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View Full Version : PEX versus Polyethelene


PJNTJ
09-28-2011, 11:07 AM
Why don't irrigation installers use PEX instead of regular poly? Based on what little research I've done PEX is superior in every way, except for sunlight damage which isn't really a concern. PEX is becoming so much the standard now that I see its cheaper than poly. I can't be the first person to think of this, there has to be a reason besides "we use poly or PVC because that's what we've always used and that's the way it is".

Cross-linked Polyethelene meets ASTM standards for heat, cold, pressure, etc etc, certified for outdoor use, cold weather, etc, etc, seems far superior to poly. What am I missing here?

Thanks for your opinions.

Paul

Wet_Boots
09-28-2011, 11:10 AM
Sunlight damage is an immense concern. :hammerhead:

PJNTJ
09-28-2011, 11:15 AM
In the northeast we don't get any sunlight 16 inches below ground.
:)

irritation
09-28-2011, 11:18 AM
Ease of installing fittings. I've never seen a saddle for pex.

PJNTJ
09-28-2011, 11:27 AM
Ease of installing fittings. I've never seen a saddle for pex.


Sharkbite fittings are press and pull. Parker has the Prestoloks, etc, etc. I suppose those would be a little more cost prohibitive, but there's a lot of fitting companies out there these days. I'm still thinking...

Wet_Boots
09-28-2011, 11:45 AM
Just why are you worried about poly pipe at a burial depth of 16 inches?

PJNTJ
09-28-2011, 11:54 AM
Just why are you worried about poly pipe at a burial depth of 16 inches?

I'm not actually, I want to go much more shallow, I was throwing that number out there to act like a tough guy. Freeze/thaw cycles is actually my main concern, which is why I'm looking at all PEX versus poly. I can't find many drawbacks.

Wet_Boots
09-28-2011, 12:14 PM
Freeze thaw is why you don't consider PEX, because it is a phenomenon (frost and heave) that can bring pipe to the surface, where it is exposed to sunlight.

PJNTJ
09-28-2011, 12:26 PM
Freeze thaw is why you don't consider PEX, because it is a phenomenon (frost and heave) that can bring pipe to the surface, where it is exposed to sunlight.

ok, yea, I'm new but your messing with me right?? :dizzy:

Wet_Boots
09-28-2011, 12:29 PM
You would have to be new to not know that sprinkler pipes not covered by a lawn can work their way to the surface, in freezing climates.

Kiril
09-28-2011, 12:30 PM
Why don't irrigation installers use PEX instead of regular poly? Based on what little research I've done PEX is superior in every way, except for sunlight damage which isn't really a concern. PEX is becoming so much the standard now that I see its cheaper than poly. I can't be the first person to think of this, there has to be a reason besides "we use poly or PVC because that's what we've always used and that's the way it is".

Cross-linked Polyethelene meets ASTM standards for heat, cold, pressure, etc etc, certified for outdoor use, cold weather, etc, etc, seems far superior to poly. What am I missing here?

Thanks for your opinions.

Paul

Compare the costs of exterior grade PEX and fittings to that of poly and you will probably have your answer.

PJNTJ
09-28-2011, 12:54 PM
You would have to be new to not know that sprinkler pipes not covered by a lawn can work their way to the surface, in freezing climates.

Heck yea I'm new, 4 posts and I just joined yesterday. PEX or Poly won't make any difference if it gets that close, it's going to freeze, I think PEX is a better choice, except for fitting cost which may or may not be a consideration for everyone.

Let me ask this way: if cost were not a consideration, would you go all PEX?
And for the really real pro's: what's the gpm loss of 1" ID versus OD over 100 feet? 200 feet? Is this a consideration at 60 PSI?

rlitman
09-28-2011, 01:22 PM
Compare the costs of exterior grade PEX and fittings to that of poly and you will probably have your answer.

Do they may PEX fittings that can handle freeze/thaw?
I know the PEX tubing itself is more resilient in that way, but wouldn't the fittings still be subject to freeze damage?

txirrigation
09-28-2011, 01:31 PM
Heck yea I'm new, 4 posts and I just joined yesterday. PEX or Poly won't make any difference if it gets that close, it's going to freeze, I think PEX is a better choice, except for fitting cost which may or may not be a consideration for everyone.

Let me ask this way: if cost were not a consideration, would you go all PEX?
And for the really real pro's: what's the gpm loss of 1" ID versus OD over 100 feet? 200 feet? Is this a consideration at 60 PSI?

Most heads operate best 30-40 psi... so no.

Wet_Boots
09-28-2011, 01:32 PM
Heck yea I'm new, 4 posts and I just joined yesterday. PEX or Poly won't make any difference if it gets that close, it's going to freeze, I think PEX is a better choice, except for fitting cost which may or may not be a consideration for everyone.

Let me ask this way: if cost were not a consideration, would you go all PEX?
And for the really real pro's: what's the gpm loss of 1" ID versus OD over 100 feet? 200 feet? Is this a consideration at 60 PSI?Why go with a material that cannot withstand exposure to the light? Old systems can have poly at the surface, exposed to the light, and not have it fall apart. PEX would not endure in those conditions.

