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 Post subject: 2018 70E 130.7 C(2) Hair & Beard Nets
PostPosted: Thu May 24, 2018 11:15 am 

Joined: Wed Jul 12, 2017 6:06 am
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Do hair and beard nets need to be arc rated if the incident energy is less than 1.2 calories? Previously it had to be made of non melting materials if less than 1.2.


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 Post subject: Re: 2018 70E 130.7 C(2) Hair & Beard Nets
PostPosted: Fri May 25, 2018 5:42 am 
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ewbengineering wrote:
Do hair and beard nets need to be arc rated if the incident energy is less than 1.2 calories? Previously it had to be made of non melting materials if less than 1.2.


As of the more recent editions of 70E, there is no PPE requirement below 1.2 cal/cm2. So, no by the letter of the way it is written.

Under previous editions, 70E states that an "incidental" amount of meltable materials is acceptable such as underwear and sock elastic and name tags. Whether or not a hair/beard net is "incidental" or not is something of a judgement call.

70E also makes exceptions for PPE that addresses other risks. A respirator for instance is worn to address a hazard that is likely as opposed to an arc flash which is rare so 70E is very clear that given a choice between wearing FR PPE and some other PPE such as a respirator, wear the other PPE. I would think that the hair and beard nets would fall into the same category of taking priority over arc flash concerns.

So even though 70E dropped it, does that mean you should drop it, too? Let's consider the reason for the nonmeltable policy in the past and whether or not it should be retained.

First off the reason it was dropped and this is as Al Havens the guy that put in the change is that clothing is not PPE. 70E addresses PPE, not clothing. So if it's clothing it shouldn't be in there. The old "PPE 0" (which is not PPE) rule caused all kinds of political and practical problems so getting rid of it made a lot of sense.

From more of a technical point of view there is published testing on natural (T-shirt) and synthetics that shows that up until it either chars or melts untreated materials provide an ATPV of about 10. This is intuitively clear. A cotton FR treated work shirt typically has an ATPV of around 10. The "thermal" (ATPV) rating is entirely due to the natural thermal insulative properties of the base material, not the fire retardant treatment. These are published on IEEE Xplore. The price is fairly steep from IEEE for prints unless you have a subscription or a library card at a university library that subscribes but you may be able to obtain a preprint from the folks over at E-Hazard that actually did the testing and published the articles if you need documentation.

Once we exceed that rating, that's where things change. FR materials still burn but they immediately extinguish when the source of heat is taken away so there is no further injury from anything other than the direct application of heat (arc flash). The non-FR materials behave a little differently. Nonmeltable materials can char and sometimes burst into flame. Meltable materials soften and melt and also can burst into flame. Unlike FR materials the flames don't immediately extinguish. The melting and flames adds to the thermal load on the material and increases the injury. Nonmelting materials may char but will not ignite if they are behind an outer FR layer that is rated (ATPV) for the arc flash (incident energy).

So going back to your concern. IEEE 1584 which is behind 70E in terms of incident energy establishes the potential incident energy at the fair/chest area of a victim. So for instance with someone working on an energized panel with a screwdriver, obviously their hands and arms are much closer and the incident energy is higher. In that circumstance obviously a "nonmeltable clothing" policy would be very appropriate because for instance an insulated winter long sleeve polypropylene shirt might melt or catch on fire if an arc flash occurred even though the incident energy is under 1.2 cal/cm2 as measured at the face/chest area compared to the wrists and arms. Clearly the "cutoff" for the long sleeve shirt is more like an ATPV of 8-10 but there are no established rules or standards for boundaries other than at the face/chest area, and nonmeltable clothing is required when it is worn as underlayers underneath FR PPE anyways, so the "nonmeltable clothing" rule just makes all kinds of good practical sense even though it is clearly overly conservative.

On the other hand, hair and beard nets are at or behind the arc flash boundary at the face/chest area, so the calculated incident energy would apply here. The fact that they actually have a higher rating than 1.2 cal/cm2 (which is really intended for bare skin) suggests that there is some "wiggle room" and that not requiring nonmeltable hair/beard nets makes sense as long as the exposure is under 1.2 cal/cm2. Once we go above that then the "underlayer" rule applies and it needs to be nonmeltable at a minimum.

