Hi JIm

Greetings from Canada. Being the President of a local electrical contractors chapter, I am very often confronted by fellow electricians on simply the term cal/cm2. This is not exactly a familiar term to allot of electricians in oppose to temperature in either degrees C or F scales. Now when we throw the 40 cal/cm2 at them it can become more confusing. If I have it correctly the term cal/cm2 goes back to the Alice Stoll experiments in the late 1950's and early 1960's? Regarding the "more emphasis on de energizing". I agree and like the comment above that, is that not what NFPA 70E and CSA Z462 are all about? De energizing as the first choice. If the 40 cal/cm2 is going to remain in both standards, perhaps we should focus our efforts on inserting some information in an annex on conversions to PSI or other terms that are more familiar to the maintenance worker. Some real to life examples of how much energy 40 cal/cm2 really is and why it is so dangerous. Something similar to as what we know that 1.2 cal/cm2 for 1 second is the same as holding your finger an inch away from the hottest part of the flame of a cigarette lighter.

There is a chart I use in presentations to put it in perspective:

1.0 cal/cm2 = Equivalent to a finger tip exposed to a cigarette lighter flame for one second
1.2 cal/cm2 = Amount of energy that will instantly cause 2nd degree burns to bare skin
4.0 cal/cm2 = Amount of energy that will instantly ignite a cotton shirt
8.0 cal/cm2 = Amount of energy that will instantly cause incurable 3rd degree burns to bare skin