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ABB Azipod® PropulsionSystems with On-LineMeasurement of Moisture in Oil

Hand-held measurementsNew Relative Humidityand Temperature Probesfor MI70 Indicator

New technology for high accuracy measurements Vaisala DM500 PrecisionSAW Hygrometer

Studying the Carbon Cycles of World’s Ecosystems

2 160/2002

Contents

Editor-in-Chief:Ritva Siikamäki

Publisher:Vaisala Oyj , P.O. Box 26FIN-00421 HelsinkiFINLAND

Phone (int.):+358 9 894 91

Telefax:+358 9 8949 2227

Internet:http://www.vaisala.com

Design and Artwork:Edita Oyj

Editors:Bellcrest LanguageServices Oy

Printed in Finland byEdita Oyj, Finland

ISSN 1238-2388

Cover photo:The ABB Azipod® Propulsion System is used innumerous types of vessel, such as cruise vesselVoyager of the Seas. Photo by Gero Mylius, © INDAV Ltd, Finland.

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Vaisala in Brief– We develop, manufacture andmarket products and services forenvironmental and industrialmeasurements.

– The purpose of these measure-ments is to provide a basis for abetter quality of life, cost sa-vings, protection of the environ-ment, improved safety and bet-ter performance.

– We focus on market segmentswhere we can be the world leader,the preferred supplier. We put ahigh priority on customer satis-faction and product leadership.We secure our competitive advan-tage through economies of scaleand scope.

The AMT100 Series Ammonia Detectorswere launched a year ago. They have proventheir reliability in both cold and warmenvironments. Demanding installation siteswith different background odors and gaseshave shown that the AMT100 AmmoniaDetectors have excellent ammonia selectivity,which is a key concern for many customers, forinstance in the food processing industry.P H OTO C O U RT E S Y O F I N G M A N

Orion Pharma, the leading Finnishpharmaceutical company, has awarded acontract to Vaisala to support their operations.Vaisala’s Humidity and TemperatureTransmitters are used as part of a validatedsystem that provides measurement data inOrion’s manufacturing and storage facilitiesin Turku. The system follows strict GoodManufacturing Practice (GMP) guidelines.

Vaisala supports the lifetime accuracy of theinstruments by making regular calibrationseasy and affordable. The calibration reminderand service program offers both standard andaccredited calibrations, enabling customers toget the best possible performance out of theirproducts.

The historic site of Mawson’s Huts in theAustralian Antarctic Territory boasts a richcultural heritage but is located in verydemanding environmental conditions.Supporting the effort to preserve the site,Vaisala equipment is used to monitor andstudy the environmental conditions.P H OTO C O U RT E S Y O F S T E V E M A RT I N ,S TAT E L I B R A RY O F N S W

President’s Column 3

Ammonia

Vaisala Ammonia Detectors’ First Year 4

Humidity

New Options for Hand-Held Measurement with MI70 Indicator 6

Preserving Our Antarctic Heritage - Mawson’s Huts 8

Validated Data in the Most Demanding Environments 11

On-line Moisture Measurement of Oil 14

New Radiation Shields 17

Moisture Assessment in Power Transformers 18

Dewpoint

New Technology for High Accuracy Measurements: DM500 22

How to Fully Benefit from Using the DM500 24

NWS Relies on Vaisala Instruments for Dewpoint Measurement 26

When Direct Dewpoint Spot Measurement Isn’t Possible: DSS70A 28

Accurate Monitoring of Plastic Drying Process 30

Safe Measurements in Hazardous Areas: HMT360 Series 31

Pressure

CMA Invests in Accurate Vaisala Barometers 32

Easy Measurements on Site: PTU200MIK1 34

Carbon dioxide

Studies on Carbon Cycles of the Ecosystems of the World 35

Versatile Carbon Dioxide Meter for Professional Use: GM70 38

Additional features

Lifetime Measurement Accuracy 39

gies are examples of this. All ourproducts are based on our ownR&D activities. We do not copyor purchase licenses. We invest12 percent of our turnover inR&D and have committed morethan 250 people to this work.We hold numerous patents onthe technologies we have devel-oped. We also cooperate withthe world’s leading research in-stitutes.

Vaisala is reliable. This ap-plies both to us as a companyand to our products. We wantour products to operate faultless-ly even in the most demandingconditions. Our products under-go many tests - often conductedin cooperation with key cus-

tomers - before theirmarket launch. Our in-house design rules havebeen formed throughexperience. Concerningmeasuring instruments,accurate calibration is

of paramount importance. Forthis purpose we have an accred-ited calibration measurementstandards laboratory which an-swers for traceability to primarystandards. As a company, Vaisalais stable and financially sound.We follow strict ethical princi-ples. We only promise what weknow to be feasible and we keepour promises. We don’t leaveour customers without support.

Vaisala’s products and cus-tomer relationships are long-last-ing. We dimension our productsfor professional use and for de-manding conditions. To theuser, our products are invest-ments which are expected to bein service for many years. We de-sign our instruments to requirerecalibration as seldom as possi-

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President’s Column

W e manufacture in-struments for envi-ronmental measure-

ment – using the term “environ-ment” in its broadest sense. Forus, the environment also includesclosed research premises and pro-duction and process facilities.Concerning weather measure-ment applications we also pro-vide total system solutions, whilein industrial measurement appli-cations our focus is on supplyinginstruments. In all its businessoperations, Vaisala subscribes toa few key principles, designed toachieve satisfied customers andcreate mutual, lasting benefit.

Vaisala is innovative. We aretechnology leaders in our ownfield. HUMICAP®, BAROCAP®

and many other sensor technolo-

ble. But when needed, we pro-vide recalibration. We supplyspare parts and upgrades for ourproducts. Our products do notbecome obsolete, even thoughneeds may slightly change overthe product lifecycle. The sameobjective characterizes our cus-tomer relationships. We believethat successful business is basedon continuing customer rela-tionships. They can be main-tained only if the customers aresatisfied with the products andthe service they get. We want toserve our customers well, andnot to maximize our own short-term interests.

Vaisala provides solutions.We do not sell our productsthrough a product catalogue andleave the customer alone withtheir product selection. We fa-miliarize ourselves with the ap-plications where our productsare used. This allows our expertsto assist customers in the selec-tion of instruments, and in theirinstallation, use and mainten-ance. We want to serve cus-tomers well to ensure they get anappropriate, reliable and durablesolution for their needs. We arenot out there only to obtain or-ders and the customers’ money,which would be shortsightedand foolish.

We have adhered to theabove principles for a long timealready. I believe that you havenoticed it. Vaisala is an innova-tive and reliable solutionsprovider. �

Pekka KetonenPresident and CEO

Vaisala’s principles

O ne of our customers isa company calledKWH Freeze, who of-

fer cold storage. Their CEO, Pe-ter Lång, explains, “KWH Freezerents refrigerated storage spaceto anyone who needs it, and alsoprovides internal logistics. Thequality of our services is a highpriority for us as KWH Freeze isone of the biggest companies inthis area in Finland. We choseVaisala’s AMT100 Series Ammo-

nia Detectors for our new stor-age rooms because of their per-formance in cold temperaturesand flexible interfacing. It can beconnected directly to automa-tion systems or to typical gascontrollers.”

AMT100 Series enteringthe Japanese marketWe have also been successful inintroducing our AMMONI-CAP® sensor in a very impor-tant industrial nation, Japan.One of our ammonia detectorcustomers, Nichirei, is a generalprocessed food company basedon storage operations. The com-pany is a leader in the refrigera-

tion warehousing industry andalso the number one frozenfood company in Japan. Mr.Norihiro Koishikawa, whoworks as team leader of the tech-nical section delivery team, com-ments on their experiences withprevious instruments: “We hadbeen having problems withsemiconductor type ammoniadetectors, the main problem be-ing false alarms caused by othergases such as hydrogen in thecold storage rooms. We thentested the AMT101 and foundthat it does not react to othergases.” Mr. Koishikawa indicat-ed that their alarm system isworking well with AMT101 at -25°C (-13°F). He also appreci-ates the option of extra inter-changeable probes for easy andfast maintenance even in criticalsituations.

Demanding users in thefood industryIt is not difficult to find a de-manding environment in thefield of ammonia detection, thefood industry offers excellentchallenges, for example. TheApetit Group markets its prod-ucts primarily in Finland, but

has gradually expanded its mar-ket area to include the BalticRim. Apetit develops, producesand markets frozen foods, fishproducts, jams and marmalades,all from pure, carefully selectedraw materials. Apetit meets therequirements of clean and safefood production in order toachieve sustainable develop-ment. Mr. Kyösti Lind, whoworks as a automation engineerin the maintenance departmentat Apetit Group, points out:“Apetit is Finland’s marketleader in frozen foods, as well asin jams and marmalades pro-duced for retail. We have twoproduction sites in Finland, onein Säkylä and another in Turku.When Vaisala launched theirnew AMMONICAP®-basedAmmonia Detector, we saw agood opportunity to replacesome old ammonia detectors inproblematic places.”

Enabling the production of high-quality ice creamWithin the food processing in-dustry, ice cream factories arebig users of ammonia. One ofVaisala’s ammonia detector users

4 160/2002

Irma YlikangasM.Sc. (Chem. Eng.)Product Line Manager Sensor Systems DivisionVaisala HelsinkiFinland

Vaisala AMT100 AmmoniaDetectors are highly ammoniaspecific, which reduces costly falsealarms.

Vaisala’s AMT100 Series ammonia detectors celebrate their 1st Birthday

Vaisala Ammonia Detectors’successful first year

It was one year ago that we launched the AMT100 Series Ammonia Detectors.Vaisala’s polymer thin film sensor, AMMONICAP®, has proven its reliability in bothcold and warm environments (–40°C to +60°C). Demanding installation sites with

different background odors and gases have shown that the AMT100 Series Detectors have excellent ammonia selectivity – thanks to the AMMONICAP® Sensor.

Moreover, the low maintenance and short warm-up time of only 3 minutes havebrought us many satisfied customers. This article summarizes some comments from

our global customers and also gives information on AMT100 Series applications.

is an ice cream facility located inthe United States. This ice creamplant is using ammonia as a re-frigerant in its facility, situated ina densely populated area. As aconsequence, ammonia leak de-tection units are imperative forsafety reasons. The plant has avery elaborate control system inorder to monitor numerous pa-rameters, including ammonialeak detection. They had a prob-lem with the former ammoniasensor, a catalytic sensor, whichwas very inaccurate and requiredfrequent maintenance. Becauseof the numerous odors at the icecream facility and the tempera-ture of the rooms, -31°C (-23°F) ,the catalytic sensor would notfunction correctly. Annoyed bythe inaccuracies of this sensor,the facility installed four VaisalaAMT101 Ammonia Detectors inits ice cream production rooms.With no false alarms and all de-tectors functioning correctly atsuch a cold temperature, ourcustomer will be replacing allcatalytic sensors in the facilitywith Vaisala AMT101 AmmoniaDetectors in the future.

