How this Dangerous Hazard Can Change Your Life in Split Second!
By Perry A. Kuznar, PE
Client Services Manager
I Will Miss You!
For those of you who read this blog, you will remember our December article on safety training. It had the heart-tugging title “Your Dog Will Miss You-Why Safety Training Makes the Difference”. The first paragraph of that blog sets the tone for this month…
Another Tuesday. You kiss your spouse and holler to the kids to be good. You give the dog a quick pat on the head and out the door to work you go…never to return! Three hours later, you reach out to check a system you are working on. There is a sudden flash and deafening zap. You suffer fatal injuries. Your family will never see you again. Your dog will wonder when you are coming home-it will never know what happened. Just another Tuesday.
Hotter than the Surface of the Sun!
Accidents happen! Even on Tuesdays! The above scenario depicts an arc flash incident. It is an invisible danger that can reach out and hurt or kill you if you are not cautious and prepared.
An arc flash is the light and heat which is produced as the result of an arc between one live electrical conductor and ground or between two live conductors. The key is that the arc travels through ionized air, also known as plasma, which turns the normally nonconductive air into a conductive path. The plasma temperature can reach 20,000 Kelvin (or about 35,000 Fahrenheit). That is hotter than the surface of the sun! Does that get your attention? We are just getting started!
With that extreme temperature, the “flash” is violent. High power arc-flash faults are electrical explosions, releasing a great deal of energy. That energy combines radiant heat, intense light, and high-pressure waves.
When the flash occurs, the instantaneous temperature increase rapidly expands the air volume. The resulting pressure wave can blow you off your feet and damage or destroy anything in its wake. The accompanying radiant energy burns dramatically.
There is more! The high temperature can also change circuit components from solid to vapor. If your conductor is copper, for instance, it would instantly vaporize at this arc flash temperature. This further adds to the destructive power of the arc flash. How? The vaporizing copper expands to over 60,000 times its original size. This significantly increases the pressure wave. This also increases the likelihood of shrapnel and toxic gases. Again…do I have your attention?
The bottom line… if you are in an arc flash zone, you risk injury, burns, and even death.
Not All Hazards are Created Equal!
The effects of an arcing fault depend on the energy at the point of interest. Different levels of danger and destruction result from particular-site energy levels. This is important to know!
There are four main factors that determine the energy level:
- Distance between Conductors
- Arcing time
What is certain is that an arc flash can cause equipment damage and be hazardous to personnel. Fortunately, there are protective steps to take that can optimize electrical safety.
Know Your System!
A facility has different voltage and current levels, depending on where you are in the system. Conductors can be close together or far apart. Different spots have different specifics and different levels of danger.
A professional arc flash study reviews your facilities’ electrical system and determines the danger levels at specific spots in the system.
Specialists start with as-built system drawings and documentation. This is typically the facilities’ layout and electrical one-line drawings.
They field verify this information by following the system through the plant or facility. Any changes are updated in the documentation.
Equipment covers are removed to inspect and gather:
- Protective device manufacturer/types/sizes/settings
- Cable size/lengths
- Transformer impedance values
- KVA sizes
Equipment of interest are those electrical system items personnel may interact with while energized. These would include:
- Electrical Panels
- Motor Control Centers
- Fused Disconnects
- Control Panels
Field data is loaded into a power system analysis software to run a:
- short-circuit analysis
- coordination analysis
- arc flash analysis
Arc Flash Labels and PPE
The results from the completed analysis are used to generate arc flash labels. These labels are placed in clear view at the equipment of interest locations. The labels warn of an arc flash hazard, the level of hazard, and the required personal protective equipment (PPE) required to work in that area.
When You Need Surgery, You See a Surgeon!
You would not think of asking your general practitioner to perform knee surgery. He or she may know a thing or two about it, but that is not their expertise. You want an orthopedic surgeon specializing in knee replacement surgery. Someone that does this as their profession! The odds of a successful outcome are much better!
Our Arc Flash Experts are Ready to Serve You!
Excel Engineering has been a trusted advisor and guide to our clients for 32 years! We assist Industrial Manufacturers and Power Utility Companies with consulting expertise. This includes the following disciplines:
- Arc Flash Studies
- Electric Power Systems Studies
- Electrical Design for Facilities and Processes
- Controls and Automation Engineering for Processes
- CAD Services
- Contingent Workforce Personnel
- Electric Transmission Systems Studies
- Electrical Safety Training
We work with you to turn challenging projects into high-value outcomes. Invite us to look at your situation. We offer valuable solutions. These will speed up your business, improve your bottom-line, and relieve stress. You and your team can focus on running your business.
Click here now to submit your request for your Arc Flash Study. It is easy and takes just a couple of minutes.