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Appendix 1: Terms and concepts related to wind turbine infrasound Date: Aug. 8, 2014

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A P P EN DIX 1

EX P L A N A T IO N O FT ER M S A N D C O N CEP T S R EL A T ED T O W IN D T U R BIN EIN FR A S O U N D

R ICHA R D JA M ES ,IN CE

E-C O U S T IC S O L U T IO N S ,O KEM O S ,M IA U GU S T 8,2014

Th e w in d in d ustry,itstrad e association s,an d expertcon sultan tsrepresen tin gth e in d ustry h ave claim ed th at

m od ern utility scale w in d turbin esd on otprod uce in frasoun d . A tleast,n on e th atisd istin guish able from

n aturally occurin gbackgroun d in frasoun d . Th ey alsoassertth ateven if w in d turbin esd id em itin frasoun d ,it

could n otbe th e cause ofth e w id ely reported com pain tsof ad verse h ealth effectsan d sym ptom sn ow associated

w ith W in d Turbin e S yn d rom e 3 0 . C om plain tsan d law suitsby people experien cin gad verse h ealth effects

ad d ressed tospecific utility ow n er/ operatorsare respon d ed toby attorn eys,n otqualified m ed icalstaff,w ith

statem en tsof blan ketd en ial. A n y attem pttolin k w in d turbin e operation toth e com plain tsascause an d effect

in law suitsisfough th ard . Expertsare som etim esbrough tin from oth ercoun tries. O ften ,th ese experts,

especially th ose th atrepresen tth em selvesasm ed ical

experts,d isclose little orn oh an d son experien ce w ith

people w h oare reportin gth e sym ptom sd urin gd eposition s.

In stead ,th e expertsin trod uce spuriousargum en tsth at

serve tocloud th e factualevid en ce. Forexam ple,on e

w id ely used explan ation forth e com plain tsisth atth e

com plain an tsare sufferin gfrom a“ n ocebo” effect.

B efore respon d in gtoth e in d ustry position sw e n eed to

d efin e som e term s. First,w h atisin frasoun d ? In frasoun d is

acoustic en ergy,soun d pressure, justlike th e low toh igh

frequen cy soun d sth atw e are accustom ed toh earin g( see

Figure 1 ) . W h atm akesin frasoun d d ifferen tisth atitisat

th e low esten d of th e acousticalfrequen cy spectrum even

below th e d eep bassrum ble of d istan tth un d erorallbutth e

largestpipe organ ton es.3 1 A sth e frequen cy of an in frason ic ton e m ovestolow erfrequen cies: 5 H z,2 H z,1 H z

an d low er,th e soun d sare m ore likely tobe perceived asseparate pressure pulsation sin stead of a

30The term “Wind Turbine Syndrome” was coined by Dr. Nina Pierpont in the mid-2000’s to describe the symptoms she was

observing in children coming to her clinic that lived proximate to utility scale wind turbines in a nearby community. She later foundthat the symptoms were reported by adults living near wind turbines at utilities in the US and elsewhere. Wind Turbine Syndromehas much in common with Low Frequency Noise Syndrome and Sick Building Syndrome. Dr. Pierpont published a report on herresearch titled: “Wind Turbine Syndrome” published in 2009.31

The lowest tone of the large cathedral pipe organs is approximately 16 Hz, just below the threshold for infrasound. At thatfrequency some music listeners can hear the organ’s tone but for many people it is more of a palpable sensation than an audiblesound.

Figure 1-Range of Sound Frequencies

Appendix 1: Terms and concepts related to wind turbine infrasoundrum ble/ th um p oroth erform of aud ible soun d . A ton e isacon cen tratio

frequen cy ran ge. Itislike th e soun d of aw h istle orastrin ged in strum en tplayin gasin gle n ote.

