Is it ok to run sprinklers in a closed loop?

Las Vegas, NV(Zone 9b)

Are there any benefits to, or reasons that I shouldn't run sprinklers in a closed loop?

I have a small L shaped area where I'm planting grass. One leg is about 5'x15' the other is about 12'x4'. About 130 total sq. feet. In order to have what I understand to be proper sprinkler coverage, (the spray from neighboring heads overlapping completely) I'm installing 16 heads. Each head will only spray between four and five feet. I hope to water the entire area from one valve. Is it ok to run a T from the valve and close the loop or should I leave the loop open? I'm hoping I'll have enough pressure for complete coverage. If not I'll have to install a new valve and run new wires. If that is the case, my original question is moot.:(

Thanks in advance, David

Everett, WA(Zone 8a)

I don't see any downside, and not much upside.

By closing the loop back to the source, in effect you are putting a "Y" at the source, so that instead of having one 30' run, you have two 15' runs. Very slightly less pressure drop at the far end. But how much can the pressure drop in 15 or even 30 feet? Not much.

If that were a 100-200 foot run, the pressure drop difference MIGHT be noticable.

Before closing the loop, is the sprinkler at the far end of the hose noticably wimpier than the first sprinkler?

I would suspect that as little as 2 feet of height difference would make more pressure difference than running a few (or 5) gallons per minute through 3/4" hose. Isn't all the pressure drop all at the sprinklers, not in the hose itself?


Las Vegas, NV(Zone 9b)

I believe you are right about the pressure drop. I've got 55psi at the hose bib out back,and thats with 1/2"copper. I have 3/4" pvc to the valves, though I don't know the pressure. Everything is pretty flat. Honestly, I stopped reading the web page listed in the other threads about irrigation design and am trying to finish the project. It's getting hot here,(yes it's a dry heat, but tomorrow is supposed to be 105. Luckily I'll be at Disneyland! ) and I've got a patio to finish yet. Lots of dirt to sift (clay, sand, gravel, rock, boulders).

Thanks for your response, David

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