Another example of an icecream manufacturer that usesVaisala technology is the Finnishfood industry group IngmanFoods, which is a wholly ownedsubsidiary of Ingman Group.The Group has been systemati-cally developed over the years tobecome one of Finland’s leading

food manufacturers, with an im-portant position in the dairy sec-tor. The strategy of the Group isto concentrate on milk-basedproducts and complimentaryproducts that apply the sameproduction technology. Theproducts are safe and of a highquality. Fresh Finnish milk is themost important raw material,forming the basis of production.Ingman’s main product groupsare:

- chilled dairy products - liquid milk products - ice cream products - cheese, butter and powder. “Our production facilities in

Sibbo, close to Helsinki, invest-ed in a bigger +2°C storageroom facility in 2002. Vaisala’sAmmonia Detector was the ob-vious choice because of its highammonia selectivity,” commentsMr. Antero Pasanen, a technicalmanager in Sibbo Factory.

Ammonia detectionwithout false alarmsIn food processing industrythere are numerous demandingmeasurement needs and ammo-nia detection is a very challeng-ing field for manufacturers ofmeasurement instruments. Con-trolled Environments Construc-tive, Inc. is a general contractingfirm in Tustin, California. Thecompany is involved in numer-ous applications, ranging fromthe pharmaceutical industry tocold storage warehousing. With-in their organization they alsospecialize in control systems forthese applications. ControlledEnvironments Constructive pur-chased six AMT101 units in thesummer of 2001. Mr. MarkSmith, who works in the systemcontrols and integration divi-sion, incorporated these unitsinto a control system. In this sys-tem, temperature and defrostcontrol were also monitored in acold storage warehouse whereammonia was used as a refriger-ant. He utilized the 4-20mA sig-nal from the units, which was re-ceived on his control panel.There are 3 alarm levels pro-

grammed into the panel, whichactivate different actions withinthe facility depending on thelevel of ammonia that theAMT101 senses. The units havebeen placed outside in a dockingstation, in a machine room, infreezers, and also in an ice creamroom. Mr. Smith comments: “Ihave been very pleased with theVaisala AMT101 Ammonia De-tectors. This is the first time I

have not had any false alarmswith an ammonia detector.”

These examples of customercomments are encouraging.Continuous co-operation withour customers is essential duringthe whole lifetime of products.Our aim is to continue intensework in the ammonia detectionfield and to develop even betterinstruments in the future - withthe help of our customers. �

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New accessory for ammonia detectors V aisala is launching

the new IP33 Boxfor AMT100 Series Am-monia Detectors. TheIP33 Box has been de-signed for use in eitheroutdoor or harsh in-door environments,where the unit mayneed extra protectionfrom water. Continu-ous cleaning and washing with sprayed water sometimes causesextra coverage need for the ammonia detector body, especially atprocess sites in food processing industry.

The detector slides into the IP33 Box and the unit is then pro-tected from falling water. The box protects the unit up to a maxi-mum raining water angle of 60 degrees. �

Ammonia is a common refrigerant in cold stores and the food processingindustry. Despite its many advantages, ammonia is a hazardous chemical

and must always be handled in a safe manner.

Antero Pasanen stresses theimportance of high selectivity thatthe AMT100 Ammonia Detectoroffers.

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Versatile indicator

The fully digital MI70 Measure-ment Indicator represents thelatest generation of Vaisalahand-held indicators. The indi-cator has been designed to be ro-

bust and easy to use. A cleargraphic display together with anintuitive menu-based interfacemakes it easy for the user to getaccustomed with the indicator.The language of the user inter-face can be selected from six dif-

ferent alternatives: English, Ger-man, French, Spanish, Swedishand Finnish. Graphical trendsenable the user to monitor thestabilization time of the meas-urement and in this way indicatewhen a reliable reading can be

Timo Ranta-aho, Tec.Lic.Product Line Manager

Heikki Joensuu, B.Sc.(Eng.)Product DevelopmentManager

Sensor Systems DivisionVaisala HelsinkiFinland

New options for hand-held measurement

New Relative Humidity and Temperature Probes for MI70 IndicatorThe family of new hand-held instruments for dewpoint and carbondioxide measurements based on Vaisala MI70 Measurement Indicatorwas launched in 2001. A new member is now added to this productfamily: three new relative humidity and temperature probes in com-bination with HM70 Hand-Held Meter set further extend the selection of measurement parameters and applications.

taken. Furthermore, a sophisti-cated Windows® software pro-gram is available to transfer datafrom the indicator to a PC,where it can be processed furtherand copied to other Windows®

programs. With an analog out-put cable the measurement re-sults can also be transferred to achard recorder or to an externalcontrol system.

The MI70 Measurement In-dicator automatically recognizesthe connected probe and dis-plays which parameters theprobe is able to measure. Thismakes it easy to measure differ-ent parameters by simply chang-ing the probe. Two probes canbe connected to the MI70 simul-taneously and three measure-ment parameters can be dis-played and logged into the indi-cator memory at the same time.

Its durable and rugged struc-ture, compact size and lightweight make the MI70 suitablefor a wide variety of applica-tions.

HM70 Hand-Held Relative Humidity andTemperature MeterThe three new measurementprobes for relative humidity andtemperature which, togetherwith the indicator, form theHM70 family, now further ex-tend the application base of theMI70 Measurement Indicator.The probes are based onVaisala’s proven HUMICAP®

technology. The HMP75 Hu-midity and Temperature Probe issuitable for general-purposemeasurements. The HMP76 Hu-midity and Temperature Probeenables measurements in moredemanding conditions. Its longstainless steel shaft enables evendifficult places to be reached.The rugged probe structure canalso take rough handling betterthan other models. The HMP77Humidity and Temperature

Probe is designed for high tem-peratures up to 180 ºC. Theprobe has a 5-meter cable be-tween the small sensor head andthe handle, making it ideal foruse in tight and difficult-to-reachareas and for the on-site calibra-tion of Vaisala’s process trans-mitters.

The HMP76 and HMP77probes also have the parallel ver-sions HMP76B and HMP77B,providing chemical purge andsensor pre-heat options. Thechemical purge option makesthe probes stable even in envir-onments where high concentra-tions of chemicals or cleaningagents are present. In chemicalpurge, the sensor performance isreturned to normal by evaporat-ing the interfering chemicalsfrom the sensor polymer. Chem-ical purge helps to maintainmeasurement accuracy betweencalibrations. Sensor preheat en-ables the installation of theprobe in processes where highhumidity exists at an elevatedtemperature. If the temperatureof the humidity sensor duringprobe installation is lower thanthat of the process, dew is easilyformed on the sensor and it maytake a long time to evaporate inhigh humidity conditions. Withthe sensor pre-heat function theformation of dew can be pre-vented. In this way an unwanteddelay in starting the actual meas-urements can be avoided.

The HM70 directly meas-ures relative humidity and tem-perature. Based on the measure-ment of these parameters, theMI70 calculates dewpoint, ab-solute humidity and several oth-er humidity parameters, whichcan then be displayed numeri-cally or graphically and stored inthe data logging memory.

Calibration of the HM70 iseasy. The indicator provides aguided calibration procedurewhich can be used together with,

for example, the HMK15 Cali-brator. The probes can also besent to a Vaisala service centerwhich will provide a traceablecalibration in several humiditypoints. The calibration can alsobe sealed making the HM70 atraceable humidity reference foreven demanding applications.

Supporting the maintenance ofVaisala’s transmittersThe HM70 effectively supportsthe maintenance of most ofVaisala’s fixed relative humiditytransmitters. Connection cablesfor both analog and digital hu-midity transmitters are available,enabling the comparison oftransmitter readings with a cali-brated reference probe. It is evenpossible to adjust the humidityoutput of the transmitter in ap-plication conditions without re-moving the transmitter from theinstallation site or disconnectingit from the monitoring or con-trol system.

Wide selection of measurement parametersWith the new relative humidityand temperature probes theMI70 Indicator is now availableas three different sets, HM70 forrelative humidity and tempera-ture measurements, DM70 fordewpoint measurements andGM70 for carbon dioxide meas-urements. Probes for different pa-rameters are also available indi-vidually, enabling the same indi-cator to measure several differentparameters. This makes the MI70suitable for many multiparame-ter applications, such as green-house monitoring, health inspec-tion, incubators, control meas-urements in building automa-tion, etc. With Vaisala’s stableand reliable HUMICAP®,DRYCAP® and CARBOCAP®

sensor technology, innovative de-sign and easy-to-use features, theMI70 and its several probes pro-vides lifetime value and readingsyou can trust in all conditions.�

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Main Features of HM70 Series Measurement Indicator MI70

• Graphical trend display shows stabilization• Multi-lingual user interface• Programmable shortcut keys• Measurements easily reported to PC using Windows

software • Two probes can be connected and measured

simultaneously• Rechargeable and alkaline battery versions available

HM70 Series of Humidity and Temperature Probes

• HMP75 basic humidity probe for relative humidity and temperature measurement.

• HMP76 rugged probe with a long stainless steel shaft. Preheat and Chemical Purge options available.

• HMP77 probe with a cable for industrial processes up to180 °C. Preheat and Chemical Purge options available. �

The three new relative humidity andtemperature probes, used togetherwith the MI70 MeasurementIndicator, form the HM70 family.

L atitude 67 degrees south,longitude 142 degreeseast, pinpoints the bleak

and inhospitable Cape Denisonsituated on Commonwealth Bayin the Australian Antarctic Terri-tory. The windiest place on earthat sea level, Cape Denison ishome to a site classified as rarein a global context and uniquein Australian history. It is the lo-cation of one of only six surviv-ing complexes from the HeroicEra of Antarctic exploration…the historic site of Mawson’sHuts.