So in summary, regardless of the edition of 70E there were already 2 exceptions established for "incidental" materials and other than arc flash PPE. The change to eliminating nonmeltable clothing might deserve reconsideration for underlayers as well as long sleeve clothing regardless of whether 70E accepts it or not but when it comes to articles of clothing that would only be worn in the face/chest area and not as underlayers such as hair and beard nets, an FR or nonmeltable exception has a lot of merit to it.


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 Post subject: Re: 2018 70E 130.7 C(3) Hair & Beard Nets
PostPosted: Fri May 25, 2018 6:39 am 

Joined: Wed Jul 12, 2017 6:06 am
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Thanks for the informative response. The last line of 130.7 C(3) in 2018 states hairnets or beard nets they must be arc rated, so that is what is confusing as it doesn't say its optional below 1.2 calories. I personally would struggle making the judgement call of those items being under the incidentals. Maybe the hairnet if wearing a hard hat, but I always took that incidentals statement to refer to under clothes not something I am wearing on my face which is an exposed outer layer.


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 Post subject: Re: 2018 70E 130.7 C(3) Hair & Beard Nets
PostPosted: Sat May 26, 2018 4:35 pm 
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ewbengineering wrote:
Thanks for the informative response. The last line of 130.7 C(3) in 2018 states hairnets or beard nets they must be arc rated, so that is what is confusing as it doesn't say its optional below 1.2 calories. I personally would struggle making the judgement call of those items being under the incidentals. Maybe the hairnet if wearing a hard hat, but I always took that incidentals statement to refer to under clothes not something I am wearing on my face which is an exposed outer layer.


Nothing is required below 1.2 cal/cm2.


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 Post subject: Re: 2018 70E 130.7 C(2) Hair & Beard Nets
PostPosted: Thu May 31, 2018 8:28 am 
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Sorry, I'm seeing some scary answers here. There is no established safe IE level for non-FR synthetics. Incidental refers to a few threads in an otherwise non-melting fabric. And if you fail to see a specific requirement in OSHA or NFPA, look to the General Duty clause in OSHA. If there is a possibility of arc flash of any level, clothing needs to be non-melting.


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 Post subject: Re: 2018 70E 130.7 C(2) Hair & Beard Nets
PostPosted: Thu May 31, 2018 3:13 pm 
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stevenal wrote:
Sorry, I'm seeing some scary answers here. There is no established safe IE level for non-FR synthetics. Incidental refers to a few threads in an otherwise non-melting fabric. And if you fail to see a specific requirement in OSHA or NFPA, look to the General Duty clause in OSHA. If there is a possibility of arc flash of any level, clothing needs to be non-melting.


Sorry but you have to have some kind of lower cutoff and that has been clearly established at 1.2 cal/cm2 by 70E and 2 cal/cm2 by OSHA for 1910.269. Below that level, no PPE is required. Clothing is not PPE.

Furthermore, it is pretty clear that when choosing between PPE for ANY OTHER PURPOSE than arc flash, arc flash is subordinate to those requirements. That's in 70E. There is nothing scary about this.

Second, the amount of incidental material is not defined. I submitted a public input to set a specific amount (square inches). It was rejected. So the 70E Committee obviously doesn't care either.


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 Post subject: Re: 2018 70E 130.7 C(2) Hair & Beard Nets
PostPosted: Tue Jun 05, 2018 9:32 am 
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PaulEngr wrote:


Sorry but you have to have some kind of lower cutoff and that has been clearly established at 1.2 cal/cm2 by 70E and 2 cal/cm2 by OSHA for 1910.269. Below that level, no PPE is required. Clothing is not PPE.


In 1910.269, the lower limit is clear: non-melting.

OSHA wrote:
The employer shall ensure that each employee who is exposed to hazards from flames or electric arcs does not wear clothing that could melt onto his or her skin or that could ignite and continue to burn when exposed to flames or the heat energy estimated under paragraph (l)(8)(ii) of this section.

Note to paragraph (l)(8)(iii) of this section: This paragraph prohibits clothing made from acetate, nylon, polyester, rayon and polypropylene, either alone or in blends, unless the employer demonstrates that the fabric has been treated to withstand the conditions that may be encountered by the employee or that the employee wears the clothing in such a manner as to eliminate the hazard involved.


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