2 0 H z isoften ,in correctly,presum ed tobe th e low erlim itof h um an h earin gan d soun d sare gen erally

con sid ered tobe in frason ic if th eirfrequen cy islessth an 2 0 H z. S oun d sin th ese low erfrequen cy ran gesh ave

som e ch aracteristicsth atare d ifferen tfrom th e m ore aud ible frequen cies. O n e m ajord ifferen ce isth atin fra

an d low frequen cy soun d stravelfarth erth an h igh f

sign ifican td istan cesfrom th e em itter. Th isisespecially true in oth erw ise quietruralorw ild ern essareas.

In frasoun d prod uced by rotatin gm ach in esisd istin ctive from backgroun d in frasoun d because

be con cen trated in n arrow frequen cy ban d s( ton es) th atare related toth e rotation alspeed of th e d rive sh aft,

th e n um berofblad es,an d th e n um berof structuresth atth e blad es“ pass

h an d ,in frasoun d from n aturalprocesses,such asth un d erstorm s,h igh w in d s,fires,earth quakes,etc. w illn ot

prod uce ton es,butin stead prod uce in frasoun d th atcoversaw id er,broad erfrequen cy ran ge w ith out

con cen tration of en ergy in n arrow ran gesoratsin gle frequen cies

in frasoun d isn otblocked by com m on con struction m aterials. A ssuch ,itisoften m ore of aproblem in sid e

h om esw h ich are oth erw ise quietth an itisoutsid e th e h om e w h ere oth erm id an d h igh frequen cy soun d sof

com m un ity activity m od erate itsperceptibility.

Forexam ple,asim ple sin usoid al1 H z ton e h asah igh an d low pressure poin tevery 1 secon d . O n e ( 1 ) H z

m ean sth e pressure w ave cyclesfrom positive ton egative an d back in on e secon d . Un d ern orm alatm osph eric

con d ition sth e len gth ofth ispositive- n egative w ave isabout3 4 0 m eters( 1 1 1 5 feet) . Th e pressure w ave isvery

large com pared tom osth om esan d structures. Th ispressure w ave isn orm ally d epicted ash avin gasin usoid al

en velope w ith pressure risin gan d fallin ggrad ually w ith it.

Th e sh ape ofth e pressure w ave prod uced asth e w in d turbin e’sblad espassth e tow erortraverse aregion w ith

turbulen tairisn otsin usoid al. In stead itism ore d yn am ic w ith large ch an ges

aslittle asfew m illisecon d s. Th e w in d turbin e in frasoun d tim e sign ature ism uch m ore com plex th an asim ple

sin usoid alw ave. D r. M alcolm S w in ban ksh assh ow n in arecen tpaperth atif

th e w aveform isn otsin usoid al,but,

con cen trated in ash ortd uration pulse,th e poten tialforperceivin gth e

pressure ch an ge/ pulse isin creased relative tow h atw ould be expected for

perception of asin usoid alw aveform w ith equivalen ten ergy. Th us,h

sh ow sw h y itisexpected th atsom e people can feelapressure w ave w ith a

sh ortd uration pulse of5 0 to1 0 0 m illisecon d sw ith arapid rise toth e peak

pressure fallin gback toth e low erpressure forth e restofth e secon d . W in d

turbin e ton esh aveFigure2 -L argeU tility BoxFan

Appendix 1: Terms and concepts related to wind turbine infrasound

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rum ble/ th um p oroth erform of aud ible soun d . A ton e isacon cen tration ofacoustic en ergy in an arrow



in frason ic if th eirfrequen cy islessth an 2 0 H z. S oun d sin th ese low erfrequen cy ran gesh ave


an d low frequen cy soun d stravelfarth erth an h igh frequen cy on es,w h ich m ake th em apoten tialproblem at