Hurriedly constructed bythe Australasian Antarctic Expe-

8 160/2002

Ken AndersonCommunications Manager Australia's Commonwealth Scientif-ic and Industrial Research Organisa-tion (CSIRO)CSIRO Built Environment Highett, VictoriaAustralia

Preserving our Antarctic Heritage -

Mawson’s HutsThe historic site of Mawson’s Hutsin the Australian AntarcticTerritory is the location of one ofonly six surviving complexes fromthe era of Antarctic exploration.The site’s rich cultural heritage anddemanding environmentalconditions have been taken intoaccount in the ConservationManagement Plan beingdeveloped to manage the manyconstraints, issues andopportunities the site offers.Supporting the effort to preservethis site, CSIRO has chosen Vaisalaequipment to monitor and studythe environmental conditions.

Latitude 67 degrees south, longitude 142 degrees east, pinpoints the bleak andinhospitable Cape Denison situated on Commonwealth Bay in the AustralianAntarctic Territory.

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dition led by Sir Douglas Maw-son in 1912, the site consists offour buildings - the Main Hut,Magnetograph House, TransitHut and Absolute Magnetic Hut- and numerous scattered arte-facts. Mawson remained therefor two years, directing severalarduous journeys of explorationfrom the site and conducting sci-entific experiments.

Many constraints, issues andopportunities have been takeninto account in the Conserva-tion Management Plan that is be-ing developed to manage thesite’s significant cultural heritage.

The Historic Site - the“Home of the Blizzard”The Mawson’s Huts HistoricSite and associated elements is acomplex cultural landscape thatillustrates, in its surviving formand setting, the isolation andharsh conditions encounteredby the original expedition mem-bers. Foremost is the preserva-tion of Mawson’s Main Hut, aformidable task due to the loca-tion, environment and lack ofaccessibility. Cape Denison canonly be reached by sea in theAustralian summer between De-cember and March – a durationof one week’s sailing from Ho-bart, Tasmania.

The historic site and itsbuildings face an extremely de-manding climate, with tempera-tures ranging from –20°C to oc-casionally over 0°C. The con-stant onslaught of abrasive snowand ice coupled with severewinds that average a daily maxi-mum of 71 kph (82 km/h) isproving to be the greatest singlelong-term threat to the buildings.

Since the 1970s various pro-posals have been made as tohow best conserve Mawson’sHut. These include covering thebuilding with a transparentdome, over-cladding the originalexterior timbers, dismantling theHut for relocation to Australia,and sundry other options for re-moving the ice which has invad-ed the building over its manyyears of solitude.

Action plans

In 1997-98, based on previousheritage and condition assess-ments, AAP Mawson’s HutsFoundation sent a conservationteam to generally stabilize thebuildings. The team spent sevenweeks at the site to assess thecondition. The Main Hut andthe Magnetograph House hadweathered their 89 years reason-ably well, maintaining intactstructures and cladding, whereasthe Transit Hut and the Ab-solute Magnetic Hut were subse-quently stabilized for conserva-tion as “standing ruins".

Remedying the ice abrasionand ingress in the Main Hut hasbeen the most frequently pro-posed conservation option, andits removal appears to be a faitaccompli. However, prior to acommitment to any preserva-tion strategy, it is crucial to gaina full understanding of the likelyimpact of action plans. Is thesnow/ice inside the Hut helpingthe building to be more wind-re-sistant? If the ice is removed, willthe temperature increase aroundthe foundations thereby jeop-ardizing the Hut’s anchorage?Will ice removal expose metalsurfaces to increased contactwith salt? Will it increase the hu-midity thereby exacerbating cor-rosion in the original bolts andnails and/or increasing mouldand staining on artifacts still notfully documented?

MonitoringCSIRO has been providing ex-pertise in monitoring corrosionrates at Mawson’s Hut since1983. Although Antarctic tem-peratures do curb the two mostimportant factors in timber de-terioration - fungus and insects -the common belief that a freez-ing climate will prevent bio-dete-rioration and corrosion, thusgiving perfect preservation, hasbeen exposed as a myth.

To further understand thedeterioration processes affectingthe building structure and arte-facts, equipment for monitoring

temperature and relative humid-ity, corrosion, salt depositionand erosion of timbers was in-stalled in 1999. Data-loggers or-ganized by the Consortium forHeritage Collections & TheirEnvironment, which consists ofCSIRO Department of Build-ing, Construction and Engineer-ing, the Australian Museum, theUniversity of Canberra and theUniversity of NSW, were posi-tioned in the Main Hut anddownloaded by a much-publi-cized couple, Jim and YvonneClaypole.

A Campbell ScientificCR10X monitoring system wasused, with eight combinedVaisala HM35A Relative Humid-ity Temperature Transmitters and10 surface temperature thermo-couple sensors variously placedfrom floor to ceiling height andfrom the outer walls to the centerof the Hut to record differingconditions within the building.

The Claypoles also exposedlow-alloy copper steel couponson top of a research team build-ing near the Main Hut for at-mospheric corrosion study andanalysis.

Revealing statisticsCSIRO’s Wayne Ganther saidthat the immense volume of da-ta collected over the 1999-2000period revealed some incongru-

ous statistics. The steel corrosivi-ty samples indicated an atmos-pheric corrosion rate similar tothat of suburban Melbourne andSydney – 12.2 microns per year.The data collected from insidethe Main Hut demonstrated thatdaily internal temperature andhumidity peaks only occur whensolar radiation is significant dur-ing the Antarctic summer. Thetemperature in the Main Hutdid not rise above 0°C, except atthe highest ceiling point, at anytime during the year. Interesting-ly though, the relative humiditydid not fall below 80% in themajority of locations through-out the Hut. Time of wetness(TOW), a major factor in corro-sion study, was extrapolatedagainst the International Stan-dard 9223 and the newly chris-tened “King” TOW criteria de-veloped by King and Gantherfrom CSIRO-based work at Ter-ra Nova Bay, Antarctica, 2000.

Research published in “Stud-ies in Antarctica Help to BetterDefine the Temperature Criteri-on for Atmospheric Corrosion”by CSIRO scientists GeorgeKing and Wayne Ganther, JanetHughes from the NationalGallery of Australia, and PaoloGrigioni and Andrea Pellegrinifrom ENEA Italian NationalAntarctic Research Program, re-vealed that the standard

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➤

The Mawson's Huts Historic Site and associated elements is a complexcultural landscape that illustrates, in its surviving form and setting, theisolation and harsh conditions encountered by the original expeditionmembers.

Ultimate responsibility forthe conservation and manage-ment of Mawson’s Huts HistoricSite rests with the AustralianAntarctic Division as custodianfor the Australian Antarctic Ter-ritory on behalf of the Aus-tralian Government. The statu-tory context for this responsibil-ity for both cultural and naturalheritage conservation is provid-ed by the Antarctic Treaty. �

benchmark ISO 9223 criterionfor estimating time of wetness isincorrect and needs to be re-vised.

Utilizing King’s alternativecriteria, the recently calculatedTOW data together with the de-terioration of the metal artefactsobserved on previous expedi-tions shows there is significantrisk to the building. Previousstudies have indicated that bio-deterioration of timber is said to

be possible above 20% equilibri-um moisture content. The sur-face equilibrium moisture con-tent in Mawson’s Hut was meas-ured as continually above 16%and above 20% more than 80%of the time. If decay is indeedpossible at these temperaturesthen there is more than enoughwater available for it to proceed.

Despite the severe-site limi-tations, the collected data hasdemonstrated that the current

state of the building offers someinsulating effect. While it is ini-tially surprising that theseprocesses are occurring, it is wor-thy to note that it is incrementalover a long period of time withsignificant intermissions duringwinter conditions. That beingsaid, even sluggish processes be-come a major factor when con-sidering the need to preserve his-torically significant buildings forfuture generations.

10 160/2002

CSIRO Australia CSIRO Australia is one of the world’s largest and most diversescientific research institutions. With a staff of more than 6000,CSIRO conducts some 10% of Australia’s total R&D effort in-cluding about 12% of the R&D contracted out by industry.

Globally CSIRO is active in more than 70 countries, withover 700 current or recently completed projects. Almost athird of CSIRO’s international activity is in collaboration withleading scientific organizations and firms in the USA. A fur-ther third of the international activity is with leading institu-tions and firms in Europe and Japan.

CSIRO Built Environment CSIRO Built Environment offers leading science, technology,products and services to infrastructure and built environmentindustries, marketing its people, technology, products andservices through three core science capabilities: Thermal &Fluids Engineering, Sustainable Materials Engineering and In-frastructure Systems Engineering. �

CSIRO has been providing expertise in monitoring corrosion rates atMawson's Hut since 1983. Although Antarctic temperatures do retard thetwo most important factors in timber deterioration - fungus and insects - thecommon belief that the freezing climate will prevent biodeterioration andcorrosion, a la 'perfect preservation', has been exposed as a myth.

To further understand the deterioration processes affecting the building structure and artifacts, equipment for monitoring temperature and relative humidity,corrosion, salt deposition and erosion of timbers was installed in 1999.

O rion Pharma is a re-search and develop-ment oriented phar-

maceutical division of the OrionGroup, the leading Finnish com-pany specializing in healthcareproducts. Pharmaceutical R&Dat Orion Pharma focuses on fourtherapy areas: Central NervousSystem (CNS) disorders, Cardi-ology and Critical Care, Hor-monal therapies, and Respirato-ry disorders. New innovative

pharmaceutical products are dis-covered, developed, manufac-tured and marketed both for hu-man and animal health.

In Scandinavia, which is Ori-on Pharma’s home territory, com-pany operations include a broadselection of human and veteri-nary preparations, as well as ac-tive pharmaceutical ingredients.In Finland, Orion Pharma is theleading supplier of pharmaceuti-cals with a 13% market share.

The research and develop-ment and production units ofOrion Pharma are situated inseveral locations in Finland. Ori-on Pharma also has a researchand development center in Not-tingham, United Kingdom,which focuses on cardiovascularand CNS drug development.Moreover, subsidiaries in Den-mark, Germany, the UK, Franceand Sweden have medical de-partments. In the US,

160/2002 11

Vaisala’s Humidity Measurement in the Pharmaceutical Industry

Validated Data even in the Most Demanding Environments

➤

Orion Pharma, the leading Finnish pharmaceutical company, hasawarded a contract to Vaisala to support their operations. Vaisala’sHMP233 and HMP243 Humidity and Temperature Transmitters areused as part of a validated system that provides measurement data in all manufacturing and storage facilities at Orion’s premises inTurku. The system follows strict Good Manufacturing Practice (GMP)guidelines.

Päivi T. Laitinen B. Sc. (Env. Eng.)Application EngineerSensor Systems DivisionVaisala HelsinkiFinland

Orion Pharma collaborates inclinical research projects withpartners.

