1、VEREIN DEUTSCHERINGENIEUREUmweltmeteorologieMeteorologische Messungen fr Fragen der Luftreinhaltung WindEnvironmental meteorologyMeteorological measurements concerning questionsof air pollution WindVDI 3786Blatt 2 / Part 2Ausg. deutsch/englischIssue German/EnglishKommission Reinhaltung der Luft (KRd
2、L) im VDI und DIN NormenausschussArbeitsgruppe WindAusschuss Meteorologische MessungenVDI/DIN-Handbuch Reinhaltung der Luft, Band 1bVDI-RICHTLINIENZu beziehen durch/ Availablefrom Beuth Verlag GmbH, 10772BerlinAlle Rechtevorbehalten / All rightsreserved VereinDeutscher Ingenieure, Dsseldorf 2000Verv
3、ielfltigung auchfr innerbetriebliche Zwecke nicht gestattet / Reproduction even for internal use not permittedDer Entwurf dieser Richtlinie wurde mit Ankndigung im Bundes-anzeiger einem ffentlichen Einspruchsverfahren unterworfen.Die deutsche Version dieser Richtlinie ist verbindlich.ICS 13.040.10;
4、07.060Dezember 2000December 2000The draft of this guideline has been subject to public scrutinyafter announcement in the Bundesanzeiger (Federal Gazette).No guarantee can be given with respect to the English transla-tion. The German version of this guideline shall be taken asauthoritative.Inhalt 6HL
5、WH9RUEHPHUNXQJ (LQOHLWXQJ 1 Grundlagen 3KVLNDOLVFKH *UXQGODJHQ 0HVVYHUIDKUHQ 2 Messwertgeber 3 Standortwahl und Messgertetrger 6WDQGDUGDXIVWHOOXQJ $XIVWHOOXQJ I U VSHLHOOH =ZHFNH 0HVVJHUlWHWUlJHU (LQQRUGXQJ GHV :LQGULFKWXQJVJHEHUV 4 Datenerfassung LJLWDOH DWHQHUIDVVXQJ $QDORJUHJLVWULHUXQJ DXI 3DSLHU
6、 5HFKQHUJHVW WWH 0HVVZHUWHUIDVVXQJ 5 Kalibrierung und Datenqualitt .DOLEULHUXQJ 4XDOLWlWVPDQDJHPHQW 40 DUOHJXQJ 4XDOLWlWVOHQNXQJ 4 eingebaute Anzeige; temporre MessungenStaudruck-Handanemometer Staudse 1,0 keine Registrierung mglich, nicht fr kontinuierliche automatische Messun-gen geeignetThermisch
7、es Anemometer Thermistor, Hitzdraht, Heifilm0,2 + sehr empfindlich, nicht fr kontinuierli-che automatische Messungen geeignetB. Messgre: WindrichtungWindfahne mit einfachem oder doppeltem BlattPotentiometer oder opto-elektronischer Impulsgeber1,0 2b +Codegeber Umformung des Codes in Strom- oder Span
8、nungssignaleC. Messgre: Windgeschwindigkeit und WindrichtungSchalenstern koaxial mit Wind-fahne kombiniertelektrisch, siehe A und B 2,4 2c +Schalenstern kombiniert mit Wind-fahne bereinander elektrisch, siehe A und B 1,0 + kompakte Bauart, unteres Messgert kann durch Haltebgel beeinflusst sein neben
