Cindy
I would have a hard time accepting the exposed ufer connection for the reasons you are concerned about. As far as other piping I have never been required to scrape the galvanized coating off water piping and doing so would cause the plumber and plumbing inspector to have a fit. Black iron gas piping and fittings are not supposed to be installed where they are exposed to weather unless they are coated for protection. Again it would be a violation to remove any protective coating.
I would also not permit an acorn clamp to used to connect the grounding electrode conductor to the ufer. I have never seen one listed for this purpose and doubt there are any. Copper and steel should never be in direct contact with each other because of electrolysis. I don't have a problem with using standard brass or bronze clamps even thought most are also not listed for this purpose. I know most of the T&B U-bolt type ground clamps are listed for rebar.
Curt
