Why use copper pipes instead of PVC pipe for all water and non-potable lateral?

[cjung]

Hi, I am working for a contractor and entry level for roadway construction.
I am curious why all specifications called out for copper pipes for all lateral, although the mains are PVC pipes.

Please help me to better understand the piping construction.

vty,
YC

 

[bimr]

Probably just tradition as well as ease of construction.

Note that the street water mains are probably bell and spigot pipe, with mechanical joints where necessary for restraint. It is generally recommended to use flexible joints (bell and spigot) for buried piping rather than solvent welded joints. The flexible joints will not break as easy when the ground moves.

Bell and spigot PVC pipe is not readily available in small diameters. PEX is probably a better alternative for the water service if your building code allows it:

https://www.rehau.com/us-en/mechanical-and-plumbing/municipal-piping

 

[coloeng]

Not just ease of construction, but reliability also. Copper tubing has been around a lot longer than the newer plastics that are being used for service lines and have a proven track record. PEX appears to be reliable, but there have been alternatives in the past that were touted as being better than copper and low and behold 15 to 20 years later they were having to be replaced. Copper is typically more expensive, but again, it has a proven track record.

 

[cjung]

Thanks, ALL.

We need to test the water pipe for 200 psi. The lateral pipe is smaller than main.
is it because of lateral pipe experiencing higher pressure during testing and PVC can't take the pressure?

 

[bimr]

Nothing to do with the design or test pressure. Nonmetallic pipes are fully capable of meeting the pressure and test requirements, if properly designed, specified and installed.

The reasons that PVC are not typically used for this application are detailed in the previous posts.

 

[mk3223]

The selection of either PVC or copper pipe could be based on the size and the flow requirements. As regarding the design or test pressure, the wall thicknesses of the PVC pipe could be different from the copper pipe for the same pipe size. So, the small copper pipe with thinner wall thickness may be used to provide the needed flow rate.