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 Post subject: PPE Category/Incident Energy Hybrid Method??
PostPosted: Thu May 24, 2018 1:09 pm 

Joined: Thu May 24, 2018 11:03 am
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After reading the relevant sections of 2018 70E, I'm fairly certain of the answer to this. Still, I need the collective experience/knowledge of this forum.

I must choose one method for selection of PPE, the Incident Energy or PPE Category method per 130.5(F). It has been suggested to me that a valid approach would be to choose a category of PPE based upon a software-calculated incident energy analysis, which yields a number in cal/cm2. The label would not have the incident energy on it, but would have a PPE category on it. Further, it has been suggested that a site-specific determination could made such that only category 2 (<8.0 cal/cm2) and category 4 (8.0 cal/cm2 and greater) PPE would be used, and energized work is prohibited for > 40cal/cm2.

For example, the software tells me that for Bus A, the incident energy is 9.2 cal/cm2. Per the criteria above, that number would generate a label, attached. The Arc Flash Boundary blank would also be populated with the distance given from the software analysis.

Is this approach permitted by 2018 70E? Kindly include references to 70E when you give feedback, if you are able.


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 Post subject: Re: PPE Category/Incident Energy Hybrid Method??
PostPosted: Fri May 25, 2018 6:05 am 
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jperry wrote:
After reading the relevant sections of 2018 70E, I'm fairly certain of the answer to this. Still, I need the collective experience/knowledge of this forum.

I must choose one method for selection of PPE, the Incident Energy or PPE Category method per 130.5(F). It has been suggested to me that a valid approach would be to choose a category of PPE based upon a software-calculated incident energy analysis, which yields a number in cal/cm2. The label would not have the incident energy on it, but would have a PPE category on it.


That's almost correct. The standard states that you can have a PPE level (using the current terminology) determined as per the table method or an incident energy (using a user-supplied method...software is one option), but not both since using both would be mixing and matching methods. That's not to preclude a site from using their own categories but if for instance in the future you start supplying PPE with different (higher) ATPV ratings, you'd have to redo all your labels where if you just put the incident energy on it, it's a much simpler system to maintain. You can go ahead and call the categories whatever you want a long as you don't call them "H/RC" or "PPE Levels" because those terms are "taken" and the values can be whatever you want, but I'd suggest sticking with the standard which states that incident energy goes on the label.

There is another very good reason for doing this. Say a lineman comes into your plant and has a knit FR shirt on that only has an ATPV of 6 but your sticker states a minimum of 8, and the actual incident energy might be 5. See the problem? The lineman has to go find 8+ rated PPE but is wearing a shirt that meets the requirement. As soon as contractors come into the mix, you'll find that although you might support and stock a 2 level system, you really should just use incident energy for the actual labels. It avoids a ton of issues.

Quote:
Further, it has been suggested that a site-specific determination could made such that only category 2 (<8.0 cal/cm2) and category 4 (8.0 cal/cm2 and greater) PPE would be used, and energized work is prohibited for > 40cal/cm2.


There is no upper limit except the limit established by your PPE. There is PPE on the market with an ATPV over 100 (Oberon makes it). Work cannot and should not be "prohibited". It causes all kinds of problems using that approach from a very practical point of view. Instead we need to be clear that work is restricted to certain activities...those where the task is unlikely to cause an arcing fault. For instance operating equipment that is properly maintained has only a very remote chance of causing an arc flash as stated in 70E so PPE would simply not be necessary for operating the equipment under the table-based method. You can't just stick a label on the cabinet. You MUST analyze the tasks to be performed and the risk associated with them and whether or not PPE is needed as per OSHA. Risk assessments are not when the guys walk up and tick off a bunch of check boxes and pencil whip it. They are done in a formal setting with a team of experts looking at the tasks to be performed. It's pretty simple to figure this out because 70E as well as OSHA (1910.269 annexes) provides convenient task charts as examples. You just need to make it site specific. That addresses clear and obvious problems (doors are blown off or soot marks everywhere) but it does not address the risk assessment that is done in the office deciding what tasks have risk and which don't. It has been stated several times in the responses to public inputs on 70E that just walking by does not pose a risk. The first table in the current edition of 70E addresses risk and the other two tables establish the PPE level and finally the specific PPE required. You've skipped a step.

Quote:
For example, the software tells me that for Bus A, the incident energy is 9.2 cal/cm2. Per the criteria above, that number would generate a label, attached. The Arc Flash Boundary blank would also be populated with the distance given from the software analysis.

Is this approach permitted by 2018 70E? Kindly include references to 70E when you give feedback, if you are able.


Typical arc rated work shirts have an ATPV of at least 10 although some of my very old ones had 8.6. Pants are at least 10-14. Face shields are similarly around 12. In the utility industry (I'm assuming that's why you chose 2 cal/cm2 as the cutoff) OSHA sets up 12 cal/cm2 as a sort of standard boundary so there is pressure on PPE manufacturers to upgrade to ATPV 12 compared to the old ATPV 8 cutoff from almost 20 years ago so establishing a cutoff of 8 cal/cm2 if it's internally generated seems awful low.

70E not only supports but encourages a "2 level" PPE system in one of the annexes. Annex H specifically addresses PPE when you develop your own system.


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