By W. Jon Wallace, CSP, MBA; Workplace Safety and Hugh Hoagland: e-hazard.com Due to the potential of an electric arc flash, many employees who perform work on energized conductors (qualified persons) are exchanging flammable and/or meltable clothing, such as pants and shirts, for flame resistant (FR) clothing. In recent years qualified persons are increasingly wearing flame resistant clothing as a daily wear garment for protection against electric arc flashes. It is important to note, however, that a workers’ outer garment also needs to be flame resistant. Otherwise, the worker may suffer severe injuries during an electric arc flash. In this article, we will discuss the appropriate outer garments needed for qualified persons.
Rainwear: Qualified persons who perform work on energized conductors while working outside typically wear rainwear (rain jacket and pants) during rain showers. Most rainwear, however, are made from meltable fabrics that could melt during an arc flash. Also, although rainwear often says it is flame resistant (FR) this may have no correlation to an actual hazard. Many materials in the United States are still marked with FR even when it only passes a vertical flame test. This test has no correlation to how a material will perform in flash fire OR electric arc – most of this rainwear will melt. Therefore, only arc resistant rainwear complying with ASTM F1891: Standard Specification for Arc and Flame Resistant Rainwear should be worn by qualified persons.
Cold Weather Protection: If an outer jacket or coat is worn by a qualified person, the garment must meet the requirements of ASTM F1506: Standard Performance Specification for Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.
Fall Protection – Full Body Harness: Qualified persons commonly perform work tasks on energized conductors from elevated heights, such as in an aerial lift. Fall protection typically consists of a full body harness and lanyard. To ensure the fall protection is not destroyed during an arc flash, use a full body harness and lanyard satisfying the requirements of ASTM F887: Standard Specifications for Personal Climbing Equipment. These harness designs have been subjected to a 40 cal/cm² arc test and must still pass the drop test afterward. Kevlar harnesses, which are becoming increasingly popular, have an added advantage of sustaining no ignition, melting or dripping at any exposure.
FDA, Cleanroom Applications: Employees working in FDA covered facilities are required to wear hairnets and/or beardnets. www.ArcStore.com, Salisbury, and NSA Manufacturing offer arc-rated nets for used in FDA applications. For cleanrooms, several companies offer arc rated cleanroom suits including White Knight Engineering, Universal Overall and Oberon. Each of these has differing characteristics and not all cleanroom suits will meet your criteria – check with the manufacturer.
In summary, although daily wear flame resistant (FR) clothing provides significant protection to qualified workers in the event of an arc flash, sometimes additional protection is needed. Review all work tasks performed by your qualified persons to ensure outer garments provide adequate protection.
Rainwear: Qualified persons who perform work on energized conductors while working outside typically wear rainwear (rain jacket and pants) during rain showers. Most rainwear, however, are made from meltable fabrics that could melt during an arc flash. Also, although rainwear often says it is flame resistant (FR) this may have no correlation to an actual hazard. Many materials in the United States are still marked with FR even when it only passes a vertical flame test. This test has no correlation to how a material will perform in flash fire OR electric arc – most of this rainwear will melt. Therefore, only arc resistant rainwear complying with ASTM F1891: Standard Specification for Arc and Flame Resistant Rainwear should be worn by qualified persons.
Cold Weather Protection: If an outer jacket or coat is worn by a qualified person, the garment must meet the requirements of ASTM F1506: Standard Performance Specification for Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.
Fall Protection – Full Body Harness: Qualified persons commonly perform work tasks on energized conductors from elevated heights, such as in an aerial lift. Fall protection typically consists of a full body harness and lanyard. To ensure the fall protection is not destroyed during an arc flash, use a full body harness and lanyard satisfying the requirements of ASTM F887: Standard Specifications for Personal Climbing Equipment. These harness designs have been subjected to a 40 cal/cm² arc test and must still pass the drop test afterward. Kevlar harnesses, which are becoming increasingly popular, have an added advantage of sustaining no ignition, melting or dripping at any exposure.
FDA, Cleanroom Applications: Employees working in FDA covered facilities are required to wear hairnets and/or beardnets. www.ArcStore.com, Salisbury, and NSA Manufacturing offer arc-rated nets for used in FDA applications. For cleanrooms, several companies offer arc rated cleanroom suits including White Knight Engineering, Universal Overall and Oberon. Each of these has differing characteristics and not all cleanroom suits will meet your criteria – check with the manufacturer.
In summary, although daily wear flame resistant (FR) clothing provides significant protection to qualified workers in the event of an arc flash, sometimes additional protection is needed. Review all work tasks performed by your qualified persons to ensure outer garments provide adequate protection.
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