Professionals who do installation or maintenance work in industries like energy production or network and distribution are often well aware that they are at risk of arc flash. But factories or industrial plants often also contain heavy equipment where electronic switch boxes can cause arc flash or flashovers. How do you protect employees in the work environment with the right protective clothing?
Arc flash clothing: protecting workers against thermal hazards of an electric arc
Arc flashes are low impedance connections in an electrical system, which causes unwanted electric discharge via the air. As a result, there is a rapid rise in temperature (up to 19,000 degrees Celsius, which is almost four times as hot as the sun) and pressure in the air between electrical conductors. This causes an explosion which is known as an arc blast.
Protective clothing is a crucial part of arc flash protection to prevent flashovers (the transfer of fire) from causing injuries or life threatening situations.
What are EN IEC 61482-1-1 and EN IEC 61482-1-2?
Luckily there are standards for protection against thermal hazards of arc flash. It can be tested in two ways: the open-arc method (IEC 61482-1-1) and the Box test (IEC 61482-1-2).
- Open-arc method (IEC 61482-1-1)
This method is often used in the USA but is becoming increasingly popular in Europe. Three panels are arranged at an angle of 120 degrees to each other. The test generates, with high voltage, an arc with varying intensity. The results are expressed in ATPV (Arc Thermal Performance Value and/or EBT (Energy Breakopen Treshold) in cal/cm². In May of 2019, a new version of IEC 61482-1-1 was published. It includes a new type of arc rating for materials called the Incident Energy Limit Value (ELIM). With ATPV/EBT, there could be a 50% probability that there is enough heat transfer to cross the Stoll Curve (ATPV), or for the material to break open and create exposure (EBT) which can result in a second degree burn. The ELIM value is more conservative. It needs to be 100% sure that all product responses remain below the Stoll Curve.
- The Box test (IEC 61482-1-2)
The Box test (or arc-in-a-box) is a different test method which is often used in Europe. An arc is generated from one direction (the box) by short-circuiting with 4 kA (for class 1: low level of simulated arc exposure) or 7 kA (for class 2: high level of simulated arc exposure). In practice, it is often quite difficult to match your risk assessment with a class 1 or 2 of the Box test, because test results are not expressed in cal/cm².
Strive for safe and confident workers under any circumstance
Often, professionals that are at risk of arc flash work in highly challenging environments. Near traffic, in industrial plants, at high voltage cables, underground... apart from arc flash clothing, chances are that they need protective clothing for other work related hazards as well, such as high visibility clothing or garments that are fire resistant.
As a Health and Safety manager, it can feel quite daunting to be informed of all possible risks and corresponding rules and regulations.
That is why at TenCate Protective Fabrics, we encourage you to collaborate with fabric suppliers, garment makers and industrial laundries. Together with our partners we are able to develop protective fabrics that are Made for Life. Read more and find out how you can activate your role in the protective clothing value chain.