Arc Flash Calculations
It looks like the new 2008 NFPA 70E might be putting more weight on calculations. I understand as drafted, the labels require either the PPE to be listed or the calculated incident energy.
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| Author: | TRF2000 [ Fri Jul 06, 2007 8:19 am ] |
| Post subject: | OSHA Arc Flash Study Requirements |
We have been trying to figure out where OSHA says you have to perform an arc flash study. Is this requirement actually in there? |
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| Author: | JoeB [ Fri Jul 06, 2007 8:32 am ] |
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OSHA and Calcs. It's a bid convoluted. OSHA talkes about PPE that is appropriate but stops short of giving detals. It refers to concensus standards such as NFPA 70E. 70E gives a few options. 1 is to use hazard risk tables for selecting PPE subject to footnotes in the tables that define limits of short circuit current and clearing time. Method 2 is to calculate the incident energy for PPE selection. Right now, IEEE 1584 is the calculation method that people use when conducting studies. |
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| Author: | Grunge28 [ Sun Aug 05, 2007 2:39 pm ] |
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Arc Flash Calculations It looks like the new 2008 NFPA 70E might be putting more weight on calculations. I understand as drafted, the labels require either the PPE to be listed or the calculated incident energy.
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| Author: | ARC_Dave [ Mon Aug 06, 2007 10:32 am ] |
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Required, yes! The 29CFR1910.132 requires that employers assess hazards in the workplace, and make appropriate PPE for those hazards available to workers. Any hazard. The implication, then, is that electrical hazards must be assessed, and the present industry accepted assessment is arc flash hazard analysis. There is even a press release by Richard Terrill of the US Department of Labor that says companies that perform an arc flash analysis will be deemed in compliance with the OSHA requirement for hazard assessment. We presently offer this service to our customers, and the label format we use has a matrix that indicates which articles of clothing constitute the level of PPE indicated on the label. Everyone we have done this for thusfar is quite happy with them, and we're confident, based on what the NFPA is saying about the 2008 70E revision, that this label format will remain compliant. |
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| Author: | Kyle K [ Sat Sep 22, 2007 12:31 pm ] |
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Auuggg! Just when we begin to figure this out, it gets more complicated.
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| Author: | Gary B [ Thu Oct 18, 2007 7:23 pm ] |
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Also Referenced in NEC 110.16 Gary B |
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| Author: | davidr43229 [ Thu Nov 22, 2007 4:27 am ] |
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Quote: We have been trying to figure out where OSHA says you have to perform an arc flash study. Is this requirement actually in there? Arc Flash studies are not a requirement. However when the study is not preformed, the task tables must be used in the back of the NFPA-70E. Quote: Right now, IEEE 1584 is the calculation method that people use when conducting studies. There are 2 methods for calculating Arc Flash, while the IEE1584 is 1, the math in the NFPA-70E is different and shows different results. This is a great source of debate since different PPE is required by both results. Quote: It looks like the new 2008 NFPA 70E might be putting more weight on calculations
The revised NFPA-70E will be coming out in 2009, with additional Task tables and a revised version of Arc Flash, which reads: Flash Hazard. A dangerous condition associated with the possible release of energy caused by an electric arc. FPN No. 1: A 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. Per the FPN, the hazard is considered to exist if energized parts are exposed or a person is interacting with the equipment IN SUCH A MANNER TO CAUSE AN ELECTRIC ARC. Not all interaction with energized equipment will cause an electic arc. Need to be careful how this is interpreted. Racking a breaker certainly would fit the bill, but I don't think resetting a breaker would. Simply put......an Employee must wear the appropriate PPE to delatch or relatch the Equipment, regardless of covers, guards & shields. Additionally I hear that due to garment improvements, cotton underwear "maybe" removed from the Dupont clothing standard.Just my $.02 |
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| Author: | Pierre [ Sat Nov 24, 2007 9:13 pm ] |
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The Arc flash issues around us today are really creating quite the stir in our industry - the industry as a whole. It seems that the plants/factories.warehouse type of buildings are mostly getting a handle on the fact it has to become the culture of the way electrical work is to be done in the future. The construction end of the industry is way, way behind. The lack of proper training/enforcement of what has been learned is extrodinary. The lack of fines or the small fines has not made a dent in how these guys are dealing with the situation as of today. I am curious to see how it pans out. |
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| Author: | Sparky [ Thu Feb 07, 2008 6:38 pm ] |
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Arc Flash Calculations New to the forum so forgive my ignorance of the procedures ! I have been involved in issuing training of the 70E to fellow employees for approx. 1 year. Our interpetation is 130.3 requires a Flash hazard Analysis be performed. While 130.3 A indicates a Default Flash Protection Boundary for systems under 600 volts, systems over 600 volts must have calculations performed to determine this Boundary. While the last part of 130.B allows for the use of the PPE tables in lieu of calculations, there is no out for determining the Boundary. Therefore we are approaching it as using the default and tables for systems under 600 volts and madatory calculations be performed for systems over 600 volts. |
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| Author: | haze10 [ Fri Feb 08, 2008 2:29 pm ] |
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Sparky, check out NFPA70E Annex D Paragraph D5. Here they use the same Ralph Lee Equation that they cite in the guideline as only being good to 600V in a 4160V example. Since the equation is from Ralph Lee I guess we can also assume based upon Table D.2 that the equation is good to 230KV. |
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| Author: | Sparky [ Fri Feb 08, 2008 6:59 pm ] |
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haze 10 Great observation. A prime example of why our recommendation within our company is for calculations to be performed and performed only by competent, qualified parties. The 70 E in the wrong hands is a dangerous weapon ! If it is not considered mandatory to do calculations now, it won't be long before it is. |
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| Author: | Aaron [ Tue Apr 22, 2008 8:40 am ] |
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There is even a press release by Richard Terrill of the US Department of Labor that says companies that perform an arc flash analysis will be deemed in compliance with the OSHA requirement for hazard assessment Does anyone have a link to this release? I am having trouble finding it. Thank you, Aaron |
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