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 Post subject: 2005 DRAFT OSHA regulations
PostPosted: Mon Oct 06, 2014 2:25 pm 

Joined: Wed Nov 12, 2008 10:26 am
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Location: CA
Is anyone familiar with “2005 DRAFT OSHA regulations” to analyze arc flash hazards?


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Mon Oct 06, 2014 4:49 pm 
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Not sure why there would be 2005 Draft OSHA Regulations when OSHA has released new regulations for the utilities for arc flash and a lot information can be gotten from that.
My understanding is that OSHA will regulate what the safety is but not tell you how to accomplish that. They defer to standards.


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Tue Oct 07, 2014 9:47 am 
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There was no standard in 2005 other than the general duty clause.

There is a new version of 1910.269 that takes effect now and the arc flash engineering study is supposed to be completed in 2015.

Below 250 V all we have is some test work. None of the models are very accurate partly because it is prohibitively hard to create a stable arc below 250 V.

From 250 V to 10 kV OSHA recommends IEEE 1584 as do most others.

From 10 kV up, OSHA does not mandate but suggests that ArcPro software is the best option. Duke heat flux looks suspicious at best. IEEE 1584 does not work at least above 15 kV, and Lee method severely overestimates.

EPRI is working on developing models for "long" arcs such as at transmission voltage levels but so far there are no results.


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Tue Oct 07, 2014 8:36 pm 

Joined: Wed Nov 12, 2008 10:26 am
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Location: CA
I asked about the “2005 DRAFT OSHA regulations” because our local utility cited that as the basis for their AF hazard analysis of a 60kV substation next to a middle school playground. See below. I could find no references to that OSHA regulation on the internet.

The utility recently installed a static var compensator and four very large 'sound absorbing' walls around the substation perimeter. I suspect that the walls will contain and deflect any arc flash or explosion. But I would still like to see their calculations.

Before I get back to them for more info, I wanted to check with the experts. Thanks for your comments.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From XXX:
“We at XXX appreciate and welcome the concerns and questions in regards to arc-flash. At XXX, Employee and Public safety is our top priority. … It is with this in mind that XXX completed arc-flash hazard analysis for XXX substations on a system wide basis based on the 2005 DRAFT OSHA regulations.

At YY substation the arc-flash hazards are limited to the areas inside the substation perimeter fence. As all new equipment being installed as part of this project is located inside the perimeter fence, there is no change in the arc-flash hazards to the public. While the sound wall’s main purpose is for sound absorption/deflection, it will also serve as an added protection from any potential arc-flash.”


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Thu Oct 09, 2014 5:38 am 
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PaulEngr wrote:

From 250 V to 10 kV OSHA recommends IEEE 1584 as do most others.

From 10 kV up, OSHA does not mandate but suggests that ArcPro software is the best option. Duke heat flux looks suspicious at best. IEEE 1584 does not work at least above 15 kV, and Lee method severely overestimates.


Actually OSHA's Table 3 Selecting A Reasonable Incident-Energy Calculation Method has:

IEEE 1584 for 600V and less for Single and Three phase open air arcs & arcs in a box and 601V to 15kV for Single and Three phase open air arcs & arcs in a box

ArcPro for 600V and less for single phase open air arcs and 601V to 15kV for single phase open air arcs

Above 15kV only ArcPro is noted for single and three phase open air arcs and arcs in a box with three phase arcs in a box using the ArcPro multiplier.


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Tue Oct 14, 2014 10:53 am 
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Those are not usually "sound proofing". They are electrically insulated barriers so that someone working on one section of the equipment is protected from energized parts on another section. The only time I've seen sound proofing is around transformers to try to reduce the noise ("buzz") to meet local noise ordinances but that's usually an actual enclosure not just a sheet of material.


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Mon Oct 20, 2014 11:18 am 
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The 2005 Draft has been superceded by the new standard but AF Calculations are not to be implemented until Jan 2015 so if they are using 2005 DRAFT, they are ahead of the game but the calculations could be different since the new standard would recommend a table or using ArcPro.


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Fri Nov 21, 2014 2:00 pm 

Joined: Wed Jun 24, 2009 4:45 pm
Posts: 41
Location: WA State
ZeroSeq wrote:
Is anyone familiar with “2005 DRAFT OSHA regulations” to analyze arc flash hazards?


For the detailed history, refer to the discussion provided in the Federal Register related to the newest regulations.
http://www.gpo.gov/fdsys/pkg/FR-2014-04-11/pdf/2013-29579.pdf

"OSHA published a proposed rule (the subpart V proposal) on June 15, 2005 (70 FR 34822)."


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 Post subject: Re: 2005 DRAFT OSHA regulations
PostPosted: Mon Nov 24, 2014 10:11 am 
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Certainly the draft provided no specifics on how to handle barriers in a calculation. It sounds like the utility ignored the barrier and found the arc flash boundary was inside the perimeter even without the wall.

Seems to be some mixing of the codes here. OSHA is about safety in the workplace, not public safety. NESC Part 1, is about public safety for these installations. The hazard here is not a random arc flash getting through the wall, it is a the kid trying to retrieve a ball getting in.


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