Plastic Pipe Compatibility

Plumbing Forums

Help Support Plumbing Forums:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

sburtchin

Active Member
Joined
Feb 9, 2015
Messages
40
Reaction score
4
Location
,
I have a sizable collection of various kinds of (mostly white) plastic pipe and a bag of white fittings. I need to replace all of my (copper) waste drain plumbing. My local Lowes and Menards have white PVC and black (?ABS?) all for the same purpose. First, which is better and why? Second, what can I salvage from my pipe collection?

(Pipe) I have:
- lots of white SCH 40 PVC (like sold at Lowes & Menards)
- gray PVC SCH 40 conduit
- white Non Pressure (ASTMF-891) (same wall thickness)
- black DWV (same wall thickness)
- white DWV (same wall thickness)
- white PVC SCH 20

What about the fittings? They are all white, but do I need to be concerned about the type of plastic or "SCH"?
 
The only pipe and fittings you should be using are DWV. The local codes in your area would specify weather PVC or ABS is preferred
 
My Original statement:
This is a DIY poject. As long as it's safe and will last forever, I don't care what the codes say, especially ones that say I have to use the worst quality materials available - like the DWV copper - which is the reason I'm in this predicament now. If it's as good or better than code, is all I care about.
What I was trying to express:
This is a DIY poject. I want it to be safe and last forever. I don't care if the codes say I should to use the worst quality materials available - like the DWV copper - which is the reason I'm in this predicament now. If it's as good or better than code, is what I care about.
Edit made 12:40 PM 1-22-2016

I'm just guessing, but isn't the white PVC we use for drinking water just a better grade of the same material used in the white "DWV" and "Non Pressure" pipes. Wouldn't that be better than code?

And, what is the purpose for the "Non Pressure" designation?
 
Last edited:
Nothing last forever and DWV copper is still being used today. I have only seen it fail when corrosives have been added to it.
The only corrosive that DWV pipe ever saw was biologic acion on the organics froim the kitchen sink. After 50 years I could push my finger through the side of that copper pipe.

I still need to know, can I mix the white DWV, white Non Pressure and gray schedule 40 PVC with the white schedule 40 PVC? This is only for waste water.

What is "non Pressure" pipe used for?
 
This is a DIY poject. As long as it's safe and will last forever, I don't care what the codes say
dont%20care.gif
, especially ones that say I have to use the worst quality materials available - like the DWV copper - which is the reason I'm in this predicament now. If it's as good or better than code, is all I care about.

Why would someone take the time and energy to write code and most localities enforcing it?
 
Why bother asking professionals for advice on hack jobs? Codes are made for a reason, if you don't want to work by them then you're kind of barking up the wrong tree. You can plumb a whole house with garden hoses and slinky ducts, but that doesn't make it right.
 
allright man, sch 40 is the thickness

sch 40 pipe is the pipe you will use to install dwv.in your house

not for pressure is a foam core pipe, used mainly for drains and vents
not for pressure/ as in water piping

grey piping is for electrical, not plumbing,

2 types of white pvc sch 40,

1 is pressure fittings
th


the other is dmv
th


you can see the difference, dwv is drain directional, pressure is not
 
Last edited:
Wow! Leave a little opening to be taken out of context and the sharks are everywhere!

Please read the edit to my second post in this thread. Both paragraphs say exactly the same thing.

I NEVER said I did not care about the codes! A quote is not a quote when a phrase is taken out of context, or the punctuation or formatting is changed to emphasize something that was never intended to be emphasized.

Of course I care about the codes. I also care about why the codes exist, which is why I use #10 wire where the code says I need #12, and I use all commercial grade receptacles where the code says the 39 cent ones are OK. I bet Bob and Norm have used a lot of those 39 cent receptacles. It's not a hack job if everything is as good or better than the code requires.

If I wanted to do a hack job I could get all the info I needed from You Tube in just a few miinutes instead of expending all this effort to seek professional advice. Let me restate my origial request explicitly: What can I salvage from my collection that would be as good or better than the code requires?

No conduit,that is for electricians. Non pressure such as vents and gravity drains. Pressure such as pumped discharge.
I'm still fuzzy on the purpose for the "Non Pressure" designation. I get that I can use it for vents and to drain the water from my roof, but this looks like a graviy drain situation to me being a non-professional. Is it a lower grade than the DWV pipe?
 
Cell core and regular PVC are considered to be completely interchangeable. Both types can even be used underground.

The biggest difference that I know of is that the cell core PVC is much lighter than regular PVC. Cell core PVC is also much easier to cut... ;)

The weight issue isn't a big deal until you start getting into 20 foot lengths of 4" PVC and larger pipe sizes and then you really can start to appreciate the lighter material!

Finally, the cell core PVC is also a more BRITTLE material in that it has a tendency to crack/shatter if mishandled, especially in colder weather like we have here in my area.



the purpose, is weight. you hump pipe all day,you appreciate the difference
 
Last edited:
not for pressure is a foam core pipe, used mainly for drains and vents
.
.
you can see the difference, dwv is drain directional, pressure is not
OK - I will save the "Non Pressure" for vents, diverting rainwater, and non-plumbing projects.

Thanks! That demistifies the fittings. I can see where the sharp bends in the pressure fittings could be problematic for water containing solid waste.

If I'm reading you right, the same white SCH 40 PVC pipe is commonly used for both pressure and waste water, and the white SCH 40 PVC with the "DWV" markings may be used only in drain/waste/vent applications.

I will check to see if the local code allows me to use the white PVC.

What is the purpose for SCH 20? Looks like that stuff would shatter if you bump it.
 
The Sch 20 might be intended for irrigation. Don't use it for drainage, it is easily damaged.

Personally, I would use only Sch 40 PVC pressure rated pipe that has not been exposed to too much sunlight or fluorescent light. The UV rays in either of those will eventually weaken the pipe. And DWV fittings, PLUS no double 1/4 bends, crosses, or double wyes.
 
Lowes tried to sell me a SCH 20 trap for my kitchen sink. The price difference was huge, but I replaced with the brass. I use that area for storage. I can just imagine the mess when you bump that thing with a mop bucket!

you cant use pvc as a water line inside a building, only outside the building
Ok, I learned something new.

Interesting Story:
I saw a lot of white PVC in my neighbor's house. Earlier, his type M copper had started to develop some leaks. I said: "Great! That's easy to fix. Just remove the bad sections and sweat in some new type L copper as needed". Some years later I was in his basement and noticed he had replaced about half of his plumbing. Code be da##ed! No pipe went to waste in that house. I never knew there were so many different kinds of fittings and clamps available to join together so many diffrent types of pipe without the use of heat or cement. There was even a section of garden hose feeding the water softener.
 
There was an interesting discussion here a few months ago concerning PVC/CPVC residential water supply. It (PVC COLD side only) was allowed up to fairly recently but confusion identifying either type (COLD or HOT supply) was difficult for the AHJ inspector even though the tubing ID markings had to be displayed outwards. I guess there were some runs not easily viewable so code was changed to CPVC only.

That is maybe why you are seeing mixed usage in an older home?

Anywho, proper ID of plastic PVC pipe should be fairly easy as it will be marked by the manufacturer for the plumber to determine if approved by code for install.

PVC Piping Identification.jpg
 
Back
Top