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Arc Flash 101

Posted on Tuesday, September 6th, 2016 by Mila Adamovica

Arc flash concerns were first published in 1982 in Ralph Lee’s paper “The Other Electrical Hazard: Electric Arc Blast Burns.” Arc flash hazards were not formally studied until 1993, which is why they are still the least understood electrical hazard existing in most industries. Wikipedia defines arc flash as “the light and heat produced from an electric arc supplied with sufficient electrical energy to cause substantial damage, harm, fire, or injury.”  Because arc flash temperature can reach 35,000° F, which is three times higher than the Earth’s core temperature, the severity of workers’ injuries can be devastating: permanent loss of hearing or eyesight, severe burns, and even death.

Causes of Arc Flash:

  • Unintentional contact between an energized conductor with another conductor or earthed surface,
  • human error including dropped tools that can produce a spark, accidental contact with electrical systems, and improper work procedures,
  • buildup of conductive dust, corrosion or contamination.

Primary Hazards:

  • Thermal radiation and intense heat,
  • pressure wave blast,
  • molten metal.

Best Practices:

1. Risk assessment

The first step in selecting the right protective measures at work place is performing a complete risk assessment. According to ANSI/ASSE Z690.1-2011, risk assessment includes three distinct components: risk identification (finding, recognizing and recording hazards); risk analysis (understanding consequences, probabilities and existing controls); risk evaluation (comparing levels of risk and considering additional controls). This process helps determine safe work practices, arc flash and shock boundaries, and proper PPE levels.

A qualified worker entering the arc flash boundary must be wearing the appropriate PPE. In order to identify the necessary level of protection, the heat energy to which workers are exposed must be calculated. NFPA 70E requires wearing Arc Flash clothing for any potential exposure above 1.2 cal/cm2.

When being exposed to electric arc hazards at work, OSHA requires wearing clothing that must not ignite, melt or continue to burn. Since the amount of energy that workers can be potentially exposed to varies greatly, the level of protection that the clothing provides must match the degree of hazard severity.

2. Full protection+comfort

Arc Flash clothing is meant for continuous wear. While employees have to stay fully protected, sufficient range of motion should not take a back seat. If workers have to wear protective clothing for a whole duration of their shift, they will be looking for the comfortable gear, and will develop personal brand and style preferences. Product reviews can help you make the right decision when looking for the appropriate PPE. We recommend extra comfortable materials such as Nomex® fiber and Protera® fabric. Keep an eye on clothing tags, because they can be flammable. Nomex embroidery or direct printing of logos are possible ways of eliminating this danger.

3. Clothing maintenance

It is important that work clothing must be cared for as instructed by the manufacturer. A general rule of thumb is to wash each set of clothing once a week. If possible, opt to wash at home with mild detergent and warm water, rather than using industrial laundering service that is likely to cause more wear-and-tear. To help clothes last longer, avoid bleach and chlorine-based detergents, as they may break down Arc Flash protective quality of the fabric. Tumble dry your clothes on low.

To sum it up, arc flash is the exposure to the tremendous thermal energy released by an arc fault. In order to select the right Arc Flash clothes for your project, first, perform risk assessment, then check safety ratings of the garments to ensure that they are in line with OSHA requirements, evaluate fabric choices for comfort, estimate costs, find a trusted supplier, and, finally, train your team on proper ways to wear their work clothes.

Arc Flash

If you have questions or would like help selecting the right Arc Flash clothing, please give us a call at 1-800-829-9580, or visit us online at www.pksafety.com.