Validated system forproduction controlOrion Pharma’s Turku premiseshave used Vaisala products for adecade to measure relative hu-midity and temperature, bothindoors and outdoors. They arenow building a separate, validat-ed system to measure conditionsin laboratories, production,packaging and storage rooms. Inaddition to humidity and tem-perature, other variables are alsomeasured. Measured conditionsvary from normal room condi-tions to more demanding envir-onments.

GMP – Good Manufacturing PracticeThe pharmaceutical industry fol-lows Good Manufacturing Prac-tice (GMP) regulations on safetyand quality in manufacturingpharmaceutical preparations.According to the World HealthOrganization (WHO), GoodManufacturing Practice is a sys-tem for ensuring that productsare consistently produced andcontrolled according to qualitystandards. GMP covers all as-pects of production from rawmaterials, premises and equip-ment, to the training and per-sonal hygiene of staff. Detailed,

written procedures are essentialfor everything that could affectthe quality of the finished prod-uct. There must be systems toprovide documented proof thatcorrect procedures are consis-tently followed at each step ofthe manufacturing process,every time a product is made.

“Compared to ISO9000quality systems, GMP is much

stricter,” says Mr. Salminen fromOrion Pharma’s maintenancedepartment. Orion Pharma’svalidated measurement systemfulfils GMP regulations. The ob-jective of the system is to pro-vide proven information aboutthe environment in Orion Phar-ma at all stages of production.

Superior accuracy andeasy calibrationVaisala was the clear winnerwhen the supplier for new instal-lations was decided upon, due tothe superior performance oftheir instruments. “With Vaisalainstruments we can always besure the readings are true – if thesignal is zero, it really means ze-ro! This is a simple thing as such,but it was not so obvious withthe other instruments we test-ed,” points out Mr. Salminen.

Easy calibration was alsofound to be a clear advantage forVaisala. “Each measurement in-strument is calibrated and ad-justed both in the sensor and aspart of the measurement system.Because of the validated system,

the measurement instrumentscannot be dismantled for cali-bration. Vaisala could offer usthe solution – the HMK15 SaltBath Calibrator and the HMI41Indicator with HMP45 Humidi-ty and Temperature Probe - foron-site calibration and adjust-ment. We are extremely happywith it,” says Mr. Kollanus,Maintenance Manager of OrionPharma, Turku.

HMP243 for wash-downareasMoreover, Vaisala’s technologyprovided a solution for humidi-ty measurements in spaces thatare often washed. “Our produc-tion facilities are high pressurecleaned with water once or eventwice a day. Traditional humidi-ty transmitters show overscalefor hours after washing due towater in the sensor. Vaisala’sHMP243 with warmed probe re-covers much faster from suchhumidities and we have there-fore used them to equip ourwash-down areas,” says Mr.Salminen. �

12 160/2002

Mr. Pasi Kollanus (right) and Mr. Jyrki Salminen from Orion Pharma’smaintenance department in Turku.

The manufacturing of drugs and other pharmaceutical products is strictly controlled by GMP guidelines.

160/2002 13

Vaisala HMP233 Humidity and Temperature Transmitterfor tight places

Vaisala HMP243 Humidity and Temperature Transmitter - designed for use in high humidity

The HMP233 is suitable forduct installations, tight spacesand outdoor installations.

The HMP243 can beequipped with anoptional temperaturesensor for ambienttemperature andrelative humiditymeasurement.

T he HMP233 is a versatileand easy-to-use transmit-

ter for demanding industrialand air conditioning applica-tions. The transmitter meas-ures relative humidity andtemperature, and also outputsdewpoint and wet bulb tem-perature as calculated vari-ables, mixing ratio and ab-solute humidity. The HMP233Transmitter can be configuredto the customer’s require-ments on the production line;configuration and parameters

can also be set by the user.Both analog and serial out-puts are available as well asseveral other options: differ-ent cable lengths, power sup-ply modules, serial interfacemodules and a local display.

The sensor head in theHMP233 Transmitter is smalland fits into tight spaces. Itcan be fitted with two differ-ent cables: one is for lowertemperatures of up to +80 °Cand the other is for tempera-tures of up to +120 °C. �

T he Vaisala HMP243 Humid-ity and Temperature Trans-

mitter is specially designed forreliable and fast dewpointmeasurement at high humidi-ties and/or rapidly changingtemperatures, where condens-ing water vapor has been aproblem. The HMP243 incorpo-rates Vaisala’s advanced HUMI-CAP® technology and awarmed probe head to guaran-tee accurate and reliable dew-point measurement even incondensing environments.

The HMP243 works wellboth at lower humidities andin saturating conditions. In ad-dition to industrial applica-tions it is suitable for use inoutdoor/meteorological appli-cations where sudden temper-ature changes and windy con-

ditions can occur. The HMP243Transmitter is fully config-urable and outputs dewpoint,relative humidity, ppmv andtemperature.

Excellent Performanceunder High HumidityVaisala’s unique warmedprobe provides fast and reli-able dewpoint measurementsin environments where hu-midity almost reaches satura-tion. The sensor also recoversvery fast from condensation inextreme conditions. As theprobe is warmed, the humidi-ty level inside the head staysbelow the ambient. With ac-curate temperature measure-ment the dewpoint of the am-bient environment can be pre-cisely calculated. �

ABB Marine is a lead-ing global elec-

trotechnical partner with the ma-rine industry. ABB suppliespower plants and electricpropulsion systems - includingazimuthing electric propulsion,total automation systems and awide range of other electrotech-nical products and drive sys-tems. ABB Marine has providedthe world’s shipbuilders with

state-of-the art electric propul-sion drives for luxury cruise ves-sels, ro-ro vessels, tankers andoffshore and special purposevessels for more than half a cen-tury.

Azipod® Propulsion System – the world’sleading propulsion systemABB introduced Azipod, the

first azimuthing podded propul-sion system on the market, at thebeginning of the 1990s. The Azi-pod propulsion system com-bines the advantages of variousconventional propulsion sys-tems available today. Thepropulsion system provides themajor benefits of excellent dy-namic performance and maneu-vering characteristics, hydrody-namic efficiency resulting in

14 160/2002

Päivi T. Laitinen B. Sc. (Env. Eng.)Application EngineerSensor Systems DivisionVaisala HelsinkiFinland

HMP228 Moisture and Temperature Transmitter for Oil

On-line Measurement of Oil Givesup-to-date Information for Operators

The Propulsion Unit of ABB Marine and Turbocharging relies onVaisala to measure the moisture in lubrication oil on-line. The VaisalaHMP228 Moisture and Temperature Transmitter for Oil is a standard

feature in the ABB Azipod® propulsion system. The HMP228 providesfast, reliable and accurate measurements of moisture in oil in the cir-

culation lubrication system of under-water propulsion motors.

shorter harbor times, reduced fu-el consumption and safer opera-tion even in harsh weather, re-stricted passages and offshoreenvironments.

The Azipod system is an azi-muthing electric propulsiondrive with a propulsion motorinstalled inside a submerged azi-muthing (unlimited 360 degrees)pod, coupled directly to an ex-tremely short propeller shaft.The variable speed electric(AC/AC) drive producessmooth torque over the entirespeed range, including zerospeed. ABB designs and manu-factures Azipod propulsionunits for all marine propulsionapplications, with units availablewith powers of up to 25 MW.

Over 10 years marineexperienceAzipod was first conceived in1987. After several years of re-search and development, theworld’s first Azipod® propul-sion system (1 x 1500 kW) wasdelivered in 1990 to the servicevessel “Seili”. This was followedby the first tanker application“Uikku” (1 x 11 400 kW) in1993, the first icebreaker appli-cation “Röthelstein” (2 x 560kW) in 1994, and the first cruisevessel application “Elation” (2 x14 000 kW) in 1998. By 2002, 76Azipod units had been deliveredto a total of 36 ships, with 11 de-livered to ice breaker applica-tions. Azipod units now havemore than 472,000 cumulativeoperating hours in the world’sseas.

Vaisala HMP228 Moistureand Temperature Transmittersfor Oil are being installed in Azi-pod propulsion systems to meas-ure on-line the moisture in theoil in circulation lubrication.Each ship has from one to threepropulsion units and eachpropulsion unit has its ownHMP228 to control oil.HMP228 units have already

been installed in over twentyAzipod systems. It is a standardfeature in new propulsion unitsand retrofittings are also beingdone on old units. “The on-linedetection of moisture in oil withHMP228 has raised a lot of in-terest and customers are reallywilling to have the HMP228units in their ships, even as retro-fittings,” says Mrs Lundell, Pro-duction Engineer of ABB Ma-rine and Turbocharging, Propul-sion Units.

On-line measurementhelps operators monitor oil qualityWater contamination reducesthe performance of oil, increas-ing the risk of corrosion, over-heating, machine malfunction

and other problems. Measuringand controlling the moisture inlubrication systems is essentialto avoid costly failures. Carefulmonitoring of the moisture inoil within lubrication systemshelps to plan servicing and pre-vent unscheduled downtime,thus potentially cutting main-tenance costs substantially. On-line detection is especially im-portant in applications with arisk of water contamination, forexample marine applications.

In the Azipod propulsionsystem the electric propulsionmotors are located under water.Each motor has two bearings, apropeller bearing and a thrustbearing. The lubrication systemcirculates oil from bearings inthe propulsion unit to inside the

ship’s machine room, where theHMP228 unit is located. Thepurpose of on-line detection ofmoisture in oil is to monitor oilquality and to secure the properlubrication quality. “Theamount of oil in the Azipodpropulsion system is rather small-- only around 200 liters -- com-pared to traditional propulsionsystems that have up to 4000liters of lubrication oil,” explainsMrs Lundell. “With such a smallamount of oil even a smallamount of water will reduce lu-brication quality, therefore, themoisture in the oil in the lubrica-tion system must not exceed cer-tain limits. The HMP228 issues awarning immediately somethinghas happened so that the oil canbe changed or purified.”

160/2002 15

Mrs Susanna Lundell, ProductionEngineer of ABB Marine andTurbocharging, Propulsion Units.

The ABB Azipod® propulsionunit.

➤

HMP228 provides flexible and easy measurementThe first system ABB used to de-tect moisture in oil was an opti-cal measurement system. “Opti-cal measurement was expensiveand difficult to assemble,” re-marks Mrs Lundell. “After test-ing the HMP228 and finding itfast, reliable and accurate we de-cided to change to it for on-linemoisture detection. Above all,the HMP228 is easy to assembleand use: just fix the ball valveand connect the cables and theHMP228 is ready to go!”

