New study explores the effectiveness of arc-rated clothing and equipment in real arc flash incidents
At the 2009 IEEE Electrical Safety Workshop held in St. Louis in February, we presented the results from our new study, “Field Analysis of Arc Flash Incidents and the Related PPE Protective Performance.” In this survey, we reported on 22 industry incidents in which workers wearing arc-rated clothing and equipment were involved in an arc flash.
Over the past decade, there has been limited anecdotal evidence on workers being protected by arc-rated clothing and equipment. However, in this study, we provide a comprehensive analysis of the protective performance of the arc-rated protective clothing and equipment based on the data available from real arc flash incidents (Photo 1). We also reviewed ASTM F18 test methods for determining arc ratings of protective clothing and equipment based on laboratory-generated arc flash exposures (Photo 2) and standards for testing arc-rated clothing finished products. New ASTM testing initiatives for determining the arc rating of gloves, creating a rating system for arc-protective blankets and developing a new arc-in-a-box test method, were also discussed (Photo 3).
Existing ASTM testing methodology and the range of available hazard analysis methods can create potential mismatches between hazard levels and protective performance of arc-rated PPE. For this reason, we focused on two issues: (1) Whether or not the field performance of arc flash protective clothing and equipment provided the expected protection in real-world arc flash incidents, and (2) Whether or not there has been a pattern of mismatches between arc flash protection and the arc flash hazard level.
Based on our findings, we concluded that arc-rated clothing and equipment does provide the expected protection level. However, of the 30 workers exposed in the 22 arc flash incidents, 18 received burn injuries. These injuries were not caused by underperforming PPE, but rather by the workers not wearing all of the elements of necessary PPE — or not matching the arc rating of PPE with the hazard level of the task they were performing. Following are some statistical highlights from the study:
Eight of the workers received burn injuries because of failure to wear the needed hand or face protection.
One worker received a burn injury due to wearing a short sleeve shirt.
Five workers received burn injuries due to wearing clothing with an arc rating below the exposure level or clothing that was not designed to provide adequate body coverage.
Four workers received burns due to ignition of non-melting cotton clothing comparable to the NFPA 70E HRC(0) level of protection.
For 18 of the 30 workers involved in an arc flash incident, a hazard analysis approach was employed in selecting protective clothing and equipment.
For the remaining 12 workers, no hazard analysis approach was employed in selecting protective clothing and equipment, and 10 of these 12 workers received burn injuries.
We also drew the following conclusions, based on our analysis of the PPE performance:
Arc-rated protective clothing and equipment provides the expected level of protection when it is matched to the exposure level and worn in accordance with the NFPA 70E standard.
Selecting protective clothing and equipment based on an arc flash hazard analysis is an effective way to reduce arc flash burn injuries.
Selection of protective clothing and equipment based on a hazard analysis does not mean workers will actually use all of the required protective clothing and equipment that is needed. About half of the injuries were due to not wearing gloves, a face shield, or a hard hat.
Author's Note: Additional incident data would be helpful to increase the value, range, and effectiveness of this ongoing study. If you have an arc flash incident to report, please contact us directly for an arc flash incident survey form (contact information is below). A copy of the 2009 IEEE Electrical Safety Workshop paper should be available soon on the IEEE Xplore® database at http://ieeexplore.ieee.org/Xplore/dynhome.jsp.
Doan is a principal consultant with DuPont, Wilmington, Del. He can be reached at doan@ieee.org. Neal is a principal consultant with Neal Associates, Bonita Springs, Fla. He can be reached at nealassoc@earthlink.net.
The original technical paper on which this article is based was presented at the IEEE Electrical Safety Workshop in St. Louis, Mo., in February 2009. The copyright of the original paper is assigned to IEEE.