Hello All,
I have a quick question regarding dryer venting. I wanted to run my 4″ rigid ducting in galvanized vice aluminum.
The only problem I have run into is that “offset elbows” seem to all be in aluminum. E.g – http://www.amazon.com/Builders-Best-10162-Venting-Offset/dp/B000DZDPHW
I don’t want to mix metals due to galvanic corrosion. The humid dryer air will likely cause corrosion. http://www.galvanizeit.org/about-hot-dip-galvanizing/how-long-does-hdg-last/in-contact-with-other-metals
There is contrary information here (saying galvanized may contact aluminum): http://www.eng-tips.com/viewthread.cfm?qid=245894
Is there a supplier of galvanized dryer fittings?
Do you just isolate the metals?
Should I just not worry about it?
Even if I went with aluminum ducting the lint trap and roof vent are galvanized, so disimilar metals would be in contact.
My other option would be to use a regular galv. ducting but that would make the dryer stick out more.
Replies
Galvanized elbows are more common than aluminum, big box stores have them in the heating area. I would try to keep the vents all similar metal, but I don't think it matters much.
I wouldn't worry about that one offset elbow. It goes right behind the dryer, so in 20-30 years, when it finally corrodes through, you can simply pull out the dryer and replace it.
Don't worry one bit about mixing the two--remember that the standard pipe for venting gas appliances ("B-vent") is a double-wall pipe, aluminum on the inside and galvanized on the outer pipe. They are crimped together on the ends and are in contact with condensation from the combustion gases throughout their life.