Thursday, May 5, 2016

Copper Systems

Chief issue found with copper systems is lack of dielectric union when transitioning between copper and black iron.  A common misconception is held by some designers.  That misconception is there must be "water flow" in order for dissimilar metal [galvanic] corrosion to occur.  This is factually incorrect.  There only need be electrical conductivity in order for galvanic control.

The NFPA 13 design standard does not say dielectric unions may be eliminated if there is no water flow.

Identification of missing dielectric unions or notation of an install with dissimilar metals is NOT within the scope of NFPA 25.

A different issue below.  Design/Install.  Connection was soldered rather than brazed.

Missing dielectric, below:

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