Electric Arc: Protecting Against Thermal Effect - Part 3: State of the Art and Standardization
- Mikhail Golovkov (consultant) | Holger Schau (Ilmenau Technical University) | Gavin Burdge (freelance writer)
- Document ID
- American Society of Safety Engineers
- Professional Safety
- Publication Date
- September 2017
- Document Type
- Journal Paper
- 43 - 48
- 2017. American Society of Safety Engineers
- 3 in the last 30 days
- 7 since 2007
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- This series of three articles provides a broad overview of today’s state of the art for protecting electrical workers against electric arc thermal hazard.
- Part 3 discusses arc hazard assessment, limitations of arc rating and research on protective time current curves.
- It also identifies standardization misconceptions and associated challenges, and suggests improvements for the future.
The downward trend of electrical fatalities is a reflection of several factors: ongoing replacement of ignitable materials in electric arc protective clothing that started about 20 years ago, wider awareness about electric arc hazards and improvement in workplace safety standardization. However, little or no change has taken place with arc hazard assessment methods, electric-arc-rated (AR) PPE test methods, and methods of proper AR PPE selection since their original adoption in the late 1990s and early 2000s. This is reflected in the stagnant rate of electric burn trauma with thousands of cases known from available statistics outlined in Part 2 of this series of articles.
Variability of AR numerical values depending on fault current has been known since 2004, but the standardized test method for AR fabric was frozen to only one 8 kA level of test arc current. The test methods have not evolved to include a range of test currents. The fault current occurring in a workplace arc event has an extremely low likelihood of matching the fault current used in the test method. Yet, a numerical value of arc rating is directly used for PPE selection by matching the PPE arc rating to some calculated or otherwise projected value. Reliable statistical support of proper electric arc protection based on current methods of PPE selection is questionable. Nonetheless, new research on electric arc properties, material behavior and classification of arc types opens new opportunities to close existing gaps in electric arc protection.
|File Size||717 KB||Number of Pages||6|