COMMERCIAL FEATURE ELECTRICAL HAZARDS VS. ARC FLASH PROTECTION FROM DUPONT Arc flash is a potentially lethal hazard that some professionals face every day. Garments made of DuPont™ Nomex ® fibre help companies protect their employees – and their business – effectively. A n electric arc is a continuous electric discharge of high current between conductors, generating extremely bright light and intensive heat. The arc blast presents a serious hazard (potentially fatal) to employees due to the risk of severe burn injuries caused by the intensive heat. PERMANENT PROTECTION FROM NON-FLAMMABLE FIBRE DuPont™ Nomex ® fibre is inherently flame-resistant, will not melt or drip, and does not support combustion in the air, thus providing excellent arc flash protection. And because the protection is woven straight into Nomex ® garments, it cannot wear off or wash out over time. When exposed to flame, the man- made high-performance aramid fibre swells, becoming thicker and forming a protective barrier between the heat source and skin. This protective barrier stays supple until it cools, helping to give the wearer vital extra seconds of protection to reach safety. Chemically dependent flame- retardant fabrics provide a different type of protection to flame-resistant fabrics. In the case of flame-retardant fabric a chemical additive in the fibre or treatment on the fabric is used to provide some level of flame retardancy. During an industrial fire, chemically dependent fabrics rely on a chemical reaction triggered by heat and exposure time to extinguish the flame. As the time and heat exposure increase, heat transfer and the resulting burn injury to the wearer increase dramatically as the flame-retardant chemicals activate. These chemicals and the fabric produce vigorous after flame, hot gases, smoke, and tars that can adversely affect the wearer. When exposed to the intense heat typical of electric arc, Nomex ® fibre carbonises and thickens. This increases the protective barrier between the heat 24 source and the wearer’s skin and helps minimise burn injury. RESPONDING TO ELECTRICAL HAZARDS Many industrial jobs put electricians and utility employees at risk of electrical hazards. In response, DuPont created Protera ® fabric for arc flash protection which offers NFPA 70E Category 2 compliance, making it ideal for those exposed to intense arc flash heat. Protera ® brand fabric offers superior heat- resistant arc protection and will not melt and drip or combust when exposed to air. Being able to work productively and responsibly means wearing protective garments that fit comfortably and feel good. Along with built-in protection against electric arc hazards, Protera ® offers better comfort and durability than other FR cotton nylon blends. One of the lightest weight NFPA 70E Category 2 technologies on the market, Protera ® proves that less is more. That’s why when we designed DuPont™ Protera ® , comfort was a priority. TESTS PROVE WEARERS NOTICE THE DIFFERENCE In an independent, double-blind comfort study DuPont ™ Protera ® was the clear winner in overall comfort compared to FR cotton nylon blend garments of the same weight. In fact, wearers found NFPA 70E compliant garments made of DuPont ™ Protera ® to be less prickly, heavy, stretchy, stiff, clingy, clammy and scratchy than FR cotton nylon blend garments. As part of our on-going commitment to innovation, we continue to develop and improve the arc flash protective properties of Nomex ® fabrics. At our European technical centre in Switzerland, the DuPont ™ Arc-Man ® test simulates electric arc incidents in a controlled environment. This enables manufacturers to assess and compare the performance of their different fabrics and garments under highly demanding conditions. This test equipment developed by DuPont measures the ATPV and the EBT value of protective fabrics and garments in simulated open electric arc incidents according to IEC/EN 61482-1-1. It is capable of exposing the fabrics or garments to incident energies of up to 70 cal/cm². Arc-Man ® can test fabrics on panels, measuring the ATPV of the fabric system (in cal/cm²) so that it can be compared to the incident energy calculated in the end user’s risk assessment. Arc-Man ® can also perform complementary garment tests on a torso to show the effect of a garment’s design and integrity of manufacture, allowing a prediction of the garment’s behaviour in sections such as the closure system or pockets. ESI Electric arc test results and recommendations • The arc rating of a fabric not only depends on its weight, but to a large extent also on characteristics such as fibre and yarn constructions and their combinations. • DuPont recommends that all layers of arc protective clothing in a multi- layer system should be made of inherently flame-resistant materials. • Inappropriate underwear could ignite or melt, thus having an adverse effect on protection and aggravating the outcome of an electric arc incident. DuPont™ Nomex® and DuPont™ Protera® and all products denoted with ® or ™ are registered trademarks of E.I. DuPont de Nemours and company or its affiliates ESI AFRICA ISSUE 4 2014