Optimizing The TurfgrassCanopy Environment With Fans

Fans can help overcome poor growing environments.

by PATRICK M. O'BRIEN

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;rHOUGH most people in theturf industry have seen electric

or gas-powered fans used onthe golf course, the rationale fortheir use often is misunderstood. Asan agronomist for the USGA GreenSection, I am frequently asked ques-tions about the use of fans. To helpthose involved with this issue, a dis-cussion of the benefits and liabilities ofthe use of fans is presented.

Affect on the Health ofBentgrass Putting Greens

Years of experience have shown thatgolf superintendents have the mosttrouble growing bentgrass or Poaannua greens during the summer at asite surrounded by trees or other bar-riers that allow almost no air move-ment. A USGA-type green provides avery effective base for growing puttinggreen turf, but it cannot compensate forthe lack of air circulation. In this envi-ronment, disease and higher rootzonemoisture associated with these areascause turfgrass plants to decline. Fanshelp improve air flow across greens,and the survival of bentgrass has beenshown by Taylor to improve at siteswith the increased air movement pro-vided by fans. 1 The positive effects offans drying out the soil and increasingevapotranspiration are the two majorbenefits influencing the bentgrass. Fansoffer little cooling benefit to the turf-grass, which is contrary to mostpopular opinion.

Fans are sometimesmounted in trees

instead of using poles.

Gas-powered fans can be used as a last resort in sites not located in close proximity toan electrical source, but they require intensive labor to operate.

Which Greens Need Fans?Fans should be specifically used to

help improve turf quality at problemgreen sites. By far the most popular useof fans is at boxed or pocketed sitessurrounded by trees or other featuresthat restrict air movement. In the past,these sites have been more prone tosummer decline caused by disease,excess moisture, and surface algae.Green sites with wet rootzones alsobenefit from a fan program. Even smallproblem areas at open sites can benefitfrom the use of fans directed to thespecific problem area.

Placement of the FansMost superintendents place two

stationary fans at the 10 and 2 o'clockpositions at the rear of the green,approximately 15 to 30 feet from theedge of the green. Fan height above thegreen surface normally is 10 feet or lesswith these stationary fans. Most fancompanies sell poles that are usuallyseven feet tall, since OSHA requires

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finger guards on any fans positionedat lower heights. Finger guards canrestrict air flow distance by up to 12%.Hand guards, which restrict air flowless than finger guards, are required forfans on poles taller than 7 feet. Treesare sometimes used instead of a poles,if available. _

The key is to position the fan asclose to a green and as low to theground as possible to generate maxi-mum air flow across the green surface.The main goal is to achieve a 3- to4-mph wind speed over the turfgrasscanopy. If fans are too far away orelevated too high, wind speed powerwill be lost by deflection off the grassitself, or by natural friction loss. ATurbometer, which costs about $120,is an effective instrument to helpdetermine fan placement at each site.The Turbometer should be set on thegreen surface during measurements,and with the fans running, checkvarious areas around the green forthe 3- to 4-mph wind speed.

Another popular method to helpdetermine fan location is the use ofengineering flags. On a calm morning,place engineering flags over the greensurface at 3- to 5-foot intervals withthe flag height at approximately 3inches above the ground. Clipping themetal pole on the engineering flags toa 3-inch length will speed this step.Turn the fans on and adjust the fanposition until most of the flags arewaving. Other superintendents checkfan position by igniting smoke bombsat several sites on a green to detect airmovement.

When to OperateGolf superintendents need to pay

attention to fan schedules, since eachsite may have different requirements.Fans usually run 24 hours per day atgreen sites that hold soil moisture andat pocketed areas. Running fans fromearly to mid morning to the early eve-ning is advised at the small problemsites on certain greens. Other sites may

Extension cords and above-ground wiring should be avoided wherever possible.

require fan usage only during the earlymorning to mid morning when dewand surface moisture are greatest. Inthe Southeastern Region, surface mois-ture also can come out of the rootzoneduring the daylight hours, even at timesof very high humidity. Fan use seldomwill be required at open-air sites onsunny days with low humidity.