In frasoun d prod uced by rotatin gm ach in esisd istin ctive from backgroun d in frasoun d because


th e n um berofblad es,an d th e n um berof structuresth atth e blad es“ pass- by” d urin garotation . O n th e oth er

om n aturalprocesses,such asth un d erstorm s,h igh w in d s,fires,earth quakes,etc. w illn ot


con cen tration of en ergy in n arrow ran gesoratsin gle frequen cies. Un like m id an d h igh frequen cy soun d ,



un ity activity m od erate itsperceptibility.



n egative w ave isabout3 4 0 m eters( 1 1 1 5 feet) . Th e pressure w ave isvery


fallin ggrad ually w ith it.


turbulen tairisn otsin usoid al. In stead itism ore d yn am ic w ith large ch an gesin pressure oversh ortperiod sof



th e w aveform isn otsin usoid al,but,in stead h asm uch of th e acoustic en ergy



perception of asin usoid alw aveform w ith equivalen ten ergy. Th us,h




turbin e ton esh ave th e ch aracteristic of rapid pressure ch an ge w ith peak

Date: Aug. 8, 2014n ofacoustic en ergy in an arrow



in frason ic if th eirfrequen cy islessth an 2 0 H z. S oun d sin th ese low erfrequen cy ran gesh ave


requen cy on es,w h ich m ake th em apoten tialproblem at


In frasoun d prod uced by rotatin gm ach in esisd istin ctive from backgroun d in frasoun d because th e en ergy w ill


by” d urin garotation . O n th e oth er

om n aturalprocesses,such asth un d erstorm s,h igh w in d s,fires,earth quakes,etc. w illn ot


. Un like m id an d h igh frequen cy soun d ,





n egative w ave isabout3 4 0 m eters( 1 1 1 5 feet) . Th e pressure w ave isvery



in pressure oversh ortperiod sof



in stead h asm uch of th e acoustic en ergy



perception of asin usoid alw aveform w ith equivalen ten ergy. Th us,h isw ork




th e ch aracteristic of rapid pressure ch an ge w ith peak

Appendix 1: Terms and concepts related to wind turbine infrasoundsoun d pressure levels1 0 to3 0 d B h igh erth an th e average w h en averaged overperiod sof asecon d orlon ger.

Th isiscovered in m ore d etaillaterin th isappen d ix.

Furth er,th ese ton esan d pulsation sare en tirely pred ictable based on establish ed an d accepted firstprin ciples

of aerod yn am ics,an d oth eren gin eerin gfield s. W ith respecttoh ow an d w h attype of n oise isp

scale w in d turbin esm ay be con sid ered tobe sim ilartolarge in d ustrialscale coolin gfan s. Th e prim ary

d ifferen ce isth atin stead of usin gelectricity toprod uce airm ovem en t,th ey use airm ovem en ttoprod uce

electricity. Th ere isan exten sive literature on h ow tod esign quietfan san d h ow tod iagn ose fan n oise

reason able pred iction ofth e soun d sth atw in d turbin esw illprod uce. B ased on th atpred iction th e acoustician

sh ould be able tod esign aprotocoltotestforth

un ique ch aracteristicsofw in d turbin e soun d sin th e in frasoun d region such th atth e read ercan see

in strum en tssen sitive toin frason ic ton esan d sh ortrapid pulsation sin th e in frasoun d reg

soun d stobe m easured occuraston esan d h arm on icsstartin gatth e blad e passfrequen cy an d th atth e ton es

sh ow large pulsation sattributed toblad e/ tow eran d oth eraerod yn am ic con d ition sth atcause th e blad e tolose

liftoroth erw ise prod uce ash ortd uration pressure pulses.

32There are other causes of these pulsations related to blade interactions with turbulence

purpose of this paper the focus is on the blade and tower interactions.

Figure 3- Wind turbine blade and tower interactionsproducing pressure pulsations

Figure 4-Idealized acoustic energy pulses at 1 Hz

from blade/tower interaction at 20 rpm

One Second


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soun d pressure levels1 0 to3 0 d B h igh erth an th e average w h en averaged overperiod sof asecon d orlon ger.

