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 Post subject: HRC 0 Heavy Duty Leather Gloves
PostPosted: Wed Jun 20, 2012 11:41 am 
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According to the 2012 NFPA 70E Hazard Risk Categories and Task Lists (Table 130.7(C)(15)(a)), HRC 0 requires heavy duty leather gloves (As Needed) with a note attached that says 'If LV gloves with leather protectors are used, additional gloves are not required'. Personally, I dislike the term 'As Needed', as it adds a significant amount of ambiguity to the rule, especially since the legend uses the word 'optional' in brackets. In a phone conversation I had with an NFPA 70E representative, I asked for clarification as to when HD leather gloves are required and his reply was that the note explains that they are required whenever LV gloves with leather protectors are not required. I asked him why the AN was there at all if that is the case, as it should just say 'see note 1' instead of '(AN)(See Note 1)', but he kept reiterating that HD leather gloves were required whenever LV gloves were not required. So my first question is: Are companies using HD leather gloves for all HRC 0 tasks when applying Table 130.7(C)(15)(a)?
Looking into it further, I see that all other HRCs require some form of glove (HD or Arc-rated) and simply refer to Note 1 and drop the AN that is listed in HRC 0. Using the interpretation given above by the NFPA, why would these not have 'AN' attached as well? It seems to me that the 'AN' designation given to the HRC 0 is actually supposed to allow the reader to apply his or her judgement in whether HD leather gloves are required, which seems out of character for the NFPA when they have so clearly defined all of the other PPE and when to use it.

Next question: if using incident energy analysis, are you requiring HD leather glove use as part of Level 0 PPE? Obviously, if the incident energy is below 1.2 cal/cm2 at 18" working distance, that means the AFB is anywhere between 0.1" and 17.9". Therefore, in order to operate a Level 0 30A stand-alone disconnect switch your hand is probably going to cross the AFB unless it is a VERY low IE. If we are not allowed to account for the latched door, even at 4" your hand will probably cross the AFB during operation. In my eyes there are three options:
1) Label every switch individually and only require HD leather gloves when there is a possibility that your hand will cross the AFB.
2) Require HD leather gloves for all Level 0 PPE applications that do not require LV gloves with leather protectors
3) Create Hazard Analysis Risk Estimation, and Risk Evaluation using Informative Annex F in the 2012 NFPA 70E to decide if the task requires additional protection ie. does switch operation require gloves.

I would love some insight from the community as to how this is being handled.


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PostPosted: Thu Jun 21, 2012 4:10 pm 
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Gloves of some sort (leather or rubber) needed when an arc flash hazard exists. Some testing that was done showed that leather gloves work up to 8 cal/cm^2. There are "arc rated" gloves and for a while that was an option but further testing showed that virtually any voltage rated glove (rubber) gives adequate protection even over 40 cal/cm^2.

Yes, the incident energy at your hands is always well above the calculated incident energy level. The incident energy levels in IEEE 1584 are calculated based on exposure at the face/chest areas and the goal is to give you a 95% chance of SURVIVAL, not to give absolute protection. So at that point if you lose a hand or two, at least you are still breathing. Also, incident energy is calculated based on worst case so there's a significant probability that you have better than a 95% chance of survival.

Note: Don't get confused by that 50% ATPV stuff. IEEE 1584 testing used a complete test paradigm that included both failure rates of PPE AND uncertainties in the calculation.


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PostPosted: Fri Jun 22, 2012 4:59 am 
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Thanks for your response PaulEngr. I agree that gloves of some type are required for Levels 1 through 4 (based on the HRC guidelines in the NFPA 70E), but anything under 1.2 cal/cm2 (commonly referred to as level 0) is a different story. As you said, 1.2cal/cm2 is calculated at the face/chest, which is why we use a working distance of 18 inches. However, if the Arc Flash Boundary is only 3 inches, for example, your entire body is outside of the arc flash boundary and no PPE would be required. This would be fine, if all level 0 calculations had an AFB that low, but really it could be anywhere between 0 and 17.9 inches. The equipment would still be labelled as a level 0 hazard, but depending on the AFB you might need additional protection for the hands and possibly the arms. How are people dealing with this? Do you have several different categories for level 0 PPE? Example; at this switch you need gloves, this switch you need nothing, and this switch you need gloves plus additional PPE on your arms. Or do you just take the worst case AFB and apply that category of PPE to all Level 0 applications? Example; you have 10 Level 0 switches with an AFB of 16" (hand and arm protection) and 200 level 0 switches with an AFB of 3" or less, do you require 'worst case' level 0 PPE (hand and arm protection) at all 210 level 0 switches to avoid confusion?
How are most companies dealing with 'Level 0 PPE' (Incident Energy less than 1.2cal/cm2) with respect to PPE enforcement and labelling?


