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PVC vs DUCTILE

wrc

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Joined
Feb 20, 2014
Messages
156
Location
Topeka
What is everyone's opinions on pvc vs ductile iron for water mains? I've been thinking here lately as a lot of local systems are seeing a huge amount of breaks. Is pvc as prone to breaks as ductile? Which one last longer? Are the breaks worse on pvc or ductile? Are the breaks the came type, dose pvc get radial breaks just like pvc? Or are they lateral breaks? If it is a lateral break will it run the full stick length? Dose pvc develop blow holes as often? Sorry for the lengthy question. I'm just curious to hear others experiences/thoughts.
 

CM1995

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Jan 21, 2007
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Alabama
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Running what I brung and taking what I win
Moving this to General Industry.

Depends on the installation IMO.
 

skyking1

Senior Member
Joined
Nov 3, 2020
Messages
7,727
Location
washington
I've yet to fix a water main break.
I do like the fact that you can encounter a ductile pipe with an excavator and not break it. PVC is not as tough to that kind of damage.
Both are gasketed installs with some flexibility.
Ductile can have a more aggressive field lock gasket.

All-Black-Field-LOK-350-e1611866047599.png
 

wrc

Well-Known Member
Joined
Feb 20, 2014
Messages
156
Location
Topeka
I've yet to fix a water main break.
I do like the fact that you can encounter a ductile pipe with an excavator and not break it. PVC is not as tough to that kind of damage.
Both are gasketed installs with some flexibility.
Ductile can have a more aggressive field lock gasket.

All-Black-Field-LOK-350-e1611866047599.png
I also like the fact ductile bells will accept a large amount of deflection where as pvc will not.
 

JLarson

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Joined
Aug 23, 2020
Messages
657
Location
AZ
Occupation
Owner- civil and heavy repair/fab company
I'm a big fan of all DIP and fittings but like the price and weight of C900 pipe better.

Most of the leaks we fix on plastic are older IPS PVC, usually cracks inside 90's or around tee branches.
 

skyking1

Senior Member
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Nov 3, 2020
Messages
7,727
Location
washington
I worked for a company that did ductile mains with case backhoes. All single axle dump trucks, and we had a trailer that we would drop by the supply house and they would load 10 tons of fittings on it, and the pipe would get drop shipped from the plant. Yes those fittings added up!
 

CM1995

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Jan 21, 2007
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13,436
Location
Alabama
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Running what I brung and taking what I win
Can you elaborate on install cm1995?

Well installation wasn't the best choice of words, environment it will be used in is a better term.

Soil conditions being first and foremost.

DIP - Good for rock and rocky trench installations. Urban and certain industrial applications where there are multiple utilities and the likely hood of digging around it is high.

However DIP can deteriorate in acidic soils if the cement coating is compromised. Certain chemicals can also eat DIP up rather quickly. I saw the video of a 6" DIP lateral less than 1 year old where the bottom of the pipe was completely gone - you could see the #57 stone bedding. That lateral was for a recently built Taco Bell...take what you will out of that.

C900 PVC is lighter but more fragile than ductile however it can withstand acidic soils and chemicals better than DIP. A country water main stretching a couple of miles in sandy or clay soils is a perfect use of C900. Lighter and cheaper to purchase and install. So more bang for a local water dept's budget.

On the flip side the city I live in just replaced about 2 miles of a 30 year old 8 and 12" PVC main that was installed in rock and apparently not bedded properly. Our house was serviced by this line and it constantly leaked. It was replaced with ductile.

Just my $.02. Both have their place.
 

cuttin edge

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Nov 9, 2014
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2,754
Location
NB Canada
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Finish grader operator
Where I live, some water mains are shallow, and they use iron so they can unthaw it with electricity. Public works has equipment just for that. I notice even new installs using iron. Never questioned the choice between the blue bruit or the iron. All water mains are bedded and back filled with gravel, and all sanitary are bedded with stone. I used to think it had something to do with the 2 former communities on either side of the river, but both sides have been engineered for either iron or plastic.
 

IceHole

Senior Member
Joined
Aug 14, 2023
Messages
675
Location
AK
Where I live, some water mains are shallow, and they use iron so they can unthaw it with electricity. Public works has equipment just for that. I notice even new installs using iron. Never questioned the choice between the blue bruit or the iron. All water mains are bedded and back filled with gravel, and all sanitary are bedded with stone. I used to think it had something to do with the 2 former communities on either side of the river, but both sides have been engineered for either iron or plastic.
Why do they freeze it?
 

WaterDoc

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Joined
Nov 2, 2010
Messages
126
Location
Toronto
Occupation
Complete water system disinfection services
Finally, an interesting topic. Lol.

Here in this part of Ontario PVC is the most widely used pipe material for distribution watermains. I only run into DIP at railway crossings or as risers in a fire system for an ICI building.

Transmission mains are CPP or concrete encased welded steel.

The PVC is easier to work with and has the same service life or better than DIP.

HDPE pipe is starting to show up more and more these days. Directional bore guys love using it.
 

WaterDoc

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Joined
Nov 2, 2010
Messages
126
Location
Toronto
Occupation
Complete water system disinfection services
I also like the fact ductile bells will accept a large amount of deflection where as pvc will not.
As a guy who makes his living performing hydrostatic pressure and leakage tests on watermains, I assure you that neither DIP or PVC joints can be deflected enough to be useful without leaking ( at test pressures).
 

cuttin edge

Senior Member
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Nov 9, 2014
Messages
2,754
Location
NB Canada
Occupation
Finish grader operator
Not enough cover over it and or flow through it in the winter time and it freezes.
I believe he was being facetious, considering the name IceHole. But yes, a lot of the older mains in the city are shallow.
 

hvy 1ton

Senior Member
Joined
Jul 24, 2006
Messages
1,947
Location
Lawrence, KS
HDPE pipe is starting to show up more and more these days. Directional bore guys love using it.
I'm a big fan of HDPE. Stronger than PVC, welded joints, and cheaper than PVC. Johnson County, KS requires any sewer lateral run of more than 80' be welded SDR 17 HDPE. Their code department has a lot bad ideas, but I can't argue with that one.
 
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