We always use schedule 40 for anything that is pressurized.

On all previous repairs, we encountered the same. On the last two repair projects, we found a company using the thin wall stuff on live lines. I told the owners I didn't find that to be too good. New homes and expensive at that. Freezing climate is probably going to tear them up in my opinion. How about ideas and opinions?

Thanks ,

John

Hehe...95% of the people here use SDR-35 or 21 (the so called thin/eggshell pipe) on their high pressure lines.

I use SCH 40, because its a bit more fracture resistant, and I work in a rock infested area. If I installed in pure clay or sand all the time, I would use SDR-21...Its still rated for 200 psi.

And for whats its worth, SDR pipe is usually more freeze tolerant than sch 40 in my experience.

 

Class 200 PVC?

That is all that we & every other irrigation contractor here in Pittsburgh use. In fact, it is very rare that I find schedule 40 while servicing systems. Usually, the only time that I see sch. 40 is if the contractor used PVC inside the home (which we do not do - copper only inside! ).

Rob

 

SDR-21 rated at 200 psi, and SDR 26 rated at 160 psi is fine for live pressure lines. Sch 40, SDR-21 and SDR 26 all have a hydrostatic burst pressure of 2000 psi.

Advantages of SDR pipe - Lower friction loss at same flows and velocities. Less cost in the smaller sizes. Pressure rating remains constant from 3/4" on up to 8" and beyond. As SDR pipe size increases so does the wall thickness by the standard dimension ration (SDR) thereby maintaining the 200 psi rating. As Sch 40 increases the wall thickness also increases by not by a ratio but by an equivalent size of steel pipe. As a result Sch 40 working pressure actually decreases as the pipe gets larger. In fact at 4" SDR is 200 psi while Sch 40 is 210 psi. At 5" SDR still has 200 psi while Sch 40 is under 200.

Advantages of Sch 40 - only one I can think of is more resistance to damage in rocky soils when pipe is pulled or if the backfilling on trenched lines is done haphazardly. It also satisfies the plumbing inspector in some municipalities who has convinced the city that Sch 40 is better.

Apparently SDR pipe is deemed proper for large commercial applications and for golf courses where the pipe is under higher pressures and is cycled more than most residential systems ever will be. It is not the structure of the pipe that causes the problems that I have observed over the years. It is the installer that is usually at fault. Piling the dirt back in the hole including rocks and other debris which can cause puntures and abrasion over time. It takes a little more time, but a 3"-4" bed of clean backfill will save a lot of headaches down the road. As far as freeze damage Sch 40 will freeze as readily as SDR if given the opportunity. But since most systems are drained and blown out up north this shouldn't be too much of a problem.

The only time I run across Sch 40 on the systems down here is when the system was put in by a plumber (usually 3/4" and a really crappy job) or on a homeowner installed system and they bought the parts at the box store.

Just my $.02

Jerry

Jon do people up that way really use SDR-35? That is usually non-pressure sewer pipe.

 

Yes, it is the thin wall stuff that I thought was only for laterals off a main line where there was dynamic pressure and not static all the time. See vent pipe the same type.

John

 

SDR-21 rated at 200 psi, and SDR 26 rated at 160 psi is fine for live pressure lines. Sch 40, SDR-21 and SDR 26 all have a hydrostatic burst pressure of 2000 psi.

Advantages of SDR pipe - Lower friction loss at same flows and velocities. Less cost in the smaller sizes. Pressure rating remains constant from 3/4" on up to 8" and beyond. As SDR pipe size increases so does the wall thickness by the standard dimension ration (SDR) thereby maintaining the 200 psi rating. As Sch 40 increases the wall thickness also increases by not by a ratio but by an equivalent size of steel pipe. As a result Sch 40 working pressure actually decreases as the pipe gets larger. In fact at 4" SDR is 200 psi while Sch 40 is 210 psi. At 5" SDR still has 200 psi while Sch 40 is under 200.

Advantages of Sch 40 - only one I can think of is more resistance to damage in rocky soils when pipe is pulled or if the backfilling on trenched lines is done haphazardly. It also satisfies the plumbing inspector in some municipalities who has convinced the city that Sch 40 is better.

Apparently SDR pipe is deemed proper for large commercial applications and for golf courses where the pipe is under higher pressures and is cycled more than most residential systems ever will be. It is not the structure of the pipe that causes the problems that I have observed over the years. It is the installer that is usually at fault. Piling the dirt back in the hole including rocks and other debris which can cause puntures and abrasion over time. It takes a little more time, but a 3"-4" bed of clean backfill will save a lot of headaches down the road. As far as freeze damage Sch 40 will freeze as readily as SDR if given the opportunity. But since most systems are drained and blown out up north this shouldn't be too much of a problem.

The only time I run across Sch 40 on the systems down here is when the system was put in by a plumber (usually 3/4" and a really crappy job) or on a homeowner installed system and they bought the parts at the box store.

Just my $.02

Jerry

Jon do people up that way really use SDR-35? That is usually non-pressure sewer pipe.

Damn nice job Jerry!

We pretty much stick to CL 200 for everything here. It will carry more water in it until you reach 6" diameter where the difference between SCH 40 and CL 200 switch places on the friction loss charts. When we get that large we usually switch to C-900 pipe anyway. You cannot buy 1/2" CL 200 here through the supply houses because it is just too thin. All the suppliers switch to CL 315 for 1/2" pipe. However, you can buy some really thin stuff at Cheapo Depot.

