1. What Is An Arc Flash?
To put it simply, an arc flash is an electrical explosion, (sometimes call ‘electrical arcing’, or a ‘flashover’).
Arc flash at a glance:
- Flash of intense electrical energy
- Can be fatal
- The HSE has reported that around 1,000 workplace electrical incidents are reported to them annually and around 25 of those injuries result in fatalities
- Exposure energy is expressed as cal/cm2
- Exposure of only 1 to 2 calories cause second degree burns
- Arcs are around 5-30 calories
2. Why Are Arc Flash Explosions Dangerous?
The temperature of the sun is 5,505oC degrees. Temperatures can reach up to over 19000 oC degrees in an arc flash incident.
The power of the blast from an arc flash explosion 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 arc flash clothing in such a case? The PPE and clothing don’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.
3. When Can An Arc Flash Occur?
An arc flash 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 an accident.
4. Which Industries Can An Arc Flash 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 sectors are at the highest risk of an arc flash.
5. What Is The HSG47 And How Does It Apply To Me?
HSG47 (Avoiding Danger From Underground Services) is part of the Health and Safety Guidance Act. If your organisation is involved in digging or excavations this means there is a risk of hitting underground services and employees need arc flash workwear.
One of the key dangers are electrical cables – if one of your team hits these there is a real hazard regarding an arc flash explosion. 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 appropriate health and safety measures.
What Arc Flash Protective Clothing Is Needed And Why?
Layering certified garments under Arc Flash rated products will offer increased protection beyond the sums of their individual protective values. This is largely due to the air in between layers adding extra insulation and helping to eliminate the risk of ignition. Your team will need certified arc flash clothing, including arc flash polo shirts, jackets, trousers and coveralls along with gloves and helmets.
7. What Is Never Talked About?
Underwear! Even if your team is fully kitted out in arc flash clothing, if they are wearing polyester underwear it can melt in the heat of a flash and cause serious damage. Cotton underwear such as the ProGARM® flame resistant men’s and ladies boxer briefs should be worn.
During the colder months of the year FR Arc thermal base layers are recommended, to benefit from the extra protection that layering garments brings.
8. What is the IEC 61482-2?
Arc flash testing establishes rigorous safety benchmarks for all arc flash clothing and protection. 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 flash 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. 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.
9. Arc Flash Ratings
Arc clothing can be rated to an ATPV or ELIM rating. Arc Thermal Performance Value (ATPV) 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.
Meanwhile ELIM (Energy Limit Value) is the point at which the clothing gives a 0% probability of the wearer receiving a second-degree burn. It is the newly updated cal/cm2 measurement and factors in incident energy levels to calculate the probability of injury. The testing method for ELIM is the Open Arc Test.
10. What Are The Features Of High Quality Arc Clothing?
All arc flash clothing must be long sleeved and made from high performing inherently flame-retardant fabric. Key features include:
- High performing inherently flame-retardant fabric, 250gm
- Arc flash coveralls with stand-up collar with velcro closure
- Arc flash trouser legs with zip and snap for adjustment
- Ribbed cuffs
- Knee pad pockets
- Stretch panels for additional comfort
- FR heat reflective tape
- Bartacks at all stress points
- Fully certified to all arc flash safety standards
11. What Is The Difference Between FR And Arc Flash Clothing?
All arc flash clothing is rated to be effective against flame and arcs. In contrast not all FR clothing is resistant to an arc flash. This is because arc resistant clothing insulates FR clothing from arc flashes.
Why Buy From Clad Safety?
Clad Safety is a leading UK supplier of arc flash clothing. When you place an order with us, we can provide a wealth of technical and safety knowledge to ensure your team is adequately protected from the risks of an arc flash explosion with our extensive range of arc flash jackets, trousers, polo shirts, coveralls and PPE.
Proudly supplying companies with workwear and PPE for over 30 years, Clad Safety works with a wide spectrum of industries including Construction, Engineering, Rail and Utilities. We aim to simplify the buying process so that your team can get to work safely and efficiently.