Iron Cast vs Plastic pipes

I am part owner of an apartment building that received 15 feet of Gulf waters during a hurricane. Cast iron pipes were used and are visible on the first level garages. Plumbing is a common element, not individual to each apartment. Many sections were torn or broken away during the storm winds/flood. The cast iron pipes were submerged in the water for a number of weeks. The pipes/plumbing have not been used in 11 months. Inspection reveals a substantial amount of rust. The plumbing system was installed 25 years ago. We have received flood insurance money (maximum). At this time all units (24) are open and not occupied and debris has been removed. Is this the time to make a change or patch the system?

This is an interesting topic. First, in multistory buildings, many jurisdicitons will not allow any plactic DWV.

As for the corrosion, cast iron does not corrode readily, but of course salt water is different. I presume the pipes were subject to salt water inside and out. I think I would seek advice from a corrosion control expert to see if the pipes would continue to corrode, and to see if some recommended treatment could halt the corrosion and allow the pipes to remain.

My 3 Cents

Generally speaking ,local codes would specify cast on a comercial building.

Things are different in different parts of the country. Local plumbers in your area are dealing with your unique situation. They have probably already set the standard procedure for repairs or replacement. local plumbing inspectors may help also .good luck tool

Why cast?

Just wondering, why is cast iron required for commercial? Not that I think about it, we had pvc in our condo in Chicago.

Just wondering.