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 Post subject: Effective means to mark Arc Flash Boundary
PostPosted: Tue Jul 10, 2012 10:18 am 
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I am currently working on a project to complete an arc flash study on our expansion units that have recently been implemented.

Aside from the calculations and labels that are required to be printed, I am exploring ways to mark arc flash boundaries in front of the equipment to increase awareness and ensure qualified personel are fully equiped with the proper PPE when entering beyond the marked point.

The most cost effective and effecient way in my mind is to use colored tape (red or orange) on the floor indicating where the boundary begins. My concern with this method is that a lot of the equipment below 600V are outside. The tape method only works for MCCs and switchgears indoors. Plus, this method is ideal in the event that the boundary is required to be changed in the future. I was once recommened painting the floor indicating the boundary, personally I don't think that is the best option.

I want to know your thoughts on this. What method would you recommend for marking arc flash boundaries (aside from the value on the label, ofcourse!)? And what are the pros and cons to that method? We would like to implement the most cost-effective yet effecient option.

Any feedback is appreciated.


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PostPosted: Wed Jul 11, 2012 6:46 am 
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What about using your layout drawing (either in the MCC Room, or Outdoor Panels) and sketching the boundry on them either by CAD or hand? Laminate and post with a note what the border represents. That way it should be relatively weatherproof and shouldn't fade too bad... If they can read it, and key measurements are noted it should be easy to figure out...
Just a thought..


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PostPosted: Wed Jul 11, 2012 7:49 am 
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Method of sketching the boundary on the MCC layout drawing is effective; however, for the panels outdoors, we do not have an accurate layout of each of the equipment since we have over hundreds of them.

Do you have any thoughts on actually creating a physical boundary both indoors and outdoors? I say this because a lot of times we have bystanders nearby while work is being completed on energized equipment. Having some sort of boundary will raise awareness for those folks without the proper PPE.

I just can't think of a way to implement a boundary for the outdoor panels.


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PostPosted: Mon Jul 16, 2012 9:34 am 
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Location: Plano,Texas
In my limited experience physical barriers are necessary and even they don't always work.

If it is outside and not all on a concrete pad then sink some pvc pipe in the ground at the boundary vertices and use it to shove some poles with netting zip tied them to control egress into your restricted/arc flash boundary. On concrete pads just paint the vertices and use weighted poles or poles with flanges and concrete achors.


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PostPosted: Mon Jul 16, 2012 10:23 am 
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I do not recommend spending the money to mark the arc flash boundary. Especially at this point in time when the IEEE 1584 Standards and equations are about to be updated. A new standard is scheduled for early 2013. The new standard and equations will most likely change the arc flash energy and boundary. NFPA 70E recently eliminated the default 48" arc flash boundary. Both NFPA 70E and IEEE-1584 Standards change periodically.
I would recommend spending the money on training and purchasing barrier tape and barrier stands or cones. If you educate the electricians and make it mandatory that they set up a barracad at the AF Boundary. This way, if the standards or your distribution system parameters change, then you will not have to go through your facility and change the boundaries.

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Robert Fuhr, P.E.; P.Eng.
PowerStudies


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PostPosted: Mon Jul 16, 2012 12:05 pm 
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I agree with Bob above.

I'd also add that the boundary is only applicable when there are exposed energized parts.


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PostPosted: Mon Jul 16, 2012 1:24 pm 
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I respectfully disagree with Matt's statement, "I'd also add that the boundary is only applicable when there are exposed energized parts." NFPA 70E has the following definition for Arc Flash Hazard. The term "interacting with" can mean opening or closing the switch or circuit breaker. I have seen several accidents where the interrupting device has failed when operated. If you do a search on the Arc Flash Forum for interacting with, you'll see that there has been a great deal of discussion and opinions.

Arc Flash Hazard. - A dangerous condition associated with the possible release of energy caused by an electric arc.

Informational Note No. 1: An arc flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.

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PostPosted: Mon Jul 16, 2012 8:50 pm 
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Ok. Does your company have an Electrical Safety Program? Within the ESP you should designate an "Electrical Work Zone" which will be the greater distance of the arc flash boundary or shock approach boundaries. Workplace electrical safety is more than arc flash.

After that I don't recommend painting any lines, this is not a "barrier." Occupational health and safety management system Standards like ANSI Z10 outline the preventive and protective control measures that must be considered and addressed in your "Safety Management System" in this case the Electrical Safety Program. They identify "Warning Signs and Barricading" as a priority over training, procedures and PPE.

You should use "Red" Danger - Authorized Personnel Only tape, portable plastic tape by the role provides maximum flexibiliy for establishing the Electrical Work Zone. You can also get plastic Stanchions with the red tape retracteable same as in airports or this can be ordered in a magnetic version which is easy to transport. You can actually get the magnetic retracteable in bolt on version and put them into your elecrical rooms permanantly. For the outside applications the Stanchions or plastic role of Red Danger tape are an option.

In many cases for electrical rooms that are smaller just use the man doors as the location where you put the "Red" Danger tape.

Sorry Bob I don't agree with your conservative interpretation of when an arcing fault risk is probable. We need to be carefully with this type of interpretation or the lighting panels in homes will be considered an "arc flash risk." Not true and not true for electrical equipment.

Normally approved energized electrical equipment installed to the NEC / CEC is safe to approach, stand in front, read meters/relays etc. Low voltage isolations require NO special PPE, and for high voltage I think it is conservative for branch circuits when the load is turned off, shouldn't open disconnects for breakers under load anyways. For Main Breakers, industry is trending to conservative approach given high incident energy on the line side, in many cases you will have to wear the arc flash suit you have (e.g. 65 cals when the IE is be much higher) to do the Main Breaker isolation as the Utility will not open their fused disconnects until they have this isolation, an evolution needs to occur here.