Th isiscovered in m ore d etaillaterin th isappen d ix.


of aerod yn am ics,an d oth eren gin eerin gfield s. W ith respecttoh ow an d w h attype of n oise isp



en sive literature on h ow tod esign quietfan san d h ow tod iagn ose fan n oise

problem s. Th ere isan en gin eerin gsociety

d evoted toun d erstan d in gh ow toproperly use

fan s( Th e A m erican S ociety of H eatin g,

Refrigeration an d A ir- con d ition in gEn gin eers

( A S H RA E) ) . Th isgroup w asactive in ad d ressin g

S ick B uild in gS yn d rom e d urin gth e lasth alf of

th e lastcen tury.

In m y opin ion ,an en gin eerw h oisfam iliarw ith

prin ciplesof fan d esign an d en gin eerin g,in

particularan acousticalen gin eerw h oisfam iliar

w ith w h y som e fan sare n oisy an d oth ersare n ot,

sh ould be able totran slate th atkn ow led ge tom akin ga


sh ould be able tod esign aprotocoltotestforth attype of n oise. Th isappen d ix h asexplain ed alittle aboutth e


in strum en tssen sitive toin frason ic ton esan d sh ortrapid pulsation sin th e in frasoun d reg



prod uce ash ortd uration pressure pulses.

Th isisagood tim e totake areview of w h ath asbeen said . O f

m ostim portan ce isth atth e greatestacoustic en ergy

con cen tration sw illbe foun d atfrequen ciesrelated toth e

speed ofth e d rive sh aftan d th e n um berofblad es. A sth e

blad e passesth e tow er,th e resultin gpressure w ave is

prod uced .3 2 Th ese pressure pulsation sappearaston es

There are other causes of these pulsations related to blade interactions with turbulence in the in-flow air stream. But, for thepurpose of this paper the focus is on the blade and tower interactions.

tower interactions

Idealized acoustic energy pulses at 1 Hz

Date: Aug. 8, 2014soun d pressure levels1 0 to3 0 d B h igh erth an th e average w h en averaged overperiod sof asecon d orlon ger.


of aerod yn am ics,an d oth eren gin eerin gfield s. W ith respecttoh ow an d w h attype of n oise isprod uced ,utility



en sive literature on h ow tod esign quietfan san d h ow tod iagn ose fan n oise

problem s. Th ere isan en gin eerin gsociety

d evoted toun d erstan d in gh ow toproperly use

fan s( Th e A m erican S ociety of H eatin g,

con d ition in gEn gin eers

. Th isgroup w asactive in ad d ressin g

S ick B uild in gS yn d rom e d urin gth e lasth alf of

In m y opin ion ,an en gin eerw h oisfam iliarw ith

prin ciplesof fan d esign an d en gin eerin g,in

particularan acousticalen gin eerw h oisfam iliar

som e fan sare n oisy an d oth ersare n ot,

sh ould be able totran slate th atkn ow led ge tom akin ga


attype of n oise. Th isappen d ix h asexplain ed alittle aboutth e


in strum en tssen sitive toin frason ic ton esan d sh ortrapid pulsation sin th e in frasoun d region are required . Th e



of w h ath asbeen said . O f

m ostim portan ce isth atth e greatestacoustic en ergy

con cen tration sw illbe foun d atfrequen ciesrelated toth e

speed ofth e d rive sh aftan d th e n um berofblad es. A sth e

blad e passesth e tow er,th e resultin gpressure w ave is

Th ese pressure pulsation sappearaston es

flow air stream. But, for the


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d urin gan alysisbutare n oth eard aston esby m ostpeople. In stead th ey m ay feelth e pressure ch an gesas

pulsation s,in tern alorgan vibration s,orasapain ( like earach esorm igrain es) . Th isfrequen cy iscalled th e

B lad e P assFrequen cy often abbreviated asB P F.

