SteveA wrote:
I'll summarize my thoughts, which I believe PaulEngr's post agrees with in content as well...
This leaves no ambiguity as to what should be worn if the worker does not take the time to look at the study and determine if a lesser level of PPE can be work for the task.
Not quite. The concept is valid but there is a practical issue with it and the reason that I recommend "normal" or "worst normal" rather than worst case. If you are dealing with a plant with only radial feeds and no emergency backup generator, then your approach works because worst case is the normal case without for instance maintenance switches turned on. The problem comes in with a plant that has large emergency backup generators (particularly whole-plant generators) or a significant cogen capability or double ended switchgear. In those circumstances, "worst" case is either relatively rare (e.g. running on generator power) or might never have actually occurred during the plant's operational history such as running a study with all mains and all ties closed on double ended switchgear. So the "worst case" is the rare case and plant personnel are basically instructed to ignore the labels at all times and get the information needed to do their jobs some other way because the label serves no practical purpose.
See where I'm going here? The label gets ignored and the secondary information may be confusing, hearsay, wrong, or subject to various "lookup errors". The label may as well be the generic kind "Warning! Arc flash hazard present" since it is not used in the first place. I'm not advocating for or against the use of labels or an alternative to a label system here but pointing out that the goal here should be to make things as simple to understand as possible to avoid mistakes and errors as much as possible, particularly when as you said the correct action is both task and condition specific.
The conditions that I'm describing may seem unusual to you but I can assure you that in the paper/wood products industry, glass plants, water industry, power generation, iron/steel, refineries, and chemical plants, these scenarios are the norm rather than the exception. Thus the approach needs to be one of deciding what particular scenario goes on the stickers and what additional content can or should be identified in conjunction with procedures and practices developed to support the label system.