Great catch Dave - That is pretty disturbing because as you say, NFPA 25 has gone out of it's way, and there have been LONG discussions on forums all over about that. I'll be following this one pretty close, may even put it up on some other boards.
I'd look in to the corrosion potential of the concentrate on whatever pipe material you're using. I'm guessing though that if you have the proportioner 190' away from the bladder tank then anything before the proportioner is concentrate, and would be considered as part of the total volume.