9、einander elektrisch, siehe A und B 1,0 2i + groer Abstand der Messwertgeber mindert gegenseitige BeeinflussungWindfahne mit integriertem Pro-peller-Anemometerelektrisch 2,0 2e + geeignet fr Fluktuationsmessungen2-D-Ultraschall-Anemometer elektronisch 1,5 2g + trgheitslose Messung, geeignet fr Fluktu
10、ationsmessungenWindrichtungsunabhngiges ther-misches Anemometerelektrisch/elektronisch; beheizter Zylinder2,2 2f + keine mechanisch bewegten TeileD. Messung des vollstndigen WindvektorsVektorwindfahne mit integriertem Propeller-Anemometer0,7 + geeignet fr Fluktuationsmessungen; stranfllig bei Nieder
11、schlag und hoher WindgeschwindigkeitOrthogonal-Propeller-Anemometer optischer Impulsgeber 12 2d +3-D-Ultraschall-Anemometer elektronisch 2 2h + trgheitslose Messung, geeignet fr FluktuationsmessungenB55EB1B3E14C22109E918E8EA43EDB30F09DCCB7EF86D9NormCD - Stand 2012-08Alle Rechte vorbehalten Verein De
12、utscher Ingenieure, Dsseldorf 2000 9, %ODWW 3DUW Table 1. Wind-measuring instrumentsNote: 9DOXHV JLYHQ DUH WSLFDO IRU LQVWUXPHQWV FXUUHQWO RQ RIIHU Sensors Mass (approx.)kgFigure Needs electric power supplySpecial characteristicsTransducersA. Quantity to be measured: Wind speedCup anemometer AC gene
13、rator 1,0 2aDC generator 1,0Contact switch 1,0 Variable operating sequence Counter 1,0 Integrated display, recording impossiblePulser, magnetic 1,0 + Any number of additional instruments possible,Pulser, inductive 1,0 + linear scale possible, remote measuring, Pulser, opto-electronic 1,0 + independe
14、nt of line resistance(Hand-held anemometer) eddy current measuring system0,4 Easy handling; integrated display; temporary measurements Hand-held pressure-tube anemometerPressure tube 1,0 Recording impossible, not suitable for continuous automatic measurementsThermal anemometer Thermistor, hot wire,
15、hot film0,2 + Very sensitive, not suitable for continuous automatic measurementsB. Quantity to be measured: Wind directionWind vane with single fin or two finsPotentiometer or opto-electronic pulser1,0 2b +Encoder Conversion of code to current or voltage signalsC: Quantity to be measured: Wind speed
16、 and directionCup anemometer and wind vane mounted coaxiallyElectrical, see A and B 2,4 2c +Cup anemometer and wind vane vertical combination Electrical, see A and B 1,0 + Compact design; lower instrument subject to interferences from the support horizontal combination Electrical, see A and B 1,0 2i
