Question
Hello, I'm working on designing an underground sprinkler system for my front lawn, approx 110 x 100 square of grass.  The ground is flat and clear with minimal trees.  I want to go with rotary heads for the length of spray to minimize the number of heads needed.  Based on the below data, could you recommend some heads and what size line to use to feed them, would 1" work?  Ideally, I'd like to be about to get a 45-50' radius if possible.  Also how many heads could I put on one zone.  Again, I'd like to keep the zones to a minimum.  Anything you can tell me would help.  Thanks

Pressure = 70psi
5/8" Meter
3/4" copper supply
8 GPM


Answer
Good question.
The rotor sprinklers which would work in your situation are: Rainbird-5000, Hunter-PGP, Toro-800, K Rain-K1, or Orbit-Rotor. I would suggest using the nozzle that is closes to a 2.5 GPM. You will need to look at a nozzle chart for the sprinkler you chose. With any of the sprinklers you are not going to get 45'-50' radius, unless you use a 6-10 GPM nozzle. That would require 1 valve per sprinkler, I'm sure your not looking to do that. 35'-40' is the radius you should be working with. Sprinkler radius charts tend to be exaggerated a bit, trust me on this one.
The water service you have should supply 3 or 4 rotors with good pressure. Any more on a zone and your asking for a problem. 1" pipe for the whole system is fine.
Don't forget to use a larger nozzle for the 360* sprinklers. They are watering twice the area a 180* sprinkler.
Hope this helps.

Matt