The fire extinguisher is not just for show
No, it's not. it's used among departments on both the east and west coast, but it's far from a standard, and definitely not common with a standard defintion.It’s common on the West Coast and East Coast.
your department might use them, but mine doesn't. doesn't make you right and me wrong, or me right, and you wrong. It's a local/regional term, and very department-specific. Stop generalizing; you're embarrassing yourself.