Fan TypesNearly all fan types commonly seen

have done a good job when positionedand run properly. Caged, oscillating, orturbo fans are the most common typesobserved. Oscillating fans are by farthe most popular at golf courses. In thepast, fan oscillating motors have causedproblems, but today oscillating motorshave improved power, similar to theother fan motors. Fan diameters canrange from 22 to 48 inches. Becausemost fans are stationary to poleselevated above the greens, fan diametersize has been increasing with thedemand for additional air movementfrom these products. Many fans nowcan throw a column of air more than200 feet. With the improved power ofmany fans, some air movement canoccur even at areas where the fan isnot directed. Stationary fans do havethe potential to dry the turf, since windspeeds can be much higher than 3 to 4mph next to the fan. Extra irrigationmay be needed for the turf in somesituations when these fans are used.

Portable or floating fans are alsopopular, and most courses have at leasttwo available. Most portable fans arethe 48-inch cage types. A combinationof both permanent and portable fansis a plus at some problem greens.Portable fans are used to treat specialareas that require extra air circulation,such as a wet soil condition. Manysuperintendents move these floatingfans to problem sites late in the eveningand allow them to run all night. Thefans can be positioned right next tothe green during the night to provide anextra "blast" of air without affectinggolfers. The portable fans can be repo-sitioned and moved further away fromthe green the next morning, especiallytaking into consideration the holelocation for that day. The additionalair movement and mixing from thisfan, especially when combined with theprevailing wind and the permanentfans, promotes faster drying. Portablefans can also be used at the main-tenance building to help cool themechanic's working area on hot days.

Tips on InstallationSetting up the electrical system for

the fans on an existing golf course isvery difficult, so a certified electricianshould do all electrical work. Unfor-tunately, the electrical wire at theirrigation control boxes is too smallfor the high current requirements ofelectric fan motors, so alternativepower supplies are needed. Usually,water coolers, irrigation pump houses,lift pumps, bathrooms, maintenancebuildings, and clubhouses are sourcesof electrical power. Often, sites withfans are not close to any of these

sources, and new meter service thenis the only option. Gas generators area last resort, with the inconvenience ofrefilling the generator with gas, trans-portation requirements, and the extranoise. New golf courses should initiallyinstall larger wire coming into the irri-gation control boxes so that if electricityis required later for fans, the larger wirecan handle the additional amperagefor a fan motor.

Most fans used today have single-phase motors, although three-phasemotors are preferred because of theirhigher power efficiency. Smaller wire

JULY/AUGUST 1996 11

can be used for three-phase motors,resulting in a lower initial installationcost. Many water coolers, irrigationand lift stations, and clubhouses havethree-phase power for fans near thesesites. Sometimes step-down trans-formers are needed, especially for theoscillating motor, which is alwayssingle-phase power, and luckily thesetransformers usually cost just $30.

All new electrical equipment andservice must meet the local codes.Tables are available to calculate thewire size needed based on the distancefrom the power sources to the fan andthe resistance loss in the wire. Directburial cable wire (usually #4 or #6cable) normally is pulled into theground with a vibratory plow on aditch-witch trencher with minimal dis-turbance to the surface, although occa-sionally small trenches are made toinsert the wire. Wire depths varyaccording to the local.codes, but mostinstallations require an 18- to 24-inchdepth. Wire is sometimes placed in aplastic conduit (depending on thelocal codes) under cart paths andservice roads and across bridges foradditional protection. Avoid the use ofjunction boxes whenever possible, asthey could become sources of prob-lems later.