17、 + Large distance between sensors reduces mutual influencesWind vane with integrated propeller anemometerElectrical 2,0 2e + Suitable for measurements of fluctuations2-D ultrasonic anemometer Electronic 1,5 2g + Measurement without inertia, suita-ble for measurements of fluctuationsDirection-indepen
18、dent ther-mal anemometerElectrical/electronic; hea-ted cylinder2,2 2f + No moving partsD. Measurement of the complete wind vectorVector wind vane with integra-ted propeller anemometer0,7 + Suitable for measurements of fluctua-tions; susceptible to faults due to precipitation and at high wind speedOr
19、thogonal propeller anemo-meterOptical pulser 12 2d +3-D ultrasonic anemometer Electronic 2 2h + Measurement without inertia, suita-ble for measurements of fluctuationsB55EB1B3E14C22109E918E8EA43EDB30F09DCCB7EF86D9NormCD - Stand 2012-08All rights reserved Verein Deutscher Ingenieure, Dsseldorf 2000 9
20、, %ODWW 3DUW 2 Messwertgeber7DEHOOH JLEW HLQH hEHUVLFKW EHU GLH XUHLW LQ GHU0HVVSUDLV EHZlKUWHQ :LQGPHVVJHUlWH %HLVSLHOHI U :LQGPHVVJHUlWH VLQG LQ %LOG D ELV L GDUJH VWHOOW 5RWDWLRQVDQHPRPHWHU VLQG XP $QWULHE HLQHU JUR HQ9LHOIDOW YRQ 0HVVZHUWXPIRUPHU EHVRQGHUV JHHLJQHW :HFKVHOVWURP XQG *OHLFKVWURPJH
21、QHUDWRUHQ RSWL VFKH LQGXNWLYH XQG PDJQHWLVFKH ,PSXOVJHQHUDWRUHQVRZLH UHKDKOPHVVJHUlWH LH $XVZDKO GHV 0HVVZHUWJHEHUV ZLUG GXUFK GLH0HVVDXIJDEH EHVWLPPW :HVHQWOLFKH *HVLFKWVSXQNWHGDI U VLQG 1DFKZHLVJUHQH $XIO|VXQJVYHUP|JHQ GQDPLVFKHV 9HUKDOWHQ 0HVVEHUHLFK VRZLH $UW GHUDWHQHUIDVVXQJ VLHKH $EVFKQLWW LH
22、:LQGIDKQH GDUI QXU HLQH *OHLFKJHZLFKWVVWHOOXQJKLQVLFKWOLFK GHU :LQGULFKWXQJ KDEHQ $X HUGHP GDUIVLH EHL :LQGVWLOOH NHLQH 9RUXJVHLQVWHOOXQJ HLQQHK PHQ LH 5HLEXQJ GHU :LQGIDKQH ZLUG GXUFK .XJHOODJHUPLW NlOWHEHVWlQGLJHQ 6FKPLHUPLWWHOQ JXWH $XVEDODQ FLHUXQJ XQG GXUFK JHULQJHV *HZLFKW JHULQJ JHKDOWHQ (LQH
23、 9HUPLQGHUXQJ GHU 5HLEXQJ LVW DXFK GXUFK PDJ QHWLVFKH (QWODVWXQJ P|JOLFK ) U GLH 9HNWRUZLQG IDKQH DOV NRPELQLHUWHV 6VWHP JHOWHQ VLQQJHPl GLHJOHLFKHQ $QJDEHQ HU PLW GHU :LQGIDKQH JHNRSSHOWH 0HVVZHUWJHEHU LVWLP :HVHQWOLFKHQ HLQ UHKZLQNHO hEHUWUDJXQJVVV WHP +LHUYRQ VLQG YHUVFKLHGHQH 7SHQ LP *HEUDXFK 3R
24、WHQWLRPHWHU :HFKVHOVWURP XQG *OHLFKVWURP 6Q FKURQJHQHUDWRUHQ YHUlQGHUOLFKH .DSDLWlWHQ XQG ,Q GXNWLYLWlWHQ VRZLH URWLHUHQGH 6FKDOWHU XQG GLJLWDOH:LQNHOFRGLHUHU %HL GHU :DKO GHV *HEHUV VROOWHQ GLHMHZHLOV EHVWHKHQGHQ 0|JOLFKNHLWHQ GHU :HLWHUYHUDU EHLWXQJ GHU DWHQ QDFK $EVFKQLWW EHU FNVLFKWLJWZHUGHQ 8OW