Oil type, age and temperature irrelevantMeasurement with the HMP228is independent of oil type, ageand temperature. The HMP228Transmitter measures water inoil in terms of water activity(aw). The water activity measure-ment indicates directly whetherthere is a risk of free water for-mation. With a relative scalefrom 0 (no water present) to 1(oil is saturated with water) itgives a reliable indication of howclose the saturation point is. Wa-ter in its free form has a water ac-tivity of 1. As the solubility ofwater in oil increases with risingtemperature, the saturationpoint of oil pulls further away.Thus water activity decreaseswith rising temperature.

According to Mrs Lundell,using water activity as a unit isnew in the marine industry: “Wehave become accustomed in thisfield to seeing water saturationexpressed as ppm. ABB has there-fore had a conversion diagramfrom aw to ppm made by theVTT Technical Research Centreof Finland. Water activity has cer-tain advantages in its independ-ency of oil type, age and tempera-ture, but as long as our customersin the marine industry are morefamiliar with ppm than aw valueswe will use them too.” �

The Vaisala HMP228 allows the on-line moisture measurement of oil

16 160/2002

The on-line detection of moisture inoil is especially important in thoseapplications with a risk of watercontamination, such as marineapplications.

A HMP228 unit installed in aship’s machine room. Installation iseasy and convenient to performthrough a ball valve.

T he HMP228 Moisture and TemperatureTransmitter for Oil offers fast, reliable and

accurate on-line detection of moisture in oil.The transmitter is especially designed for lubri-cation and hydraulic oil systems, such as papermachines, diesel engines and power plants.

The Vaisala HMP228 Transmitter measureswater activity and temperature in oil. The wa-ter activity (aw) measurement offers several ad-vantages compared to the traditional ppm-measurement. The HMP228 provides reliableinformation on how close the oil is to its satu-ration point. Oil-specific calibration is not nec-essary, as water activity is not affected by thetype or age of the oil. Moreover, the transmit-ter can be ordered with a ball valve set, allow-ing the probe to be installed and removed forcalibration without needing to drain the oilsystem.

The HMP228 incorporates Vaisala’s HUMI-CAP® capacitive thin film polymer sensor,known for its accuracy, reliability and long-term stability. �

The HMP228 controls the lubrication oil of apropulsion unit’s bearings.

The Vaisala DTR502B Radi-ation Shield is a naturally venti-lated 9-plate radiation shieldcomplete with accessories to al-low easy installation of the sen-sor heads of HMP233 andHMP237 Humidity and Tem-perature Transmitters into theshield. In addition to the sensorhead accessories, the mechanicsfor pole installation (i.e. verticalinstallation) is included.

The Vaisala DTR503A Radi-ation Shield is a naturally venti-lated 12-plate radiation shieldincluded with a similar verticalpole, horizontal beam or flatsurface installation set to that ofthe DTR502B Radiation Shield.

160/2002 17

V aisala has launched newradiation shield modelswhich are available for

vertical pole, horizontal beam orflat surface, such as wall, installa-tion. The new radiation shieldmodels are easy to install, main-tenance free, and available sepa-rately as an additional accessoryfor the humidity instruments, tobe integrated, for example, intoHVAC application ventilationsystems or a wide variety ofweather stations and observingsystems. The shields protectmeasurement instruments fromscattered and direct solar radia-tion and rain, ensuring reliablemeasurement data.

The new radiation shields are usedin outdoor installations to protectrelative humidity and temperaturemeasurement instruments from rainand sun radiation.

The DTR503A Radiation Shieldoffers an accessory forHMP45A/D Humidity andTemperature Probe mounting.

In both models, the plates ofthe shields are made of a specialmaterial that offers excellentthermal characteristics and UVstabilized construction. For max-imum protection, the outer sur-faces are white to reflect radia-tion and the insides are black toabsorb accumulated heat thuseliminating the possible warm-ing inside the shield and result-ing in very good measurementresults in outdoor applications.�

New Radiation Shield ModelsDTR502B and DTR503A

W ater in transformersappears as an un-wanted substance,

decreasing insulation breakdownstrength and shortening trans-former life dramatically. Highwater content in paper may re-sult in bubbling, the formationof free water and an increasedrisk of dielectric breakdown. Wa-ter also causes accelerated paperaging, corrosion of core/tankand progressive consumption ofoil additives.

Water contamination intransformers comes from threemain sources: residual moisturein the “thick structure elements”,ingress from the atmosphere,and the aging decomposition ofcellulose and oil.

Residual moisture in a newtransformer after factory dry out,prior to transportation, is expect-ed to be less than 1%, with a tar-

get value of 0.5%. Excessiveresidual moisture of 2-4% can re-main in some thick insulationcomponents, particularly plas-tics1. During service, this mois-ture gradually seeps into the oil,increasing the water content inthe thin insulation structure1.

Atmospheric water is themain source of transformer con-tamination. Three mechanismsare acting here: the absorptionof water from the direct expo-sure of the insulation to the air(installation and repair works),the ingress of moisture in theform of molecular (Knudsen)flow due to the difference in thewater concentration in the at-mosphere and in the oil in thetank, and the viscous flow of wetair into the transformer causedby the difference between the at-mospheric pressure and the pres-sure in the tank1.

The molecular flow of mois-ture is practically negligible. Themain mechanism of water pene-tration is the viscous flow of wetair through “poor sealing”, i.e.through the sealing points ofbushings, the explosion ventand the cooling circulation loopetc., due to the pressure gradi-ent. Large amounts of rainwatercan be pumped into the trans-former in a very short period oftime (just a few hours) if there isimproper sealing and a rapiddrop in pressure1.

Methods and instrumentation formoisture measurementThe term “moisture” in thetransformer industry is com-monly used to indicate waterwhich is absorbed in the paperor dissolved in the oil. Occasion-ally, the terms “water” or “watercontent” are used as an alterna-tive way to describe the samesubstance.

Water in transformers can befound in different parts of theinsulation system. It can accu-mulate in solid insulation, bedissolved in oil, or be found inthe form of liquid water at thecore or bottom of a transformer.Depending on the media, differ-ent methods and instrumenta-tion are used for moisture meas-urement. For example, to evalu-ate water content in oil, polymerrelative humidity/relative satura-tion sensors are frequently used.By measuring the relative satura-tion of oil one can easily deter-mine its absolute moisture con-tent expressed in parts per mil-lion (ppm). In this case the watersolubility characteristic for thespecific oil must be known inadvance. Being a real-time effi-

18 160/2002

V. G. DavydovMonash University Australia

O. RoizmanIntellPower Australia

Moisture assessment in power transformers

Lessons LearnedThe need to know the water content of paper accurately underall operating conditions is essential for the safe operation oftransformers. To improve existing methods of determining thewater content of paper, a concept of “water-in-paper activity”has been developed. The water solubility parameter is of paramount importance for the accurate evaluation of watercontent. A stand-alone software application, the Transformer Moisture Monitor (TMM), is recommended for moisture assessment. The development of a new classification procedureprovides a means of ranking dry and wet transformers.

cient on-line method, the mois-ture-in-oil measurement has at-tracted a lot of attention in re-cent years. A number of com-mercially available sensors havebeen tested in different condi-tions using the Monash test rig.

Another method for ppmdetermination is a techniquebased on the well-known KarlFischer titration reaction. How-ever, this method is not a real-time one and requires appropri-ate chemical instrumentation forits implementation. It is alsoprone to a high level of error andits results are often difficult tointerpret. A timely and accuratemeasurement of the oil tempera-ture should be made when ob-taining the oil sample.

There is also a group ofmethods based on the measure-ment and analysis of dielectricproperties of insulation. Diagno-sis with these methods is basedon the fact that paper and oilchange their dielectric propertieswhen moisture levels increase.Therefore, by measuring para-meters such as the dissipationfactor, polarization and depolar-ization currents (PDC) and re-turn voltages (RVM) in the fre-quency and time domains, it ispossible to relate these changesto water concentration in a pa-per-oil insulation system. How-ever, with most of these meth-ods it is difficult – if not impos-sible – to distinguish the effectsof moisture on the insulationfrom the effects of aging causedby other processes. This creates alot of confusion over the relia-bility of dielectric responsemethods. Interpretation of theresults still remains more artthan science.

Water content of paperinsulation

One of the aims of the moistureassessment of oil-filled powertransformers was to evaluate thewater content of its paper insula-tion. The term “paper insula-tion” is a generic term that de-scribes solid cellulose material,such as paper, pressboard, woodand cotton. Another term, “wa-ter content of paper (WCP)”, isused to quantify the amount ofwater present in paper insula-tion. Traditionally, the termWCP refers to a ratio betweenthe mass of water and mass ofdry non-oily paper, expressed ina percentage. The mass of wateris calculated from the differencebetween the masses of wet anddry paper. The paper is usuallydried out in an oven prior to themeasurement of the dry papermass. The traditional term WCPgives a clear meaning for non-oil-impregnated paper.

For oil-impregnated paperthe WCP can still be measured,in this case using the Karl Fisch-er titration method. Followingthe measurement of water massin the Karl Fischer apparatus, theoily paper is degreased and onlythen placed in an oven for dry-ing. To obtain an accurate meas-urement, the thickness of thepiece of paper or strip of press-board should not exceed a fewhundred microns. However, fora paper-oil insulation systemwith both thin and thick paperinsulation the situation formeasuring the WCP is com-pletely different.

In a study conducted atMonash University under anEPRI, USA sponsored project, anew method of moisture assess-

ment in operating transformerswas developed, based on a water-in-paper activity concept. Theparameter of water-in-paper ac-tivity is used to access moistureconditions in both new and oldtransformer insulation systems.Another term, “active water con-

tent of paper (WCPA)”, was alsointroduced. The term WCPA re-flects the water available in thetransformer insulation for ex-change between paper and oil. Anew moisture equilibrium chart(shown in Figure 1) relating theparameter of water-in-paper

160/2002 19

Figure 1. Moisture Equilibrium Curves relating water-in-paper activity toactive water content of paper for temperatures from 0 to 100 °C.

Figure 2. Moisture Equilibrium Chart as published in “MoistureEquilibrium Charts for Transformer Insulating Drying Practice”.2

➤

activity to the WCPA was devel-oped.

Numerically, water-in-paperactivity (Awp) is equal to the equi-librium percentage of relativesaturation (RSeq) divided by 100.

