NFPA 70E arc flash hearing PPE

[stevenal]

The 2009 70E standard, while not available for delivery yet, is however, viewable at

http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70e

I see that the requirement for hearing protection (Table 130.7(C)(10) has dropped two levels to risk category 0. In 2004 is was at 2, then went to three for the preprint proposal. This was never had an AR designation, so I assume the protection is for the sonic effect of a possible arc. Do you agree? Why is it the target moving around so much? And are not the insert style protectors melt-able and likely to contribute to injury?

Thanks.

 

[Zogzog]

I have the 2009 70E sitting on my desk, got it about 3 weeks ago. I also noticed the hearing protection is in the FR PPE catagory, wonder if they need to be FR? Dont think so, because they would be covered by a head sock or flash suit hood but I am not sure on that. Cant find any guideance in the standard.

 

[stevenal]

Guess it the handbook I'm waiting on.

Most of the stuff listed under FR equipment is not arc-rated. I agree that the inserts would normally be covered by a face shield, sock, or hood. But risk category 0? Our worker has mad sure he is wearing no melt-able fabric, then sticks plastic foam in his ears?

 

[dpc]

It's an interesting question. I don't recall ever seeing any guidance on FR rating of ear canal inserts.

It's a work in progress - as always....

 

[stevenal]

I did a little more pouring over

http://www.nfpa.org/assets/files/PDF/ROP/70E-A2008-ROP.pdf

Seems a proposer had an article showing category 0 arcs exceeding the OSHA impulse level of 140 dB. The committee rejected his proposal twice, but I guess it made the cut further into the process. No consideration to how hearing protection might contribute to injury could be found in the document.

There is at least one hearing protection product that is geared toward arc blasts. No mention of FR or arc ratings in any of it's literature.

To add to the confusion, it was suggested that the X under category 2 in the '07 70E was in error along with the reference to note 8.

 

[stevenal]

Update:

Seems e-hazard has done some testing. The yellow foam (don't use red) will not sustain a flame, and they won't fuse into the ear canal as I feared. A little bit of melting at the exposed end can occur, and they are still removable afterward. Doesn't neet NFPA, but it's all we got.

 

[wbd]

Is the yellow foam the same across all brands or was a specific brand tested?

 

[Zogzog]

If you are wearing all of the proper PPE the hearing protection wont be exposed to the arc flash. Thats why there is not a FR requirement for them.

 

[stevenal]

wbd,
I believe a sampling of brands was tested, with similar results.
Zog,
HRC 0 does not require any PPE over the plugs, such as as an FR face shield or balaclava. The table lists the hearing protection under "FR Protective Equipment."

 

[Zogzog]

And HRC 0 is for Ei's less than 1.2cal/cm2, the plugs wont melt. As far as the section they were placed in the tables, where else would they put them?

 

[stevenal]

Zog,

At HRC 0 and higher, one is forbidden from wearing meltable articles. E-hazard's testing confirms that they do melt, although minimally.

I don't know where they should be put, but the presently available plugs cannot be considered to be FR. NFPA seems to have got in front of the manufacturers and ASTM by requiring a protective item that does not yet exist.

 

[Zogzog]

"NFPA seems to have got in front of the manufacturers and ASTM by requiring a protective item that does not yet exist"

They exist, just not widely available. I will talk to the ehazzard owner on Monday and get more info on the testing.