25、UDVFKDOO XQG WKHUPLVFKH $QHPRPHWHU HQWKDOWHQNHLQH GXUFK GHQ :LQG DQJHWULHEHQHQ PHFKDQLVFKHQ.RPSRQHQWHQ XQG VLQG GDKHU EHVRQGHUV UREXVW XQGZDUWXQJVDUP (YHQWXHOOH 9HUlQGHUXQJHQ GHU 0HVV VWUHFNHQ GXUFK PHFKDQLVFKH %HVFKlGLJXQJ N|QQHQDXWRPDWLVFK EHUZDFKW ZHUGHQ :LQGPHVVJHUlWH PLW DWHQIHUQ EHUWUDJXQJ XQG
26、 5H JLVWULHUXQJ KDEHQ LQ GHU 5HJHO 1HWDQVFKOXVV EHLHLQLJHQ *HUlWHQ LVW DXFK %DWWHULHEHWULHE P|JOLFK %HLIHKOHQGHU 6WURPYHUVRUJXQJ N|QQHQ DXFK UHLQ PHFKD QLVFK DUEHLWHQGH :LQGPHVVJHUlWH HLQJHVHWW ZHUGHQ 2Sensors7DEOH JLYHV DQ RYHUYLHZ RI ZLQG PHDVXULQJ LQVWUX PHQWV ZKLFK KDYH EHHQ SURYHQ LQ SUDFWLFH (
27、DPSOHVRI ZLQG PHDVXULQJ LQVWUXPHQWV DUH UHSUHVHQWHG LQ)LJXUHV D WKURXJK L 5RWDWLQJ DQHPRPHWHUV DUH SDUWLFXODUO VXLWDEOH IRUUXQQLQJ D ODUJH YDULHW RI WUDQVGXFHUV $& DQG &JHQHUDWRUV RSWLFDO LQGXFWLYH DQG PDJQHWLF SXOVHUV DQG LQVWUXPHQWV FRXQWLQJ WKH UHYROXWLRQV 7KH PHDVXUHPHQW WDVN GHWHUPLQHV WKH VHOH
28、FWLRQ RI WKHVHQVRU (VVHQWLDO FULWHULD DUH WKH GHWHFWLRQ OLPLW UHVR OXWLRQ GQDPLF EHKDYLRXU PHDVXULQJ UDQJH DQG WKHWSH RI GDWD DFTXLVLWLRQ VHH 6HFWLRQ )RU DQ JLYHQ ZLQG GLUHFWLRQ WKH ZLQG YDQH VKDOO QRWKDYH PRUH WKDQ RQH VLQJOH HTXLOLEULXP SRVLWLRQ )XU WKHUPRUH LW VKDOO QRW KDYH D SUHIHUHQWLDO RULHQW
29、DWLRQGXULQJ FDOP )ULFWLRQ RI WKH ZLQG YDQH LV NHSW WR D PLQLPXP EPHDQV RI EDOO EHDULQJV ZLWK QRQ IUHHLQJ OXEULFDQWV SURSHU FRXQWHUEDODQFLQJ DQG ORZ ZHLJKW FRQVWUXF WLRQ ,W LV DOVR SRVVLEOH WR UHGXFH IULFWLRQ E PDJQHWLFEHDULQJ 7KH VDPH SULQFLSOHV DSSO E DQDORJ WR WKHYHFWRU YDQH ZKLFK LV D FRPELQHG VV
30、WHP %DVLFDOO WKH VHQVRU OLQNHG WR WKH ZLQG YDQH LV D UR WDWLQJ DQJOH WUDQVPLWWLQJ VVWHP 9DULRXV WSHV RIWKLV VVWHP DUH FRPPRQO XVHG SRWHQWLRPHWHUV $&DQG & VQFKURQRXV JHQHUDWRUV YDULDEOH FDSDFLWRUV DQG LQGXFWLRQ FRLOV DV ZHOO DV URWDWLQJ VZLWFKHV DQGGLJLWDO DQJOH HQFRGHUV 7KH WSH RI VHQVRU WR EH VH OH
31、FWHG VKRXOG EH FRPSDWLEOH ZLWK WKH HLVWLQJ GDWDSURFHVVLQJ IDFLOLWLHV VHH 6HFWLRQ 8OWUDVRQLF DQG WKHUPDO DQHPRPHWHUV DUH SDUWLFXODUOUREXVW DQG UHTXLUH OLWWOH PDLQWHQDQFH DV WKH GR QRWLQYROYH DQ PHFKDQLFDO FRPSRQHQWV WKDW DUH GULYHQE WKH ZLQG 3RVVLEOH FKDQJHV RI WKH PHDVXUHPHQWSDWKV DV D FRQVHTXHQFH R
32、I PHFKDQLFDO GDPDJH FDQ EHPRQLWRUHG DXWRPDWLFDOO ,Q JHQHUDO ZLQG PHDVXULQJ LQVWUXPHQWV ZLWK UHPRWHWUDQVPLVVLRQ DQG UHFRUGLQJ RI GDWD DUH OLQH SRZHUHG 6RPH WSHV RI LQVWUXPHQWV DOVR DOORZ IRU EDWWHURSHUDWLRQ :KHUH QR HOHFWULF SRZHU VXSSO LV DYDLOD EOH LW LV DOVR DOORZHG WR XVH SXUHO PHFKDQLFDO LQVWUX
