By Hugh Hoagland

It was on the 6 PM news. A utility had a serious incident involving two of their employees. The images were disturbing; the reporters’ and bystanders’ interpretation of the events was catastrophic. The crisis at the utility had begun. The crisis was a fault in an underground network in a downtown area. The fault current was high because of the type of system. None of the public was hurt but they did see the incident. The workers had

first and second degree burns, even though the evening news reported they had second and third degree burns. The utility had been thrown into a crisis.

Language is important in shaping our ideas, philosophies and interpretation of events. Even language structure and subtle word meaning affect our outlook and offer hints into a cultural psyche. For instance, the Chinese language uses a combination of symbols for some words. The Chinese symbol for “crisis” is a combination of the symbol for “opportunity” and “change”. This might affect how Chinese speakers would see a “crisis”. The might tend to see it as a “change opportunity”. This is my philosophy surrounding crisis and was the philosophy of the utility I consulted with on this incident.

When the smoke cleared, the utility assessed their clothing program. They had required the use of FR clothing for some time to comply with the OSHA 1910.269 standard and the 1994 language that clothing must not “increase the extent of the injury,” but this utility had gone beyond the minimum requirement and had required an additional layer in this particular work situation to better protect the workers. In their analysis of the incident the utility sought some arc testing to replicate the incident with the clothing the workers had worn and additional PPE the utility had required. The utility saw an opportunity for change or at least self examination. They were ultimately concerned about their workers. In the subsequent investigation, we determined the shirts the workers wore out-performed its rated performance by over 2X. The shirt was rated for 8 cal/cm² and with the t-shirt would have been rated at about 12 cal/cm² and might have protected to around 20 cal/cm² with a high probability of ignition of the t-shirt under certain conditions. The reality was that the Indura® UltraSoft® 7.5 oz shirt protected the workers from all third degree burns in close to a 30 cal/cm² exposure far beyond its predicted arc rating. Something I have seen in many investigations. I based the 30 cal/cm² estimate on the damage to the shirt and t-shirt and the energy the utility predicted in the system three feet away, where the workers were when the arc struck. If the workers had worn the additional PBI®/Kevlar® 4.5 oz coverall they were supposed to wear, the burns would have been negligible under the garments. Additional training and using the incident to reinforce the need for the PPE required has done a lot to increase compliance.

Additionally, the utility learned that the face shields they had provided, but not worn by the workers, were insufficient for the exposure and would have ignited and caused a greater hazard under the conditions. Arc resistant face shields were specified and the workers in this division received remedial training on the incident to ensure compliance to the company policy which provided comfortable, protective flame resistant clothing. This crisis became an opportunity for change by pointing out weakness in the face shield, reinforcing the choice of the Indura® UltraSoft® for the shirting material, and the need for an additional layer and a flash hood or arc resistant face shield in the network system.

The new OSHA standard recently published in the Federal Register will be a crisis for some in a positive or negative sense. Some of the more proactive utilities already comply with the spirit of the new standard but many utilities do not currently comply with the new regulation. This standard will be easier to comply with because of the advancement in clothing materials including Indura® UltraSoft®, Nomex® AP®, Carbtex®, PBI®/Kevlar® and so many others which protect workers from electric arcs. Other innovations such as lightweight flash suits like those from Steelgrip, NSA, Workrite, Stanco and others, more readily available FR undergarments and new double layer front shirts such as those from Riverside Manufacturing, are leading the way to protect workers more affordably and comfortably.

Workers are seeing great improvements in FR clothing programs and more sophistication on the part of safety professionals. Safety professionals and electrical managers are beginning to understand they must avoid thinking of FR as a general category and must specify clothing meeting ASTM F1506 and rainwear meeting ASTM F1891 to assure worker protection and compliance with electric arc standards such as OSHA 1910.269 and NFPA 70E. The continuing improvement of company policies, updates in consensus standards and research and developmental improvement in flame resistant materials and has increased worker protection. Companies like NASCO Industries, Inc (www.nascoinc.com) have moved the protective rainwear forward with comfortable offerings like their new MP3 (Multiplatform Protection), a breathable Nomex® material which is more than just raingear, and the industry standard, the ArcLite™ ProSeries™ which has improved in every generation with greater tear strength and durability in a comfortable rainwear material. I recently tested a 7-year old ArcLite™ ProSeries™ which performed like a new one even though soiled and obviously abused.

