Irrigation sprayheads and rotors are wasting less water and hitting their targeted areas more accurately as manufacturers are focusing their design efforts on efficient irrigation. “Water efficiency is influencing the design and performance of sprayheads and rotors,” says Bob Burrous, product manager for contractor rotors, Rain Bird Corp., Azusa, Calif. “Quality, ease of use and speed of installation will also drive new innovations.”
Many irrigation design changes, such as pressure regulation, are taking place at the nozzle, but manufacturers are also making adjustments at the sprinkler heads to improve efficiency. Some recent innovations include flow-stop devices so contractors can shut off individual sprinklers and a feature that returns a rotor back to its original position when knocked out of place. Other trends include snap-in check valves to reduce leaking, increased pop-up heights and vandal- or damage-resistant heads. These design changes give contractors the opportunity to sell potential efficiency savings to their clients.
| ROTORS VS. SPRAYHEADS |
Coverage area is usually the biggest factor when deciding whether to install irrigation rotors or sprayheads. Sprayheads are ideal for smaller and more intricate areas, while rotors usually provide better coverage in large, open spaces, says Bob Burrous, product manager for contractor rotors, Rain Bird Corp., Azusa, Calif. “Since rotors have a longer radius of throw, this makes rotors the obvious choice for large, unobstructed landscape areas,” Burrous says. “On the other hand, sprays tend to work better for smaller areas and offer a greater variety of options for specialty applications. For example, sprays are available in many pattern shapes that can address long rectangular areas. Their smaller radius and high precision also make them ideal for today’s curving borders along sidewalks and beds.” Rotors can usually cover any area greater than 25 feet, whereas sprayheads typically have a throw radius of 15 to 17 feet, says Rick Hall, manager of technical services, K-Rain Manufacturing, Riviera Beach, Fla. To accommodate areas greater than 15 feet but less than the 25-foot-plus range covered by larger rotors, manufacturers have introduced mini gear-driven rotors that can be used on the same zone as large gear-driven rotors and still emit the same volume of water, Hall says. “That void between 15 and 25 feet was always taken care of by adding an extra row of pop-up sprayheads, but now manufacturers have mini gear-driven rotors to use for that area,” Hall explains. Irrigation contractor Pablo Santoyo says area usually plays the biggest role when he decides whether to install a rotor or sprayhead. “I happen to like sprayheads better on smaller areas – say if you have an area that is 20 feet by 20 feet, you’re probably not going to use rotors, but if it’s 100 feet by 50 feet, I may be inclined to use rotors vs. sprayheads,” says Santoyo, an account manager with ValleyCrest Landscape Maintenance’s Laguna Branch, Aliso Viejo, Calif. But area isn’t the only factor to consider when installing irrigation heads. Rotors and sprayheads have different precipitation rates, so soil type can also become an issue. Precipitation rates for sprayheads range from 1.5 to 2.5 inches per hour compared with 0.2 to 1 inch per hour for rotors, Burrous says. So tighter soils, such as clay, may be better suited for rotors because they absorb water more slowly, whereas sprayheads are suited to loose soils that can absorb water quicker, says Kevin Gordon, senior product development manager, Hunter Industries, San Marcos, Calif. But that doesn’t mean contractors can’t use sprayheads in tight soils. “If you’ve got tight soils, you can use sprayheads, but you need to cycle your start times so you have shorter durations,” Gordon says. “Don’t try to put 10-minutes worth of water down in 10 minutes. Break it up in three-minute intervals, so the soil can take the water in.” As for cost considerations, rotors are more expensive than sprayheads, but because they cover larger areas, contractors can irrigate more turf with less irrigation heads, pipe, wire fittings and valve stations with rotors, says Don Fisher, a product and marketing manager with The Toro Co.’s Riverside, Calif. irrigation division. Rain Bird’s list price for a sprayhead with a variable-arc nozzle is $4.90, and the list price for a spray body with a rotary nozzle is $11, according to Burrous. Rain Bird’s most common rotor sets range in list price from $13.45 to $15.90, he says. |
FLOW STOPPERS. Previously, contractors had to service an irrigation rotor by either shutting off the rotor’s entire zone or working on it while the water was still flowing. Now, by turning a mechanical device on top of the rotor’s head, contractors can shut down an individual sprinkler while the zone is still operating. With the flow-stop feature, contractors can reduce water waste by turning off rotors that shouldn’t be in use.
“It was incorporated as a direct request from contractors who said they were installing sod and didn’t want to install it based on the zoning of the irrigation system,” says Rick Hall, manager of technical services, K-Rain Manufacturing, Riviera Beach, Fla. “So they want the ability to turn on zones but isolate heads they don’t need to work, which would just be spraying dirt and making it muddy. Another advantage could be that when these companies aerate lawns, it’s always been a problem where contractors have to flag heads so they don’t run over them. Now, the contractor can turn the system on, shut off each head, and the heads will pop up without spraying water.”
