“Hotter than the surface of the sun” is a way we often describe the temperatures generated by an Arc Flash – so why is an Arc Flash incident so hot and how hot is an arc flash?
Arc Flash incidents can create temperatures of up to 35,000 Fahrenheit for a short amount of time. The surface of the sun is generally accepted to be around 10,000 Fahrenheit. Like the sun, the energy in an Arc Flash incident is created by its light and heat.
So why is an arc flash incident so hot? Much like lightening, an arc flash is the movement of electrical charges which in themselves are not hot. What causes the heat is the resistance to the electrical charges, so good conductors which allow the charges to pass through them easily won’t get as hot as poorer conductors which resist the movement of the charges.
The key thing here is the body’s ability to conduct electricity, as the level of resistance it provides will influence the amount of heat generated.
The human body is intrinsically a bad conductor of electrical currents, which is why it’s possible to sustain serious burns in an arc flash incident without there even being a fire. The body’s ability to resist electrical charges is why an Arc Flash incident is so hot if you’re caught in one.
For more detail on the kinds of injuries possible in an Arc Flash incident and the difference between Arc Flash injuries and those likely with electrocution, look at our blog here.
The heat created in an Arc Flash incident is one component of the incident energy. This is the term used to describe the severity of the incident and is calculated by measuring the energy on a surface at a specified distance away from the working area.
The electrical discharge moving through the air during an Arc Flash can produce rapidly expanding superheated vapour which can cause an explosion-like blast, throwing people and equipment many metres away from the site of the incident.
Only the appropriate personal protective equipment (PPE) can protect you from the heat and other risks of an Arc Flash incident.
From understanding the potential incident energy by using an Arc Flash study for the particular system and piece of equipment you’re working on it’s possible to work out the level of protection needed, expressed as a Cal rating.
What’s critical is that every piece of clothing a worker wears is Arc Flash-rated, just wearing an Arc Flash top layer won’t provide adequate protection from the heat, which can melt other fabrics, for example in socks and underwear, causing additional injuries.
For more about the benefits of layering to provide adequate protection take a look at our blog explaining how to ensure your team are comfortable to work, able to move to do the job they need to, but still protected from the heat and other dangers of Arc Flash incidents.
We hope that’s been a useful explanation of why an Arc Flash incident is so hot – for advice on how best to protect your teams from the risks of Arc Flash, call our friendly sector experts on +44 (0) 1482 679600.
Read our free guide on the top considerations when choosing Arc Flash clothing & PPE below and make the best choice for you and your team via the link below ⬇.
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