Irrigation Experts! Need help designing an acreage system

[ExtraSlow]

Hey, a buddy of mine has a small acreage and is asking for my help designing the irrigation system. At the tap on the house, he says he has 6 gpm and 40 psi.
It's about 130 feet to where he wants the main valve box, and from there he wants five runs, none longer than 100 feet.
Thoughts on how he should go about sizing his pipes?

[ExtraSlow]

Does that flown rate seem low? What's a normal city house flow at?

[speedog]

https://www.irrigationtutorials.com/gpm-psi-municipal-water-source/ - might be helpful.

[blitz]

The flow rate seems ok, but the pressure is fairly low compared to the city. I think I'm around 70 psi.

[94CoRd]

The best thing I ever did when planning my irrigation, was taking a to-scale drawing of my property, along with pressure and flow rate, to Regency Irrigation. Took them about 20 minutes to draw up a plan, and 10 minutes to pull all the parts for me. I think you can also submit your drawing online, and they'll let you know when it's done.

[klumsy_tumbler]

6 gpm sounds really low to me.... I remember one of my parents' neighbours having 4 gpm and it was brutal just waiting to fill up horse troughs. I can't imagine it would make for a very robust irrigation system. Maybe it depends on how much space they are trying to water?

[kertejud2]

Hey, a buddy of mine has a small acreage and is asking for my help designing the irrigation system. At the tap on the house, he says he has 6 gpm and 40 psi.
It's about 130 feet to where he wants the main valve box, and from there he wants five runs, none longer than 100 feet.
Thoughts on how he should go about sizing his pipes?

The handy pressure loss chart for polyethylene

http://www.rainbird.ca/documents/turf/ref_Polyethylene%20SDR%20Pressure%20Rated%20Tube.pdf

3/4" would be the absolute minimum, but you're probably looking at closer to 10psi loss with the length of pipe and the fittings coming into it. 1" would be a lot better to not worry about that friction loss. There's also the slopes to take into account. Each foot of elevation drop adds .433 psi, each foot up takes the same away. Most residential systems it doesn't come into play at all but a lot that size with a pressure that low it can make a difference. So the more downhill you have the better.

He won't be able to have more than one run going at a time so he can use the same pipe size from the source to the valves and for each run. I guess it depends on the heads he's using but given that pressure and flow I would have to say he will need to run multiple lines through each trench since a conservative guess is he won't be able to run more than 2 heads at a time (3 if they're directionals) and still keep up efficiency.