There are a number of waysto evaluate the WCPA of paperinsulation in a paper-oil insula-tion system. One of them is ap-parent from Figure 1. To use thecurves of Figure 1 we need to es-tablish equilibrium conditionsin the system and measure theparameter of Awp using a relativesaturation (RS) sensor.

Another way to evaluate theWCPA of paper insulation in apaper-oil insulation system is touse a moisture equilibrium chart,similar to the well-known mois-ture equilibrium chart publishedin 2 and shown in Figure 2.

The chart in Figure 2 givesthe relationship between the wa-ter content of oil (WCO) ex-pressed in ppm, the temperatureand the “% Moisture in Paper”,which, in fact, for thin paper in-sulation is equal to the WCPA.Again, to evaluate the WCPA, weneed to establish equilibriumconditions in the system andthen measure the WCO usingthe Karl Fischer apparatus. How-

ever, we must measure one moreparameter in this case, prior tothe evaluation of the WCPA.This parameter is called the “wa-ter solubility of oil S(T)”, or, asin Figure 2, the “Solubility Lim-it, ppm”.

The moisture equilibriumchart in Figure 2 was developedfor new oil. The figures aroundthe chart show the water solubil-ity parameter S(T) for new oil attemperatures from 0 to 100 °Cin 10 °C intervals.

Assessment of moisturein an operating transformerIt is known that an operatingpower transformer is never inmoisture equilibrium. Thus, thetwo moisture equilibrium chartsin Figures 1 and 2 cannot be ap-plied directly when assessingmoisture in the field. To addressthis, a method for the moistureassessment of transformer insu-lation has been developed. Themethod is based on the Monashwater-in-paper (WIP) algorithm,which incorporates the follow-ing three steps:

- Evaluation of true oil rela-tive saturation in the trans-former

20 160/2002

Figure 3. Chart for off-line moisture diagnostics of transformers containingnew oil.

- Evaluation of the water-in-paper activity (Awp) for the trans-former oil

- Evaluation of the active wa-ter content of paper (WCPA) as afunction of Awp and temperature.

A software application, theTransformer Moisture Monitor(TMM), has been developed onthe basis of the WIP algorithm.The TMM uses neuro-fuzzycomputing to evaluate the con-sistency of the moisture sensoroutput, to access the WCPA, andto alert the user when insulationconditions require attention.The TMM acquires data fromthe Vaisala HMP228 Humidityand Temperature Transmitter.The probe of the transmitter hasboth moisture and temperaturesensing elements at its tip.

New classification procedure for off-linemoisture diagnosticsThe research conducted atMonash University has shownthat, for the accurate moistureassessment of transformer insu-lation, the continuous monitor-ing of a number of parameters,including transformer load, tem-perature and oil relative satura-tion, is required. The measure-ment of water solubility charac-teristic of oil in the transformeris also required.

A utility may operate tens oreven hundreds of transformers.However, not all of the trans-formers require continuousmonitoring. How is it possible toidentify a transformer with mois-ture concerns for further moni-toring? There is a demand for aclassification procedure, whichwould rank transformers bymoisture levels.

A traffic light approach is theEPRI adopted way of rankingthe health of plant equipment.Red, yellow and green colorswould indicate the ‘wet’, ‘re-quires attention’ and ‘dry’ statesof moisture in transformers.

A new classification proce-dure was developed to rank,from a population of powertransformers, critical transform-ers in terms of moisture for fur-ther continuous monitoring.The new classification procedureaims to improve the effective-ness of the management of trans-former life.

The new classification proce-dure is based on a method ofmoisture assessment that evalu-ates the WCPA and was brieflydescribed in the section above. Itis available in the form of achart, shown in Figure 3. Valuesof WCO in ppm represent theresults of Karl Fischer (KF) meas-urements and values of the tem-perature T represent the temper-ature of the oil at the moment ofoil sampling. In Figure 3, valuesof WCPA are distinguished bycolor. Green corresponds to aWCPA of less than 1%, yellowcorresponds to a WCPA of be-tween 1% and 2% and red corre-sponds to a WCPA of more than2%. The numbers in the squaresrepresent the diffusion time con-stant for moisture across a 1-mmpressboard plate exposed to oilfrom both sides. The 1-mmpressboard was chosen to reflectthe approach of the water-in-pa-per activity applied to the trans-former ranking and classifica-tion.

At an oil temperature below45 °C and WCO of less than 20ppm, the moisture diffusiontime is too long for the reliablediagnosis according to the pro-posed procedure. To reflect thisfact the bottom left corner of thegraph in Figure 3 is shadowed.

The classification procedurechart in Figure 3 is valid for oilwith a water solubility character-istic close to that of new oil. Inthe previous section of this pa-per it was demonstrated that thewater solubility characteristic ofnew and aged oil can differ sig-nificantly. This means that for

the accurate ranking of agedtransformers, evaluation of theoil’s water solubility characteris-tic would be required.

In light of the new know-ledge presented here, the tradi-tional approach, which states: “Ifthe WCO exceeds 20 ppm, thetransformer requires further at-tention, if the WCO is less than20 ppm no action is required,”must be reconsidered. From Fig-ure 3 it follows that atWCO=20-25 ppm a transformerwith new oil would be consid-ered “probably wet” if the oilsample was taken at a tempera-ture of below 55 °C. However, ifthe oil sample was taken at atemperature of above 80 °C,with the same WCO=20-25ppm, the transformer would beconsidered “probably dry”. Toprove or reject the conclusion,one more sample of oil shouldbe taken in the number of hoursshown in the related square onthe chart. This example illus-trates the importance of themeasurement of oil temperatureduring the oil sampling, the im-portance of the second oil sam-pling, and the importance of thelength of time between the twosampling events.

It is apparent that knowledgeof the WCO only, gained from asingle Karl Fischer measure-ment, is insufficient for the ac-curate assessment of transformermoisture condition. Knowledgeof the temperature of the first oilsample, the dynamics of mois-ture and temperature gainedfrom the second oil sample, andthe water solubility of the oil arealso required.

ConclusionsOil type, age and flow rate con-tribute to the measurement andsubsequent accuracy of moistureassessment in a paper-oil insula-tion system. Sensor positioningalso contributes to the accuracyof moisture assessment.

The parameter of the watersolubility of oil is required forthe validation of the moisturesensor installed in the trans-former. Water-in-paper activitywas found to be a factor in deter-mining the state of dryness in apower transformer.

A stand-alone software ap-plication called “TransformerMoisture Monitor” (TMM) isproposed for the moisture as-sessment of a transformer.

A new classification proce-dure that aims to identify criti-cal units for further continuous

monitoring is suggested for theranking of power transformersby the level of moisture. Red,yellow and green colors wouldindicate the ‘wet’, ‘requires atten-tion’ and ‘dry’ states of moisturein transformers. The classifica-tion procedure presented is onlyvalid for oil with a water solubil-ity characteristic close to that ofnew oil. For the accurate rankingof an old transformer, the watersolubility characteristic of thetransformer’s oil would need tobe evaluated. �

References:1. V. Sokolov and B. Vanin, “Experience

with In-Field Assessment of the WaterContamination of Large PowerTransformers”, Proceedings of EPRISubstation Equipment DiagnosticsConference VII, New Orleans, 1999

2. T. V. Oommen, “Moisture EquilibriumCharts for Transformer InsulatingDrying Practice”, IEEE Trans. onPower Apparatus and Systems, Vol.PAS-103, 10, 1984, pp.3063-3067

160/2002 21

T he HMP228 Transmitter provides on-linemeasurement of moisture and temperature

in transformer oil. The measurement gives con-tinuous information and enables better mainten-ance against transformer failures.

Vaisala’s microprocessor-based HMP228Transmitter is accurate, reliable and fast. The ba-sic model of the HMP228 Transmitter calculatesthe average water solubility in mineral trans-

former oil. The water solubility in oil is tempera-ture dependent: water solubility increases astemperature raises. In addition to traditionalppm-output, the transmitter measures water ac-tivity. The water activity (aw) indicates directlywhether the oil is too moist. The aw measurementis independent of the type, aging or temperatureof the oil. �

HMP228 Moisture and Temperature Transmitter for Transformer Oil

The determination ofmoisture in oil is an

essential part of acomprehensive

transformermaintenance

program.

T he Vaisala DM500 Preci-sion SAW Hygrometeroffers excellent measure-

ment performance with SurfaceAcoustic Wave (SAW) technolo-gy. The DM500 is the bestchoice for calibration laborato-ries and for use as a transfer stan-

dard. Due to the rugged sensingtechnology, the DM500 is alsosuitable for use in industrial ap-plications, such as metal treat-ment processes. The innovativeDEWCAP® SAW Sensor offersthe advantage of high accuracyand reliable dewpoint measure-

ment with excellent repeatabilityand fast response time. In addi-tion, DEWCAP® technologycan withstand particulate con-tamination and distinguish dewand frost directly.

Product conceptThe DM500 Precision SAW Hy-grometer consists of a DMI500User Interface Unit and aDMP501 Dewpoint SensingUnit. The User Interface Unit in-cludes display, keypad, powersource and analog outputs. TheDewpoint Sensing Unit includesthe SAW -based sensor andmeasurement and cooling elec-

22 160/2002

New technology for high accuracy measurements

Vaisala’s DM500 - Dewpoint Reference

Vaisala’s new DM500 Precision SAW Hygrometer has been specificallydeveloped for applications where high accuracy is needed. TheDM500 offers reliable measurements and ease of use, enhancedthrough additional product features, such as the graphical user interface. With excellent measurement performance and an easy-to-use product concept, the DM500 represents a new generation of highaccuracy dewpoint measurement instruments.

With the DEWCAP® sensorcondensation on the cooled surface isdetected by a high frequency SAWsignal which attenuates in dew orfrost.

Jan Grönblad, M.Sc. (Eng.)Product Line ManagerSensor Systems DivisionVaisala HelsinkiFinland

The DM500 provides highlyaccurate dewpoint measurementwith excellent repeatability.

tronics. Three different installa-tions are available for theDM500: installation in a 19" rack,remote installation, and use ofthe DM500 as a desktop/portableinstrument equipped with op-tional handle.

High measurement performanceThe DM500 is an automatic,continuously controlling con-densation hygrometer measur-ing dewpoint temperatures from-75 °C to +60 °C Td with ±0.2°C traceable accuracy. For lowfrostpoint measurement, theDM500 has a connection forwater cooling. In order to pre-vent condensation when meas-uring high dewpoints it is alsoequipped with an optional heat-ed gas sampling system and acontrol for external pipelineheating.