Form od ern utility scale w in d turbin esth isfrequen cy isat1 H z orlow er. A th ree blad ed w in d turbin e w ith a

h ub rotation of 2 0 revolution sperm in ute ( rpm ) h asa

B P F of 1 H z. W h en w in d turbin e blad esrotate pastth e

tow erash ortpressure pulse ( figure 4 ) occursprod ucin g

aburstof in frasoun d . W h en an alyzed th e resultisaw ell

d efin ed array of ton alh arm on icsbelow 1 0 H z. ( red bars

in figure 5 ) Forim pulsive soun d of th istype th e

h arm on icsare all“ ph ase- correlated .” Th ism ean sth e

peaksof each occuratth e sam e tim e. Th e peaksad d

togeth erin alin earfash ion w ith th eirin d ivid ual

m axim um soun d pressuresallcoin cid in g. Th us,foran im pulse h avin g4 equalam plitud e h arm on ics( B P F,2 n d ,

3 rd an d 4 th ) each of th e sam e am plitud e,th e peak levelis+ 1 2 d B . 1 0 equalh arm on icsw ould prod uce apeak

levelof + 2 0 d B .

Foraw in d turbin e w ith ah ub rotation of 1 5 rpm ,th e blad e passfrequen cy w ould be aton e at0 .7 5 H z ( ( 1 5

passesperm in ute * 3 blad es) / 6 0 secon d s= 0 .7 5 H z) . Th e blad e passfrequen cy w illbe accom pan ied by

h arm on icsth atw illalsopresen taston esw ith th e frequen cy of each h igh erh arm on ic bein gam ultiple of th e

blad e passfrequen cy. Th e secon d h arm on ic w ould be at1 .5 H z an d h igh erh arm on icsw ould occurat2 .2 5 ,3 .0 ,

an d 3 .7 5 H z.

W h en stud iescom m ission ed by th e w in d in d ustry in vestigate w in d turbin e in frasoun d th e testprotocolsare

n otselected / d esign ed toad d ressitsch aracteristics. In stead of d esign in gtestprotocolsaroun d th ese

pred ictable ch aracteristicsofw in d turbin e n oise th e acoustician sw h oh ave con d ucted testsforin frasoun d

often use m icroph on esth atare n otsen sitive tosoun d below 2 - 3 H z,usin gstan d ard acousticalm icroph on es

an d 1 / 3 octave ban d an alyzersw h ere th e filtersforth e very low estin frasoun d ran gesh ave kn ow n lim itation s

lead in gtoun d erstatin gth e soun d pressure level. Th ese in strum en tsare th en setton otm easure th e sh ort

d uration soun d pressure levelsbutin stead settod olon gaveragestypically of 1 0 m in utesorm ore. Itiseasy to

un d erstan d th atif allon e h aseverm easured isw in d turbin e in frasoun d usin gin strum en tsth atd oreport

average valuesforth e ton esorpulsation san d h ave lim itation sin th e frequen cy ban d filtersth atresultin

un d er- reportin gth e m easurem en tson e m igh tcon clud e th atw in d turbin esd on otem itin frasoun d . H ow ever,

th atcon clusion isbased on aflaw ed m eth od ology n otarealabsen ce of in frasoun d from th e w in d turbin e’s

im m ission s..

Ton esprod uced by w in d turbin esare d istin ctively d ifferen tfrom n orm ally occurrin gbackgroun d in frasoun d

caused by n orm alw eath eran d oth ern aturalprocessesw h ich are gen erally broad ban d an d n otton al.

Figure 5-Harmonics of fundamental BPF at 1 Hz.

Appendix 1: Terms and concepts related to wind turbine infrasoundM easurem en tsin sid e h om esin ruralareasth atare d istan tfrom operatin gutility scale w in d turbin es( 2 0 to5 0

m iles) d on otsh ow th e ton esan d pulsation sobserved in m easurem en tstaken in h om esn earsuch utilities

d urin gtim esw h en th e w in d turbin esare rotatin g/ operatin g.

