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 Post subject: PPE for VERY Low IE
PostPosted: Tue Jan 16, 2018 2:45 pm 
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Joined: Tue Jan 16, 2018 1:49 pm
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Location: Midland, TX
Hello to All,

Was hoping to get some input on some IE calcs I have for quite a few pump jack sites out here in TX. 12,470 dist to low kVA step down banks between 30-45. T style cutouts clear fault in about a cycle so I end up with IE of .07-.09 cal/ cm^2. Anyone have any thoughts on necessary PPE for this instance? Guys already have leather gloves, arc rated clothing, hearing protection, safety glasses, and hardhats; however, I'm, wondering if adding a face shield might not be a bad idea...Any thoughts? Would this be unnecessary/ over kill?

Thanks!!

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 Post subject: Re: PPE for VERY Low IE
PostPosted: Tue Jan 16, 2018 7:43 pm 
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Joined: Tue Oct 26, 2010 9:08 am
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Location: North Carolina
I think IEEE 1584 states that results below 0.1 cal/cm2 are invalid.

Human skin is good for 1.2 cal/cm2. That's why NFPA 70E-2015 and later has a lower cutoff of 1.2 cal/cm2 for the PPE. Previous editions recommended avoiding meltable fiber clothing (and NESC still does) due to a possibility of secondary injuries from having melted synthetic fiber glued into the skin and exacerbating a burn but that's about it. Up until the point that it melts, the stuff has a pretty decent arc rating even if it's not rated.


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 Post subject: Re: PPE for VERY Low IE
PostPosted: Mon Jan 22, 2018 9:37 am 
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Joined: Fri Apr 15, 2011 7:43 am
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Location: Colorado
When Paul says "Human skin is good for 1.2 cal/cm2" he means we can fully recover from a burn at that energy. It is slightly more than holding your hand over a disposable lighter


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 Post subject: Re: PPE for VERY Low IE
PostPosted: Tue Jan 23, 2018 3:15 pm 
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Location: Louisville, KY
1.2 is a second degree burn.

I recommend looking at the work situation and do a risk assessment.

Some companies use arc rated, cut resistant sleeves and AR gloves and allow a cotton t-shirt.

There are a few manufacturers of the sleeves and gloves.

If there is a shock hazard, of course, rubber gloves with protectors is required.

Hugh Hoagland


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 Post subject: Re: PPE for VERY Low IE
PostPosted: Mon Jan 29, 2018 2:31 pm 
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Joined: Wed Jun 04, 2008 9:17 am
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Location: Spartanburg, South Carolina
You will find that the IE on the low side is much, much higher.


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