Are there any issues such as galvanic corrosion if black and galvanized steel will be mixed in the fire sprinkler installation?
Are there any issues such as galvanic corrosion if black and galvanized steel will be mixed in the fire sprinkler installation?
Hi Milton,
Will the zinc coating create galvanic corrosion to non-coated black steel when in contact? A reviewer of our project insisting to provide a transition from galvanized pipe to black steel pipe. I can't find any listed dielectric fitting for 6" pipe and I'm not sure if there is a such a thing.
Thank you.
Cristian
Hi Cristian:
2016 NFPA 13 section 10.4.1.3:
Rubber gasket joints (push on or mechanical joints) are considered not connected electrically.
The joint in threaded fitting would be bare steel for both the coated pipe and black pipe. Are you really contacting two dissimilar metals? It is always best practice to have no dissimilar metals in contact or to insulate the metals from one another.
I have seen dielectric flange fittings use to connect the underground fire sprinkler piping from the aboveground piping where the electrical code requires bonding of the above ground piping to the the electrical grounding system. This prevents the under ground piping from becoming a grounding electrode and the current between the soil and pipe corroding the piping.
Respectfully.
Milt Werner
Hi Cristian:
Galvanized pipes are steel pipes that have been dipped in a protective zinc coating. Therefore, the threaded fittings is have no dissimilar metals.
Respectfully,
Milt Werner