[Scott Bentley]

Originally Posted by rob love

I did some quick research on the color and temp ratings, and I don't think the color has anything to do with it. There are two different ratings for the red line extinguisher, which include a low temp version which are good to some ungodly temp like -65, so it is doubtful that you would have one rated below that. All are presently painted red.
From the product spec sheet:
Temperature Ranges: -40° F to 120° F (-40° C to 49° C) and -65° F to 120° F (-54° C to 49° C) for Low Temp models

What I did find was that the old British rating system had french blue as indicating the extinguisher had dry powder in it. That system was changed in 1997, but it could very well be that the DND colored it's extinguishers based on the British system or an earlier Canadian system, and has never changed it's specs. Currently, the Canadian spec does call for the C type extinguishers to have a blue circle on them with the letter C in it.

Next time I see some of the guys I know at the base fire hall, I'll ask them.

This makes sense...

My 5 lb Purple K (Light Blue) has a decal right on it that says "LOW TEMPURATURE" in big letters. I'll take a pic when I get home.