nsf-pw vs. dwv

[dudeman508]

well after reading all of the new posts written to help noobs i wanted to make my own.

this is a comparison of Dwv and nsf-pw



hope it helps!!!

[FishBoy]

unfortunately, this already exists in the wiki...

[dudeman508]

.....oh . I didnt see that when i looked at spud wiki

[jon_89]

Well I got pipe that says nsf-pw and then it says nsf-dwv. Whats up with that? I just realized this the other day.

[dudeman508]

thats really weird, did you paint over the pipe? Can you clearly see the writing?

[daberno123]

As long as it has a printed pressure rating on it it should be fine. Most of my pipes have both printed on it, along with a pressure rating to XXX psi

[JDP12]

almost all nsf-pw will have nsf-dwv written on it- like above said- look for a PSI rating

[jon_89]

Thank god the pressure is on it. Why do they put both on the pipe?

[Ragnarok]

Why do they put both on the pipe?

This is not uncommon. Any pipe that is suitable for PW (Potable Water) and is pressure rated is certainly up to the tasks of DWV (Drain Waste Vent, all low pressure applications).

It's a certification of what the pipe is usable for, not a pressure rating in itself. Unfortunately, DWV has incorrectly become a synonym for "non pressure rated", which is what has caused this confusion.

[MrCrowley]

DWV has incorrectly become a synonym for "non pressure rated"

And we're still working on the 'Sch 40 = Pressure Rated' synonym that dominates the web.

[dudeman508]

this is kind of random but on sch 80 pipe is the outer diameter bigger than that of a sch 40 pipe or is the inner diameter smaller. I'm guessing the inner diameter is smaller because if it wasn't people would use sch40 for golf ball barrels

[starman]

unfortunately, this already exists in the wiki...

Yeah it is, but since soooo many seem to skip wiki, this is a reasonably informative post...well put together. Anything to help raise awareness overall is a good thing....even if it's post by post..... 8)

this is kind of random but on sch 80 pipe is the outer diameter bigger than that of a sch 40 pipe or is the inner diameter smaller. I'm guessing the inner diameter is smaller because if it wasn't people would use sch40 for golf ball barrels

You are exactly right. The inner diameters are [maddeningly] not consistant with much of anything. The outer diameters have to fit common couplings.

One of the better "inner diameters" you can count on is the 2" sched 80....fits the outer dia of 1.5" pvc pipe like a glove.

[Ragnarok]

And we're still working on the 'Sch 40 = Pressure Rated' synonym that dominates the web.

Indeed. Considering SCH40, a dimensioning standard, to be a pressure standard can't have good results - however, it is better that people flock to unrated SCH40 than they use unrated thin wall or cell core pipe.

Obviously, killing both misconceptions dead would be ideal, but that's unlikely to happen. In spite of this forum being the biggest spud forum on the web, we do not make up enough of spudding as a whole - we make up a healthy majority of the high quality spudding, but not much overall.

However, as in the end, pressure ratings do not relate to the circumstances of a spudgun, a pressure rating is little more than a guarantee of more quality control and thus less likelihood that you'll get a dud piece of pipe.

The maximum burst pressure (That being the absolute maximum that could be expected the pipe would hold before bursting - i.e. add 1 more psi, and you could guarantee the pipe wouldn't withstand it) of rated SCH40 and unrated SCH40 specimens could take would be the roughly the same.
However, samples of unrated SCH40 specimens will have a lower "minimum burst pressure". (That being the lowest pressure at which the pipe will burst).

@dudeman508: Your assumption is correct, the internal diameter is reduced. The external diameter is unaffected.

[D_Hall]

DWV has incorrectly become a synonym for "non pressure rated"

And we're still working on the 'Sch 40 = Pressure Rated' synonym that dominates the web.

Thing is, Sch 40 = pressure rated USED to be a true statement.

Seriously.

ONCE UPON A TIME.....

Schedule = 1000 * Pressure / Allowable_Stress

....So yeah, once upon a time "sch 40" had very real implications regarding a pipe's ability to handle pressure. Alas, somewhere along the line the dimensions were standardized (made sense) and then materials changed (which then made the sch XX nomenclature meaningless!).

[MrCrowley]

Wow...you learn something new every day