Copper Pipe Size Question - Plumbing - DIY Home Improvement | DIYChatroom


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Plumbing

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-30-2009, 02:31 PM   #16
Member
 
Join Date: Nov 2007
Posts: 325
Rewards Points: 296
Default

Copper pipe size question


Here type L is required for any domestic water use, M can only be used in heating systems (someone else stated similar perhaps we live in the same state). I would go with type L regardless, my house is 40 years old and the copper pipes are failing I've been replacing them with type "L" (which is required here anyway, and possibly my area eats copper and why L required).

The short answer about the 3/4" or 1/2" thing has to do with the velocity of the water (how fast it runs through the pipes). With all fixtures turned on to a branch the velocity of the water in the pipe must flow under 8 fps, anything more and the water flows so fast it starts scraping the copper pipe rapidly shortening life.

A 1/2" pipe can usually supply enough water for 3 fixtures keeping velocities under 8fps... which is typically a single bathroom (shower,toilet,faucet). If your upstairs has 2 bathrooms you need 3/4" feeds but only need 1/2" branches off it to each bathroom.

A bathroom with 4 fixtures (toilet, shower, 2 sinks). The cold line has to be 3/4" coming in since cold supplies all 4 fixtures (toilet, shower, 2 sinks) the hot only needs to be 1/2" since it only feeds 3 fixtures (it doesn't feed the toilet).

3/4" pipe can only feed 6 fixtures, so an upstairs with a full bathroom with 2 sinks (4 fixtures) and a full bathroom off the master bedroom (another 3 fixtures) would require a 1" cold water feed and 3/4" hot. Confused yet!?

1/2" pipe can typically supply water for up to 3 fixtures.
3/4" pipe can typically supply water for up to 6 fixtures.

It's okay to use 3/4" and branch off to 1/2" as long as there isn't more than 3 fixtures on each 1/2" branch or more than 6 fixtures in total the 3/4" feeds.

I have no idea about PEX.

Advertisement


Last edited by Piedmont; 01-30-2009 at 02:40 PM.
Piedmont is offline   Reply With Quote
Old 01-30-2009, 03:02 PM   #17
Safe, Most of the Time!!
 
brokenknee's Avatar
 
Join Date: Dec 2008
Location: MN
Posts: 652
Rewards Points: 500
Default

Copper pipe size question


If required by code, then that is what you should use regardless of your opinion. Codes are put in place for a reason.

I googled copper history and found,

"Corroding copper tubing has been reported in cities as far apart as Phoenix, Arizona;
Andover, Massachusetts; Santa Clarita, California; Lima, Ohio; Washington, DC; and Jacksonville, Florida."

Something to do with low PH levels in the water.

If pex is permitted by code in your area, I would look into that.

Edit: life expectancy of copper pipe was rated from 25 to 40 years. It made no mention of the type of copper it was rating.

I have no affiliation with any company or anyone that has anything to do with pex. I have just started using it and IMHO it is the best thing since sliced bread in plumbing.
__________________
"Clarity to Agreement" Dennis Prager

Picture/Photo Pitcher/Carafe ------- Where/Someplace Were/Be

Last edited by brokenknee; 01-30-2009 at 03:06 PM.
brokenknee is offline   Reply With Quote
Old 01-30-2009, 04:46 PM   #18
Member
 
Join Date: Jun 2008
Posts: 1,264
Rewards Points: 500
Default

Copper pipe size question


Quote:
Edit: life expectancy of copper pipe was rated from 25 to 40 years. It made no mention of the type of copper it was rating.
C'mon man. Let's be keeping it real in dis place here.

Copper piping became the norm during the 1950's. My apartment block was built in 1960, and it has copper piping for all the domestic water. Ditto for my father's building built in 1961. One sister has a house built in 1972 and the domestic water supply piping is all copper. My other sister has a house built in 1978 and also has copper piping throughout.

So far, ONE pinhole leak in a copper pipe that seemed to be in place when the concrete floor was poured around that pipe in a laundry room. I suspect that pin hole leak may have been a matter of highly alkaline concrete being in contact with the outside of the copper, and the pin hole leak forming on the outside of the pipe, not the inside.

