IEC 61482 ELECTRIC ARC PROTECTION
IEC 61482-2:2009 PERFORMANCE & DESIGN REQUIREMENTS
This part of IEC 61482 is applicable to protective clothing used in work if there is an electric Arc hazard. This standard specifies requirements and test methods applicable to materials and garments for protective clothing worn by electrical workers to protect them against the thermal hazards of electric Arc based on relevant general properties of the textiles, tested with selected textile test methods, and one of the Test Methods as defined below.
IEC 61482-1-1:2009 'OPEN ARC' TEST METHOD
'Open Arc' test method (ATPV test and garment test). This replaces IEC 61482-1:2002. The 'Open Arc' test method is the same as the original North American method for measuring the Arc Thermal Performance Value (ATPV), as used in ASTM F1959. Materials or assemblies are given an ATPV value, expressed in kilojoules per square metre (kJ/m2), which can be converted into the familiar cal/cm2.
IEC 61482-1-2:2007 'BOX ARC' TEST METHOD
'Box Arc' test method (Fabric classification and garment test). The ‘Box Arc’ test method is based on the original European method described in ENV 50354, with a heat transfer measurement. Materials or assemblies are classified as Class 1 (4 kA) or Class 2 (7kA). During this test, a fabric sample is exposed to an electric Arc produced by a 4kA or 7kA short circuit. In the test, the Arc does not last any longer than 500ms. The amount of heat transmitted through the sample is measured during and after the test. On the basis of the resulting data and a Stoll curve, the length of time it would take to cause the onset of second-degree burns is subsequently determined. Samples are also assessed for after-flaming, hole formation, melting, etc.
GARMENT TESTING & FABRIC TESTING
It is important to note that not only the fabric should be tested for conformance to the Arc Flash Standard, but also the complete garment or garment assembly itself. The garment test is not testing for energetic value but is testing to ensure that the garment structure remains intact after the Arc exposure and that components such as zippers and buttons are still functional and do not contribute further injury to the wearer by melting or heat transfer.
LIMITATIONS OF USE
With Arc protection, the environmental conditions and the risks at the working site shall be regarded. For example a test under the standard using a 4kA test current (Class 1) subjects the garment/fabric to an incident energy of 135 kJ/m2± 56 kJ/m2 (3.2 ± 1.2 cal/cm2) over a 500ms exposure at 18-28°C at 45-75% RH. If the working environment deviates from this temperature/humidity range the level of protection may be reduced. Exposure to higher incident energies or longer duration Arcs may result in the garment providing insufficient protection. Therefore risk assessments should be conducted prior to live working.
For full body protection, the protective clothing shall be worn in the closed state and other suitable protective equipment (e.g. helmet with protective face screen, protective gloves and footwear (boots) shall be used. No garments such as shirts, undergarments or underwear should be used which melt under Arc exposures - e.g. made of polyamide, polyester or acryl fibres. For maximum protection against Arc Flash Exposure garments should be worn as part of a layering system i.e. in conjunction with a shirt or other undergarment.