Back to the "barricading" as per OHSMS Standards, the painted line IS NOT a barrier and can be miss interpreted, as I mentioned above the arc flash boundary only exists when there is truly and arcing fault risk which can lead to an arc flash.

One last item we need the Qualified Electrical Worker to have competency in applying the practices, they need to complete shock and arc flash hazard analysis and then establish the Electrical Work Zone, with painted lines they will be complacent to "understanding" what the boundaries mean and the rules that apply to them.

I have the manufacturers listed in a document if you email me at terry.becker@espsi.ca.

Regards;
Terry Becker, P.Eng.
Owner, ESPS Electrical Safety Program Solutions INC.
(the name of my company is what I do)


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PostPosted: Thu Jul 19, 2012 2:24 pm 
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Robertefuhr wrote:
I respectfully disagree with Matt's statement, "I'd also add that the boundary is only applicable when there are exposed energized parts." NFPA 70E has the following definition for Arc Flash Hazard. The term "interacting with" can mean opening or closing the switch or circuit breaker. I have seen several accidents where the interrupting device has failed when operated. If you do a search on the Arc Flash Forum for interacting with, you'll see that there has been a great deal of discussion and opinions.
...


Bob,

Thanks for disagreeing with me so agreeably. Internet forums can get pretty harsh and I want to recognize and applaud your respectful tone. I stand corrected. I disagree with myself as well. Here's my revised statement.

I'd also add that the arc flash boundary is not always applicable but permanently applied floor tape could make it appear that the boundary always "exists". The boundary is not applicable when walking by the normally operating equipment, for example.


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PostPosted: Fri Jul 20, 2012 9:24 am 
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Hi all. In order to establish our Arc Flash Boundary that anyone inside must be in proper PPE, I am having a conflict to what needs to be in the boundary. For example, racking in or out a 480V or 6900V switchgear breaker, does the boundary need to extend from the breaker cubicle door, or end of the enclosed bus. Is it a circle from that enclosed bus or just in front of the breaker? Any opinions?


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PostPosted: Mon Jul 23, 2012 8:01 am 
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Robertefuhr wrote:
I respectfully disagree with Matt's statement, "I'd also add that the boundary is only applicable when there are exposed energized parts." NFPA 70E has the following definition for Arc Flash Hazard. The term "interacting with" can mean opening or closing the switch or circuit breaker. I have seen several accidents where the interrupting device has failed when operated. If you do a search on the Arc Flash Forum for interacting with, you'll see that there has been a great deal of discussion and opinions.

Arc Flash Hazard. - A dangerous condition associated with the possible release of energy caused by an electric arc.

Informational Note No. 1: An arc flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.


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PostPosted: Mon Jul 23, 2012 8:27 am 
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Location: washington
I also agree with Bob Fuhr-
The 2012 edition of NFPA 70 E Informative Annex C Limits of Approach states-
C.1.2 Qualified Persons, Safe Approach Distance.

C.1.2.1
[SIZE=2][font=Times-Roman]Determine the arc flash boundary and, if the[/font][/size]

boundary is to be crossed, appropriate arc-rated protective

equipment must be utilized.-
We have more than one Category "Dangerous" pirce of Equipment-Ranging from 77 to 125 Cal/CM In my opinion as well as the Engineering Firm that did our study-These areas of ,"System Deficiencies", represent immediate danger to equipment or personnel..
Our current operating procedure aks that workers take daily voltage and amperage readings in front of this equipment with only Safety glasses.
I have questioned whether this is a safe practice.I am waiting for a writtrn statement that states that it is.
In the intrest of worker safety as well as Engineerin reccomendations of the means to mitigate this hazard,I have the opinion that it is not. No PPE exists that will protect you from an equipment failure.It does not help that some of the Circut Breakers in these sections have been determined to be Defective through testing Twice.So all odds are off.
Your comments are welcome.


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PostPosted: Mon Jul 23, 2012 9:51 am 
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Brodie wrote:
I have questioned whether this is a safe practice.I am waiting for a writtrn statement that states that it is.


It is your company that must make this decision as part of your NFPA70E compliant Electrical Safe Work Practices program.

You really should perform a risk analysis.
If the workers, taking the reading, are simply looking at meters (i.e. not operating instrument switches) the likely hood of a flash occurring is pretty slim. What precautions do you take for your workers taking pressure readings near boilers? Do you make your workers wear respirators, as part of their normal PPE, when they are near ammonia based chillers?


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PostPosted: Mon Jul 23, 2012 10:10 am 
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Brodie wrote:
It does not help that some of the Circut Breakers in these sections have been determined to be Defective through testing Twice.So all odds are off.

Twice? Once wasn't enough? Or was it a different CB in the same section?


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PostPosted: Mon Jul 23, 2012 10:28 am 
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Same Circuit Breakers,Breakers were tested with Primary Current Injection,they are obsolete and exspensive to repair/replace.Still defective,has been determined to be a Bussiness Risk not a Safety Risk.

I think many times people have the impression that Arc Flash/Blast only occurs when interacting with the Equipment,this is not always the case.

Boilers etc,If well maintained,maybe no risk-145 Cals in a small area-Survival is doubtful.
Regardless of Company Interpretation-The Hierarcy of Risk Control would dictate to eliminate the task in consideration of the Hazard.
I consider my safety my bussiness,as I am the affected worker.

[font=Calibri] [font=Calibri] A recent 2.5 Million Burn Settlement involving an 80 year old piece of equipment was attributed to a Spontaneous Occurence.[/font][/font]


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