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 Post subject: Please help...Painting Fr Clothing
PostPosted: Wed Jun 03, 2015 8:36 am 
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Does anyone have any advice as to how to approach the FR clothing requirement for painting transmission towers. Our employees are not doing any kind of electrical work and are outside the minimum approach distances on all the structures. We work with flammable paints and our clothing is completely saturated with the coating after each structure. We are now required to use FR clothing but feel that the combination of flammable paint on the FR Clothing completely defeats the purpose of even using them. Does anyone have any information or advice on the incident heat energy level regarding this type of work so that I may get around using such a costly measure since we will be disposing of clothes after each use?? Please help!!


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Thu Jun 04, 2015 7:42 am 
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A couple of thoughts come to mind:

1. Arc Rated PPE is only needed when the risk assessment of the task indicates that there is a high probability of an arc flash event. Some companies have work rules that state some sort of AR PPE is standard uniform.

2. Flammable liquids on the AR clothing will defeat the purpose of the clothing.

3. Since you mention transmission towers, I assume this is high voltage like 115kV or higher. Most likely, since you are outside the MAD, the incident energy will low, probably even less than 1 cal/cm2.

4. Ask for the actual incident energy level at the closest distance that you would be to the energized conductor.

5. I would probably be more concerned with shock from induced voltage than an arc flash.

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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Thu Jun 04, 2015 7:54 am 
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Yes you are correct we typically go anywhere from 120 kV to 345 kV. Would you be able to steer me in a direction as to some data supporting the low levels outside the MAD?


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Thu Jun 04, 2015 11:09 am 
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morrisptg wrote:
Yes you are correct we typically go anywhere from 120 kV to 345 kV. Would you be able to steer me in a direction as to some data supporting the low levels outside the MAD?


That is just my observation from doing studies. You have to ask the utility for the incident energy analysis performed for their system to get the actual incident energy at the distance you are at.

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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Mon Jun 08, 2015 4:52 am 
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Barry is correct, the companies you are doing this painting for are supposed to have performed an incident energy study and will be able to give you that information. you shouldn't be close enough to the hazard to be in the exposure boundary while painting. here is the chart for determining the MAD right out of OSHA 1910.269:

https://www.osha.gov/pls/oshaweb/owadis ... &p_id=9870

If they are persistent and continue to require you to use this Arc Rated clothing, there are companies that makes a disposable arc rated clothing. Here is an example:

http://www.grainger.com/product/34C871? ... 08114713:s

Hope this helps!


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Mon Jun 15, 2015 7:51 am 
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Being outside of MAD doesn't mean there is no arc flash. I wouldn't trust "studies" of 115kV systems. The calculations are based on little information. Use ArcPro only but even then, the software assumes the arc will not track. Wear the AR clothing and use a good AR non-melting disposable.

http://e-hazard.com/arc-flash-resources ... -Exposures

http://ecmweb.com/content/disposable-fr ... ifferences

We don't sell the PPE but I have done most of the research on this subject. You are better off in an AR garment with some paint on it than in polycotton with paint on it if anything occurs. I agree with the engineer that you are likely outside of the AR boundary (<2 cal/cm2) but with high voltages strange things happen and there has been NO research on AFB >33kV. Real life experience says it isn't easy to predict that is why the utility is making you wear the AR gear.

Hugh Hoagland
e-Hazard.com/ArcWear.com


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Tue Jun 16, 2015 9:33 am 
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EPRI has been doing studies on arcs well above 33 kV. I know they did some work at least at 80 kV and they've been looking at the scaling issue...how voltage impacts arcing.

They did a study on arcs in the neighborhood of 6-12". This extends results above IEEE 1584 gap length and the equations are fairly straightforward.

Above 35 kV and arc lengths getting out well beyond 12", the modelling the arc is no longer really a "point source". Its an ambitious project to attempt to quantify arc flash for transmission towers. The arc termination points and the arc column are distinctly different regions with different properties, and the end points definitely act totally differently as well. At the termination you get sort of a "spray" effect and in the arc column it is somewhat random in terms of movement but more or less a much cooler line instead of a big cone shape. Among other things one of the consequences is that the position and orientation of the arc relative to the worker would have to be considered because for instance hanging on a tower above the arc in a vertical direction would be very different from working from a bucket truck parallel to it, and their data reflects this.

I would not suggest that it is as exhaustive as IEEE 1584 modelling. I'm not even sure that it's quite to the point where we can legitimately compare ArcPro results to actual physical models but it's getting closer.


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Wed Jun 17, 2015 6:42 am 
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I was aware of the EPRI studies but didn't know they went to 80kV. Marcia Eblen, now training with us on Arc Flash Tables and Tools for utilities was involved with Tom Short on this EPRI testing and I'm sure she could assist with questions. The last work I knew about was 33kV but the IEEE 1584 committee hasn't used that data in their models. While models may someday exist. The idea that cotton or ignitable and melting clothing could be worn if you are on a transmission line isn't something I would recommend. Even FR clothing with some paint will only burn the paint in the area where the paint is and any part which is not soaked in paint will still be totally flame resistant.

In our study of flammable contaminants the soaked areas were functionally no longer flame resistant but clean areas were fine and areas with a small amount of mineral oil, diesel and many other combustible materials did not burn on the flame resistant garments. I wouldn't assume that because you have paint on a flame resistant garment that it is useless. It will be no worse that a flammable garment in ANY case and in most real life scenarios will be totally protective. I would still use FR and you could use the non-melting FR disposable coveralls or a true arc rated disposable.

http://incident-prevention.com/ip-artic ... d-clothing
This article has a reference to the full IEEE paper if that helps.

Hugh Hoagland
hugh@e-hazard.com


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Wed Jun 17, 2015 7:21 am 
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The problem is that the garments are saturated with paint, and it is also common that the underlying clothing is saturated as well. Think of being covered completely from head to toe in paint.


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Thu Jun 18, 2015 12:37 pm 
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Definitely get the coveralls listed. The prevent the paint from getting through. You should change them periodically but they will be safer without paint next to the skin.

Hugh Hoagland
ArcWear/e-Hazard.com


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Fri Jun 19, 2015 1:39 pm 
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I've seen the testing that was done for a potash mining company in the past, and I'm about 99% sure that Arcwear did the testing. The most interesting test to me anyways was when the coveralls were smeared with grease. The grease caught fire and burned out eventually. My memory is that my counterpart in Canada said the coveralls were essentially untouched. So in my mind what we have here is that the coveralls provided the ATPV as claimed and the burning grease laying on top of the surface caused the arc flash injury. It's hard to say that the coveralls "failed" in that test. In the strictest sense they didn't provide protection equal to or better than the Stoll curve but I can't wrap my head around the idea that the coveralls actually "failed". Paint should work the same way...it doesn't matter what the underlying clothing is if it catches fire while sitting on it.

I stand corrected on the voltage. I didn't find anything reported by EPRI that got over 33 kV.


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 Post subject: Re: Please help...Painting Fr Clothing
PostPosted: Fri Jun 19, 2015 2:05 pm 
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Thanks Paul. That small thing I did for Potash has been superceded by the new study I did in the IEEE paper. It showed a little grease (like the Potash test) does what you say but the thermal transfer underneath works like sweat to lower the rating. If the grease is all over and thick it eliminates the FR entirely by burning up the FR material. Small amounts aren't really a hazard. What he describes is.

I didn't know about any EPRI up to 80kV. I knew about the 33kV Tom did at Kinectrics.

Hugh Hoagland
ArcWear/e-Hazard.com


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