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PostPosted: Fri Jun 22, 2012 10:10 am 
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Just off the top of my head, I would think that the point of having different levels would imply incorporating a uniform minimum set of standards for each level. From what I have read on the subject, if it is a level 1, you need to have PPE for the maximum incident energy for level 1 to be in compliance. I would presume that the same goes for level 0. Or am I missing something?


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PostPosted: Sat Jun 23, 2012 3:41 am 
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m_cmbl wrote:
How are people dealing with this? Do you have several different categories for level 0 PPE? Example; at this switch you need gloves, this switch you need nothing, and this switch you need gloves plus additional PPE on your arms. Or do you just take the worst case AFB and apply that category of PPE to all Level 0 applications?


Yes, that is how it's done. Consider the pathetically low melting temperature for Rayon and nylon. You'd be better off working naked than wearing that stuff around electrical equipment. We do not require gloves for <1.2 cal/cm^2 work. They are simply recommended and we explain why the chart "stops" at 1.2 cal/cm^2, which recommends a long sleeve shirt and gloves. Frankly I recommend TIG gloves. They are both fire retardant, meet the leather requirement, and are thin enough to have plenty of dexterity when working on electrical parts.


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PostPosted: Mon Jun 25, 2012 7:12 am 
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PaulEngr wrote:
Yes, that is how it's done. Consider the pathetically low melting temperature for Rayon and nylon. You'd be better off working naked than wearing that stuff around electrical equipment. We do not require gloves for <1.2 cal/cm^2 work. They are simply recommended and we explain why the chart "stops" at 1.2 cal/cm^2, which recommends a long sleeve shirt and gloves. Frankly I recommend TIG gloves. They are both fire retardant, meet the leather requirement, and are thin enough to have plenty of dexterity when working on electrical parts.

Don't forget the shock protection part of the equation. We have trouble at our plant with people focusing on the arc flash portion and forgetting about the shock protection component.


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PostPosted: Mon Jun 25, 2012 7:54 am 
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Comments;
70E-2012 Rayon is listed along with wool, cotton and silk as a natural fiber, permitted in category 0. Nylon is not permitted.

The tables also distinguish between door open and door closed (for operating a CB). They show door closed as a H/RC lower than door open.

In the tables in some applications I see that opening hinged covers is a H/RC 0 and in the same table thermography or other non-contact inspection is a category 1. huh. So you can open the door, but not look at anything without cat 1 ppe? Also, I have always used TIG gloves when I use gloves for work other than shock hazard. However, operating an infrared camera with any gloves is next to impossible.


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PostPosted: Wed Jun 27, 2012 1:19 pm 
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PaulEngr wrote:
We do not require gloves for <1.2 cal/cm^2 work. They are simply recommended and we explain why the chart "stops" at 1.2 cal/cm^2, which recommends a long sleeve shirt and gloves.

Are you using the HRC tables in the NFPA 70E, or are you using IE analysis? I'm assuming you're using IE analysis since you reference the 1.2cal/cm2 boundary, which is a calculated value. Article 130.5(B)(1) of the 2012 NFPA 70E states: 'Recognizing that incident energy increases as the distance from the arc flash decreases, additional PPE shall be used for any parts of the body that are closer than the distance at which the incident energy was determined'. To me, this speaks almost exclusively to Incident Energy calculations that are <1.2cal/cm^2, since all of the other levels require some form of glove as a basic PPE. I understand that most Level 0 tasks with exposed energized parts would require LV gloves anyway, but I'm more concerned with switch operation. If your hand crosses the AFB during switch operation (ex. AFB is 10"), doesn't the rule listed above require additional protection for the hands? It would be a different story altogether if we could account for the equipment doors being closed during switching, but there is no consensus that it will add protection, and worst case is generally applied.
Out of curiosity, what justification do you have for NOT using gloves for <1.2cal/cm^2 work? Did you complete a risk analysis?
I used to tell people that the standard was created to prevent loss of life, and that limbs were 'expendable' in the eyes of the NFPA (hence the 18" working distance), but the rule above indicates that this is not the case. I certainly don't want to force glove use for all switch operation, as I don't believe the risk of creating an arc flash while operating a well-maintained Level 0 switch with the doors closed and latched is very high, but I'm pretty sure a risk analysis is the only way to prove that.


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PostPosted: Wed Jun 27, 2012 5:11 pm 
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Quote:
Out of curiosity, what justification do you have for NOT using gloves for <1.2cal/cm^2 work? Did you complete a risk analysis?


Yes.

We also have one breaker where the entire PLANT is within the arc flash boundary.


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