Irrigation Installation

There are 3 types of irrigation heads (Spray, Rotor, & Rotary/MP's). First lets talk about spray heads. They come in 4-inch, 6-inch, and 12-inch pop-ups. The 12-inch is also what's known as a shrub riser to help get the water over existing plants/shrubs. Spray heads are generally used to irrigate smaller areas because their area of coverage is between 5 and 15 feet. A precipitation rate is the measure of how fast water is being applied to a given area and it's generally given in inches per hour. These are the heads that when they pop up, they have a fixed spray pattern -they're not moving and they're not turning, but they're continuously hitting one area which gives them a higher precipitation rate. We even use strip spray nozzles that are specifically made for spraying long, skinny strips of turf without excessive concrete overspray. Spray heads have an optimal operating pressure of 20-30 psi, and a typical perception rate of 1.3 to 2 inches per hour.

Next, we have the rotor head. These are the heads that when they're operating, they project a large single stream of water and they have a turret that rotates from side-to-side or a full 360. These heads are generally used for larger turf areas because they have an average radius of throw between 15 and 50 feet. They have a higher optimal operating pressure between 45 and 55 psi and they have a precipitation rate which is much lower than spray heads because they have a larger area to cover with one single stream. Their precipitation rate is between 0.5 and 1 inch per hour.

Next we have our favorite, the rotary nozzle which we often call "MP's" because we primarily use Hunter brand MP rotary nozzles on our systems. This head/nozzle system is a hybrid of the first two heads we talked about because it is a multi-stream rotary nozzle that goes on top of a spray head body, meaning you can have it on a 4", 6", or 12" head. They deliver water in multi-trajectory, revolving streams, and are generally used for areas between 10-30 feet. They have a precipitation rate of between 0.5 and 0.6 inches per hour, and are very water efficient. Their optimal operating pressure is around 40 to 45 psi.

In conclusion there are 3 types of irrigation spray heads (Spray, Rotor, & Rotary/MP's), and each type has many different nozzle options for distance and coverage to fit any size or shape of turf area.

One thing you want to remember is that you don't want to mix different head types on the same irrigation zone. That's because they all have different precipitation rates like we talked about. Remember, the spray heads have a precipitation rate that's two to three times more than your rotors or your rotary heads. This means a rotor or a rotary head has to run two to three times longer than a spray head to put out the same amount of water. If you have all these on the same zone and you were to set your run time minutes based on your precipitation rate for your rotors, your rotors will water correctly, but your sprays will have way too much water. If you set that same irrigation zone to run based on the precipitation rate of your spray heads, well then they'll have an adequate amount of water, but the areas with the rotors or rotary nozzles are going to be severely underwatered. So you don't want to mix them as they have very mixed precipitation rates and there would be very uneven watering.

Now you know the difference between a spray, a rotor, a rotary nozzle, and why you don't ever want to mix them all together. Reach out to ABI Systems if you have any further questions.