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Is using poly for mainline ok?

grey

Advanced Member

Posts: 90

Location: Eastern WA

1

Tuesday, June 28th 2011, 12:33am

Is using poly for mainline ok?

I just read in 2 sources that it's not advisable to use poly for mainlines. What does industry say? We have freezing winters. I was thinking that using 160 PSI rated poly pipe in 60 PSI static circuit would be fine.

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

2

Tuesday, June 28th 2011, 8:23am

You are still winterizing the mainline, regardless of material. 160 psi poly is fine for your use.

Mitchgo

Supreme Member

Posts: 502

Location: Seattle

3

Friday, July 1st 2011, 1:46am

People are intimated with products they don't know about too well.

we use 200 psi poly for our main lines and 100 psi poly for our laterals. Superlon is the best quality poly out there in my opinion

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

4

Friday, July 1st 2011, 7:31am

If the mainline isn't pressurized 24/7, it only has to have a pressure rating above the static pressure of the system. I see no performance issues with systems that use 100 psi for a non-pressurized mainline so long as the static pressure is less than 100 psi.

Mitchgo

Supreme Member

Posts: 502

Location: Seattle

5

Friday, July 1st 2011, 9:28am

100 psi in my opinion is like using class 200. The pipe will be nicked with a blow to the shovel if someone was digging

vs the 200 .. you can take an axe to that thing and not cut it ( not really but you know what i mean)

grey

Advanced Member

Posts: 90

Location: Eastern WA

6

Friday, July 1st 2011, 11:05am

it will be under pressure 24/7 except for winter.

ChrisM

Unregistered

7

Tuesday, June 17th 2014, 5:04pm

I want to know the same thing. I live in MN and we freeze up bad in winters. Is something like a 200psi 1" poly mainline going to be ok? I'm on a well and only get 6GPM and 50PSI static. Was planning zones to have around 6GPM throughput.

Specifically I'm looking at this for the main lines (pipe from PVB to back of the valves) http://www.menards.com/main/plumbing/rough-plumbing/pipe-tubing-fittings/pipe/polypipe/1-x-300-flex-water-pipe/p-1459373-c-8570.htm

Thanks!

Central Irrigation

Supreme Member

Posts: 364

Location: Central Minnesota

8

Tuesday, June 17th 2014, 6:36pm

With our winters and your watersource, 80psi NSF rated poly would suffice. I would recommend all the above grade plumbing be done in copper. In case of a late blowout, you could thaw ice in a copper line, whereas poly and PVC render you at the mercy of the thaw, or lack there of.

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