NESC requires utilities to assess hazards for employees that work near or on energized equipment. If energies present exceed 2 cal/cm2, workers must wear AR/FR clothing with an arc-rating equal to or greater than the energies of the electrified equipment with which they work. 

To comply with NFPA 70E, employers also are required to perform an arc flash risk assessment to determine the potential energy level of the hazard and the flash protection boundary, or the total area in which the hazard exists. Where required, employees must wear AR/FR protective clothing that meets ASTM F1506, the minimum performance specifications for protective clothing for workers exposed to the risk of electrical arc flash.

To anticipate energy levels, NFPA 70E denotes two main incident energy analysis schemes: the calculation method and the table method. It's critical to note these procedures cannot be combined on the same piece of equipment.

For the calculation method, the potential incident energies of various equipment are calculated using formulas and/or commercially available software. The difficulty of the calculation method is relative to the complexity of the electrical system. The table method characterizes AR/FR garments and garment systems by PPE categories. In the table, the NFPA 70E standard lists typical pieces of equipment, their operating conditions and the required PPE category for each energy level.

Specify the Fabric

Once the energy level and arc-rating are determined, you'll be able to move forward in selecting the best AR/FR clothing. Start with selecting the fabric first: it's important to understand the FR fabric manufacturer – history, experience, product line and capabilities – and look for brands that provide the comfort and performance that meet the needs of your workplace and job tasks.  

AR/FR daily wear also must be comfortable while working. Conduct a wear trial of various garments to assess movement and breathability to ensure workers will be able to work effectively and comfortably.

External work conditions should be considered. The fabric and fabric system needs in diverse climates can are different, such as insulated products for northern climates and lightweight, single-layer constructions for hot and humid conditions.

Arc flashes are unexpected and dangerous and can occur during various points of electrical workers' daily operations. By wearing AR/FR, workers can equip themselves to perform their jobs safely, efficiently and comfortably, all of which help them concentrate on the task at hand: getting the job done right and going home to their families.

Scott Francis is the midwest regional market manager for Westex by Milliken. Francis has been involved with the safety industry since 1991 and has extensive experience with protective apparel fabrics and programs.