# Is there ever an example of a larger lateral pipe causing issues. Better to always go big?



## stormlight (Nov 27, 2018)

Is there ever a scenario in which you oversize a lateral line and it can cause issues? (Pressure, etc?)

For example, I have a 6GPM city feed currently. And am putting in a sprinkler system now.

In a year or two I will have a 15-20 GPM or more well system.

Can I put a 1-1/4 lateral pipe in now even though that is overkill for 6GPM without any negative effects?

I do not want to have to put something small in now to work with the 6GPM and then change it when it goes to 15-20


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## g-man (Jun 15, 2017)

The short answer is no other than cost. The longer question is, will you join two laterals in the future? I would think you could run two zone at once in the future, but the flow(gpm) thru each lateral would be the same since it is driving the same heads.


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## SCGrassMan (Dec 17, 2017)

Do 1" Blu Lock all around. It will handle as much water as you can throw at it.


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## unclebucks06 (Apr 25, 2018)

SCGrassMan said:


> Do 1" Blu Lock all around. It will handle as much water as you can throw at it.


Dont think 1" is going to handle 15-20gpms appropriately.


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## ABC123 (Jul 14, 2017)

if You could install a holding tank you don't need a well. Your city water can prime the tank whenever it's depleted.


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## SCGrassMan (Dec 17, 2017)

unclebucks06 said:


> SCGrassMan said:
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> > Do 1" Blu Lock all around. It will handle as much water as you can throw at it.
> ...


Based on what?


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## Ware (Jan 28, 2017)

SCGrassMan said:


> unclebucks06 said:
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> > SCGrassMan said:
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5 ft/s max velocity is the industry standard for maintaining irrigation system integrity.

1" Blu-Lock has an ID of 1.07". 15-20 gpm through 1.07" ID pipe would be 5.35-7.14 ft/s. (calculator)

That is why flows above 13 gpm are grayed out on the Blu-Lock spec sheet. :thumbup:


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## sanders4617 (Jul 9, 2018)

@Ware Does that correlate across the board with 1" pipe? No matter if its Blu-Lock or just PVC? I'd assume so, but just curious.

And based off what's been posted... if you're setting up a zone, using 1" PVC as carrier, then you should not have more than 12-13gpm per zone?


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## Ware (Jan 28, 2017)

sanders4617 said:


> Ware Does that correlate across the board with 1" pipe? No matter if its Blu-Lock or just PVC? I'd assume so, but just curious.
> 
> And based off what's been posted... if you're setting up a zone, using 1" PVC as carrier, then you should not have more than 12-13gpm per zone?


Here are some friction loss tables for various types of pipe: Hunter Friction Loss Tables

Note the shaded areas of the charts indicate velocities over 5 ft/s, which is typically not recommended and should be used with caution.

Below is a screenshot of the table for Schedule 40 PVC. So for example, with 1" Sch 40 you would not want to exceed 12-13 gpm.

Could you exceed 5 ft/s and not have problems? Sure. But I say using the proper size pipe for the job is never the wrong answer. :thumbup:


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## Ware (Jan 28, 2017)

sanders4617 said:


> ...if you're setting up a zone, using 1" PVC as carrier, then you should not have more than 12-13gpm per zone?


To further answer your question, Class 200 PVC is very common among irrigation installers where I live - I think mostly because it is thinner wall and easier to work, but the slightly larger ID also allows higher safe flow rates.

When I had my system installed, I requested Schedule 40 mainlines.


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## SCGrassMan (Dec 17, 2017)

Hubris is a bitch lol


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## SCGrassMan (Dec 17, 2017)

SCGrassMan said:


> Hubris is a b---- lol


Clarification: MY Hubris - as in, I was sure I was right when I wasn't.


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## unclebucks06 (Apr 25, 2018)

SCGrassMan said:


> unclebucks06 said:
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> > SCGrassMan said:
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What Ware said.

As he said, I use class 200 after the valves only. I just did a system with 1 1/4 schedule 40 main an 1" class 200 laterals pushing 17 gpms. That is the max I will do for 1" class 200. Schedule 40 1" i prolly wouldnt go over 12 maybe up to 15 in a pinch.


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