Stainless drain?

Has anyone come across this Type of DWV? My only findings of 409 stainless were for vehicle exhaust systems. Processing: 3B41810E-4FC6-4DF7-B493-1B1349B3E6AC.jpeg…
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Thanks, Jeffrey, I did read that same article, but it only mentions 304 316 types. I don’t want to split hairs but 409 stainless was only mentioned in vehicle applications, (Which seems to be a higher quality) leading me to believe work was performed by a non-professional.

Remember… when it comes to “Listed materials”, if it’s not on the list, it’s not approved, regardless of quality!

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Ahh, good call! I wasn’t thinking of it in that way. Much appreciated sir!

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The San-T fitting looks like copper - what age was the house? In Oregon I see copper DWV systems a few times a year. Usually during the mid/late 60s. An old plumber once told me it was due to the Vietnam war and copper was cheaper. All the steel was being used for bullets and planes.

Fwiw, I’ve never seen stainless steel piping in houses but that pipe is pretty clearly stamped. Probably a homeowner special.

The sanitary tee looks like a wrought brass fitting. As mentioned by JJ, the stainless steel material is likely not an approved DWV material.

It looks like this is not the first instance of the material being installed in a home. Is it possible this piping was intended for commercial use?


Interesting because it’s impossible to know what was an approved material at the time of installation.


1960 bi-level, I’ve never seen it either!

You’re right… I’m trying to remember now when I’ve seen copper DWV is the fittings are brass like that. I’m thinking not… it seems like they are smooth like the copper piping.

If OP’s house is 60s that’s right in the era of copper due to steel shortage but it doesn’t make sense since stainless-steel is, of course, steel. The guy that installed it has probably been dead for 30+ years so we may never know.

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You are correct.

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Interesting catch. Since, you’ve dived this deep into it, I think I would write it up something like, “Stainless steel used in DWV does not appear rated or approved for this use, but no problems were visible. Evaluation by a licensed plumber is recommended.”


I have, thank you Lon!

Exactly. Many would call this “fluff reporting”, but IMO, it is making our clients aware of a situation without saying there is a current defect, merely that it is ‘unconventional’ and merits an experts opinion.