Copper Kitchen P-Trap and Drain

[WorldPeace]

I've been reading a popular plumbing book by Hemp. He suggested making the kitchen drain assembly completely out of copper all the way up to the main drain/sewer and then insulating it. He found that it decreases the chances of clogs because copper retains heat better. He did admit that this is more expensive.

Has anyone tried this? Also, where can you purchase copper kitchen P-traps. I can't seem to locate any with compression fittings. Wondering how much more they are.

 

[Reach4]

He suggested making the kitchen drain assembly completely out of copper all the way up to the main drain/sewer and then insulating it. He found that it decreases the chances of clogs because copper retains heat better.

That "retains heat" thing sounds ridiculous to me.

 

[Sponsor]

 

[Terry]

Copper pipes to kitchen sinks and sinks in bars have never been a good idea. The bottom of the pipe tends to rot out and then replacement is needed.

You're better off with PVC or ABS for a kitchen sink drain. If you need to prevent snaking, pick up some enzyme cleaner to keep the grease at bay.

1983 plumbing job to add a bigger window, drop the vent down a bit lower too.
The Johnson Tee is to the right. The original was done in the 60's and still in use in 2022.
That being said, I have pulled out old copper on kitchen lines because the pipes were leaking.
I was a lot thinner back in 83.

 

[Jeff H Young]

Whatever? Copper is conductive meaning it dissipates heat plastic is an insulator figure that out. Ignore the book

 

[Tuttles Revenge]

Nobody has done this because its a bad idea.

 

[wwhitney]

I think I agree it's not a good idea, but the argument for it would go like this:

Copper is a good conductor, so it will heat up from the hot water. The insulation around it is a better insulator than plastic pipe, so the system as whole should cool off slower.

So an initial run of hot water would cool off faster in the pipe than with plastic, as the copper takes some heat from the water. But after enough water runs through over a short enough period of time, the copper will have heated up, and the thermal mass of the copper will keep any deposits from cooling off as quickly (i.e. congealing). So if hot water is run sporadically, then there's a better chance of the things not cooling off between runs.

Again, not saying I endorse the idea.

Cheers, Wayne

 

[WorldPeace]

Given the consensus that copper is a bad idea, it's interesting that Hemp actually devotes an entire paragraph on the topic. He heavily promotes the use of copper in a kitchen drain assembly because it's the best at preventing clogs. I'm wondering why he so strongly believes in it. Below is the actual passage in the book.

Nevertheless, copper pipe has its advantages in the DWV system. If you can afford to use it for a kitchen-sink drain line, you will have fewer stoppages than with other materials. I recommend running a copper kitchen-sink drain line as far as possible toward the main building drain/sewer and insulating the drain line. That way the hot water heats up the copper and grease and soaps remain liquid all the way to the 4-in. building drain, where they are flushed out quickly. The same advice applies to the shower drain, but again, only if you can afford it. (Plumbing a House, Page 24)​

Copper pipes to kitchen sinks and sinks in bars have never been a good idea. The bottom of the pipe tends to rot out and then replacement is needed.

You're better off with PVC or ABS for a kitchen sink drain. If you need to prevent snaking, pick up some enzyme cleaner to keep the grease at bay.

 

[Terry]

And I can give you paragraphs about cutting out and replacing copper sink lines. But sure, run copper if one guy liked it. We'll be there to replace it when the time is right.

https://terrylove.com/forums/index.php?threads/copper-drain-lines.32433/

https://terrylove.com/forums/index.php?threads/replacing-a-copper-drain-pipe-inside-a-wall.73391/

 

[Jeff H Young]

world peace member, I really don't think you'll gain anything by running copper I'd just run conventional PVC or ABS save you time, money , and still be very long lasting

 

[Tuttles Revenge]

Preventing goop from collecting on the side walls of pipe and having proper grade is what prevents clogged pipes. IMO Plastic piping is the best at doing that. But I haven't studied that specifically enough to write a book about it. Thats just from emperical evidence, that when I open up drain lines and I barely see a thin line where the mean water level is from usage, I see the least on ABS/PVC. And honestly we just dont see that much copper drains as it was only cheap enough to replace steel for a short time before it was replaced by plastic.

It might even marginally outperform plastic in the long run for antistick. But plastic pipe is going to outlive the copper.

 

[WorldPeace]

Definitely. Given people's experience here, I'll stick with PVC, especially since it's so much cheaper.

I was just curious. The book by Hemp was highly thought of by several pros. And, after reading it, I can tell you that it's well-written. It's better than Modern Plumbing and Plumbing 101 by PHCC. So, I'm just wondering why Hemp, an experienced and well-qualified plumber felt copper was good DWV material.

world peace member, I really don't think you'll gain anything by running copper I'd just run conventional PVC or ABS save you time, money , and still be very long lasting

 

[Tuttles Revenge]

Copper DWV is the thinnest walled copper tube for plumbing. We use it a lot in buildings that require fire rated materials. Its small, lightweight and uses typical plumbing tools to assemble. However, it doesn't stand up to a lot of abuse of chemicals that people put down their drains. But maybe that is the trade off. No clogs No chemicals. I dunno. The book was written in the mid 90s from my bit of research so well into when plastic DWV would have been widely used and accepted so its not like the guy wouldn't have any experience with plastic DWV.

I always was told that keeping grease a liquid longer by keeping it warm and letting it dump into a larger pipe was just a good way to clog your larger diameter pipes. But its not something I have direct experience with except for that one new restaurant I plumbed with a 2k gallon grease interceptor who chose to dump theirs down a drain that didn't go to the interceptor.. they ended up clogging an entire strip mall.

I just find that when I demo out properly installed plastic drains, they almost always look brand new on the inside. Only a bit of dried bits at the high water mark as material passes through.

 

[WorldPeace]

Great answer. Thanks.

Copper DWV is the thinnest walled copper tube for plumbing. We use it a lot in buildings that require fire rated materials. Its small, lightweight and uses typical plumbing tools to assemble. However, it doesn't stand up to a lot of abuse of chemicals that people put down their drains. But maybe that is the trade off. No clogs No chemicals. I dunno. The book was written in the mid 90s from my bit of research so well into when plastic DWV would have been widely used and accepted so its not like the guy wouldn't have any experience with plastic DWV.

I always was told that keeping grease a liquid longer by keeping it warm and letting it dump into a larger pipe was just a good way to clog your larger diameter pipes. But its not something I have direct experience with except for that one new restaurant I plumbed with a 2k gallon grease interceptor who chose to dump theirs down a drain that didn't go to the interceptor.. they ended up clogging an entire strip mall.

I just find that when I demo out properly installed plastic drains, they almost always look brand new on the inside. Only a bit of dried bits at the high water mark as material passes through.