Dew/frost determination

The DM500 detects the differ-ence between dewpoint andfrostpoint at dewpoint tempera-tures below 0 °C directly, with-out any additional cooling cy-cles. In traditional condensationhygrometers such as chilled mir-rors the optical beam can not seethe difference in the condensate.The problem exists when highaccuracy measurement has anadditional uncertainty factor inthe typical range –30…0 °C Td.The presence of liquid condens-ation on the DEWCAP® sensoralters the signal in a repeatableway. Freezing the condensate

causes a distinctly different sig-nal change, thus enabling the de-termination of dew or frost onthe DM500’s sensor.

Fast response timeThe SAW signal is attenuated bydew/frost, which absorbs the en-

160/2002 23

Standard without a Mirrorergy of this micromechanicalwave. The SAW detects verysmall amounts of condensate - aslittle as one-tenth of that re-quired by an optical detectionsystem. This means substantiallyfaster response times, particular-ly at low frostpoints. ➤

The DM500 has a high-qualityLCD display with menu -based userinterface.

What is the pressure of thesample gas?

• Identifies the need for a pump option if pressure is ambient,

• Assures that maximum process pressure is within safe limits,

What is the temperature of thesample gas?

• High temperature gas shouldbe cooled to ambient before measurement,

What is the composition of thesample gas?

• Assures material compatibility with the sensor,

What are the desired humidityparameters for display or out-put?

• For %RH, a temperature sensor option is required,

• For ppmv or other pressure

EvaluationEvaluation starts with an under-standing of the intended use ofthe Vaisala DM500 PrecisionSAW Hygrometer. The results ofevaluation include a “go” or a“no-go” decision as to the suit-ability of the instrument for theapplication. In the case of a“go,” the correct product confi-guration will be evident. The fol-lowing are critical things to con-sider during the evaluation:What is the anticipated dew-point or range of dewpoints tobe measured?

• Identifies the correct sensor model and any possible need for external cooling,

• Identifies whether elevated dewpoints may cause condensation in the gas system, requiring the use of a heated sensor,

24 160/2002

DEWCAP® Sensor and Surface Acoustic Wave (SAW)

V aisala's DEWCAP® Sensor uses Surface Acoustic Wave (SAW)technology to usher in a new generation of condensation hy-

grometers. In Surface Acoustic Wave (SAW) technology the tem-perature controlled quartz sensor surface is cooled until dew orfrost collects on the sensor surface. The presence or absence ofcondensation is sensed using the SAW instead of the traditionaloptical beam used in chilled mirrors. In measuring mode, the tem-perature of the DEWCAP® quartz surface is varied until condens-ation exists in equilibrium. When the equilibrium is reached, thetemperature of the sensor surface is measured by a precision Pt-100 PRT. This measured temperature equals the dew/frostpointtemperature of the measured gas. �

James TennermanBusiness Development ManagerVaisala Boston USA

Good planning is essential for achieving highperformance measurement results with anymetrology tool. Successful application of theVaisala DM500 Precision SAW Hygrometer isbest achieved with a three step planning ap-proach. These steps can be described as eval-uation, preparation, and execution.

How to fully benefit from using the

Vaisala DM500 Precisi

The DEWCAP® sensor is based on innovative SAW technology.

Withstands contamination

The DM500 operates reliablyeven with substantial particulatecontamination on the sensing element. The SAW signal is sensi-tive for condensate (dew/frost)but not for particulates.

Salt sensingHygroscopic dirt is a commonsource of error in conventionaldewpoint measurement tech-niques as it can change water va-por pressure close to the sensor.The DM500 can detect the pres-ence of salts or hygroscopic dirton the sensor surface with its in-telligent self diagnostics.

Chemically durableUse of a quartz wafer as a sensorsubstrate gives excellent resistanceto aggressive chemicals. Wettedparts are limited to stainless steel,silicone, tantalum, vectra polymerand quartz. All water absorbingmaterials are located downstream.

Various output variables

The DM500 displays user selec-table hygrometric units, such asdewpoint/frostpoint tempera-ture, relative humidity, partialpressure of water vapor, and hu-mid air volume/dry air volume(ppmv). In addition, the DM500can measure temperature, pres-sure and gas flow rate if the in-strument includes the corre-sponding optional sensor.

Wide variety ofadditional featuresThe DM500’s display can beswitched between numeric orgraphical. The multi-lingual userinterface is menu based and veryeasy to use. The DM500 also hasdata-logging capability and isequipped with the sophisticatedMI70 Link Windows® softwareprogram for easy PC connec-tion. �

the slew rate of the Peltier cool-ers and the rate of water vaporcapture at the process dewpoint.• Maintenance of the sensorshould be performed as re-quired. When liquid cooling isin use, sensor cleaning shouldonly be done when the coolanttemperature is above the ambi-ent dewpoint. • Maintenance of the coolingsystem and filtration compo-nents should be performed asrequired. �

sensitive parameters, a pressure sensor should be specified.

PreparationWhen the suitability of theDM500 has been established,preparation takes into accountthe entire measurement scenario.

FiltrationIf substantial particulate con-tamination is present in the gassample, a non-hygroscopic filtershould be installed in the sam-ple line before the sensor. Thisminimizes the need for sensorcleaning and keeps the gas chan-nel free of contaminants thatmay adversely effect measure-ment response time.

Fittings & tubingStainless steel tubing should be

used for best results with dew-point temperatures below–30°C. US users will typicallywant to use 1/4” tubing, com-pression fittings, and accessoriesthat are equipped to be connect-ed in this way. Other users willtypically specify 6 mm tubingand fittings. Rubber and/or Ty-gon tubing should not be usedfor sampling!

Flow control Samples at positive pressure willrequire some type of flow con-trol downstream from the sensorfor correct measurement of pres-sure dewpoint.

Physical locationThe DM500 should be locatedin an environment consistentwith the specifications. Access tothe back of the sensor is required

for gas and coolant connections.Appropriate line voltage shouldbe available.

%RH measurementsLocation of the temperature sen-sor is important. In general, thetemperature sensor should be inthe location where the userwants to know the relative hu-midity.

ExecutionWith the DM500 correctly spec-ified and installed, all that re-mains is to operate and maintainthe system.

• Cooling water should be circu-lating if installed; care shouldbe taken to assure that condens-ation forming inside the sensorhousing is drained.• Response time is a function of

160/2002 25

The DM500 Precision SAWHygrometer is an automatic,continuously controllingcondensation hygrometer which issuitable for calibration laboratoriesand for use as a transfer standard.

on SAW Hygrometer

26 160/2002

Jan Grönblad, M.Sc. (Eng.)Product Line ManagerSensor Systems DivisionVaisala HelsinkiFinland

Meteorological dewpoint measurements from arctic conditions to hot deserts

National Weather Service Relies on Vaisala Instrumentsfor Dewpoint MeasurementThe National Weather Service (NWS) in the USA has started to updatethe dewpoint measurement in the ASOS (Automated Surface Observing System) network with Vaisala’s HUMICAP® technology.The high measurement performance over a wide measurementrange together with the long maintenance interval were among themost important factors considered when selecting the new-generation technology for the network. Vaisala’s unique warmedsensor technology was finally chosen to satisfy the most demandingneeds in humidity and dewpoint measurement.

A fter a long evaluationperiod the NationalWeather Service in the

United States has started to re-place its dewpoint measurementinstruments with Vaisala’s HU-MICAP® technology through-out the ASOS (Automated Sur-face Observing System) networkin the USA. This network coversthe entire continent from Alaskato Texas, setting very high de-mands for the instrumentationin terms of environmental con-ditions, which range from arcticto hot desert. The sensors thatare being replaced representtechnology with a high need formaintenance, mainly due to thebasic operation principle of theinstruments. They utilized

160/2002 27

The dewpoint measurement in the ASOS network atNWS incorporates an installation kit for the sensor headtogether with an enclosure for the dewpoint transmitterand optical modem. The warmed probe of the transmitteris installed in a radiation shield with open structure.

chilled mirror technology withoptical dew detection which isknown to be sensitive to dirt.

Reliable measurementswith low maintenanceneedsThe new instrument for dew-point measurement in the ASOSnetwork is based on warmedHUMICAP® thin film polymersensor technology, used in, forexample, Vaisala HMP240 Seriesproducts. The measurement withcapacitive thin film polymer sen-sor is itself very reliable and has avery low failure rate. For exam-ple, the MTBF value (mean timebetween failures) for theHMP243 Dewpoint Transmitteris more than 18 years (with 2�

The dewpoint measurement principle in the warmed sensor head. Thetemperature of the warmed HUMICAP® sensor is measured accurately inaddition to the RH measurement. These values result in ambient dewpoint asdewpoint does not change although the temperature of the sensor rises.

� � � � � � � �� � � � � � � � � �

� � � � � � � � �

� � � � �

The dewpoint probe in the specially designed radiationshield with open structure.

Vaisala’s 30 years experience withcapacitive humidity sensors hasresulted in a sensor which satisfiesone of the most demanding needs inhumidity and dewpointmeasurement.

confidence). The measurementtechnology is also not very sensi-tive to dirt and operates with therequired accuracy over the speci-fied wide temperature and hu-midity range.

Warming prevents theadverse effects of moistureThe advantage of warming is a re-liable measurement even in situa-tions where the humidity levelsare close to 100%RH, i.e. themoisture in the air starts to con-densate and dewpoint equals theambient temperature. Warmingensures the sensor will not getwet which could result in incor-rect humidity readings (too high)until the sensor dries up. In

warmed sensor technology, thetemperature of the HUMICAP®

sensor is measured accurately inaddition to the relative humiditymeasurement from which thedewpoint is calculated. The cal-culation results in actual ambientdewpoint, as dewpoint does notchange although the temperatureof the sensor rises.

Additionally, the long-termstability provided by HUMI-CAP® technology makes the fi-nal product concept unprece-dented. It allows high-perfor-mance meteorological dewpointmeasurements with minimalmaintenance needs, meeting theexacting requirements of theNWS surface weather observingsystem. �

28 160/2002

DSS70A Portable Sampling System

Heikki Joensuu, B.Sc. (Eng.)Product Development ManagerSensor Systems DivisionVaisala HelsinkiFinland

When direct dewpoint spotmeasurement is not possible

The DSS70A Portable Sampling

System, delivered in a carrying case, includes

everything needed for sampling.

The Vaisala product family of portable dew-point measurement instruments has nowbeen enhanced with a sampling system option. The new DSS70A Portable SamplingSystem allows measurements to be made inapplications where a direct measurementcannot be used. It also allows measurementsto be made in the most demanding process-es, with dusty and hot process gas samples.