Th e ability touse th e w in d turbin e h ub rotation speed tolin k blad e rotation speed ( an d th

th e w in d turbin es) toth e m icrobarom etertestd atash ow in gton esprovid esam eth od ofseparatin gw in d

turbin e operation ton esfrom an y oth erton esin th e backgroun d in frasoun d .

Ton esatin frason ic an d very low frequen ciesh ave been associated w ith bod y an d organ sen sation sor

frequen cy asth e w in d turbin e h ub speed sch an ge. Th e soun d pressure levelsof th ese ton esvary w ith w in d

turbin e operatin gcon d ition san d w eath er,butin gen erald urin gperiod sw ith w elld efin ed stron gton al

structures,th e ton esran ge from lon gterm averagesof 6 0 to7 0 d B soun d pressure levelath om esw ith in a

rad iusof am ile an d aquarter. H om esw ith in th e core of th atrad iusare su

stron gton esbecause w in d d irection m ay be lessim portan tforah om e w ith w in d turbin essurroun d in gitin all

d irection s. Th e secon d an d th ird h arm on icsare alm ostalw ayspresen tw ith som e testssh ow in gup to1 0

h arm on ics. Th e peaksofth e acoustic en ergy associated w ith th e ton esan d h arm on icscan be 1 5 to2 5 d B h igh er

th an th e lon gterm average. Th ese are th e peak soun d pressuresprod uced w h en th e blad e passesin fron tof th e

tow er,w ith very sh ortd uration ( un d er1 0 0

Figure6-R esonating M an

Figure1 R esonating M anfigurefrom a1978paperby GunnarR asm ussen


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M easurem en tsin sid e h om esin ruralareasth atare d istan tfrom operatin gutility scale w in d turbin es( 2 0 to5 0


d urin gtim esw h en th e w in d turbin esare rotatin g/ operatin g.

Th e ability touse th e w in d turbin e h ub rotation speed tolin k blad e rotation speed ( an d th


turbin e operation ton esfrom an y oth erton esin th e backgroun d in frasoun d .


in volun tary m ovem en tsform an y yearsasseen in th e

Reson atin gM an figure from a1 9 7 8 paperby Gun n ar

Rasm ussen w h od id con sid erable early w ork on in fraan d low

frequen cy soun d . W h en pressuresch an ge rapid ly,exceed in g

th e ability of m ech an ism sforbalan cin gin tern alan d extern al

pressures,people m ay reportsen sation sof stuffin ess,

fulln ess,orpain . M an y m ore reson an cesh ave been foun d

sin ce th attim e som e ofw h ich occuratth e cellularoreven

low erlevel. D r. S ch om er’sw ork h asfoun d m ilitary stud ies

from th e 1 9 8 0 ’sofh ow vibration satfrequen ciesun d er1 H z

cause n ausea.

Th e stud iesof people in th e S h irley com m un ity reportin g

ad verse h ealth effectsalsosh ow arelation sh ip w ith th e tim es

w h en th e w in d turbin esare operatin g.

Th e m icrobarom eterm easurem en tsfrom th e S h irley

com m un ity sh ow th ath om esw ith in six ( 6 ) m ilesof on e or

m ore utility scale w in d turbin esh ave in frason ic ton esth atare

presen tw h en w in d turbin esare operatin gan d th atch an ge in


an d w eath er,butin gen erald urin gperiod sw ith w elld efin ed stron gton al


rad iusof am ile an d aquarter. H om esw ith in th e core of th atrad iusare subjected tom ore frequen tperiod sof



cs. Th e peaksofth e acoustic en ergy associated w ith th e ton esan d h arm on icscan be 1 5 to2 5 d B h igh er


tow er,w ith very sh ortd uration ( un d er1 0 0 m illisecon d s) ,an d rapid rise tim es.

