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Pipe Confusion

Posted: Fri Jun 30, 2006 10:11 pm
by Atlantis
I have a section of 2" PVC in my basement, I'm not sure if it's PW or DWV. It says, 260PSI at 76 F. The DWV is in huge letters compared to the rest, but it also has PW written on it. Can somebody clear this up.

Posted: Fri Jun 30, 2006 10:27 pm
by saladtossser
Its rated... this happens a lot, you are fine.

Posted: Fri Jun 30, 2006 10:30 pm
by Atlantis
Ok good, were finishing my basment and I get whatevers left over, not that PVC is that expensive. It was just really confusing.

Also, are all couplers pressure rated? I noticed one with DWV rating, are there PW ones as well?

Posted: Fri Jun 30, 2006 11:40 pm
by Shrimphead
Yes, they make dwv and pw fittings including couplers.

Posted: Sat Jul 01, 2006 9:37 am
by x.X.Cpt.Rollhart.X.x
dwv dont mean that its not rated, it means that its a drain pipe ...

Posted: Sat Jul 01, 2006 10:22 am
by noname
I haven't seen actual pressure ratings on a lot of the fittings around here but they say Sch 40 PVC 1 NSF-PW so I just use it.

Posted: Sat Jul 01, 2006 10:53 am
by carlbelcher
NSF PW = Pressure rated
NSF DWV = Not pressure rated (generally speaking)


Sch. = "ANSI Pipe Schedule or the thickness of the pipe"

The pipes pressure rating is written on the pipe itself (280psi @ 72 F) even pipe rated Sch.40 may not be pressure rated (Sch.40 cellular core ABS) as for fittings if they are Sch.40 they are pressure rated, since for some reason they don’t put the pressure rating on fittings.

:!: Foam / Cellular Core is not pressure rated even if it says Sch.40 :!:

Posted: Sat Jul 01, 2006 11:02 am
by Shrimphead
I don't think that you are right about the fittings, Carl. My fittings do say pw on them. Just because they are sch 40 doesn't mean that they are pressure rated. Also, if it says pw, then it is pressure rated, and will have a numerical rating as you said.

Posted: Sat Jul 01, 2006 11:33 am
by carlbelcher
PW means that it is for “potable water” and is pressure rated but DWV doesn't mean that it isn't pressure rated.

Just look for the psi rating on the pipe if it doesn’t have you its not pressure rated.

http://nsf.com/business/plastics_piping ... sPipSysCom

Posted: Sat Jul 01, 2006 6:52 pm
by frogy
DWV fittings are very very thin, look and feel a 3" Tee in DWV vs. a 3" Tee in PW, the 2" will weigh noticably more because it has much thicker walls....

DWV fittings are NOT pressure rated and can be very dangerous if they are over 2" fittings (they can still be dangerous under 2")...

PW fittings are SCH 40, DWV fittings aren't... DWV pipe might be SCH 40, but it's cellular core, which means it's definately not safe to use...

If the fittings are SCH 40 they're fine, if there DWV they're not....

Also if the fittings don't specify NSF-PW or NSF-DWV, these are other ratings...

ASTM D1785 = for Pressure applications
ASTM D2665 = for DWV

Posted: Sat Jul 01, 2006 7:24 pm
by carlbelcher
Pressure rated and non pressure rated fitting and pipe can both be sch.40 the schedule of the pipe has NOTHING to do with it being pressure rated or not.

Posted: Sat Jul 01, 2006 7:57 pm
by Atlantis
Schedule means thickness and helps you find the right size fitting for it.

My pipe does not say cellular anywhere on it, if I saw that I would'nt even have asked.

It has both of those numbers written on it conveniently.
It says 280 PSI @ 77F. 2" Pipe
My 1.5" pipe says 330 PSI @ 77f.

Posted: Sun Jul 02, 2006 10:51 am
by frogy
If it has a pressure written on it it's %100 guarenteed pressure rated... They say NSF-DWV and NSF-PW on them because if they're rated for pressure that also means they're rating for drain, waste, and vent...

Posted: Sun Jul 02, 2006 11:53 am
by Atlantis
OK so it's safe to use, thanks for the help.

Posted: Mon Jul 03, 2006 1:25 pm
by DramaPrinceWm
:twisted: ineed hulp i mav mayd a potato gun but it uosd harspray i mav 75 dllrs and need tow billd a air powered potato gun can ine but huulp me