33、PHQWV B55EB1B3E14C22109E918E8EA43EDB30F09DCCB7EF86D9NormCD - Stand 2012-08Alle Rechte vorbehalten Verein Deutscher Ingenieure, Dsseldorf 2000 9, %ODWW 3DUW Bild 2a.Schalenstern-AnemometerFig. 2a.Cup anemometerBild 2c. Kombiniertes WindmessgertFig. 2c. Combined wind-measuring instrumentBild 2e. Windf
34、ahne mit integriertem Propeller-AnemometerFig. 2e. Wind vane with built-in propeller anemometerBild 2b. Windfahne mit LeitflcheFig. 2b. Wind vane with finBild 2d. Orthogonal-Propeller-AnemometerFig. 2d. Orthogonal propeller anemometerBild 2f. Thermisches AnemometerFig. 2f. Thermal anemometerB55EB1B3
35、E14C22109E918E8EA43EDB30F09DCCB7EF86D9NormCD - Stand 2012-08All rights reserved Verein Deutscher Ingenieure, Dsseldorf 2000 9, %ODWW 3DUW Bild 2g. 2-D-Ultraschall-AnemometerFig. 2g. 2-D ultrasonic anemometerBild 2i. Beispiel fr Schalenstern-Anemometer und Windfahneauf gemeinsamer HalterungBild 2h. 3
36、-D-Ultraschall-AnemometerFig. 2h. 3-D ultrasonic anemometerFig. 2i. Example of cup anemometer and wind vane on a com-mon supportB55EB1B3E14C22109E918E8EA43EDB30F09DCCB7EF86D9NormCD - Stand 2012-08Alle Rechte vorbehalten Verein Deutscher Ingenieure, Dsseldorf 2000 9, %ODWW 3DUW 3 Standortwahl und Mes
37、sgertetrger:LQGPHVVXQJHQ VLQG KLQVLFKWOLFK LKUHU $XVVDJHNUDIWDXI GHQ 0HVVVWDQGRUW EHVFKUlQNW 8P I U JU| HUH*HELHWH UHSUlVHQWDWLYH 0HVVXQJHQ X HUKDOWHQ LVW HLQP|JOLFKVW HEHQHU XQG KLQGHUQLVIUHLHU VLHKH $E VFKQLWW 6WDQGRUW X ZlKOHQ %HL GHU 0HVVXQJ YHU WLNDOHU *UDGLHQWHQ GHV +RULRQWDOZLQGHV LVW HLQHZHL
38、WJHKHQG HLQKHLWOLFKH 8QWHUODJH LQ HLQHP JU| HUHQ8PNUHLV QRWZHQGLJ VLHKH $EVFKQLWW HU 6WDQGRUW HLQHV 0HVVJHUlWHV LVW VRPLW GHU $XIJD EHQVWHOOXQJ HQWVSUHFKHQG DXVXZlKOHQ +LHUEHL HPS ILHKOW HV VLFK HLQHQ 0HWHRURORJHQ DOV %HUDWHU KLQX XLHKHQ :LQGULFKWXQJ XQG :LQGJHVFKZLQGLJNHLWVLQG QDFK 0|JOLFKNHLW DP V
39、HOEHQ 2UW X PHVVHQ ZR EHL JHJHQVHLWLJH %HHLQIOXVVXQJ GHU 0HVVZHUWJHEHUX YHUPHLGHQ LVW %HL GHU 9HUZHQGXQJ YRQ 6FKDOHQVWHUQ $QHPRPHWHUXQG :LQGIDKQH LQ JHWUHQQWHU $XVI KUXQJ VLQG GLH0HVVJHUlWH QHEHQHLQDQGHU LQ HLQHP KRULRQWDOHQ $E VWDQG YRQ FD P DQXRUGQHQ 9HUWLNDO VLQG GLH EHL GHQ *HUlWH JHJHQHLQDQGHU
40、VR X YHUVHWHQ GDVV VLFKGLH 5RWDWLRQVHEHQH GHV 6FKDOHQVWHUQV PLQGHVWHQVP EHU GHU 2EHUNDQWH GHV )DKQHQEODWWV EHILQGHWVLHKH %LOG L %HL GHU 0RQWDJH HLQHU %OLWIDQJVWDQJH VROOWH GLH NRQ VWUXNWLYH $XVI KUXQJ XQWHU %HDFKWXQJ GHU HLQVFKOl JLJHQ 9RUVFKULIWHQ ELV GXUFKJHI KUW ZHUGHQ )HUQHU LVW GLH %OLWIDQJVWDQ