OSHA recently published proposed changes to Subpart V in the Federal Register (June 15, 2005). The published update harmonized 29 CFR 1926, the construction standard, and 29 CFR 1910. The proposed regulation also updates and clarifies some of 1910.269, specifically the clothing standard, with new requirements. Though this standard only legally affects electric utilities, it shows OSHA’s intentions for electric arc safety and supports the continuing move of non-utility electrical installations to follow NFPA 70E. The new OSHA standard is similar to the NFPA 70E standard in several ways:

 

1. Requires a hazard assessment makes a “reasonable estimate of the maximum available heat energy to which the employee would be exposed” (guidance is given in Appendix F).
2. The standard “does not require the employer to estimate the heat energy exposure for every job task performed by each employee. The employer may make broad estimates that cover multiple system areas provided the employer uses reasonable assumptions about the energy exposure distribution throughout the system and provided the estimates represent the maximum exposure for those areas. For example, the employer could estimate the heat energy just outside a substation feeding a radial distribution system and use that estimate for all jobs performed on that radial system.”
3. The standard does require the use of a commonly accepted method of estimating arc energy such as (I recommend ArcPro™ or IEEE 1584 because of the substantial research behind them and both of these are in their second revision):
1. NFPA 70E-2004 Annex D (Available from www.nfpa.org) (raw calculations which can be created in a spreadsheet).
2. IEEE 1584-02 (Available from www.ieee.org).
3. A specific IEEE-PCIC paper which is similar to NFPA 70E-2004 (available from www.ieee.org).
4. ArcPro Software from Kinectrics in Canada (available in the US from HD Electric (available from www.hdelectric.com).
5. Heat Flux Calculator (Available free from www.arcwear.com).
4. Disallows non-FR clothing in many utility conditions. Clothing may not “melt or ignite and continue to burn” under the utilities’ hazard assessment energy levels. This makes it clear that when cotton clothing ignites it fails the standard. Some got the impression from the previous wording and early test data that cotton was somehow flame resistant, which is not the case unless the cotton is FR treated cotton which meets ASTM F1506 such as Westex Indura® UltraSoft® or Indura® FR Cotton.
5. Requires FR clothing under all of the following conditions:
1. “The employee is subject to contact with energized circuit parts operating at more than 600 volts,”
2. “The employee’s clothing could be ignited by flammable material in the work area that could be ignited by an electric arc, or”
3. “The employee’s clothing could be ignited by molten metal or electric arcs from faulted conductors in the work area.”
6. Requires clothing to be worn which meets or exceeds the Arc Rating of the arc hazard identified the hazard assessment.
7. Makes justification of non-FR clothing more difficult in many situations.
8. Will force innovation in shirting since many arc exposures in utilities will be in the 20 cal/cm² range. Many will be in the 1-5 cal/cm² range but 10-20 cal/cm² is still common. Systems which are fully radial (the instantaneous breakers “seeing” the end of the line) clear much faster at the end of the line than a system which drops out of instantaneous a mile or so out from the substation which is common in Midwestern and Eastern utilities in the US.

The standard doesn’t really address the 480V issue. It rightfully does not overkill most 120-240V systems but doesn’t mention delta-wye 208-277V systems which have very high fault currents and can produce substantial arc fault energies. Utilities will be responsible for identifying these hazards on their own.

The new standard also gives good practical advice such as: Where a cable in a manhole or vault has one or more abnormalities that could lead to or be an indication of an impending fault, the defective cable shall be deenergized before any employee may work in the manhole or vault, except when service load conditions and a lack of feasible alternatives require that the cable remain energized.

Avoiding a crisis as we usually define it is most easily accomplished by seeing your safety program as a continual “opportunity for change”. Proactively protecting your workers with arc thermal resistant clothing and PPE, assessing the hazards based on standard requirements, and committing to continued auditing of safety programs and remedial action where indicated will go a long way toward keeping your workers safe.

Hugh Hoagland may be reached at hugh.hoagland@e-hazard.com or hugh@ArcWear.com. His companies are committed to testing clothing for electric arc, accident investigation, training and hazard assessment and safety program development in electrical safety. Hugh personally performs most of the electric arc testing in the US and Canada using the Kinectrics High Current Lab and e-Hazard.com is now one of the foremost training organizations on clothing and PPE exposed to electric arc and electrical safety.