refrom a1978paperby Gunnar

Date: Aug. 8, 2014M easurem en tsin sid e h om esin ruralareasth atare d istan tfrom operatin gutility scale w in d turbin es( 2 0 to5 0


Th e ability touse th e w in d turbin e h ub rotation speed tolin k blad e rotation speed ( an d th usoperation state of



in volun tary m ovem en tsform an y yearsasseen in th e

Reson atin gM an figure from a1 9 7 8 paperby Gun n ar

od id con sid erable early w ork on in fraan d low

frequen cy soun d . W h en pressuresch an ge rapid ly,exceed in g

th e ability of m ech an ism sforbalan cin gin tern alan d extern al

pressures,people m ay reportsen sation sof stuffin ess,

an cesh ave been foun d

sin ce th attim e som e ofw h ich occuratth e cellularoreven

low erlevel. D r. S ch om er’sw ork h asfoun d m ilitary stud ies

from th e 1 9 8 0 ’sofh ow vibration satfrequen ciesun d er1 H z

of people in th e S h irley com m un ity reportin g

ad verse h ealth effectsalsosh ow arelation sh ip w ith th e tim es

w h en th e w in d turbin esare operatin g.

Th e m icrobarom eterm easurem en tsfrom th e S h irley

com m un ity sh ow th ath om esw ith in six ( 6 ) m ilesof on e or

ore utility scale w in d turbin esh ave in frason ic ton esth atare

presen tw h en w in d turbin esare operatin gan d th atch an ge in


an d w eath er,butin gen erald urin gperiod sw ith w elld efin ed stron gton al


bjected tom ore frequen tperiod sof



cs. Th e peaksofth e acoustic en ergy associated w ith th e ton esan d h arm on icscan be 1 5 to2 5 d B h igh er



Figure 7-Infiltec-20 micro barometer.Resolution: 0.001 Pascals from 0.1 to 20 Hz.Data sampled 50 times a second in signed16bit integers. Range: ± 25 Pascals.

B ased on m y observation san d in terview sofm an y people w h oh ad ad verse reaction stoutility scale w in d

turbin e th ism ay be perceived by som e asad eep,rum ble/ th um p,orby oth ersasabod y partvibration or

pulsation . S om e reporth ead ach esoroth ersym ptom sth atin clud e pain asach aracteristic.

S in ce m uch of th e n ew stud y’sd ataw asd eveloped from testsusin gam icrobarom eteritisw orth spen d in gabit

Th e m icrobarom eterislocated in atesth om e usually in aroom orn earalocation th atpeople h ave foun d to

prod uce sym ptom sorin aspare bed room . P osition in gofth e un itisn otcriticalsin ce forth e

frequen ciesth e en ergy appearstobe fairly un iform th rough outah om e. Th e m icrobarom eteriscon n ected toa

d ataloggin gd evice viath e RS 2 3 2 cable. Th e d ataloggin gd evice receivesth e pressure m easurem en tsassign ed

1 6 bitin tegersw ith asam ple every 0 .0 2 secon d sor5 0 sam plespersecon d . Th e un itisleftin place forh oursto

d ays. O ften th e fam ily h ostin gth e testrecord sn oteson alogsh eet. In oth ercasesin d epen d en tobserversn ote

th e w in d turbin e operatin gstates.

A tth e en d of atestperiod th e d atarepresen tin gth e h oursof testin gare extracted from th e d atalogger. Usin g

an alysistoolsth e d ataiscon verted from aseriesof pressure read in gstosoun d pressure levelsin d ecibels. A

coun tof1 0 0 0 in th e d atarepresen ts1 P ascalor9 4 d B . Th e d atarepresen tsm an y h oursof testin gan d th usa

ch artsh ow in gth e en tire tim e span w illbe very d en se. Forth istype of d isplay Ih ave selected aspectrogram as

th e d isplay tool.


