What guidelines do you guys use, or recommend, for the ANSI Z-535 signal words? When interpreting the ANSI standard, I question if the signal word "DANGER" should ever be used.

Current practices use the word "WARNING" with an orange background and reserve the word "DANGER" with a red background for incident energy calculations above 40 cal/cm2.

Thanks for your input! I agree that it is common practice. However, here is the ANSI standard:

The ANSI Z535.4-2007 standard will use the following definitions for signal words:
• 4.14.1 DANGER: Indicates a hazardous situation which, if not avoided, will result in death or serious injury. This signal word is to be limited to the most extreme situations.
• 4.14.2 WARNING: Indicates a hazardous situation which, if not avoided, could result in death or serious injury.

The examples I've seen to select a signal word essentially come down to this:

If interaction with the hazard WILL cause serious injury or death use DANGER.
If interaction with the hazard COULD cause serious injury or death use WARNING.

I know we now have to define a "serious" injury also. I suppose if it is me that gets hurts that is really serious! I've seen just about every combination imaginable. Just another gray area for us.

By that definition, we should be using WARNING for most, if not all, arc flash labels. The possibility of an arc flash event is relatively remote during normal operations. The interaction COULD kill you, but the likelihood is small.

Definitely another one for the books, Viper.