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 Post subject: NFPA 70E 2015: No labels for previous Hazard/risk category0?
PostPosted: Tue Sep 23, 2014 11:43 am 
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Hi Friends,
I got my new NFPA 70E 2015 and, as Jim & other colleagues mentioned before, there are changes like: "arc flash hazard analysis" to "arc flash risk assessment", "shock hazard analysis"to "shock risk assessment", "hazard/risk category" to "PPE Category", etc. Above all, now with previous Hazard/risk category 0 removed, don't we have to label equipment that has less than 1.2cal/cm^2? We understand that NFPA 70E committee deleted Hazard/risk category 0 as the new PPE table determines PPE only within arc flash boundary. But if we do not put any labels on equipment for (incident energy less than 1.2cal/cm^2; working distance greater than arc flash boundary), will it not confuse technicians? Example, on a small MCC (3-Phase, 480V, 200A service), it is not uncommon to see the motor disconnect of Hazard/risk category 0, and the main service could be of hazard/risk category (now PPE category) 2 or 3 or 4 or even dangerous (depending upon short circuit contributions from utility). And if the technician don't see a label on motor disconnects, will he not overlook or think the main service too as same? And in large switchgear/switchboar/MCC, if a label is missed during label affixation, the technicians may work without proper PPE, not knowing the actual label on that equipment was missed. Please comment.


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 Post subject: Re: NFPA 70E 2015: No labels for previous Hazard/risk catego
PostPosted: Tue Sep 23, 2014 12:41 pm 
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It is my understanding that all equipment needs to be labeled, regardless of incident energy. As you've pointed out, the qualified worker has no way of knowing what PPE to wear unless he has a label to go by.

I think I put a label on a piece of equipment last week for 0.05 cal/cm^2.


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 Post subject: Re: NFPA 70E 2015: No labels for previous Hazard/risk catego
PostPosted: Thu Sep 25, 2014 2:45 am 
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As explained in Annex H, if you do a risk assment using a method other than the tables, you cannot use the H/RC category. That does not stop you from developing your own simplified system. Now that the PPE table just listsPPE for a given incident energy (no longer tied to risk), there is no longer an issue. However to simplify things further,why not use incident energy outright? It issimple to explain that you need protection from head to toe and to list the ratings in cal/cm2 of nontested PPE. Second, is an incident energy estimate more accurate than about 1 digit? 1584 gives numerical results of about 90-95% confidence. So "1.13" should be rounded to "1". Finally, look at your clothing and the tables and PPE changes. If a hood is required starting at 13 cal and the PPE you stock goes to say 10.4 cal for the shirt and pants, is there any point in listing 9 or even 11 or 12 cal? As long as the worker knows what to wear, this considerably simplifies not only the labels but even allows for stocking preprinted labels.

And finally,what are you going to do with the equipment outside of say the valid range for IEEE 1584 such as under about 300 Volts or over 15 kV? A much more 'generic' label, especially given the amount and lack of a valid calculation arc flash calculation means that a stated value such as " under4 cal/cm2" is probably all you can do withit. Never mind if you have frequently relocated equipment or network reconfigurations where at best you can give an upper limit.

I have written arc flash policies that give a stated number and state that unlabelled equipment is assumed either 1 or 4 cal depending on the facility and equipment. This value depends on the minimum required PPE (FR or just nonmelting clothitng). Unless you want to hunt down every motor termjnation enclosure (peckerhead),every receptacle, junction box, conduit body, instrumentation enclosure, etc., you will quickly realize that at some point we simply have to have a rule for unlabelled equipment of some fashion in any but the smallest installations for practical reasons. The unlabelled rule has to accommodate both unlabelled equipment for practical reasons and equipment that should be analyzed or subjected to a tabular approach such as temporary installations, or more critically,temporarysystem changes such as emergency generators. We definitely do not need 11x17 labels with huge tables of dozens of operating conditions and tasks.

As you said, simplicity has value. Labels should be used on the major areas as required by NFPA 70 (NEC), but every conduit cover does not need a label. If we can even get the shock hazard requirements right, we can cut down on twice as many injuries and fatalities as arc flash. Arc flash is important, but we should not get so hung up on it that we ignore the big picture. A safety manager at my current employer ignored the eixisting electrical safety policy (70E implementation), wrote his own 10 page summary, and never once mentioned shock hazards. As with most companies we can't seem to go a year without a shock (out of 10,000 workers) and get an a major arc flash injury every few years. So he ignored shock injuries altogether! How many times have you seen someone reaching into an energized 480 panel with bare hands to do something stupid but that's OK because they had their FR clothing?


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 Post subject: Re: NFPA 70E 2015: No labels for previous Hazard/risk catego
PostPosted: Fri Sep 26, 2014 1:25 pm 
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Voltrael wrote:
It is my understanding that all equipment needs to be labeled, regardless of incident energy. As you've pointed out, the qualified worker has no way of knowing what PPE to wear unless he has a label to go by.

I think I put a label on a piece of equipment last week for 0.05 cal/cm^2.


I believed that IEEE 1584 minimum reported incident energy was 0.25 cal/cm^2 which is the accuracy limit of the test equipment. 0.25 cal/cm^2 is also the minimum value found in IEEE 1584 tables E5, E.6 etc. However, the IEEE 1584 spreadsheet arc flash calculator reports incident energy values less than 0.25 cal/cm^2 both for all different protection device types.

Some software and online arc flash calculators utilize the .25 cal/cm^2 default whenever lower values are encountered since it is not the intent of the programs to encourage workers to go without PPE.

While putting 0.05 cal/cm^2 calculated incident energy value on label seems overprotective, using 1.2cal/cm^2 as the criteria of whether a PPE is required or not is unsafe. Only a fraction of 1.2 cal/cm^2 is required to cause 2nd degree burn when the energy is delivered fast enough. Please read this forum thread at http://arcflashforum.brainfiller.com/viewtopic.php?f=34&t=2221 for more information.


Last edited by wbd on Fri Sep 26, 2014 2:09 pm, edited 1 time in total.
Link to commercial software included


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