What is the Difference Between Irrigation Sprinkler Heads? - Ask BrightView
Ask BrightView: Episode 5
BrightView Irrigation Manager Eric Rothell explains the difference between three irrigation sprinkler heads - the spray head, the rotor head, and the rotary nozzle - and why you should never mix them in the same zone.
(For the full transcript, see below.)
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What is the difference between irrigation sprinkler heads?
ERIC ROTHELL, expert:
Hi, my name is Eric and I'm an Irrigation Manager. One of the questions I hear a lot is, "What are the different sprinkler heads in my system?"
The first head we're going to talk about is the spray head. Here, we have in a display of 4-inch, 6-inch, and 12-inch pop-ups, and also what's known as a shrub riser, which is a nozzle and an adapter on a fixed piece of pipe. Spray heads are generally used to irrigate smaller areas because their area of coverage is between 5 and 15 feet. They have an optimal operating pressure of 30 psi and have a precipitation rate between 1.5 and 2 inches. 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 that fixed spray pattern -they're not moving and they're not turning, but they're continuously hitting one area, which is very different from the next head we're going to talk about, which is the rotor head.
Next, we have the rotor head. These are the heads that when they're operating, have the large stream of water that comes out of them and they have the turret that rotates from side-to-side. These heads are generally used for larger landscape areas because they have an average radius of throw between 15 and 50 feet. They have a higher optimal operating pressure between 45 and 50 psi and they have a precipitation rate which is much lower than spray heads because they have a larger area to cover. Their precipitation rate is between 0.5 and 1 inch per hour.
Next, we have the rotary nozzle. This is kind of a mash up of the first two heads we talked about because it is a micro rotor that goes on top of a spray head body. These are generally used for areas between 10 and 30 feet. They have a precipitation rate of between 0.5 and 0.6 inches per hour, so very similar to rotors. Their optimal operating pressure is only around 40 to 45 psi.
One thing you want to remember is that you don't want to mix these all on the same irrigation zone. That's because there are the different precipitation rates we talked about. Remember, the spray heads here have a precipitation rate that's two to three times more than your rotors or your rotary nozzles. This means a rotor or a rotary nozzle 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 have plenty of water, but your sprays will have way too much water. If you set that same irrigation zone to run based on the precipitation rate for 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. 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.