A good way to explain Class I Div 1 & 2

[megloff11x]

During a recent discussion of Class I Division 1 requirements, I explained it this way:

Class I Division 1 means I can pour gasoline on the machine and it will keep running without igniting it.

Class I Division 2 means that I can pour gasoline on the machine and I can shut it down before it ignites, and when it is off it won't ignite the gasoline.

I know I omitted the group here but that complicates the explanation. Anyone who's ever tried to re-start a charcoal grill after re-lighter fluiding it or used gas to start burning leaves or scrap, knows from their unsuccessful (or maybe successful) attempt at winning a Darwin award, how easy it is to start the fire/explosion.

If anyone has better analogies, feel free. When you specify equipment for a classified location, the accountants become apoplectic and need a good answer where they walk away understanding, not thinking that maybe they're being techno-bs'd.

Matt

 

[todd99]

I'm not sure why you would need an analogy....

Class I Division I:
Where ignitable concentrations of flammable gases, vapors or liquids can exist all of the time or some of the time under normal operating conditions.

Class I Division II :
Where ignitable concentrations of flammable gases, vapors or liquids are not likely to exist under normal operating conditions.

 

[rbalex]

Part of the problem with your analogy is that you probably wouldn?t shut down the process in a Division 2 location either.