To me, it appeared a bit like a sales pitch for their services.
There was another study similar to the one in FPC that appeared in Sprinkler Age in Oct 2013 that seems to validate some of their opinions - although the use of nitrogen with galvanized pipe was the best.
The new UFC 3-600-01 Fire Protection Engineering for Facilities (Army Corp of Engineers) has prohibited galvanized piping on dry and preaction systems, where it was previously allowed.
My opinion, is a lot of the problems have to do with installation and testing problems (pipes not drainable, use of rolled groove fittings, not getting the system dry after testing, etc., but since the designer cannot always control those very well, there will continue to be problems.
I like the greater focus on using nitrogen as the atmosphere in the dry pipe. It is dry and does not promote corrosion so even if all the water is not evacuated, there is no oxygen for corrosion to occur.
Galvanized pipe should have a lower friction factor than iron piping. With a wet sprinkler system, iron piping will internally corrode for a while but after all the oxygen in the water is consumed, corrosion will no longer be significant. I have not yet seen galvanized piping used in sprinkler systems.
Chic, Every time an inspector test is opened for a quarterly, air is introduced. Granted, the corrosion rate is often at an acceptable level in a wet system with black pipe but the corrosion process does not stop.
There are millions of sq ft of galv pipe out there for dry systems. As others have noted, this has been problematic, so the new approach is black with a n2 fill.
As per NFPA-13 clause 8.4.7.2.1 - where steel pipe is used in pre-action and drypipe system, piping materials shall be limited to internally galvanized steel.
Furthermore, as per my opinion galvanized pipe can be a galvanized iron pipe or a galvanized steel pipe. what we can compare is that a black iron pipe vs. galvanized steel pipe.
Careful 3cio, I see reference to this quote pop up every couple of months. NFPA 13-2010 8.4.7.2.1 falls under 8.4.7. The title of 8.4.7 is "Control Mode Specific Application (CMSA) Sprinklers. This means that every clause from 8.4.7.1 until 8.4.7.3.4 is referring only to CMSA sprinklers. If your dry system employs standard sprinklers, black steel is A-OK.
Chicopee: regarding the c factor, it is interesting to note that the C value of 120 for galvanized pipe has disappeared in the latest edition (NFPA 13-2013 Table 23.4.4.7.1). It is now 100, just like black steel.
