Arc flash standards 101

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With so many different industries at risk of arc flash, Mark Lant, technical expert at ProGARM, explains the latest PPE legislation and guidelines to ensure protection against the potentially fatal consequences of an arc flash.

IEC 61482-2

The first standard is IEC 61482. This is the overall standard covering protective clothing that protects against the thermal arc hazards of an electric arc, and covers many aspects of garment design and testing.

The thermal energy generated by an arc flash can reach temperatures of up to 19,000°C – up to four times hotter than the surface of the sun – and is the key element that distinguishes a ‘normal’ electrical blast from an arc flash blast.

To determine whether garments meet the requirements for this standard, all prospective PPE must pass one of two test methods: Open arc or box arc. These tests will measure the ATPV or the new ELIM ratings of a garment. ATPV values are calculated from a prediction of the incident energy level of an arc flash, at which there’s a 50% probability that the heat transfer will cause the PPE material to break open and expose the operative. However, the new ELIM ratings are measured to ensure a 0% probability.

It’s crucial to note that under the new ELIM testing, a product’s ELIM rating could be different from its ATPV rating, despite it being the same garment.

BS EN 1149-5

BS EN 1149-5 is the European Standard for garments that protect against electrostatic discharge in areas where there is a risk of explosion, and is most applicable to petrochemical and fuel distribution businesses. It states that workers must be provided with appropriate clothing consisting of materials which do not give rise to electrical discharges that can ignite explosive atmospheres. In other words – the outer fabric of the garments worn must be made from antistatic materials and cover all noncomplying materials. The standard also states that non-dissipative materials (labels, reflective stripes etc.) must not exceed 50mm in length, unless they also pass the anti-static test.

RIS – 3279 – TOM

RIS-3279-TOM (formerly GO-RT 3279) is a high visibility standard that only applies to the rail industry in the UK, as opposed to the EU-wide nature of other EN standards. The aim is to ensure that rail workers on or near the trackside are sufficiently visible to trains approaching at speed or any other traffic.

BS EN ISO 20471

Another standard concerning visibility is BS EN ISO 20471 specifying the requirements for clothing noticeability during the day and at night. It deals with things like illumination in car headlights and classifies garments based on the number of square meters of fluorescent fabric/reflective tape incorporated into the clothing.  

The BS EN ISO 20471 standard has replaced EN 471 which has now been withdrawn.

BS EN ISO 14116

BS EN ISO 14116 is the standard which has replaced the withdrawn EN533. It covers outerwear that would usually be worn over other protective garments. The objective is to ensure that, once in contact with the material, the amount the flame spreads and the time it burns are limited. This is tested using different codes: Index 1, 2 and 3, with each getting more rigorous as the numbers increase.

BS EN ISO 11612

The BS EN ISO 11612 standard replaces the now-withdrawn EN531 standard and applies to clothing intended for a wide range of applications, which offers limited flame spread and provides protection against various hazards including radiant heat, convective heat and splatters of molten metal. The standard requires that the material of a garment shall not ignite or melt and shall not shrink by more than 5% with mechanical strength and heat resistance at a temperature of 180°C.

There are several fabric tests within this EN standard and the results of the tests are represented by the prefix letters A, B, C, D, E and F. The number after these letters indicate the performance of the fabric within this test. If a (0) is shown, then the fabric has not been tested or does not achieve the lowest value attainable with the test.

BS EN 13034

Protection against liquid chemicals falls under the bracket of BS EN 13034, which is in place to determine the garment’s resistance against small splatters or fumes of chemicals. This is achieved by chemical coating the garments in order to repel any contaminants and preserve the properties within the clothing. Testing for this standard consists of a ‘mannequin test’, in which the wearer must perform seven basic movements and the permeability of the clothing to chemical is subsequently determined.

BS EN 14404

BS EN 14404 relates to trousers and coveralls which offer knee pad pockets to protect the wearer when kneeling. Knee pads are tested based on three properties – penetration resistance, force distribution and shock absorption.

Two levels of protection can be provided according to BS EN 14404. Level 1 requires knee pads to provide protection against objects more than 1cm high. Level 2 requires pads to be able to withstand use under heavy conditions, such as kneeling on stones in mines and quarries.

BS EN 343

Finally, BS EN 343 outlines the requirements garments must adhere to with regards to protection against rain, snow, mist and ground moisture. BS EN 343’s icon shows an umbrella placed under two numbers that represent the X and Y values. The X value indicates the waterproofness and the Y value indicates the water vapour permeability. There are three classes for both X and Y values, with three being the highest and one the lowest.

This particular standard falls under the bracket of ‘self-certification’ meaning manufacturers are allowed to certify their own products. This is because the only risk to the wearer is getting slightly wet and is not life threatening.

For more information on EN standards and how to keep your team fully protected against the risks of arc flash, visit www.progarm.com/about-progarm/arc-flash-protection-standards/en-standards/.