Taking Steps to Protect Workers from Common Arc Flash Hazards
From illuminating homes and workplaces to powering factories and machines, electricity is an essential source of power for modern life. Keeping our surroundings electrified is the responsibility of hundreds of thousands of workers across the nation. However, severe injuries often result when workers inadvertently are exposed to accidental electric arcs as equipment is being serviced. Serious burns or life-threatening events can occur when workers are exposed to the extreme thermal energy released.
More than 2,500 nonfatal occupational electric shocks and electric burns were reported in 2007, according to the Bureau of Labor Statistics. Furthermore, electrical burns required a median of 27 days for recuperation in 2009. That adds up to significant expense and lost time that directly impacts an employer’s bottom line.
The good news is most electric arc injuries can be prevented by wearing the appropriate personal protective equipment (PPE). This specialized PPE must be compatible with the work and its associated hazards, and employers are responsible for providing the equipment best suited for the application. Employers need to understand common workplace arc flash hazards, the safety standards in place and the types of eye and face protection available for workers exposed to arc flash hazards if they are to fully protect those workers.
Understanding the Risk
Electric arc flash is a serious hazard that workers in many industries face every day. According to the Bureau of Labor Statistics, nonfatal electrical injury most often occurs from contact with the electric circuitry of machines, tools, appliances or light fixtures. Another leading cause is from contact with energized equipment including transformers, motors and switchgear of various voltage ratings.
The greatest number of nonfatal electrical injuries occurs in the construction industry, followed by manufacturing, and in these two industries the leading cause of injury is electrical burns. In all other industries the leading cause of injury is electric shock. The utility industry has the highest rate of nonfatal electrical burn injury. From utility workers, mechanics and machine operators to those working in telecommunications, construction and heavy industry, nearly anyone who works on or near electrical equipment is at risk for arc flash exposure.
Arc flash is a common – yet complex – hazard. In technical terms, an arc flash is an electrical breakdown where electric current jumps through an air gap between conductors. This can be due to the breakdown of insulation or accidental introduction of a metal object causing uncontrolled current flow, a fault that allows voltage in an electrical system to find a path to ground or lower voltage.
In layman’s terms, an arc flash event typically involves a flash of bright light accompanied by a blast of intense radiant heat, noise and, in extremely high-energy arcs, fragmented or molten metal. The temperature from an arc flash explosion can exceed 35,000 degrees Fahrenheit. The heat and energy emitted can result in personal injury, fire and substantial damage to equipment.
Overview of Safety Standards
Recognizing the severity of arc flash hazards, several organizations have developed standards to help protect workers from injuries related to them. ASTM International (formerly the American Society for Testing and Materials) sets standards related to the test procedures for the rating of electrical protective equipment. Specifically, ASTM’s Committee F18 on Electrical Protective Equipment for Workers develops critical safety standards that protect the health and safety of electrical workers, including specifications for PPE. Additionally, ASTM Standard F2178 is a test method for determining the arc rating and standard specification for eye and face protective products.
OSHA’s electrical safety standards primarily focus on the design and use of electrical equipment and systems, and on ensuring those systems are constructed and installed in ways that minimize workplace electrical dangers. OSHA’s electrical standards are based on two National Fire Protection Association Standards: NFPA 70, National Electric Code and NFPA 70E, Standard for Electrical Safety in the Workplace. The use of safety eyewear or safety goggles is required for each of NFPA’s five electrical hazard/risk categories, and the higher risk categories add head and face protection such as arc-rated face shields and hoods. NFPA is a broad-based association focusing on fire protection, including standards development related to fire safety.
When it comes to eye and face protection, the consensus standard referenced by OSHA is ANSI/ISEA Z87.1, and it covers the performance and marking requirements for this category of workplace PPE. NFPA supplements the ANSI standard with guidelines for protection specifically related to electrical hazards.
Eye and Face Protection
Specialized safety eyewear, goggles and face shields are required to protect workers from arc flash. They should be dielectric and nonconductive, meaning they should not contain any exposed metal parts that could come in contact with energized equipment. Arc flash lenses and visors typically contain infrared dye to absorb the harmful wavelength of energy corresponding to the hazard. Arc flash dyes usually are green in color, and the darker the lens, the greater protection it affords.
The hazard/risk category of the equipment being worked on and the workers’ proximity to it determine the required amount and rating of PPE. Arc ratings on PPE are represented in calories per cm2, and they are based on preventing a second-degree burn to an individual’s skin. Without proper protection, the injuries sustained from an arc flash event can be very serious caused by hazards including molten metal splash and impact from flying materials.
Whether you are building a new workplace safety program or evaluating an existing one, now is the perfect time to consider arc flash protection. Assess the electric arc hazards in your workplace and refer to NFPA standards to determine the corresponding PPE required for each task. When selecting eye and face protection, choose products with the required arc rating specific to the hazards present. Be sure that eye and face protection also provides exceptional visual acuity so workers can see fine details and perform work safely, a property assured with the use of Z87.1 compliant products.
Remember, eye and face protection is required for all levels of arc flash hazards, and most injuries are preventable with the proper safety equipment. Rather than risk the high cost of an injury – and your workers’ health – choose the arc flash protection that meets your needs and ensure workers wear it. By being mindful of common arc flash hazards and helping protect workers from them, every organization can build success into its safety culture.
Phil Johnson is director of technology for the Eye & Face Protection Group of Honeywell Safety Products. He has worked extensively in the area of product development for a variety of applications including industrial safety, laser safety and military combat protection. He has directed research in lens technology, particularly optics and light management. Johnson currently is a member of several standards development groups including the ANSI Z87.1 Committee for Occupational Eyewear.