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 Post subject: Re: Where does exposure begin per 1910.269 regarding syn fab
PostPosted: Wed Apr 12, 2017 5:12 pm 
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Joined: Tue Jan 13, 2009 5:00 pm
Posts: 566
Bumping an old thread, since the question has come up yet again. FR raingear is expensive and fragile, so the thought (not by me) is to purchase non-FR raingear for use "out of the zone" whatever and wherever that is. I believe there is some use of non-FR reflective vests as well. Since I last posed this question to the forum, 269 and NESC have both been revised. Any newer thoughts on the subject?

Quote:
The employer shall ensure that an assessment is performed to determine potential exposure to an electric arc for employees who work on or near energized lines, parts, or equipment. If the assessment determines potential employee exposure, employees shall not wear any clothing made from acetate, nylon, polyester, or polypropylene unless arc rated, and shall not wear an outer layer of clothing that could ignite and continue to burn when exposed to flames or the electric arc identified in the assessment.


Without some kind of industry standard on this, I'm having a difficult time stating there is no potential exposure at any distance. Anyone here assessing otherwise? Thanks.


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 Post subject: Re: Where does exposure begin per 1910.269 regarding syn fab
PostPosted: Fri Apr 14, 2017 1:28 am 
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Joined: Tue Oct 26, 2010 9:08 am
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Location: North Carolina
I've changed jobs twice since then and niw I'm occasionally a contractor for utilities. FR PPE is now virtually universal for utilities I work with.

You can get FR plus hi viz shirts and vests in two versions. The first uses Glengard which is a patented modacrylic blend that is very expensive ($50-120 for shirts, about half that for vests). The second is with a typical FR shirt with 3M FR striping material sewn on with Kevlar thread. This is much less expensive. The whole shirt/pants doesn't have to be fluorescent to meet ANSI requirements even for level 3. I'd love to have the Glengard "ljneman shirts" (comfort) but I'd have to clean the grease and oil out myself and pay for them. My work supplies laundry and the shirts with stripes so I use them. So I have a vest if a site insists on only vests but even the couple that do never said a word about it when Im wearing my FR/hi viz shirts. I don't have an FR vest though and so far, no need.

There has been some information published on arc flash and non-FR PPE in the last few years by Hugh's group. The "ATPV" of non-FR nylon is better than ATPV 8-10 and untreated cotton is similar. I'd have to dig to find the reports. Suffice to say that the entire body including arms and legs and not just the face/chest should be behind the "2 cal boundary" at which point it doesn't seem like it would be a problem whether the clothing is meltable ir not.

OSHA is concerned with for instance getting hit with molten metal or boric acid in a sub yard so their "2 cal" cutoff rule is that it has to be 2 Val's everywhere at working distance (also defined as 15"). So for practical purposes I don't see where utilities have any wiggle room in sub yards no matter what the distance is. That's also how Duke and Dominion are handling it. Outside the unnamed "public protection" boundary (10+ feet) AND the 2 cal arc flash boundary I don't see where an issue should exist.


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 Post subject: Re: Where does exposure begin per 1910.269 regarding syn fab
PostPosted: Fri Apr 14, 2017 8:39 am 
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Thanks Paul. The testing videos I've seen all seem to show how nasty the meltables are at 8 cal/cm^2 or greater. Haven't yet seen the test that shows they can withstand some low IE value. If you have knowledge of such studies, I'd sure like to see the references.

I suppose we could ship a bunch of raingear samples off to a testing lab, and get a report. The manufacturer of the non-FR gear would be under no obligation to retain the same formula, though.


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 Post subject: Re: Where does exposure begin per 1910.269 regarding syn fab
PostPosted: Sat Apr 15, 2017 8:16 am 
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I went back and looked. I can find lots of info on FR textiles and some on untreated cotton but not much on meltable materials. The best I can offer is if you look at some of the rainwear information on the rainwear fabrics that specifically failed miserably, most of which do OK at low incident energies but melt and/or ignite at higher incident energies, you might be able to make some sort of case by looking at the "minimum values" all of which are above about 5-6 cal/cm2. Of course this is pure speculation on my part.

I recall back when I was a teenager or maybe even earlier when my grandparents were involved in a camping club and had huge campout parties when one time a person wearing a nylon jacket had the jacket melt from a nearby lantern when their exposed hand and wrist weren't "even warm yet". And the fact that nylon, PVC, etc., melts at relatively low temperatures relative to the charring temperature for cotton (600+ F), would seem to suggest that perhaps the meltable fabrics do indeed melt at a pretty low incident energy but without test data, it's hard to say.

I recall seeing this information on one of those early "summary" style IEEE papers but when I went back looking for it, I couldn't find it.


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