At the green installation site, thewires, switches, timers, and plugsusually are placed in a sealed irrigatiQnvalve box with drainage. Avoid wiringthe fan directly, as removing the fanlater with this type of connectionsystem is more difficult. Installing anextra plug to power a portable fan thatmay be needed later is always a plus,but a larger size wire will be neededinitially to handle this extra power re-quirement. Timers also can be installedin the valve box to vary the operationof the fans. At The Honors Club,course superintendent David Stonehas even connected his fans to theirrigation radio controllers. A switchto turn the fan off and on is anotherplus. It is always a good idea to installa ground fault interrupter at the plugto act as circuit breaker to enhancethe safety of maintenance workers andgolfers. Circuit breakers at the meteralso help to avoid electrocution con-cerns. Afterwards, have an inspectorcheck all electrical work to insure thatall local codes are met.

CostsFans are used most during the

months of May through September inthe southern portion of the United

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The Turbometer is one tool that can beused to help determine fan locationsaround a green.

States. Obviously, operation time willvary depending on the location ofthe golf course and the weather eachsummer. Most utility companies offerseasonal or full-time service for thesemeters. Flexible programs dependingon the projected power consumptionand usage are offered by many powercompanies, and consultants can detailyour options. Most superintendentsreport typical electrical power costs forrunning two fans at a green site averagebetween $75 and $100 per month.

Fan MaintenanceFans have required very little pre-

ventive maintenance so far on golfcourses. Rust spots and scratches willoccur over time just from being outside.A few fan distributors even offer annualmaintenance services to wax and paintfans, but so far very few customers havetaken advantage of this service. Mostsuperintendents bring the fans insidethe maintenance building or into a polebarn for the winter months. In anycase, the structure must be tall enoughso the fans can be stored in an erectposition so moisture cannot enter thefan motor. Pole fans are easily discon-nected by unscrewing the poles fromtheir stands. The outside electrical"components are protected by cappingthe plastic storage box. Some superin-tendents prefer to leave the fans attheir permanent sites, especially if notenough storage space is available atthe maintenance area. Heavy-dutyfan covers that will not tear or blowaway are now available from mostdistributors.

NoiseThe auditory effects of fans are also

a consideration. Most courses have

home sites near some of their greenstoday, and some residents may be closeenough to hear the fan motor noise.Educating your neighbors about theimportance of the fans is essential forthe superintendent. Letters sent tothese homeowners each spring dis-cussing the agronomic value and fanoperational hours may help reducecomplaints.

Effects on the Rules of GolfFans do have an impact on the

Rules of Golf, depending on whetherthey are permanently or temporarilyinstalled. Any time fans are installedin a permanent base, the golfer canassume the fan won't be moved. Perma-nently positioned fans are consideredimmovable obstructions according tothe Rules of Golf. If the fan interfereswith the lie of the golf ball or theswing or stance of the golfer, relief isprovided under Rule 24-2. Sometimesthe fan may be found between the golfball and the hole location. Under thisRule, line-of-sight relief is not providedfor with. permanently installed fans,and the ball must be played as it lies.

Fans that have been set up on atemporary basis are treated as tempo-rary immovable obstructions. Interven-tion on the golfer's line of play wouldwarrant relief.If a golf ball deflects off a fan, it is

a rub of the green and the golfer playsthe ball where it lies. If a fan deflects agolf ball out-of-bounds, the golf ball isstill considered out-of-bounds.

ConclusionFans have made a major impact on

many golf courses by helping the turfsurvive where it previously had diedeach summer. Many golfers also enjoythe additional comfort of a cool breezewhile putting. However, sometimesfans are a nuisance to golfers becauseof the extra noise and their impact onthe Rules of Golf. These negativefactors must be weighed against thegain of improved health and playabilityof putting green turf.

IGene Rupert Taylor II. 1995. The Effectsof Mechanically Induced Air Movement onthe Temperature, Water Potential and SoilMoisture Percentage of Creeping Bentgrass(Agrostis stolinifera L.) Golf Greens. MSThesis, North Carolina University.

PATRICK O'BRIEN is director of theUSGA Green Section's SoutheasternRegion.