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 Post subject: Hazard/Risk Catagory ratings
PostPosted: Thu Dec 29, 2011 11:00 pm 
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Location: Michigan
I have noticed that there are 2 different thought process expressed here regarding the HRC and associated levels of protection. I assume this is all in how you interpret the information in Table 130.7(C)(16).

Level 2 Arc-Rated Clothing, Minimum Arc Rating of 8 cal/cm2
Level 3 Arc-Rated Clothing Selected so That the System Arc Rating Meets the Required Minimum Arc Rating of 25 cal/cm2


Does this mean HRC 2 is only up to and including IE of 8 cal/cm2 and HRC level 3 is 8.1 cal/cm2 up to 25 cal/cm2?

Annex H, Table H.2 states all HRC 1 & 2 together with clothing and gear rated for a minimum of 8 cal/cm2.

This appears to be a situation where we can read into this as far as we choose to, or not to for that matter.

Does anyone have any specific experience with this and can shed some light on this subject?


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PostPosted: Thu Jan 12, 2012 8:16 am 
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Joined: Thu Oct 27, 2011 9:34 am
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Levels of PPE-Annex H

Quote:
MIControl wrote:
I have noticed that there are 2 different thought process expressed here regarding the HRC and associated levels of protection. I assume this is all in how you interpret the information in Table 130.7(C)(16).

Level 2 Arc-Rated Clothing, Minimum Arc Rating of 8 cal/cm2
Level 3 Arc-Rated Clothing Selected so That the System Arc Rating Meets the Required Minimum Arc Rating of 25 cal/cm2


Does this mean HRC 2 is only up to and including IE of 8 cal/cm2 and HRC level 3 is 8.1 cal/cm2 up to 25 cal/cm2?


Yes-This assumption is correct

Quote:
Annex H, Table H.2 states all HRC 1 & 2 together with clothing and gear rated for a minimum of 8 cal/cm2.

This appears to be a situation where we can read into this as far as we choose to, or not to for that matter.

Does anyone have any specific experience with this and can shed some light on this subject?


Annex H was installed as "Informative" guidance to help the reader understand requirements in 70E by providing examples or situations that may help in everyday situations in this case. The Annex refers basically to place qualified electrical workers in Cat 2 PPE for applicable tasks in the tabels. Note-this PPE may need to be changed or added to for other tasks that are associated with HRC 2 tasks. Read the note below the table to ensure you are compliant with the situation.


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PostPosted: Thu Jan 12, 2012 9:29 am 
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Joined: Mon Jan 18, 2010 11:35 am
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Location: Wisconsin
The table {130.7(C)16} showing HRC levels of clothing is designed to be used with the 'task table' not with calculated incident energy levels.

The 130.7(C)16 Arc-Rating cal/cm┬▓ values are not sacrosanct when not using the task tables. There is nothing to stop you from creating your own PPE equipment list and breaking it into levels. For example, your company could create a 'Category 2' which consisted of 'HRC2' equipment but with an Arc-Rating of 11 cal/cm┬▓ for use with calculated incident energy values.

Because most people do not want to develop their own company requirements, they read the table backwards to make their PPE selection. After all this method means 'no interpretations needed'. So what if no PPE manufacturer offers 'HRC2' clothing packages rated less than 10 cal/cm┬▓. Who cares that realistically 8.1 cal/cm┬▓ is not harder to protect against than is 7.9 cal/┬▓. It is all about providing simplistic answers to variable questions.


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