History of cast iron DWV performance and lifespan?

[EmmanuelScanlan]

Does anyone have a good link to an unbiased study of the lifespan for cast iron DWV piping? It would be nice if it also discussed any time periods where the piping was experiencing production issues.

Just as an FYI here is a good link to the Cast Iron Soil Pipe Institute which has a very nice "Cast Iron Soil Pipe And Fittings Handbook". CISPI - Cast Iron Soil Pipe Institute - The Industry Standard (http://www.cispi.org/index.htm)

Thanks!

[Gary Burnett]

Emmanuel,
I have had several PE's say that between 30 and 50 years the cast will pretty well rust out. It rusts from the interior so if you are in a crawl you need to probe with a screwdriver and see if it goes through. If it is a slab you might want to have them do a hydrostatic test. This will only tell if there is a leak in the drain lines up to the cleanout where they stick the pig.
Don't know about Greenville but in Dallas it's about $160 for the test.
I have done homes that are not that old and have rusted out sections of sewer line. To repair it they cut out the bad and replace with PVC with a rubber boot. You won't know about the line that goes to the main sewer unless they run a camera and that's pretty expensive $300-375.

[Gunnar Alquist]

Does anyone have a good link to an unbiased study of the lifespan for cast iron DWV piping? It would be nice if it also discussed any time periods where the piping was experiencing production issues. Just as an FYI here is a good link to the Cast Iron Soil Pipe Institute which has a very nice "Cast Iron Soil Pipe And Fittings Handbook". CISPI - Cast Iron Soil Pipe Institute - The Industry Standard (http://www.cispi.org/index.htm) Thanks!

ES,

The only thing I have seen is the National Association of Home Builders publication that gives a 100 year lifespan estimate for cast iron plumbing. However, around here, galvanized is typically used for the 2" and smaller diameter drain/waste/vent piping, and in my experience, that is not likely to last longer than 40-50 years.

[EmmanuelScanlan]

Hey Gary,

Thank you! Yes I generally find that by year 50, when buried, it is fairly well rusted and can have chunks (not layers) flaking off by hand. I always advise that they scope old cast iron to be sure.

You mentioned homes not that old having issues. That was one of the reasons I was looking for info regarding production problems, etc. Regardless of how good a concept is there usually are periods where they get cheap in the production and have issues.

Hey Gunnar,

Thank you also! Yes I did see that study and they (NAHB) appear to have misquoted the Cast Iron Soil Pipe Institute who mentioned many times in their pages, handbooks, etc., etc., that some systems have been around 100 years. What is interesting is the CISPI does not have any lifespan predictions that I can find, only reports of older systems still in use. The NAHB study is even crediting the CISPI with the 100 year lifespan figure.

I appreciate the help guys! This weeks jag was on plumbing and plumbing issues. I get into these modes to read about specific subjects and this week it was plumbing. With all of the information out there today the internet is becoming more and more useless for finding it. But it always helps to have experienced people throw in their experiences and views!!

[Jerry Peck]

I have done homes that are not that old and have rusted out sections of sewer line.


To some extent, maybe to a large extent, it depends on where the pipe is made.

I have seen much cast iron from China which was installed in high-rise buildings I was inspecting which had faults, cracks, and bad areas in them when the pipe and fittings were unpacked.

I used to seen many older homes in Miami Beach, Coral Gables, Coconut Grove, Palm Beach, you name the places, where the cast iron was still in use but was shot, leaking, and falling apart, so I would put the life span at 30 to 50 years, not that it lasted 50 years without failure, but that the failures went undetected for 50 years before the cast iron was replaced.

I have seen some vent stacks in commercial buildings - yes, vent stack use only - that were rusted out and had come apart in layers, and the building was (as I recall) only 20-30 years old.

[Jim Robinson]

I've got it in my 57 year old house. I was kind of worried about it after reading about cast iron. On my last project I had to cut it apart and splice in a section of ABS to add in our new bathroom. There was quite a bit of solid metal left on the inside. It took a long time to cut through. In fact, the inside metal was in better shape than the exterior metal. I'm not as worried about it now.