Arc flash clothing, or more commonly known in the industry as flame resistant clothing, is essential to keep electrical workers safe from injury and death. OSHA statistics demonstrate that five to 10 times each and every day, an electrical worker somewhere in the North America is either injured or killed as a result of being caught in an accident. These injuries and deaths from these electrical explosions devastate the lives of electrical workers and their families. Had these electrical workers been wearing the correct level of protection, the number of injuries and deaths might have been much less.
PPE Defined by NFPA 70e - OSHA 29 CFR 1910.269 (1)(6)(iii) states: “The employer shall ensure that each employee who is exposed to the hazards of flames or electric arcs does not wear clothing that could increase the extent of injury that would be sustained by the employee. PPE selected for a particular application shall have a thermal performance value of (EBT or ATPV) higher than the potential hazard to prevent the onset of 2nd degree burns.
1. Grounding equipment
2. Hot sticks
3. Rubber gloves, sleeves, and leather protectors
4. Test instruments
5. Blanket and similar insulating equipment
6. Insulating mats and similar insulating equipment
7. Protective barriers
8. External circuit breaker rack-out devices
9. Portable lighting units
10. Temporary protective grounding equipment
11. Dielectric footwear
12. Protective clothing
13. Bypass jumpers
14. Insulated and insulating hand tools
Arc flash protective clothing is essential for protecting workers from the thermal hazards associated with incidents. This clothing typically includes arc-rated (AR) suits, jackets, pants, bib overalls, gloves, and face shields. The primary purpose of this gear is to provide a barrier against intense heat, molten metal, and explosive force, reducing the risk of severe burns and injuries. The arc flash rating of the clothing indicates its protective capability against specific incident energy levels measured in calories per square centimeter (cal/cm²).
FR clothing is designed to resist ignition and self-extinguish once the source of ignition is removed. While FR clothing provides protection against fire hazards, it may not offer adequate protection against the thermal energy produced by an arc flash. PPE, on the other hand, is specifically designed and tested to withstand the intense energy released during an explosion. Arc-rated clothing not only meets FR standards but also provides additional protection against the extreme temperatures and molten metal associated with arc flashes.
PPE should be worn whenever there is a risk of exposure to electrical hazards that can produce an explosion. This includes tasks such as maintenance, testing, and troubleshooting of energized electrical equipment. NFPA 70E requires workers to wear appropriate PPE, including arc-rated clothing, when the calculated incident energy exceeds 1.2 cal/cm², which can cause second-degree burns.
Arc-rated clothing is specifically designed to protect against the thermal hazards of an explosion. It is rigorously tested to ensure it can withstand high incident energy levels without breaking open or igniting. Arc-rated clothing must meet the standards set by NFPA 70E and other relevant regulations to ensure maximum protection for workers. The arc rating is a crucial factor, indicating the amount of energy the fabric can absorb before it reaches the burn threshold.
Proper storage of PPE is essential to maintain its protective qualities. The clothing should be stored in a clean, dry place away from direct sunlight and chemicals. Using designated storage bags can help protect the gear from dust, moisture, and physical damage. Regular inspections should be conducted to ensure the clothing remains in good condition and free from contaminants that could compromise its effectiveness.
To verify the efficacy of PPE, check for compliance with relevant standards such as NFPA 70E and IEC 61482-2. Look for labels indicating the arc rating (cal/cm²) and ensure the clothing has undergone appropriate testing. Regular inspections for signs of wear, damage, or contamination are also necessary. Additionally, workers should follow the manufacturer's guidelines for care and maintenance to preserve the protective qualities of the clothing.
IEC 61482-2 is an international standard that specifies the requirements and test methods for protective clothing against the thermal hazards of an explosion. It covers various aspects such as design, performance, and testing of the clothing to ensure it provides adequate protection. Compliance with this standard indicates that the clothing has been tested and proven to protect against arc flash incidents.
High-quality PPE features multiple layers of arc-rated fabric to provide enhanced protection. It should be lightweight, breathable, and comfortable to wear for extended periods. Additional features may include moisture-wicking properties, durability, and ergonomic design to ensure ease of movement. High-quality clothing also meets or exceeds the standards set by NFPA 70E and IEC 61482-2, ensuring comprehensive protection for the wearer.
A cal rating, or calorie rating, measures the protective capability of PPE. It indicates the amount of incident energy the fabric can absorb per square centimeter before it reaches the burn threshold. For example, a 12 cal/cm² rating means the clothing can protect against an incident energy of up to 12 calories per square centimeter. Higher cal ratings indicate greater protective capabilities.
Cal/cm² (calories per square centimeter) is a unit of measurement used to express the incident energy in an explosion. It quantifies the thermal energy received on a surface area during an arc flash event. This measurement is crucial for determining the appropriate level of PPE required to protect against specific incident energy levels.
Yes, a higher cal rating generally means greater protection. Clothing with a higher cal rating can absorb more incident energy before it reaches the burn threshold, providing better protection against severe incidents. However, it's important to select clothing that matches the specific incident energy levels encountered in the work environment to ensure adequate protection without compromising comfort and mobility.
PPE is a vital component of electrical safety, protecting workers from the severe hazards associated with incidents. By understanding the importance of arc ratings, the differences between FR and arc flash clothing, and proper usage and maintenance practices, workers can significantly reduce the risk of injury. Ensuring compliance with standards such as NFPA 70E and IEC 61482-2 further enhances the protective capabilities of PPE, providing a safer work environment for all.
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