Is galvanized pipe req'd on an addition to existing?

[RainbowFS]

I am doing an addition to a dry pipe sprinkler system built circa 1986. It's a tall steel warehouse and a mezzanine with offices is going in one end. We'll be running all new lines off of a new mechanical tee on the riser.
My question is- since the old system is all black pipe, can I use black pipe also?
The code pertaining to this:
NFPA 13, 2007, 8.4.7.2 states that dry systems shall be limited to using galvanized pipe. Presumably that is referring to new systems, but there are no exceptions after the rule.
Does anyone know of a chapter elsewhere that might clarify this regarding additions to existing systems?

Alex Traw
Rainbow Fire Sprinklers
Albany, Oregon

 

[Oremus]

8.4.7.2 is for a system employing large drop sprinklers so unless the existing system uses listed large drop sprinklers and were designed to that criteria then black steel is fine for dry and preaction systems. Just make sure if hydraulic calculations are necessary to use the proper hazen-williams coefficient (100).