Golf Engineering Associates Technical Help Series

Golf Sprinkler Heads

Brass Impact v.s. Plastic Gear-Driven Rotors:

Twelve or fifteen years ago the golf irrigation standard was a brass impact head enclosed in a heavy-duty plastic case, many of which are still going strong out in the field every day. Before that, it was brass impact heads in an enclosed iron case. Thousands and thousands of those are out in the field as well, working decade after decade for their owners. Brass impacts are heavy-duty and designed for long life. They are also very good for dirty water situations because they do not have intricate gears or internal parts to get clogged up. Water literally blasts right through the assembly, and the simple flow-through design has proven effective over many decades. We find brass impact heads in the field which are 35-40 years old and working fine, and they could definitely perform well as part of a new system. The main reason that new courses or renovations generally do not go with this type of head is cost: large brass rotors cost anywhere from 25% to 65% more than the more recent invention, plastic gear-driven rotors. For an average sized system, say 1000 heads for 18 holes, this would be an additional cost of approximately $40,000 to $80,000. Although brass heads will always be available from somewhere, some manufacturers have already phased them out of production.

Check-O-Matic, Hydraulic, Electric V-I-H and Other Features:

Sprinkler heads have different types of actuation, a term referring to how the sprinkler is turned on or off. The most basic type of actuation, common to the entire residential/commercial side of irrigation, is Check-O-Matic or "block style". A number of heads come on at once when a manual or electric valve opens. This type of application is not widely used for new golf systems because of the lack of sprinkler control. Check-O-Matic heads are the least expensive rotor, but you have to buy an expensive 2" or larger electric valve, valve box, wires, etc., to get it to work. Nobody (we hope) in the modern era would opt to install a "manual block system" which requires somebody to hang around all night long turning manual valves on and off by hand. With the flows of four or more heads coming on at once, you will require bigger pipe, fittings and hardware to keep system velocities and psi loss at normal levels. This all but wipes out the potential cost savings of using Check-O-Matic heads.

Electric valve-in-head (V-I-H) actuation is the most common type for golf course use. Each head has a selenoid (like an electric valve) which is activated by electric wiring going back to a field controller. There are two wires on each selenoid, a signal (control) wire and a common ground. We recommend that each and every head have it's own signal wire going back to the controller so that you can arrange your stations in any way. The common ground goes from head to head and back to the controller; we recommend that nothing smaller than #12 solid copper core wire be used for the common. ALWAYS use direct burial splice kits for your splices or you will be forever plagued by electrical problems.

Hydraulic control is not nearly as common as electric V-I-H but still very effective. Hydraulic tubing delivers water to and from the sprinkler from a controller fitted with hydraulic converters, turning the sprinkler on or off. The system performance is just as good as a purely electric system, but there are several complications involved with installation and maintenance. First of all, maintenance can become a problem because every time you break ground (for any reason) you have to worry about injuring the delicate plastic tubing. Secondly, the hydraulic satellite controllers require both power wires and a clean, filtered, separate water supply line. The main reason for using hydraulic over electric V-I-H is that the absence of miles upon miles of copper wiring in the ground makes the system less susceptible to lightning damage. Since lightning can be devastating to an irrigation system, the installation of a hydraulic system is a good choice for lightning prone areas such as South Florida.

Choosing the Right Sprinkler Head/Nozzle Combination:

The most important aspect of the design/installation process is choice of sprinkler/nozzle equipment and the proper placement of the equipment in the field. The major manufacturers each generally have four size classes of rotors for golf use, described in general terms as follows:

• Heavy-duty pop-up heads, to be installed with an electric valve. Average values are 25 - 90 psi, .5 - 30 gpm, 30 - 75 foot radius. Good for tees, narrow areas, roughs, support near cart paths, low-water use applications, etc.
• Small turf rotors, check-o-matic, hydraulic or electric V-I-H. Average values are 40 - 90 psi, 10 - 40 gpm, 50 - 80 foot radius. Good for tees, narrow/tight areas, lower water-use applications, etc.
• Medium turf rotors, check-o-matic, hydraulic or electric V-I-H. Average values are 50 - 100 psi, 12 - 60 gpm, 60 - 90 foot radius. This is the most common category used for entire golf course area; best type of head for green complex.
• Large turf rotors, check-o-matic, hydraulic or electric V-I-H. Average values are 50 - 110 psi, 20 - 80 gpm, 70 - 105 foot radius. Used for very large wide-open areas, driving ranges, double-row systems. Requires plenty of water availability.

(Click to view sprinkler head diagrams)

The medium sized turf rotors are a good choice for overall performance and cost. There is a wide range of flows and radius in this class to fit nearly all applications on the golf course except for tight turf strips or isolated tee islands. Flows in this category are well suited for 2" lateral pipe and fittings. The large turf rotors have such high flows that larger swing joints, pipe, fittings and parts will be needed to keep system velocities and psi loss within acceptable limits.

A common dilemma is the choice between going double row with large rotors or triple row with medium rotors. Our choice is for the triple row option, which generally will give you better coverage over a slightly wider path. When the costs of the additional medium heads is compared to the costs of bigger pipe, fittings and swing joints, we feel that there is really not much of a difference at all. For those who are planning a single row system, the largest rotor you can get is what will give you the most coverage. Since the typical single row system has a main line going up the middle of the fairway with swing joints coming right off it, the big flows of big rotors is no longer a problem.