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Do you list both the calculated incident energy AND the category?
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ekstra   ara
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PostPosted: Thu Nov 04, 2010 12:17 pm 
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Jim,
All this over the word "or"! Heck, it doesn't say mutually exclusive or. I myself take it to mean "at a minimum".

Anyway, 130.3 (Arc Flash Hazard Analysis) states: "An arc flash hazard analysis shall determine the Arc Flash Protection Boundary and the personal protective equipment that people within the Arc Flash Protection Boundary shall use."
Notice it said personal protective equipment, so why would some people think that 130.3(C) even remotely implies that you have to display IE on the label if an analysis is done?

If the intent of 130.3(C) was to mean that only IE has to be on the label when an analysis has been done, or even if the intent was to mean that IE instead of the required level of PPE, it would have stated that!!! It is written in English, these people are "reading into" the standard, in other words making their own interpretations.

Also, as has been said, PPE suppliers use the Categories to sell their PPE


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PostPosted: Fri Nov 05, 2010 7:58 am 
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We definitely put both items on our labels. It would absolutely make no sense at all to have a requirement that states you can only put HRC or Cals/cm2.

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PostPosted: Fri Nov 05, 2010 9:15 am 
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The reason it is an issue is that the NFPA doesn't want people doing a study and then using less conservative task table HRCs in place of the study results. If you provide HRCs based on IEs from your study then I doubt there is a problem. At least that is my take on it.


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PostPosted: Fri Nov 05, 2010 11:12 am 
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The issue comes down to the specific phrase HAZARD RISK CATEGORY.

Hazard Risk Categories come from performing tasks not from calculations. It is not correct to take a calculated incident energy and 'back-engineer' a HRC.

It is perfectly acceptable to have a range of incident energy values be called a 'Category' and then choose PPE requirements based on that Category. There is also nothing wrong with using HRC PPE requirements as the basis of your Category PPE requirements.

It is all about using the proper and specific terminology.


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PostPosted: Fri Nov 05, 2010 11:34 am 
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[quote="JBD"]The issue comes down to the specific phrase HAZARD RISK CATEGORY.

Hazard Risk Categories come from performing tasks not from calculations. It is not correct to take a calculated incident energy and 'back-engineer' a HRC......

If you are using the task table 130.7(C)(9), then I agree, the HRC is based upon the task you are performing as long as the location meets the footnotes at the end of the table.

However, if you are doing detailed calculations to determine the energy level, then you use this energy level to determine the HRC.

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PostPosted: Fri Nov 05, 2010 11:44 am 
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Robertefuhr wrote:
However, if you are doing detailed calculations to determine the energy level, then you use this energy level to determine the HRC.


Not HRC, only Category. Or if you really really want to add something before Category, the your best choice would be HC (Hazard Category) (note that you'll be the only one using the wording Hazard Category).

With the detailed calculations, you remove the Risk part (which is the probability of the hazard) for choosing PPE and only keep the Hazard part (incident energy).


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PostPosted: Fri Nov 05, 2010 11:45 am 
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If you did not perform an incident energy analysis, what HRC would you put on the label where Table 130.7(C)(9) lists different HRCs for different tasks on the same equipment. Would you put multiple labels on the equipment, like "HRC 0 if operating with doors closed", "HRC 2 if performing infrared thermography", and "HRC 2* if working on energized conductors"?


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PostPosted: Fri Nov 05, 2010 3:56 pm 
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Robertefuhr wrote:
JBD wrote:
However, if you are doing detailed calculations to determine the energy level, then you use this energy level to determine the HRC.


Absolutely not.

Hazard Risk Categories (HRC's) are specifically 'creatures' of NFPA70E. There were no incident energy calculations involved in their creation.

When we calculate incident energy we also calculate an 'arc flash boundary'.
What are the arc flash boundary distances for the different HRC's?

When we calculate the incident energy at a specific working distance (i.e. 18"), it is possible to lower the incident energy and our PPE requirements by moving further away from the arc. Does NFPA70E re-determine their HRC when using a 36" hotstick to make a voltage measurement at 480V?


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PostPosted: Tue Jan 18, 2011 7:59 am 
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Many of you have been following the debate that I have been having with a few NPFA members with highlights and commentary in this thread.

NFPA was adamant about this issue and insisted you can not use incident energy and categories together which I kept pointing out, does not make sense. I took the debate to some very high levels.

Now it looks like the 2012 edition of NFPA 70E will require the label contains AT LEAST ONE of the following:

Incident Energy
Minimum arc rating of clothing
Level of PPE
Highest HRC

This no longer says one OR the other any more. In fact, it looks like they had to add a grandfather clause for labels that were created based on NFPA's prior interpretation of one OR the other.

My congratulations and thanks to the NFPA committee for sorting out what was a very confusing issue and making it more practical.

Also thanks for everyone's support and encouragement over this issue.

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Jim Phillips, P.E.
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PostPosted: Tue Jan 18, 2011 9:20 am 
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Jim,
Thank you for "carrying the torch" so to speak for this one!!

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Barry Donovan, P.E.
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