Can copper hydronic piping hung from galvanized steel support? That was the correct answer to the question but copper is cathode and Galvanized steel is anode and will be corroded by the copper? Is that right? Can someone explain?
Hi @fanny.sahar & welcome to the ARE Community!
@heatherrivera can you explain this answer to Fanny?
Hey Fanny,
Sorry about the delay in getting back to you. It was so blazing hot here today, I tried to beat the heat in the water.
Can you cite or give a screenshot of the actual question? To your original point, copper and steel (because of the zinc) do not get along. If you make a direct connection, there will be corrosion. Without seeing the exact question, it’s hard to guess, but is it possible there was no direction connection or that a brass connection was inserted between the two?
Please @ me in your response so I can follow up with you!
Kind regards,
Heather
Hey,
Here is the Question on PPD Exam 3:
Near the end of the construction documents phase, the architect receives a drawing set from the plumbing engineer for review. The architect notices a detail for copper hydronic piping hung from aluminum supports.
How should the architect address the issue?
The Answer (provided):
Issue comments to revise the hanger to galvanized steel.
Correct. Galvanized steel will not suffer galvanic corrosion with copper.
The Reference (provided): Reference: Olin’s Construction, Principles, Materials, and Methods, 9th Edition, pp. 293-294
From what I can tell, this answer is not correct, or at least very misleading. In addition the Reference provided refers to a section about Beams and Trusses in Olin’s…
Thanks,
Jon
The question is a bit outrageous because copper hydronic pipe would get insulation over it anyway.
@jonkrizan and @jsuda thanks for writing in!
This question is testing if you understand what issue might occur given the situation described (galvanic corrosion) and if you are able to identify a solution to that issue (change one of the metals to another type of metal). Of the choices provided, two of them suggest changing one of the metals - one suggests changing the plumbing pipe to aluminum, which is not a material used for piping. So, the only logical answer is to change the support to galvanized steel.
Our reference page numbers are from digital copies of the books (from google play) - when I open Olin’s to the pages listed, I see a section about galvanic corrosion. It’s possible that a hard copy of the book has slightly different page numbering - if that’s the case sorry about the confusion!