As I've done from time to time here, I want to provide everyone a brief update about the IEEE 1584 Standard.

The IEEE 1584 working group met last week on January 26, 2015. Significant progress has been made and things are accelerating.

A special Task Group was created last year that has been working on the evaluation of all the test data and proposed equations. They have been meeting frequently via conference/web calls to work out many details and move this standard forward.

A new Task Group was just created last week that will begin finalizing the actual standard, text etc. (I'm heading up this one) An initial draft had already been developed.

Once the work of these two task groups is completed (maybe later this year ??) then the results of both have to be merged into the final document. Then the balloting/voting and comment resolution begins which can easily take 18 months or more.

So, although I cannot provide a specific date, it will likely be a few years based on what we have left to do.

I can't offer much more detail than this at the moment, but we are making good progress.

I have to stick my disclaimer here. Although I am Secretary of the IEEE 1584 Working Group, this information is my personal view and not provided on behalf of IEEE or NFPA.

Jim Phillips

Thank you for the update.

Is the new version of IEEE 1584 going to have different calculation methods or equations when the source is a generator rather than a utility transformer? Will it differentiation between 3 phase and single phase faults?

The next draft is sitting on my laptop and we have proposed language to use a piecewise solution for generator calculations so that the decrement can be accounted for. The equations will be the same regardless of the type of the source, the difference is whether you take into account the decay from the generator decrement. Most software already performs the calculations this way. There won't be anything new for single phase faults however. I do have to state two things, this is from me and not the committee and the draft is just that. It has not been finalized or voted upon so it could still evolve.

Thank you for the update, Jim!

Currently, the arc flash boundary calculations in the 1584 IEEE Guide for Performing Arc-Flash Hazard Calculations (equations 8 and 9) are usually based on 1.2 cal/cm^2 constant incident energy regardless of the amount of heat flux. In fact, the 1.2 cal/cm^2 onset to second degree burn energy value on a bare skin comes from misinterpretation of A Privettes report [1] based upon tests where the test animals were shielded with flame retardant fabrics. See this forum thread at viewtopic.php?f=34&t=2221 for more information.

I wondered if the updated IEEE 1584 standard will address the variable nature of threshold incident energy for a 2nd degree burn?

1. Alan Privette, "Progress report for ASTM Burn Stufy", Duke Power Company, 1992)

As always, these are my thoughts and not necessarily those of the IEEE 1584 Working Group or IEEE.

The existing equation for the Arc Flash Boundary and the proposed equations that are under review allow a user specified incident energy to define the Arc Flash Boundary. NFPA 70E defines the boundary as the distance where the incident energy drops to 1.2 cal/cm^2 as the onset of the second degree burn. OSHA 1910.269 uses 2 cal/cm^2 although doesn't have an AFB. The value that is used will be defined by other standards such as NFPA or OSHA and not IEEE 1584.

I think 2.0 cal/cm2 the way its written is the 1910.269 "arc flash boundary". It only gets confusing when you try to parse the limit where arc flash PPE is not required because OSHA threw non-radiant heat hazards into the mix. Similarly, the restricted approach boundary is clearly the same as the minimum approach distance (MAD) both of which come from IEEE 516. There is also clearly a limited approach boundary (10+ feet) but it is never explicitly named. Thus there is confusion only in that the terms are simply undefined but the intent is identical. In a mixed environment I taught the 1910.269 MAD term but then used the 70E terms since they are better defined and well known.

The real question is what is distribution? That's not so easy to define but is the dividing line between 1960.3xx and 1910.269.