It is currently Sun Aug 20, 2017 12:46 am



Post new topic Reply to topic
Author Message
ekstra   ara
 Post subject: Labels 130.5(D)(3) "not both"
PostPosted: Sun Nov 09, 2014 1:14 pm 
Offline

Joined: Wed Jul 30, 2014 3:27 pm
Posts: 3
Does this new wording mean that Incident Energy and PPE category (formerly HRC) cannot appear on the same label? If so, most existing labels do not comply. I could find no discussion of this new wording in either the First(ROP) or Second(ROC) draft.

•  Either the available incident energy with the corresponding working distance or the arc flash PPE category in Table 130.7(C)(15)(A)(b) or Table 130.7(C)(15)(B) shall be listed but not both.


•  Minimum arc rating of clothing is required.


•  Site-specific level of PPE is required.



Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Labels 130.5(D)(3) "not both"
PostPosted: Mon Nov 10, 2014 7:21 am 
Offline
Plasma Level
User avatar

Joined: Tue Oct 26, 2010 9:08 am
Posts: 1736
Location: North Carolina
redwoodk wrote:
Does this new wording mean that Incident Energy and PPE category (formerly HRC) cannot appear on the same label? If so, most existing labels do not comply. I could find no discussion of this new wording in either the First(ROP) or Second(ROC) draft.

•  Either the available incident energy with the corresponding working distance or the arc flash PPE category in Table 130.7(C)(15)(A)(b) or Table 130.7(C)(15)(B) shall be listed but not both.


•  Minimum arc rating of clothing is required.


•  Site-specific level of PPE is required.



Backing up and looking at it, I think that one major thing happening here is the "editting floor" issue.

In 70E-2012, we had effectively two tables. The first table described equipment and tasks performed on that equipment to determine an H/RC (hazard/risk category). It used numbers 0-4 but they might as well have been more arbitrary letters (A-E). The second table took the H/RC value and gave specific PPE for that H/RC value.

It's a bit of a technicality but the second table is not a "PPE table". There is an actual "PPE table" in Annex H. Thus technically because the "H/RC levels" are not "PPE levels", you can't use it as such and thus if an arc flash study is performed, PPE should be specified as per Annex H or by reading the labels on the PPE and following the much more detailed rules contained in the text in 130.7. In practice most sites simply read the table backwards (1.2-4 cal/cm^2 = H/RC 1), which is not what it was intended for. It's a technical error and not a practical one because other than arguments about the PPE requirements for H/RC 1 (balaclava required? Face shield required?), the table was for all intents and purposes very similar to the PPE table in Annex H.

Things have changed greatly in 70E-2015. Now the likelihood is taken care of in the first table, the hazard is turned into a "PPE level" in the second table, and our old friend the PPE table is still there as the third table. The PPE table is now truly just that and although there are specific statements in the standard that you can't use the PPE table as a PPE table (again, use Annex H), the risk part of things is addressed in the new table #1 and there is no technical reason not to calculate an incident energy rather than using table #2 and apply that to the PPE table whereas before there was something of a technical issue with doing so.

Now bringing this back to labels, we are again arguing the same issue of "risk ranking" (a PPE "level") vs. an incident energy value. Still, the table is convenient and it summarizes things much better than 130.7. So technically the site can simply adopt the PPE table and have the labels refer to the site specific table (which is the PPE table), and that's what the label requirement is saying. In reality I can't find a plant that is actually implementing the "PPE 3" (25 cal/cm^2) PPE ranking. They all generally tend to ignore it and go straight to the 40 cal/cm^2 rating since the PPE is virtually the same and only the thickness gets slightly greater. Similarly, many plants may start at 4 cal/cm^2 if they already require FR clothing for other reasons, or else merge the 4 and 8 cal/cm^2 rating and perhaps even adopt a 10 or 12 cal/cm^2 rating. These are all valid reasons for a "plant specific" PPE rating. Those that do this either keep the "H/RC" levels or use something obviously different ("A, B, C, D") to avoid confusion.

All that the label requirment is saying is to pick ONE system per label and stick with it. Don't mix them up to avoid confusion. Not using H/RC level AND incident energy on the label is a technically incorrect issue and if H/RC ever was on the table it should have included the entire task table for that equipment. So we're arguing semantics here and not reality.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: Labels 130.5(D)(3) "not both"
PostPosted: Tue Jun 28, 2016 5:54 pm 
Offline
Sparks Level

Joined: Thu Oct 18, 2007 7:10 pm
Posts: 247
Location: NW USA
Still considering this issue, and puzzling over why in the Guidance Tables in Annex H, is there no coincidental protection levels offered, matching "PPE Categories" and "determined incident energy exposure".

For example Table H2 simplified two category Arc Rated Clothing System suggests everyday work wear of Arc Rating 8 (previously PPE category 2) and and Arc Flash Suit with an arc rating of 40.

Two pages further Table H.3.(b) guidance for Selection of Arc Rated Clothing when Incident Energy is Determined, suggests three categories: 1.2 Cal/cm2, 1.2-12 Cal/cm2 and greater than 12 Cal/cm2.

What is implied or significant in the above differences? Did the writers of this Annex determine that facilities likely to perform arc flash analysis might have higher exposure than those hiding under the false security of prescriptive tables?

I fail to see why listing both the calculated calories and PPE category is now disallowed? It would seem simple to label a particular location has calculated hazard of i.e.: 10.4Cal/cm2, and then also state that PPE Category 3 is required to meet this exposure.

Any committee members on this site, that can illuminate the thought process behind disallowing what seemed to work?


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
© 2017 Arcflash Forum / Brainfiller, Inc. | P.O. Box 12024 | Scottsdale, AZ 85267 USA | 800-874-8883