- 19 -

0.001 Pascals from 0.1 to 20 Hz.Data sampled 50 times a second in signed

B ased on m y observation san d in terview sofm an y people w h oh ad ad verse reaction stoutility scale w in d


S om e reporth ead ach esoroth ersym ptom sth atin clud e pain asach aracteristic.


of tim e d escribin gth e In filtec- 2 0 m od elth atw asused .

A m icrobarom eterisvery sim ilartoastan d ard acoustical

in strum en t’sm icroph on e exceptth atitisd esign ed toon ly

respon d tosoun d pressure overth e frequen cy ran ge of 0 .0 5 to

2 0 H z. S tan d ard acousticalgrad e m icroph on escan n otm easure

soun d pressure accurately atfrequen ciesof 3 H z an d low er.

S pecialin frasoun d m icroph on esare required tom

to0 .5 H z orlow er. Even w ith aspecialin frasoun d m icroph on e

m easurem en tofth e low est3 H z isn otprecise an d subjectto

m an y sourcesof artifact. B ecause th e m icrobarom eteris

d esign ed toon ly coverth e in frasoun d ran ge itisaviable an d

relatively,reliable an d low costm easurem en ttool.


prod uce sym ptom sorin aspare bed room . P osition in gofth e un itisn otcriticalsin ce forth e



ith asam ple every 0 .0 2 secon d sor5 0 sam plespersecon d . Th e un itisleftin place forh oursto


of atestperiod th e d atarepresen tin gth e h oursof testin gare extracted from th e d atalogger. Usin g


P ascalor9 4 d B . Th e d atarepresen tsm an y h oursof testin gan d th usa


Date: Aug. 8, 2014B ased on m y observation san d in terview sofm an y people w h oh ad ad verse reaction stoutility scale w in d


S om e reporth ead ach esoroth ersym ptom sth atin clud e pain asach aracteristic.


2 0 m od elth atw asused .

A m icrobarom eterisvery sim ilartoastan d ard acoustical

itisd esign ed toon ly

respon d tosoun d pressure overth e frequen cy ran ge of 0 .0 5 to

2 0 H z. S tan d ard acousticalgrad e m icroph on escan n otm easure

soun d pressure accurately atfrequen ciesof 3 H z an d low er.

S pecialin frasoun d m icroph on esare required tom easure d ow n

to0 .5 H z orlow er. Even w ith aspecialin frasoun d m icroph on e

m easurem en tofth e low est3 H z isn otprecise an d subjectto

m an y sourcesof artifact. B ecause th e m icrobarom eteris

d esign ed toon ly coverth e in frasoun d ran ge itisaviable an d

relatively,reliable an d low costm easurem en ttool.


prod uce sym ptom sorin aspare bed room . P osition in gofth e un itisn otcriticalsin ce forth e low estin frasoun d



ith asam ple every 0 .0 2 secon d sor5 0 sam plespersecon d . Th e un itisleftin place forh oursto


of atestperiod th e d atarepresen tin gth e h oursof testin gare extracted from th e d atalogger. Usin g


P ascalor9 4 d B . Th e d atarepresen tsm an y h oursof testin gan d th usa



- 20 -

Figure 8-Typical micro barometer spectrogram showing tones from wind turbines during periods of operation

Th e m ain reportin clud esasum m ary of th e fin d in gsofth e stud y an d alsoad d ition alspectrogram ssh ow in gth e

ton esan d oth erch aracteristicsatvariousd istan cesfrom th e S h irley W in d projectouttosix m iles. Th e m icro

barom etertestscon firm th e fin d in gsofth e S h irley W in d stud y forth e P S C an d oth erearliern oise stud ies. Th ey

exten d ourun d erstan d in gofh ow in frason ic ton esare presen tth rough outth e h om esofpeople w h oare

experien cin gad verse h ealth effects.

r ichar d jam es in ce e-co u s t ic s o lu t io...

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