Workplace Solutions Arc flash Electrical

Choosing appropriate flame-resistant apparel

How do facility managers assess potential arc flash risks and select the appropriate flame-resistant apparel?

Responding is Randy Kaminsky, director of procurement, Ameri-Pride Services Inc., Minnetonka, MN.

Flame-resistant personal protective apparel is designed for continuous wear in designated areas where intermittent exposure to flame or heat is possible. However, to properly protect employees from arc flash hazards, facility managers must understand the individual risks present within each work environment. By knowing the standards that regulate workplace fire safety and taking appropriate steps, facility managers can properly protect their employees.

Arc flashes – an explosive blast of flame, debris, sound and force of up to 35,000° F – are responsible for 80 percent of all electrical injuries. By completing an assessment using the National Fire Protection Association 70E electrical workplace safety guidelines, employers can identify current arc flash risks and ascertain the corresponding safety solutions. NFPA 70E contains detailed instructions on electrical safety-related work practices and procedures for safeguarding employees during activities such as operation, maintenance and demolition of exposed energized electrical conductors or circuit parts.

NFPA 70E states, “Employees shall wear arc rated/flame resistant clothing wherever there is a possible exposure to an electric arc flash.” NFPA further explains safety requirements by presenting outlined risk categories and defining the type of protective clothing required to correspond with each risk level.

  • HRC 1: Minimum Arc Rating: 4 cal/cm2: Requires arc-rated shirt and pants or arc-rated/flame-resistant coveralls
  • HRC 2: Minimum Arc Rating: 8 cal/cm2: Requires arc-rated shirt and pants or arc-rated/flame-resistant coveralls
  • HRC 3: Minimum Arc Rating: 25 cal/cm2: Requires arc-rated shirt and pants or arc-rated/flame-resistant coveralls and arc flash suit
  • HRC 4: Minimum Arc Rating: 40 cal/cm2: Requires arc-rated shirt and pants or arc-rated/flame-resistant coveralls and arc flash suit

Additional equipment, such as gloves, masks and boots, may be required depending on the application and the risk.

Once employers know the type of personal protective equipment necessary, they must select the correct fabric. ASTM F1506, “Specification for Flame Resistant Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electrical Arc and Related Thermal Hazards,” covers performance properties of textile materials for electrical workers exposed to electric arcs. This includes a requirement that thread, findings and closures used in garment construction do not exacerbate the severity of injuries in the event of an electric arc exposure. To comply with ASTM F1506, knit or woven fabrics must not melt, drip, or have more than two seconds afterflame or 6 inches char length when tested as received and after 25 cleanings. FR fabrics of any type cannot have more than five seconds afterflame in an electric arc exposure test.

Facility managers also must know the difference between inherent and treated FR fabrics to properly care for the apparel to preserve its protective characteristics. Inherently FR fabrics are permanently resistant to combustion and will not wear or wash out. Alternatively, treated fabrics require chemical enhancement for flame resistance and need specific laundering procedures to remain effective. Uniform rental companies are one solution to provide the necessary FR apparel and ensure proper laundering practices are followed to maintain the flame resistance of the garments.

By understanding the NFPA 70E guidelines and the properties of FR apparel, facility and safety managers can minimize risks to employees by specifying the correct apparel for each potential risk.

Editor’s Note: This article represents the independent views of the author and should not be construed as National Safety Council endorsements.

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