GreenI.A.
09-28-2011, 02:15 PM
I'm going to go with pricing and availability. Pex pipe and fittings are more expensive than poly (granted I bought it at HD in small quantities for a remodel I did in my house). But what I paid for it, it was still more per fitting the HD charges for poly fittings. A big factor to is availibility, the irrigation supply houses already have PVC and poly fittings, how likely are they to bring in racks of new produts that people know nothing about

Wet_Boots
09-28-2011, 02:35 PM
....and the fact that a clamper for PEX rings costs about a hundred bucks might also be a factor, even if PEX were made to be sunlight-proof

FIMCO-MEISTER
09-28-2011, 02:44 PM
Boots I'm sorry but this sunlight thing is really weak.
Posted via Mobile Device

Wet_Boots
09-28-2011, 03:07 PM
Boots I'm sorry but this sunlight thing is really weak.
Posted via Mobile DeviceIt is truth nonetheless. If sunlight was never a factor, there would be no such thing as UV-R pipe.

DanaMac
09-28-2011, 03:25 PM
How often is poly or PEX going to be in the sun? And for how long? How often does it actually rise to the surface, other than 1/2" drip pipe in beds of rock and mulch? I really couldn't care less about whether it will get sunlight or not.
What I care about, is that I am not going to carry another style of pipe and fittings on the truck. HD is already carrying a re-branded line of the Blu-Lock stuff, that is a pale green. I'm not going to carry it, or PEX on the vehicle. Stick with what is tried and true, and available at most supply houses.

Wet_Boots
09-28-2011, 03:37 PM
An industry that can't be bothered to dig a hole over a foot deep to install a valve box is hardly to be trusted to ensure buried lines in non-lawn areas will never see the light of day.

FIMCO-MEISTER
09-28-2011, 04:52 PM
Still 52 weak man. Just admit the sunlight thing was a brain fart tangent so we can hijack this thread to baseball and whether the six or braves choke big time.
Posted via Mobile Device

Wet_Boots
09-28-2011, 05:08 PM
PEX dies from high costs before sunlight enters the equation. None the less, you don't install material that is sure to degrade from exposure.

Sox are the ones worrying big time. I wonder if tiebreaker games will be on the $3.99 MLBdotcom TV deal.

greenmonster304
09-28-2011, 09:06 PM
Heck yea I'm new, 4 posts and I just joined yesterday. PEX or Poly won't make any difference if it gets that close, it's going to freeze, I think PEX is a better choice, except for fitting cost which may or may not be a consideration for everyone.

Let me ask this way: if cost were not a consideration, would you go all PEX?
And for the really real pro's: what's the gpm loss of 1" ID versus OD over 100 feet? 200 feet? Is this a consideration at 60 PSI?

I will use pex for basement work if the customer wants to save a few bucks but I will use 3/4" pex in place of 1/2" CU and 1" pex in place of 3/4" CU because of the smaller inside diameter. That is if it is of any great length. Later this week I will use 100' of 1" pex to fix a pressure problem caused by the original installer. The original installer was lazy and didn't want to run the mainline from the POC in the basement through the dirt crawl space to the outside of the house. So he tapped the main in the pool house which was supplied through 200' of 3/4 CU and countless tees and fittings in the main house. He did this because right where the water main enters the house there is alot of hard scape so it's a pain to pipe through the crawl space but the pool house was easy for him, only about 8' of piping in the utility closet. I turned on the system and took dynamic pressure readings and there was a 20lb difference between where I will tap and where the original guy did.
Posted via Mobile Device

Wet_Boots
09-28-2011, 09:25 PM
What brand of PEX?

AI Inc
09-29-2011, 07:47 AM
do king grip manufacturers even make a bullet for pex?
could one core pex with a coring tool, or would they have to carry a drill to plumb heads.?
Is castaways in Whatley still open?

PJNTJ
09-29-2011, 10:02 AM
LOLOL, to the most important question: Yes, the "Whately Ballet" is still going strong. :laugh:

ReddHead
09-29-2011, 10:12 AM
PEX is a lot more work than Poly. After using it in my basement you have to be more precise with the cuts in your PEX so it butts up properly against the shoulder of the fitting. It's also not very flexible IMO. I don't trust SharkBite fittings in my basement, let alone buried in the ground in freezing conditions. I used one to temporarily repair my outside faucet and then quickly replaced it. I use the copper crimp rings. I also use the brass fittings as opposed to plastic. For some reason I can't bring myself to trust the plastic ones.

greenmonster304
09-29-2011, 07:02 PM
What brand of PEX?

I am not sure who makes the pipe but I use the Zurn tool and clamps. We did that job I was talking about today and it worked great. It went from 20 lbs dynamic to 40 lbs dynamic. Now I can begin to fix the horrible layout.

Question for you guys:

If you know the guy who put in a horrible system do you ever ask them what the he'll they were thinking?
Posted via Mobile Device

Kiril
09-29-2011, 09:49 PM
Question for you guys:

If you know the guy who put in a horrible system do you ever ask them what the he'll they were thinking?

No way dude ..... I've never done that. :)

AI Inc
09-30-2011, 07:31 AM
I am not sure who makes the pipe but I use the Zurn tool and clamps. We did that job I was talking about today and it worked great. It went from 20 lbs dynamic to 40 lbs dynamic. Now I can begin to fix the horrible layout.

Question for you guys:

If you know the guy who put in a horrible system do you ever ask them what the he'll they were thinking?
Posted via Mobile Device

Your assuming they were thinking. chances are , they were not.