What is an arc flash?
To put it simply arc flash is an electrical explosion, (sometimes call ‘electrical arcing’, or a ‘flashover’).
Arc flashes at a glance:
- Flash of intense electrical energy
- Can be fatal
- During 2016-2017 there were 8 deaths due to contact with electricity, or an electrical discharge *Source HSE
- Exposure energy is expressed as cal/cm2
- Exposure of only 1 to 2 calories cause second degree burns
- Arcs generally are around 5-30 calories!
Why are Arc Flashes dangerous?
The temperature of the sun is 5,5050C degrees. Temperatures can reach up to over 190000C degrees in an arc flash incident!
The power of the blast can throw your workers across a room. The sound blast can rupture eardrums, or even cause permanent deafness in certain circumstances. The sound blast can be up to 140 decibels – louder than a gunshot which is 133 decibels!
Similarly, the bright flash can cause temporary blindness. In certain extreme cases permanent blindness can occur.
Considering all this the question may be asked – what is the use of PPE or FR clothing in such a case? The PPE and clothing doesn’t eradicate these risks, by any means. The aim of arc flash clothing is to reduce the amount of second degree burns to a survivable level for the wearer.
When can it occur?
Arc flashes can happen when electricity jumps through the air between conductors – evidently some work areas can be very low risk, whilst those that work in selected industries are a far greater risk of accident.
Which industries can it occur in?
Within the rail industry there is a real risk of Arc, especially with the current electrification of the railway being undertaken with the UK.
Power generation/ Electrical industry
These may be the industries that first spring to mind when electrical arcs are talked about – and for good reason. In general workers working in these industries are at the highest risk of arc flashes.
If any kind of excavation work is being carried out by your team you may have to have arc clothing under the HSG47.
What is the HSG47 and how does it apply to me?
The HSG47 is part of the Health and Safety Guidance Act. It related to avoiding danger from underground services – so if your company does any sort of digging or excavations this means there is a risk from hitting underground services and need Arc Flash Resistant workwear.
One of the key dangers are electrical cables – if one of your team hits these there is a real hazard regarding arc flashes. PPE and arc flash clothing should be the last line of defence against these hazards, after the risk has been minimised as much as possible through best practices.
What protective clothing is needed and why?
As a bare minimum your team will need one layer of FR Arc clothing, with the required gloves, shoes and mask. In addition, it may be worth considering layering options wherever possible, to increase the effectiveness of the resistance.
What is never talked about?
Underwear! Even if your team is fully kitted out in ARC FR clothing, if they are wearing polyester underwear it can melt in the heat of a flash, and cause serious damage. Cotton underwear should be worn.
During the colder months of the year FR Arc thermal underwear is recommended, to benefit from the extra protection that layering garments brings.
What is the IEC 61482-2?
IEC 61482-2 is identical to the EN 61482-2. This standard relates to protecting wearers from the heat of an electrical arc incident.
There are 2 ways to test arc clothing. Some garments are certified to one or the other, or can be certified to both.
The first test method is the ‘open arc’ which tests ATPV – scroll down for an explanation of this. The open arc test method is categorised as EN61482-1-1.
The second test method is the ‘box test’ which provides two class rating on a pass/fail basis. Class 1 is protection against an arc to 4kA, whilst Class 2 is protected against 7kA.
Arc clothing can be rated to an ATPV rating. Arc Thermal Performance Value is measured in Calories per cm2 . The APTV is based on burns that results in 50% likelihood of a second degree under fabric. This is important – if the person wearing the garment has less than 50% second degree burns then their likelihood of survival is greatly increased.
What are the features of high quality Arc clothing?
Because all arc resistant clothing must be long sleeved and a specific type of fabric this can become very warm to wear in the summer.
Here at Clad we have several options to reduce the sweat of your team!
What is the difference between FR & Arc Clothing?
All arc clothing is rated to be effective against flame and arcs. In contrast not all FR clothing is resistant to arcs. This is because arc resistant clothing insulates FR clothing from Arc flashes.
Lightweight Hi Vis Arc Polo Shirt
Combines the features of Arc Protection with Hi Visibility (ISO EN20471) to avoid having to wear another layer of clothing
Hi-vis Two-tone Arc Coverall
Combines Arc protection with hi-vis and a tough hard wearing coverall ideal for lineworkers, cable layers and operatives working in a dirty, grimy environment
Lightweight Manager Arc Shirt
Look smart and still achieve Arc protection
Managers and office-based supervisors can wear a smart lightweight shirt and still achieve arc protection on site.
Why Buy From Clad Safety?
- Expert staff on hand to help you keep your team safe
- Bespoke online website to help you order
- In-house logo room allows us to create smart attractive uniforms for you