There have been some interesting comments recently regarding the addition of risk assessment in the 2015 Edition of NFPA 70E. The last 2 questions in the “Question of the Week� series as well as a recent [url='http://arcflashforum.brainfiller.com/threads/2998/#post-13936']post by PaulEng[/url] are stirring up the discussion.

This week's question continues the discussion.

What do you think will be the main criteria used when performing an assessment of the risk of the hazard instead of just focusing on the hazard itself as in the past? A risk assessment may possibly result in using a decreased level of PPE?

• Codes, Standards, Guides
• Judgment and experience
• Liability
• Something else (please explain)

The likely result is a repeat of the debacle following the 2000 edition of 70E when it was first referenced in NEC in 2002. That is, there is going to be a lot of confusion. Here is why:
1. As of right now it is already clear on this forum (among others) that there is a lot of confusion over the concept. There is some extremely vague wording in the fine print notes for the definition of an arc flash hazard, and scattered in a few other locations in 70E-2012 but none give any meaningful guidance. Thus we run into questions about whether PPE is required or not with the doors closed, while operating breakers, or while racking MCC buckets or switchgear buckets. We continue to see a push to glove up to do the simplest tasks, with understandable push back from those with even a modicum of practical experience. Then we get the liability types that want to treat electrical equipment as fundamentally dangerous and simply ban it altogether. The result is confusion, not clarity.
2. Annex F has been out there for a lot of years. However few people even understand what it is for. Fewer yet have actually tried to use it. And anyone who tries will give up in frustration because it is woefully incomplete and a terrible fit for electrical hazards. It is based on IEC 61508 which is intended to be used to analyze mechanical machine motions and control systems, a much different case from thermal hazards arising out of degraded equipment, or human performance issues. I proposed actually simply deleting it which would have been a much better approach than leaving it in, because it is just going to lead to even more confusion.
3. Certain industries have been doing some form of risk assessment for a very long time. OSHA mandates this but few industries actually practice it. Those are the chemical process industry, nuclear industry, automotive, machine tools, and packaging. Obviously those are the same ones that have taken steps to develop specific standards for doing risk assessments as well. So when someone uses the phrase "risk assessment" they will at least attempt to utilize the risk assessment practices they already have, with varying degrees of success depending on how amenable the industry standard is to doing so.
4. Others are not so lucky. For instance I have had inspectors from the federal Mine Safety and Health Administration (MSHA) actually tell me that right now they are not focused on and are a long ways off from even being concerned with arc flash. Their primary concern today is still shock, and even then they are very haphazard in how they view and enforce it. Anyone care to guess how many individuals in this industry have ever actually done a risk assessment? My current employer is one of a very small handful of mining companies who do them on a regular basis.
5. Even if there is a practice of doing risk assessments, the existing standards make certain assumptions about the industry or the environment which can make implementation prohibitively difficult. For instance many standards ignore human performance altogether under the assumption that human performance is so haphazard and so unreliable that the best approach is to simply ignore it, making it impossible to examine many maintenance tasks. Many are also focused specifically on electrical control system reliability and do not consider any other type of equipment (mechanical, hydraulic, or pneumatic).

This is the reason that I continue to push for practical and workable guidance on doing risk assessments, in a standards based way. The problem is that most existing risk assessment standards are so open-ended that they leave nearly every important detail up to the end user. Frequently they don't even define a "serious injury" and leave it up to the end user. The few standards that are concrete in nature (e.g. Robot Industries Association) don't lend themselves easily to use outside their niche.

Similar to the 2004 edition of 70E, if we ever hope to provide real guidance and clarity, the standard is going to have to provide it in a meaningful way. Otherwise, the only people who will benefit will be the various consultants.

I believe the main criteria used, will be Judgement and experience (i.e. gut feel).
I also believe the main criteria should be based in consensus standard.

Unfortunately I think that liability will be the main driver in the absence of clearly defined industry recognized standards that are adopted by the local AHJ.

I agree WBD. In our risk averse (lawyer fearing) environment I believe liability will be the driving force.

I agree with all of the above.

I have tried to do some research to determine what needs to be done to consider an arc flash source contained. The answer basically is some sort of an enclosure, but there are no parameters I have found as to how thick the walls need to be or as to what materials are best suited for the construction. Only that it is vented away from the operator.

What we have is vague. The Codes, Standards and Guidelines are really still in their infancy. Judgement and experience is all well and good, presuming you have someone that is really knowlegable, and not just someone who thinks they are. There are plenty of both in the field. The latter are a danger all unto themselves and to all around them. As much as I think I know, I realize I have far more questions than I have answers, so I won't delude myself. I tend to err on the side of caution.

That leaves liability. In this litigation-happy time liability will be what guides the wise. The foolhardy will try and get by with the bare minimum or that which impacts production the least.
In a perfect world, we should be able to rely on judgement and experience as JBD suggests, and the codes and standards would be mature enough to be clear, concise, and reliable enough for the inexperienced. But as Paul said there is going to be a lot of confusion.

Perhaps Shakespeare was right about Lawyers.