41、JH EHRJHQ DXI GLH+DXSWZLQGULFKWXQJ QLFKW LP /XY GHV 6FKDOHQVWHUQ $QHPRPHWHUV DQXRUGQHQ VLHKH $EVFKQLWW 3.1 Standardaufstellung8P EHL GHU %HVWLPPXQJ GHV %RGHQZLQGHV YHUJOHLFK EDUH :HUWH X HUKDOWHQ VROO LQWHUQDWLRQDOHQ )HVWOH JXQJHQ JHPl LQ P +|KH EHU HEHQHP KLQGHUQLV IUHLHP *HOlQGH JHPHVVHQ ZHUGHQ LH
42、V ZLUG DXFK DOV%RGHQZLQG EHHLFKQHW +LQGHUQLVIUHLHV *HOlQGHLVW GHILQLHUW DOV HLQH )OlFKH EHL GHU GLH (QWIHUQXQJZLVFKHQ :LQGPHVVHU XQG GHP QlFKVWHQ +LQGHUQLVPLQGHVWHQV GDV =HKQIDFKH GHU +|KH GLHVHV +LQGHU QLVVHV EHWUlJW :HQQ GLHVHU 9RUVFKULIW QLFKW HQW VSURFKHQ ZHUGHQ NDQQ VROOWH GDV :LQGPHVVJHUlW LQH
43、LQHU VROFKHQ +|KH DXIJHVWHOOW ZHUGHQ LQ ZHOFKHU GLH0HVVZHUWH GXUFK |UWOLFKH +LQGHUQLVVH P|JOLFKVW XQ EHHLQIOXVVW EOHLEHQ +LQVLFKWOLFK GHV 5DXPHV LQ GHPHLQ +LQGHUQLV GLH 0HVVXQJ EHHLQIOXVVW ZHUGHQ LQ$EVFKQLWW (PSIHKOXQJHQ JHJHEHQ ,Q MHGHP )DOO P VVHQ GLH 0HVVJHUlWH P ELV PEHU GHU GXUFKVFKQLWWOLFKHQ *
44、HElXGHK|KH EZ GHUPLWWOHUHQ +|KH GHV %HZXFKVHV LQ GHU 8PJHEXQJ DXI JHVWHOOW ZHUGHQ 3 Site selection and instrument support7KH UHVXOWV RI ZLQG PHDVXUHPHQWV DUH YDOLG IRU WKHPHDVXUHPHQW VLWH RQO 5HVXOWV WKDW DUH UHSUHVHQWDWLYHIRU HWHQGHG DUHDV FDQ RQO EH REWDLQHG DW VLWHV ZKHUHWKH WHUUDLQ LV DV OHYHO D
45、V SRVVLEOH DQG IUHH IURP REVWD FOHV VHH 6HFWLRQ :KHUH YHUWLFDO JUDGLHQWV RI WKHKRULRQWDO ZLQG DUH WR EH GHWHUPLQHG WKH VLWH PXVWKDYH D PRVWO XQLIRUP VXUIDFH HWHQGLQJ IRU VRPHGLVWDQFH DURXQG WKH ORFDWLRQ RI WKH LQVWUXPHQW VHH6HFWLRQ 7KH VLWH RI D PHDVXULQJ LQVWUXPHQW VKDOO WKHUHIRUH EHVHOHFWHG LQ DFF
46、RUGDQFH ZLWK WKH PHDVXUHPHQW WDVN ,WLV UHFRPPHQGHG WR FRQVXOW D PHWHRURORJLVW ,I SRVVL EOH ZLQG VSHHG DQG ZLQG GLUHFWLRQ VKDOO EH PHDVXUHGDW WKH VDPH VLWH $Q PXWXDO LQIOXHQFLQJ RI WKH VHQ VRUV VKDOO EH DYRLGHG :KHUH D VHSDUDWH FXS DQHPRPHWHU DQG ZLQG YDQH DUHWR EH XVHG WKH WZR VKDOO EH SRVLWLRQHG DW
47、 D KRULRQWDOGLVWDQFH RI DSSURLPDWHO P 7KHLU YHUWLFDO RIIVHWVKDOO EH VXFK WKDW WKH SODQH RI URWDWLRQ RI WKH FXS DQ HPRPHWHU OLHV P RU PRUH DERYH WKH WRS HGJH RIWKH ZLQG YDQH VHH )LJXUH L :KHQ D OLJKWQLQJ URG LV LQVWDOOHG LWV FRQVWUXFWLRQ DQGGHVLJQ VKRXOG FRPSO ZLWK WKH UHOHYDQW UHJXODWLRQV WR )XUWKHU
48、PRUH D OLJKWQLQJ URG VKDOO QRW EHLQVWDOOHG RQ WKH ZLQGZDUG VLGH ZLWK UHVSHFW WR WKHPDLQ ZLQG GLUHFWLRQ RI D FXS DQHPRPHWHU VHH 6HF WLRQ 3.1 Standard installation$FFRUGLQJ WR LQWHUQDWLRQDO VSHFLILFDWLRQV VXUIDFHZLQG VKDOO LI SRVVLEOH EH PHDVXUHG DW D KHLJKW RIP DERYH IODW RSHQ WHUUDLQ LQ RUGHU WR DFKLHYH FRP SDUDEOH UHVXOWV 7KL