RicodJour wrote:
....

Why do gas companies and many codes prohibit using galvanized fittings
in gas lines?

Because there was some evidence that impurities in gas could lead to
interaction with galvanizing leading to some particulate contamination.

Once there, as with most Codes, it's much easier to retain than remove
restrictions whether they're still needed or not.

As noted above, PG&E did extensive study and determined it didn't seem
to be an issue of concern at the time; what that study didn't do was
make the decision as to whether to change policy or not. Whether that
happened or not subsequently, I don't know. But, the issue wasn't
related to this sidebar argument as to why galvanized was/is not used w/ NG.

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