Electric Arc Flash Standard: IEC 61482
IEC 61482 is a standard that specifies requirements and test methods applicable to clothing material for protection of electrical workers against the thermal hazards of an Electric Arc. This standard provides eligibility to sell protective clothing meant for Electric arc flash protection within the European Union (EU).
IEC 61482 standard requirement is significantly different as compared to basic FR standard EN 11612. This includes testing of more rigorous parameters specific to the thermal hazards related to Electric Arc. There are a couple of standards for arc testing as per IEC 61482:
- Open Arc Test Method as per IEC 61482-1-1
- Box Test Method as per IEC 61482-1-2
The testing procedure and the results for both the versions are differently interpreted and does not have any co-relation with each other.
The Standards Explained:
IEC 61482-1-2: Box Test Method:
IEC 61482-1-2:2009 version of this method has been superseded by the new 2018 version. Currently this is the only acceptable version for placement of Electric arc flash protection clothing in the EU markets as per the PPE Regulations. The main difference between the old and the new version is the way the results are issued.
The clothing material – fabrics and garments, are tested and evaluated as per two classes: (Duration of test: 5 seconds)-
Under the old version IEC 61482-1-2:2009, results were issued as :
Class 1 for incident energy level of 4 kA
Class 2 for incident energy level of 7 kA
For the new version IEC 61482-1-2:2018, results are now issued as:
APC = 1 for incident energy level of 4 kA
APC = 2 for incident energy level of 7 kA
The test report for garments include comments on functionality of trims and accessories after exposure.
IEC 61482-1-1: Open Arc Test Method:
This method determines the Arc Thermal Protection Value (ATPV) and EBT50 (Energy Breakopen Threshold) of the clothing material, based on the Stoll Curve.
- ATPV is the maximum thermal energy any arc flash protective clothing can withstand until the wearer would have a 50% probability of getting second-degree burns.
- EBT50 value is the incident energy level at which there is a 50% probability that a protective garment would break open. Breakopen is defined as an open area of atleast 1.6 cm² after exposure.
If the material has more thermal insulation resistance to heat than the arc tensile strength then it will breakopen first, thus providing an EBT50 value. If it is the opposite, the material will allow burns before it breaks open which provides for the ATPV value. The lowest value is the one that is used in the marking of the textile material. Higher the value of ATPV or EBT50, better is the performance level of the textile material.
In comparison to the IEC 61482-1-2 Box test this testing method is not restricted to the specific energy level tests of 4kA & 7kA. This as the name suggests is an open evaluation of the textile material at unlimited energy levels to check their sustainability in case of electric arc accidents in the industries.
In May of 2019, a new version of IEC 61482-1-1 was published. It includes a new, safer protection rating for textile materials called the Incident Energy Limit Value (ELIM) in addition to the ATPV & EBT50.
ELIM the maximum incident energy that a protective clothing can prevent against in a hazardous situation with 0% probability of enough energy getting through the garment to cause a second-degree burn. ELIM has been introduced because the opinion of EU was that IEC 61482-1-1 could be in conflict with EU safety directives. According to the directives, no standard should have any chance of imposing harm to a worker. ATPV / EBT imposes 50% probability that a worker will sustain second degree burn in electric arc exposure. This means that the worker will have burns every time there is an accidental exposure to electric arc. It is this 50% chance that ELIM eliminates. Therefore, this value indicates the safest level of protection for the worker.
ATPV, EBT and ELIM can be evaluated in a single test through an open arc test as per IEC 61482-1-1. It is also important to note that products will generally have a lower ELIM rating compared with ATPV. Which means to achieve a specific ELIM rating protection as compared to the ATPV rating, wearer may be required to wear an Arc Flash base layer underneath their outer clothing to increase the layers of Arc Flash protection, or wear a heavier garment. It is therefore critical to understand the difference between ELIM, ATPV & EBT50 so that the risk assessment team can specify the right protection for their workers.
Also, it is important to note that the standard logo for the IEC 61482 has also changed. All new tested or certified clothing item as per the EU Regulations will now be marked by the new norm logo, as below: