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 Post subject: When do you relabel equipment when configuations change?
PostPosted: Wed Jan 06, 2016 6:59 am 
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Joined: Tue Mar 25, 2008 8:59 am
Posts: 14
Hello,
I am working on arc flash study for a large manufacturing facility. For this project there are approximately 1200 labels installed on the various pieces of equipment. We originally modeled, analyzed and labeled the facility in March of 2015. Now they are upgrading the original 12kV service that fed the facility from an old pole and "H" frame arrangement to an underground pad mount switch line-up with several fused branch feeders to the individual transformers. Source impedance levels from the utility also changed slightly, less the 2%.

Here is where my question begins. On our labels (installed 10 months ago) we used incident energy levels and not PPE Category's. Now that we modeled the new configuration we are seeing very minor changes in the incident energy levels (example going from 5.2 Cal to 6.3 Cal). On almost every label the incident energy and AFB has changed slightly. Some increased and some decreased.

My question to all is: Do you re-label the entire system? (Very costly and labor intensive)

Does a 5% change warrant re-labeling? Or maybe 10%?

Very interested in your opinions,

Thanks in advance.


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 Post subject: Re: When do you relabel equipment when configuations change?
PostPosted: Wed Jan 06, 2016 7:03 am 
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Joined: Tue Nov 12, 2013 6:31 am
Posts: 238
Location: Port Huron, Michigan
At the very least, I would say any changes in incident energy values that will affect what PPE needs to be worn will need to be changed. Issued PPE should have some ranges that it is good for (for instance, if the shirts the electricians wear are rated for 8.0 cal/cm2.)


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 Post subject: Re: When do you relabel equipment when configuations change?
PostPosted: Fri Jan 22, 2016 11:10 am 
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Joined: Tue Oct 26, 2010 9:08 am
Posts: 2174
Location: North Carolina
Next time, if you round UP to match your PPE, this problem will correct itself for the most part. So for instance everything under 1.2 cal/cm^2 gets a 1.2 cal/cm^2 label. If your "basic" PPE is good for 10 cal/cm^2 and you don't have a "non-face shield category" then round everything from 1.3-10 cal/cm^2 up to 10 cal/cm^2. If you only carry a 40 cal/cm^2 suit beyond that then round 11-40 cal/cm^2 up to 40 cal/cm^2.

This minimizes when labels have to be changed moving forward and still does everything it is supposed to do. The only downside to this approach is that outside vendors may struggle a little bit. For instance if you rate everything 12 cal/cm^2 because that's what your standard "low end PPE" is and a vendor comes in that only has 10 cal/cm^2 PPE, they would have to jump to the next higher level and end up in 25 or 40 cal/cm^2 suits.


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