 

I did not anticipate the wide difference of opinions. When I cut the thin stuff, it is just so brittle it snaps.

I will stick with the schedule 40 for pressure lines. Just my comfort zone, I suppose. I don't use poly for live lines, no matter their rating. I will not warranty any winterizing with the thin pipe also.

Thanks for the input, all.

John:laugh:

 

John,
Agree with you, as all I use is Sch. 40 on all my mainlines, just what I feel is right for the job regardless of the extra $3-$5 in costs. Regarding loss in pressure, I think for the most part we are talking average residental jobs here and not large commercial projects, so the pressure loss is immaterial to what the job requires.

 

When I cut the thin stuff, it is just so brittle it snaps.
John:laugh:

Even CL 200 in 1" and below can be tricky. especially if the weather is on the cool side. Quick dab of primer warms the pipe up and it cuts like butter. We use Klein snap-cutters for our pipe 1-1/4" and below. Lennox bone saws on 1-1/2" and larger until we have to take out the Dewalt.

 

Schedule 40 for sure on the mains....minimum 1 inch. We have in excess of 80 psi in my county. Somebody messes with a regulator....water hammer....bang! Not worth the risk.

 

Schedule 40 for sure on the mains....minimum 1 inch. We have in excess of 80 psi in my county. Somebody messes with a regulator....water hammer....bang! Not worth the risk.

Water hammer is not going to split the piping in 99% of the cases. It is going to blow the fittings apart first. Poor or improper solvent welded joints are normally what sustains the damage.

Read the markings on the side of the PVC pipe. For NSF water approved piping you will see a marking that reads "PVC 1120" This translates to Class 1, Type 1, 2000 psi hydrostatic burst strength. It is the same for SDR as it is for Sch 40.

 

I was simply basing my comment on the 200 psi rating mentioned in the thread.

I guess I need to learn how to read. Reading comprehension wasn't one of my better subjects.

If they're both rated at 2000 psi burst than I would probably go with the one that is cheapest and easiest to install.

 

Three friends check into a motel for the night and the clerk tells them the bill is $30, payable in advance. So, they each pay the clerk $10 and go to their room. A few minutes later, the clerk realizes he has made an error and overcharged the trio by $5. He asks the bellhop to return $5 to the 3 friends who had just checked in. The bellhop sees this as an opportunity to make $2 as he reasons that the three friends would have a tough time dividing $5 evenly among them; so he decides to tell them that the clerk made a mistake of only $3, giving a dollar back to each of the friends. He pockets the leftover $2 and goes home for the day! Now, each of the three friends gets a dollar back, thus they each paid $9 for the room which is a total of $27 for the night. We know the bellhop pocketed $2 and adding that to the $27, you get $29, not $30 which was originally spent. Where did the other dollar go????

 

That is what I mean about reading comprehension......

 

The other dollar was never there. Turn the story into a math equation, and that becomes obvious. (and didn't we all love 'word problems' in school)

 

Actually the dollar is there.....It's just that what the guests perceived they payed, what was actually paid to the clerk, and what the bellhop walks away with are 3 different things. These perceptions are all brought together in the same story. 30 bucks is still there.

 

The 'missing dollar' is what isn't there, since it was never missing in the first place. The guests paid $27 dollars for a $25 dollar room, and the bellhop pocketed $2. It does make for a head-scratcher if you let it.

 

Originally they payed 10 each for 30 bucks.

When the clerk hands back 5 dollars they now have payed 8.33333333 dollars each or 1/3 of 25 and the bellhop is holding 5 bucks.

He hands each one a dollar. They now have spent 9.333333333 dollars each. Not 9. 9.33333333333 x 3 = 28 (rounding off the odd penny).

28+the 2 dollars the bellhop is still holding=30 bucks.

The guests thought they were paying 9 dollars....but they payed 9.3333333. The total price of the room is what changes everything.

 

The guests paid nine bucks each (not nine-and-a-third) for a room which they should have paid eight-and-third apiece. The bellhop pockets the extra two-thirds of a dollar each guest didn't get back.

 

"The guests paid nine bucks each (not nine-and-a-third) for a room which they should have paid eight-and-third apiece. The bellhop pockets the extra two-thirds of a dollar each guest didn't get back"

9+2/3 they didn't get back....time 3 = 29.

This is fun ain't it.

 

Just having some fun.

Everyone forgets that after he hands them 1 dollar each...they now have spent only 27 dollars....not 30. The bellhop doesn't tell them about the other 2...which he keeps. It would have been divided into 3 parts of .66 each...which would make the total they spent.....8.33....or 1/3 of 25 dollars.

The 30 dollars being 27 is the kicker. That's one of my favorites. See ya'

 

Now that I look back on things from last night this should have been a dead giveaway that this joker was a troll.

 

He's the bellhop. If he'd swipe two bucks from the guests, a wireless notebook isn't out of the picture.

 

He's the bellhop.

Putz somehow comes to mind for me.

 

Class 200 pvc is great for most jobs because it is pressure rated high enough and has less friction loss over distance for the same size pipe as sch 40. Its common to use in irrigation.

 

Class 200 pvc is great for most jobs because it is pressure rated high enough and has less friction loss over distance for the same size pipe as sch 40. Its common to use in irrigation.

Except for 1/2" which suppliers around here don't carry because it is just TOO thin. Heck... they may not even make it any longer since I see that it is missing from my Friction Loss charts. We use CL 315 in that size.