Arc Flash Coverall

[jmd445]

We had an arc flash survey completed on our complexes and the end result for most of the motor startes, HVAC units and disconnects and a few small 120/208 panels were in the neighborhood of .08, .9, 1.2, etc cal/cm2.

The current coveralls we have are rated at 11 cal/cm2.

I can't see having mechanics on a roof working/troubleshooting roof top HVAC equipment wearing these on 85 to 90 degree days. They would die!

I can't seem to find a manufacture of lighter weight FR clothing in the realm of 2 or 3 cal/cm2. Any suggestions.

Thanks,

Jim

 

[zog]

If the hazard is less than 1.2 cal then 100% long sleeve cotton will suffice. No one makes a 2 or 3 cal FR coverall, it is pointless. Indura Ultra soft has a 5.2 cal shirt that is very lightweight. The interlock knits are just hitting the market, 10.9 cal and feels like a t-shirt, very light and wicks moisture. Tyndale has these, salisbury will have them this month.

 

[jmd445]

Zog,

Thanks for the quick reply. Where in the NFPA 70-E is this stated. I'm referring to Table 130.7(C)(11). I'm interpreting this that there is nothing allowed below a rating of 4 cal/cm2.

I have not read where standard non-melting (ie blue jeans and a long sleeve cotton shirt) are acceptable to 1.2 cal/cm2.

Sincerely,

Jim

 

[brian john]

JMD:

Just a thought, you ever watch linemen in mid-July, 95% humidity, 95 degrees, in a bucket truck hard hat, sleeves gloves, working away.....

That has to be a killer (heat humidity in a rubber suit), but they do it, for safety and because it is a requirement of their job.

 

[don_resqcapt19]

Jim,

I have not read where standard non-melting (ie blue jeans and a long sleeve cotton shirt) are acceptable to 1.2 cal/cm2.

For the jeans take a look at note 4 to Table 130.7(C)(10). They are permited for HC 1 in lieu of FR pants. You could use that along with a light weigh FR shirt.
Don

 

[jim dungar]

Zog,

Thanks for the quick reply. Where in the NFPA 70-E is this stated. I'm referring to Table 130.7(C)(11). I'm interpreting this that there is nothing allowed below a rating of 4 cal/cm2.

I have not read where standard non-melting (ie blue jeans and a long sleeve cotton shirt) are acceptable to 1.2 cal/cm2.

NFPA 70E table 130.7(C)(11) is a reference for relating the cal/cm^2 requirement of clothing to a hazard risk category chosen from table 130.7(C)(9)(a). If you have performed an actual incident energy calculation you should be able to chose clothing based on the actual cal/cm^2 instead.

NFPA70E 130.7(C)(14)(b) discusses non-melting flammable clothing up to 2 cal/cm^2.

Remember above 1.2 cal/cm^2 skin needs to be covered.

 

[zog]

Thanks Jim, you beat me to the punch. One thing to add, you cannot mix the tables with an analysis. You either use one or the other.

 

[jim dungar]

Thanks Jim, you beat me to the punch. One thing to add, you cannot mix the tables with an analysis. You either use one or the other.

It is very common to use table 130.7(C)(11) "backwards" to create PPE requirements for a facility. This method simplifies the number of PPE choices that a safety program needs to define.

It is perfectly acceptable to use calculations for part of a facility and hazard risk tables for a different part. For example, many companies calculate incident energy to the bussing of an MCC and then use the task table for the individual motor circuits.

 

[zog]

That question was asked to 3 70E commitee members at the PowerTest conference in Denver and they disagreed with you Jim. Personally I agree with you, but they said otherwise.

 

[jim dungar]

That question was asked to 3 70E commitee members at the PowerTest conference in Denver and they disagreed with you Jim. Personally I agree with you, but they said otherwise.

What did they disagree with?

Table 130.7(C)(9)(a) is based on knowing the available fault current. how do you know the availabe fault current at a location without perfroming an analysis?

Section 130.7(C)(9)(a) says "for tasks not listed... [an] analysis is required". So where the committe members saying that if you ever perform a task not listed in task table (i.e. work on an MCC rated at 208V) then the table can never ever be used in your facility?

 

[WDeanN]

One thing to add, you cannot mix the tables with an analysis. You either use one or the other.

Zog, This is my understanding as well, and I think there is a clarification to this effect proposed for the 2008 70E.

I don't think that there is a problem with performing the analysis down to a certain level, and then using the tables below that, however. The problem comes because some people will perform the analysis, and then use the tables to assign minimum PPE based on category, which often results in people being over dressed.

 

[WDeanN]

Jim,

For the jeans take a look at note 4 to Table 130.7(C)(10). They are permited for HC 1 in lieu of FR pants. You could use that along with a light weigh FR shirt.
Don

Don, I think there is also a proposal to eliminate the exception to 130.7(C)(5). I don't know how this will effect Table 130.7(C)(10). I think the exception should stay.

130.7(C)(5) also says that FR clothing is not necessary below 1.2 cal/cm2. I would think that synthetics are still not allowed, however.

 

[zog]

Jim,

I think what Wdean said "I don't think that there is a problem with performing the analysis down to a certain level, and then using the tables below that, however. The problem comes because some people will perform the analysis, and then use the tables to assign minimum PPE based on category, which often results in people being over dressed." was the discussion point, I wish I could find my notes from that meeting.

 

[jim dungar]

Jim,

I think what Wdean said "I don't think that there is a problem with performing the analysis down to a certain level, and then using the tables below that, however. The problem comes because some people will perform the analysis, and then use the tables to assign minimum PPE based on category, which often results in people being over dressed." was the discussion point, I wish I could find my notes from that meeting.

Let me get this straight, they don't want people to ever be over dressed?

My point is that the task tables can be used on equipment downstream from an analysed point, but an analysis can not be ignored because you don't like the results.

 

[zog]

Well put Jim. I sent an email to the moderator of that 70E panel discussion to see if I could get the minutes from the meeting.

 

[WDeanN]

Let me get this straight, they don't want people to ever be over dressed?

When I do my analysis, I try to get the best data I can. I don't want guys overdressed for two reasons: 1) They resist the use of AF PPE even more. 2) More clothing means more heat. This can result in more hazards.

Zog, I'd love to see those notes as well. I've got my boss convinced that we don't need to use the tables from 70E once we complete our analysis, but would like to have more info to back it up. I can't resist an "I told you so." Especially if it comes straight from the horse's mouth.