Underwear as PPE for Arc Flash

[lile001]

I have seen the arc flash protection suits for Category 2 through 4 and up , for example those sold by OBERON MFG They look like moon suits.

There is a chart in NFPA 70E that is very misleading, it seems to be very specific about what kind of underwear you need for various categories of arc flash protection, but the idea I come away with after reading this chart doesn't look very much like Oberon co's Moon Suits. It does not mention, for instance, obvious items like safety glasses, face shields, gloves, or how much of the body needs to be covered.

What, specifically, does one need to wear for category 0 and category 1 PPE for arc flash protection?

 

[ron]

Re: Underwear as PPE for Arc Flash

If you have access to 70E, look at
Table 130.7(C)(10) Protective Clothing and Personal Protective Equipment (PPE) Matrix
Be sure to also refer to the notes at the bottom of the matrix. It identifies what is needed for all categories.

[ July 22, 2005, 11:31 AM: Message edited by: ron ]

 

[jim dungar]

Re: Underwear as PPE for Arc Flash

Look at NFPA 70E 130.7(12) Factors in Selection of Protective Clothing. Basically it says that meltable fabrics shall not be worn touching skin. There is an exception for things like elestic waistbands.

Arc-flash PPE clothing is done in layers. There are several ways to get layers; put on multiple items like two pair of coveralls, or use a single multi-layered product. A true "moon suit" is only required for Category 4 and must be worn over other FR layers.

 

[lile001]

Re: Underwear as PPE for Arc Flash

Ah! Finally got my hardcopy of NFPA 70E in the mail. I wish they could put all this stuff in one chart in plain English!

Let's see if I am reading this right:

130.7(C)(10) seems to indicate that appropriate PPE for Category 0 is:

A long sleeve cotton shirt
Long Pants
Safety Glasses

But then 130.7(C)(11) (the underwear table) adds that these clothes need to be 4.5 oz/yd and made of cotton or a list of other nonmelting fabrics, 1 layer required.

Category 1 seems to be:
regular Blue jeans or FR pants arc rated 4 cal/cm
Long shirt rated 4 cal/cm
Hard Hat
Safety Glasses
1 layer of clothing required
Gloves and boots as needed (when would you not need leather boots?)

Still not too tough

Category 2 is getting more difficult
Cotton underwear (briefs or boxers)
Short sleeve undershirt cotton
FR shirt and pants rated 8 cal/cm
Hard hat
Safety glasses or goggles AND arc rated face shield
Leather gloves
Leather boots
1 or 2 layers required (except underwear is required by table 130.7(C)(11) so I can't see how 1 layer is allowed.)

(I wonder how many electricans work "commando style" i.e. no underwear?)


Category 0, 1, and 2 cover most of the situations I am likely to run into as an Engineer - the most extreme being "working on live parts - voltage testing" in 480 volt equipment.

Anybody got a different understanding of these requirements?

 

[ryan_618]

Re: Underwear as PPE for Arc Flash

Guys, I hate to do the moderator thing, but unless you have something to say about PPE, please don't tell me what kind of underwear (or lack thereof) that you wear or don't wear.

 

[ron]

Re: Underwear as PPE for Arc Flash

How do you know that Category 0-2 will cover "working on live parts - voltage testing" in 480 volt equipment. Be sure and read the notes at the bottom of the chart and realize that many installations may not fall into those fault current and OCPD clearing time ranges. If they are not in those ranges, the chart is useless. When looking at the notes be sure to get the latest change at the NFPA website.

 

[lile001]

Re: Underwear as PPE for Arc Flash

Originally posted by ron:
How do you know that Category 0-2 will cover "working on live parts - voltage testing" in 480 volt equipment. Be sure and read the notes at the bottom of the chart and realize that many installations may not fall into those fault current and OCPD clearing time ranges. If they are not in those ranges, the chart is useless. When looking at the notes be sure to get the latest change at the NFPA website.

I wish there was a more straightforward explanation of this - I've spent quite a bit of time trying to figure it out, and don't seem to get it quite yet. How is a normal electrician supposed to figure this out, let alone an employer? Until PPE signage is posted everywhere, it is just guesswork for an electrician.

So the hazard/risk catagories in Table 130.7(C)(9)(A) don't really apply to real world situations except in specific cases. No?

Arc flash calcs, I suppose, would define the risk catagory and then you could pick PPE off of table 130.7 (C) (11) and (10). I'm the poor schmo that has to inspect the equipment in order to get the info to do arc flash calcs in the first place, and of course if they have not been done, nobody really knows what kind of PPE to wear. Catch-22 again!

A photo of a guy wearing the type of PPE typical for catagory 0, 1, 2, 3 and 4 would REALLY be helpful, esp. in the Code handbook.

[ July 28, 2005, 07:07 PM: Message edited by: lile001 ]

 

[AK_Engineer]

Re: Underwear as PPE for Arc Flash

lile001

Don't give up!

Understanding takes time and a lot of conversations! Relax, put some good ole' tunes on get into the groove, slow down . . .

Now to help you understand. A normal electrician is supposed to understand that proper PPE is required to do the job, know how to care for that PPE and be qualified to perform the task assigned.

The electricians employer needs know if the electrican is qualified, and to communicate to the electrician, the hazards of the task involved.

Equipment labeling (if present) will state that an ARC FLASH HAZARD exists, or it may state the potential hazard and MAXIMUM PPE required for protection.

Table 130.7(C)(9)(A) does apply if all conditions are met. In our facilities, it was decided that if we determined OUR conditions, we have just about completed an Arc Flash Hazard analysis.

I'm the poor schmo that has to inspect the equipment in order to get the info to do arc flash calcs in the first place, and of course if they have not been done, nobody really knows what kind of PPE to wear. Catch-22 again!

To break this cycle we implemented interum PPE requirements for gathering INFO. This deals mainly with opening doors, not doing troubleshooting or repair.

Hang in there! Your concerned and approaching the issue correctly.

Remember, NOBODY GETS HURT!

Dave

 

[jim dungar]

Re: Underwear as PPE for Arc Flash

Arc-flash protectictive clothing is really based on layers of protective clothing. There is no single preferred solution so don't expect to see a picture of one. You need to look at all of the possible options before you can decide which one is best for your work environment.

It is possible to go from a HRC 1 outfit(basically normal weight fire resistant cotton) to HRC 2 by:
1) adding a light weight coverall
or
2) by changing into a heavy weight coverall

As far as I can imagine, all of the pictures would look the same. But there are still other options available. Of course the outfit salesman wants to sell you a Cadillac instead of a Yugo.