regular maintenance of equipment and training. A commitment to training is a commitment to safety.”
An added arc flash issue for data centers is that they typically are full of energy. Jay Smith Jr., executive vice president of Lewellyn Technology, says, “When you look at a data center, typically they are very electrically heavy; they tend to consume quite a bit of energy and have a large volume of distribution equipment. Their equipment is cooled; their systems are typically redundant. There are multiple layers of backup systems.“
Chris Crosby, the founder and CEO of Compass Datacenters, says the popularity of phased modular data centers in recent years “has increased the risk of arc flash due to the adding of equipment, post commissioning, to a live (energized) backplane without shutdown.”
Smith says that for the most part, the people who oversee the electrical aspects of data centers are aware of the potential hazards and trained. Where they’re lagging, he says, is on the arc flash assessment portion of electrical safety. “We still see every year new, large organizations that have multiple data centers that have not had the arc flash assessments done.”
Moreover, the data center attitude of “Get this changed or added but don’t shut it down” is often coming from the facility manager, Smith says. “We see high levels of energized work which cannot be justified. Troubleshooting is OK; live work is not. We see that while there is the knowledge that arc flash and shock hazards exist, there is still a lack of protection and de-energizing of this equipment prior to ‘live work’ occurring.”
A fact that complicates electrical safety in data centers, Smith notes, is the comparatively high value of those facilities, where down time can be financially catastrophic.
A broader problem is a general perception that serious electrical accidents only occur at big industrial plants, or are only the ones people hear about on the TV news. Smith mentions fatal arc flash accidents at a toy store at a mall and a city swimming pool, where a worker was doing routine maintenance on a pump.
In terms of arc flash awareness, Smith finds there is still an attitude of “I’ve been doing this for 20 years and I ain’t dead yet,” or, “I’ve been doing this 20 years and I ain’t ever seen one of those things.” He compares the growth of arc flash awareness to that of seat belt use, and says it’ll get there eventually.
Smith offers this arc flash advice to facility managers: “Make sure you understand that what looks like a routine daily task could, if not evaluated properly, be a lot worse than it might appear to the untrained person. There’s a lot more hazards associated with routine data center work than people understand.”
— Ronald Kovach