Also, those copper pipes removed from my building showed no signs whatever of corrosion or damage or pin hole leaks forming in them. (Whenever I would renovate a bathroom, I would remove the Type L copper pipe going up to the shower head and replace it with a piece of Type M since this pipe is only under low pressure when someone is having a shower.)

I contend that my experience with copper piping is TYPICAL, and that your suggestion that copper piping typically only lasts 25 to 40 years needs a reality check. Typically, the copper piping in new farm house 20 miles out of town will last the entire life of the house and will be salvaged for it's scrap metal value once the house is bulldozed to make way for a new shopping center. If copper piping only lasted 25 to 40 years, then on average, people would be replacing their home's copper piping as often as they replace their kitchen stove. In fact, in almost all cases, the copper piping in a house is never replaced.

You don't need to know the rest:

Why does copper last so long? With the exception of noble metals like gold and platinum, essentially all metals rust. However, for most metals like nickel, chromium, aluminum, titanium, tungsten, hafnium, etc. the oxide film they form is impermeable to oxygen, so the formation of an oxide film stops the metal from further "rusting". This is why stainless steel doesn't rust; it has sufficient chromium and nickel in it that the oxide film that forms over that steel is impermeable to oxygen. Stainless steel DOES have an oxide film over it, but it's so thin that it's invisible. (Just like low-e window glass has a film of silver about 70 atoms thick on it, but that layer of metal atoms is so thin as to be almost invisible.)

Copper oxide is only highly impermeable to oxygen molecules. So, as the copper oxide film forms, it better and better protects the underlying copper from further oxidation. This is why brand new pennies are the orangey gold colour of copper but 20 year old pennies are brown in colour, and 100 year old pennies are indistinguishable in colour from 20 year old pennies. And, it takes an imperceptible amount more sanding to sand the brown oxide surface layer off a 60 year old copper pipe than a 20 year old copper pipe, not three times as much sanding.

It's the oxide film that forms over copper that protects it from rusting and corroding when exposed to air and water with dissolved oxygen in it.

Iron (and steel is nothing more than iron with a small amount of carbon in it) is actually a rarity. Iron forms an oxide film that doesn't stick to the metal and is highly permeable to air and water. As a result, iron will rust until there's nothing but iron oxide remaining. However, iron and steel are so common in our society that we think it's common for metals to rust, oxidize and corrode away till there's nothing left. That's wrong. Most metals form oxide films on their surface, and most of the time that oxide film protects the metal from corroding further. Iron is simply an extremely common exception to that rule.
__________________
Bashing my head against the walls in some of the internet's finest chat rooms.

Last edited by Nestor_Kelebay; 01-30-2009 at 04:52 PM.
Nestor_Kelebay is offline   Reply With Quote
Old 01-30-2009, 05:02 PM   #19
Safe, Most of the Time!!
 
brokenknee's Avatar
 
Join Date: Dec 2008
Location: MN
Posts: 652
Rewards Points: 500
Default

Copper pipe size question


This is were I got my information, page two http://restoremypipes.com/adf2/pdf/h...per_piping.pdf

I am sure it has to do with a nation wide average or maybe even a worst case scenario; in areas with low ph levels, corrosion is more of an issue.

Advertisement

__________________
"Clarity to Agreement" Dennis Prager

Picture/Photo Pitcher/Carafe ------- Where/Someplace Were/Be
brokenknee is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cast iron and rusty pipe question snowens Plumbing 2 07-27-2008 11:07 AM
Reclaimed water pipe (Purple PVC) repair and glue question smcmurrey Plumbing 3 07-07-2008 10:49 PM
Copper Pipe Problems jvc120er Plumbing 8 04-15-2008 02:07 PM
How to protect 3/4" copper pipe passing through concrete Mike Warner HVAC 2 03-13-2008 01:37 AM
Replacement pipe for hot water heat? Tmb9862 HVAC 18 01-12-2007 04:31 PM




Top of Page | View New Posts