It is currently Fri Feb 23, 2018 11:31 am



Post new topic Reply to topic
Author Message
ekstra   ara
 Post subject: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Thu Oct 08, 2015 11:11 am 
Offline
Sparks Level

Joined: Sat May 17, 2008 5:00 pm
Posts: 77
NFPA 70E 130.5(2) States that an arc flash risk assessment shall:

Be updated when a major modification or renovation takes place. It shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment

At what point does everyone relabel? If the incident energy goes from 6.2 to 6.4 does this matter? The 8 cal PPE is still sufficient.
However, if the arc flash boundary goes from 4ft - 3 inches to 4 ft - 5 inches, although it's only in increase of 2 inches, it might make a difference.

Just seeing what everyone thinks about this. Basically what triggers updating the labels?

Thanks!


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Fri Oct 09, 2015 3:56 am 
Offline
Plasma Level
User avatar

Joined: Tue Oct 26, 2010 9:08 am
Posts: 1880
Location: North Carolina
K. Engholm wrote:
NFPA 70E 130.5(2) States that an arc flash risk assessment shall:

Be updated when a major modification or renovation takes place. It shall be reviewed periodically, at intervals not to exceed 5 years, to account for changes in the electrical distribution system that could affect the results of the arc flash risk assessment

At what point does everyone relabel? If the incident energy goes from 6.2 to 6.4 does this matter? The 8 cal PPE is still sufficient.
However, if the arc flash boundary goes from 4ft - 3 inches to 4 ft - 5 inches, although it's only in increase of 2 inches, it might make a difference.

Just seeing what everyone thinks about this. Basically what triggers updating the labels?

Thanks!


Accuracy is only good to 1 significant figure anyway. 6=6. 4 feet is 4 feet.

Generally revising up = relabel otherwise.

Most available PPE exceeds the values given in the table method. If you are using calculations (thus Annex H) you go by the lowest cal rating of the PPE, not the table. With an upper cutoff of 12 cal without hoods and multilayer suits, this is significant for "midrange" (8-12) cases.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Fri Oct 09, 2015 7:36 am 
Offline

Joined: Fri Sep 25, 2009 5:00 pm
Posts: 43
Great question! I have seen people trying to make a case to re label when there is any change at all which seems necessary. Mostly I think they are trying to drum up business. I have always taken this NFPA 70E statement for what it says "Review" which is not the same thing as "Re label" as some would have you think. Good discussion.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Mon Oct 12, 2015 5:12 am 
Offline

Joined: Sun Dec 12, 2010 5:00 pm
Posts: 21
Location: Idaho
What we got told in our update class is that you have to pick which method you want to use on a piece of equipment whether you use incident energy or PPE level as stated in 130.5(D) but cannot use both. If you have like we do both methods on our original labels, then you have to change the label because you cannot have both on a piece of equipment and they say that they are not grandfathered either so we have to change all and there are over a 1000 labels. Good luck....


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Mon Oct 12, 2015 7:39 am 
Offline
Sparks Level

Joined: Fri Apr 15, 2011 7:43 am
Posts: 164
Location: Colorado
What if the distance of from the point you are from the bus taking a measurement is 4'-3", at 2" further you ar now in the boundary area. What number do you use to determine it is ok? 2" 20" 200"


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Mon Oct 12, 2015 9:22 pm 
Offline
Plasma Level
User avatar

Joined: Tue Oct 26, 2010 9:08 am
Posts: 1880
Location: North Carolina
Using ANY "rounding" method will always have a "borderline". I would say though that with a lot of equipment, 3'6" and either 15", 18", or 24" (depending on type of equipment and .269 or .3xx rules) are "magic numbers". The limited approach boundary is marked anyways, and working distance cutoff means below requiring arc flash PPE. That's for arc flash boundaries. In shops where the minimum PPE is FR, the arc flash boundary for all intents and purposes should be set at that limit such as 4 cal/cm2. This would apply for instance under .269 rules, iron/steel, oil/gas, and some others. The other extreme is when the arc flash boundary exceeds the size of the room so fire walls define the border, not a calculation. Then larger is meaningless. Otherwise except for rounding, increases would trigger relabelling.

What this really highlights is the value of establishing local standards. If we pick three incident energy values...the minimum for the minimum required PPE or "none" if there isn't any, the maximum allowed with available single layer PPE and a balaclava+face shield (generally 8-12 cal), and the maximum available (40-100), then only 3 ratings are important. Similarly we can round off arc flash boundaries based on equipment type (4 options under 1584 currently) and the 3 incident energy levels to arrive at a total of 12 possible maximum boundaries which could be further simplified. In combination with system voltages for shock protection, the plant site might be down to perhaps a couple dozen stickers for all equipment instead of having individualized designs number into the hundreds or thousands. So far the thermal printers I've worked with are horrendous in terms of reliability so I'm leaning towards not printing stickers since every time is a big hassle and just stocking them.

Anyways I can't go much further than the generic description of using only boundaries because there are so many site specific details but the concept is easily applied.


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Tue Oct 13, 2015 10:37 am 
Offline

Joined: Tue Mar 02, 2010 1:50 pm
Posts: 25
At our sites I've come to the conclusion that no one really cares the exact arc flash boundary or whether, for example, it's 3 ft or 5 ft. Because I work for the utility, I have access to the available fault current, which is constantly changing (generally increasing) due to transmission upgrades. These small increases could cause small increases in the arc flash boundary. At our Windfarm sites labeling is a MAJOR task: 149 turbines * 20 labels per turbine, plus adding a 200' climb per turbine means a pretty big effort, so I made a decision to perform the analysis so I would never have to come back and make changes unless there has been a significant electrical change. To address this I ended up multilplying the arc flash boundary by 125%, then rounding up to the nearest foot. Usually the arc flash boundary for a particular voltage and category seem to differ by a foot or two so I'd pick the highest arc flash boundary in that voltage and PPE category and put that on all the labels in that cateogry. This ensures small changes in available fault from the utility will not require major label changes - plenty of redundancy built in. The arc flash boundary is almost irrelevant anyway in a small space like the nacelle of a wind turbine.

Casey


Top
 Profile Send private message  
Reply with quote  
 Post subject: Re: NFPA 70E, Major Modifications and New Arc Flash Labels
PostPosted: Tue Oct 20, 2015 12:28 pm 
Offline
User avatar

Joined: Thu Jan 29, 2015 12:40 pm
Posts: 13
Take a look at the current PPE being used. Is it grossly underrated for the calories shown under the new study? If so, you should probably update the label to avoid burn injury.


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 4 guests


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