The shut-off device also allows contractors to turn off sprinklers in poorly designed irrigation zones where some units may be placed in shadier areas than others, resulting in overwatering, says Kevin Gordon, senior product development manager, Hunter Industries, San Marcos, Calif. The shut-off device can also make maintenance tasks easier. “The sprinkler is still held up by the pressure of water, but it’s not rotating anymore because there’s no water running through it, so you can perform whatever maintenance you need to do without getting sprayed on,” explains Don Fisher, a product and marketing manager with The Toro Co.’s Riverside, Calif. irrigation division. “Then you can turn it back on when you’re finished.”
The flow shut-off function has benefited Aliso Viejo, Calif.-based ValleyCrest Landscape Maintenance’s Laguna Beach division, according to Pablo Santoyo, the division’s account manager. “I like it very much because there are always issues where the coverage is not uniform, so you end up overwatering the shady area vs. the sunny area,” Santoyo says. “Now I can turn off a head or two heads around the section that is always wet to avoid overwatering.” Santoyo says the shut-off function adds about $3 to $5 to his cost per head.
In sprayheads, a similar device is available that restricts water loss if the nozzle is removed. If the nozzle is knocked off and is no longer applying pressure to the shut-off device, the head will automatically stop operating, Fisher says. “The riser will pop up even without a nozzle on it, but there will be no flow through the riser itself, so you save an enormous amount of water that could be wasted,” he says, adding that the shut-off features typically add $1 or more to the cost of the irrigation head.
Another device that can reduce water waste in irrigation heads is a snap-in check valve. Water in irrigation systems drains out of low points when the system is idle. This can create puddling at the heads located at the lowest elevations and result in wasted water. Contractors can reduce leakage from irrigation heads located at these points by inserting a check valve between the riser and the irrigation head. Check valves typically cost $1 per unit but contractors who buy them in high volume may get discounts from their dealers, Gordon says. Previously, if contractors wanted a check valve, they would have to replace the entire sprinkler with a permanently installed one. “The addition of a snap-in check valve vs. a permanently installed check valve allows the contractor – if he has a few heads where there’s a low-drainage situation – to pull the sprinkler inside out, pop a check valve in an individual sprinkler and put it back in the ground,” Gordon says.
INDESTRUCTIBLE IRRIGATION. Whether it’s from mischievous activity or a mower bumping into them, irrigation heads are susceptible to damage. To battle back, manufacturers are including more damage-resistant features on irrigation heads. For instance, some manufacturers are connecting the turret to the rest of the rotor using a brass rod for added strength, says Burrous. This increases a rotor’s ability to withstand being kicked while in operation. In addition, some rotors now have slip clutches to prevent gear damage and a feature that returns the rotor to its original arc if the head has been tampered with, Fisher says.
“So instead of being broken and spraying in the street, the rotor will have the intelligence to return to where it’s supposed to be spraying,” Fisher explains. “Some sprinklers, if you continue to torque on the left or right stop, it will simply break. In this case, you have a mechanism that allows it not to break. It’s usually a slip-clutch mechanism that has a plastic finger that is going to absorb the pressure up to a point and then snap across a trip point and then rotate back into its preassigned arc.” These safeguards can add $1 to $2 to the cost of most rotors, according to Fisher.
Burrous agrees that rotors are becoming more durable. “Rotors are more tamper resistant if they automatically return to a pre-set arc pattern after being forced outside of an area and if the gears do not strip when the turret is held in place or turned against the direction of rotation while under pressure,” he says. “The gear trains that cause the rotor to rotate have been designed with this type of abuse in mind.”
Manufacturers are also constructing more irrigation heads with plastic instead of metal components to reduce costs and are focusing on the chemistry of plastics to make them more durable, Hall says.
| TALL ORDERS |
Irrigation heads can’t see very well these days. That’s because lawns are getting higher in response to water conservation efforts. Many municipalities are encouraging higher-cut lawns to encourage deeper, more drought-tolerant root growth. As a result, more contractors are demanding taller pop-up heights on irrigation heads, according to manufacturers. Traditionally, irrigation heads have been sold with 3- to 4-inch pop-up heights, but manufacturers are starting to produce heads with 6- and 12-inch pop-up capabilities, says Kevin Gordon, senior product development manager, Hunter Industries, San Marcos, Calif. “We’re starting to see a lot of 6-inch rotors in turf applications,” Gordon says. “It’s becoming commonplace in commercial – less so in residential.” A 6-inch pop-up head costs approximately $10 more than a head with a 4-inch pop-up height, according to Gordon. Don Fisher, a product and marketing manager with The Toro Co.’s Riverside, Calif. irrigation division, agrees that taller pop-up heights is a growing trend in the industry. “The pop-up height is increasing,” he says. “Four inches is standard, but there’s a lot more 6-inch interest now. It appears that the market trend may be toward making the 6-inch pop-up more of a standard item for sprayheads and rotors.” Pop-up heights can also become an issue when irrigating plants, such as ornamentals and shrubs. Contractors should consider the mature height of the plant and whether a riser might be necessary, Gordon says. A 4-inch pop-up height may be adequate for smaller or new plantings, but as the ground cover matures, that pop-up height may not be tall enough. “You have to plan your sprinkler selection on what’s going to happen with the plants a year or so down the road,” Gordon says. |
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