Compact designThe Vaisala DSS70A PortableSampling System is a battery-powered system for portabledewpoint sampling applications.The DSS70A system enablesdewpoint measurements to bemade from places where directmeasurement is not possible.The product is an option for the

DM70 Hand-Held DewpointMeter family, but can also be or-dered separately. This completecompact sampling system hasbeen built around Vaisala’sDM70 Hand-Held DewpointMeter.

The DSS70A is designed toprovide the greatest amount ofsampling flexibility. A battery-powered pump is used to extracta gas sample. The sample gasthen passes through a filter to re-move particulate contaminationbefore measurement. Flowthrough the system is controlledand monitored with a needlevalve and flow meter. TheDSS70A is then simply connect-ed to an appropriate samplepoint where tubing and measure-ment results can be monitoredand analyzed with a Vaisala MI70Measurement Indicator.

to adjust sampling rate• Changeable filter• Clear battery indicator• Rechargeable battery or ACusage• Graphical trend display • Sophisticated data collectionfunctions including Windows®

software

Measurement reportsmade easyThe Vaisala MI70 MeasurementIndicator offers many handy fea-tures to analyze and collect dataduring measurement. The indica-tor has numeric and graphic dis-play modes to follow the processtrends. Measurement results canbe stored in the memory andthen later easily transferred to aPC at the office, using the op-tional Windows® software. �

160/2002 29

Demanding applicationsThe DSS70A is designed to workeven in very demanding process-es, for example in metal treat-ment processes, where the meas-ured air sample is very hot anddirty. In plastic dryer applica-tions a DM70 Hand-Held Dew-point Meter together with aDSS70A Sampling System is anoptimum tool to check the dryeris working properly.

Performance• Wide measurement range –from -60 °C to +60 °C • Fast response time betweenstart-up from ambient condi-tions to low and high processdewpoints• Standard process connections1/4" SWAGELOK®

• Flow meter and needle valveMechanics Engineer Kari Bergman of Vaisala checks an injection mouldingplastic dryer at Plastoco Oy.

In plastic production plants, dewpoint measurement is essential formonitoring the drying process. Tessy Plastics Corporation’s state-of-the-art facilities have been equipped with Vaisala dewpoint measure-ment instruments for their drying units, with Vaisala technology alsorelied upon to cater for other measurement needs in their facility.

Precision plastic injection moulding requires

Accurate Monitoring of Plastic Drying Process

T essy Plastics Corporationis a custom plastics injec-tion molder headquar-

tered in Elbrige, New York(USA). The company manufac-tures products for the medical,automotive and electronic in-dustries, amongst others. Besidethe plant in New York, TessyPlastics Corporation has facili-ties in Virginia and China. Thefacility in Central New York

houses a white room and a cleanroom, with post molding, engi-neering, design and tool build-ing capabilities.

In order to be able to moni-tor the operation of plastic airdryers, Tessy Plastics use twoVaisala DM70 Hand-Held Dew-point Meters. The DM70 meas-ures dewpoint accurately in awide measurement range, whichis important in this application.

The Advanced ManufacturingFacility Maintenance Supervi-sor, Todd Eaton, who is respon-sible for the maintenance of theplant production machinery,plant facilities, plant engineeringand process improvement,stresses that the plastic dryersmust operate with dewpoints be-low -40°F (-40°C) continuouslyfor proper plastic drying. “Sincethe first DM70 unit was pur-chased in January 2002, addi-tional instruments have been in-stalled in our plant and in thedrying systems,” remarks Mr.Eaton.

The plant is also equippedwith a DMT242 Dewpoint Trans-mitter that was purchased to up-grade one of the dryers. To moni-tor a dehumidification unit, aVaisala DMP248 DewpointTransmitter is used. Moreover, aHMP233 with a radiation shieldis used to monitor outside condi-tions, measuring the wet bulband enthalpy of outside air. Thisinstrument allows the maximiza-tion of free cooling potential us-ing outside air. Additionally, theHVAC system at the plant is fit-ted with HMW40s that were re-cently installed.

Todd Eaton finds that Vaisalaproducts offer excellent accuracyand repeatability. Moreover, theability to be interfaced with PCsis important. “The instrumentsallow the recording and trackingof dewpoints and other measure-ments, which in turn allows us tooperate our equipment more ef-fectively and efficiently,” Mr.Eaton explains. Vaisala instru-ments have performed very welland proven excellent for thecompany. �

30 160/2002

At Tessy Plastics, Todd Eaton usesVaisala DM70 Hand-HeldDewpoint Meters to monitor theplastic dryers.

160/2002 31

T he Vaisala HMT360 Se-ries Industrial Humidityand Temperature Trans-

mitter was launched in 1999with the European EEx approvalfor use in hazardous areas. However, global needs in thisstrictly controlled applicationarea do not necessarily followEuropean regulations. This hascaused the need to expand the

range of local approvals forHMT360 Series Transmitters. Inaddition to the European ap-proval ATEX100a from PTB(Physikalisch-Technische Bundes-anstalt/Federal Institute ofPhysics and Metrology in Ger-many), the HMT360 series nowhas approvals from Factory Mu-tual in the USA, TIIS in Japanand Test Safe in Australia.

In industrial applications inthe USA, Factory Mutual (FM)is an authority on approving in-struments for use in potentiallyexplosive atmospheres. FactoryMutual Research electricalequipment testing is based onFactory Mutual Research stan-dards, American National Stan-dards Institute (ANSI) Stan-dards, and International Elec-trotechnical Commission (IEC)Standards.

In Japan, the Technology In-stitution of Industrial Safety (TI-IS) has also approved theHMT360 Series. TIIS is a non-governmental, non-profit, self-sustaining organization which isrecognized by the Ministry ofLabor as a juridical incorpor-ation. The objective of TIIS is tohelp reduce industrial accidents

and contribute to the benefits ofvarious industrial sectors inJapan.

TestSafe approval in Au-stralia is the most recent ap-proval for HMT360 SeriesTransmitters. TestSafe Australiais a safety testing and research fa-cility which offers manufacturersand suppliers a comprehensiverange of safety testing, certifica-tion, and approval services inthe electrical, electronic, me-chanical and personal protectiveequipment fields. Certificatesand approvals at TestSafe are is-sued for conformance with Aus-tralian Standards and legislativerequirements.

For hazardous areas theVaisala HMT360 Series Humidi-ty Transmitters are indispensa-ble. They represent the latestmeasurement technology andfulfil safety requirements laiddown in a wide variety of coun-tries. The thorough studies madeon the HMT360 Transmitterguarantee the safety of high-per-formance humidity and temper-ature measurements, even in in-stallations with continuous ex-posure to the most easily ignitedflammable gases. �

The HMT360 providesaccurate measurements andsafe operation on hazardousinstallation sites.

The regulations for equipment used in hazardous areaswhere there is a risk of explosion vary slightly in differentparts of the world. The Vaisala HMT360 Series Humidityand Temperature Transmitter used in hazardous areas hasnow received local approvals in three new countries. Newapprovals have been awarded to HMT360 by Factory Mu-tual in the USA, TIIS in Japan and Test Safe in Australia.

Safe measurements in hazardous areas

HMT360 Series Receives New Approvals

Jan Grönblad, M.Sc. (Eng.)Product Line ManagerSensor Systems DivisionVaisala HelsinkiFinland

32 160/2002

A ccording to its 10th

five-year plan (2000—2004), China Meteor-

ological Administration (CMA)has started to implement a proj-ect called Atmosphere Automat-ic Monitoring System, which ex-tends over the entire country.The project aims to set up threeclasses of weather observationstation and a monitoring net-work. The top-level stations,which are called national stan-dard stations, will be the mainweather observation bases in themonitoring network. Totalingmore than one hundred, thesestations will be equipped withthe hardware needed to improveaccuracy and long-term stability.The second grade of station arecalled basic stations and will beset up around China to raise theweather observation ability andthe density of observations. Thethird category of station, so-called general stations, will totalmore than 1000. The general sta-tions will perform observationsto further increase network den-

sity and acquire more data. Theautomatic weather stations to beemployed at these three classesof station will be manufacturedin China. However, sub-assem-blies and measurement instru-ments of foreign manufacturewill be utilized, for instance for

pressure measurement in the up-per level stations.

Extensive comparisonof barometersTo improve the implementationof this project, the Departmentof Observations and Telecom-

munication of CMA, which isthe topmost management officefor meteorology in China, or-ganized a comparison test for ba-rometer performance. The At-mosphere Sounding ResearchCentre of China MeteorologicalScience Institute was responsiblefor the test design, setup, imple-mentation and data collection.The comparison started with la-boratory tests in 2000, with fieldtests then carried out from No-vember 2000 to November 2001.They focused on the barometers’temperature stability and overalllong-term stability.

The objective of the extensivetest period was to choose whichone or two pressure sensorswould be most suitable for inte-gration into the domesticallymanufactured automatic weatherstations. Additionally, the aimwas to improve the quality of airmonitor prediction in China andto lighten the staff ’s workload, aswell as to raise atmospheric fore-casting accuracy and the level ofautomation in performing obser-

Ritva Siikamäki, MAEditor-in-Chief,Vaisala Helsinkifinland

The China National Meteorological Center which was responsible for the testis located in Beijing.

Major program to enhance national weather observation network

China Meteorological AdministrationInvests in Accurate Vaisala Barometers

China Meteorological Administration, CMA, is implementing a project around China called “Atmosphere Automatic

Monitoring System”. The objective is to set up a nationwide monitoring network of weather observation stations,

in three different categories, to form a network.

160/2002 33

vations in China. Some leadingbarometer manufacturers fromaround the world and China ap-plied for participation in this trialand test.

Vaisala barometers participated Vaisala sent 3 units of PTB210and PTB220 Barometers to beassessed in the trial. The VaisalaPTB210 series of barometers areintended for direct outdoor in-stallations. They operate in awide temperature range, with theelectronics housing protected toIP65 class against sprayed water.The PTB220 Series DigitalBarometers cater for measure-ments in a wide environmentalpressure and temperature range.Both the PTB210 and PTB220series of barometers are usedwidely in, for instance, weatherstations, data buoys and ships,and are based on the BARO-CAP® pressure sensor. All sixbarometers showed very goodperformance during the trial andtest. During the on site field teststrial, all barometers were in-stalled in wind, rain, snow andshockproof test chambers underthe same static pressure.

Comparison provedhigh performance ofVaisala barometers The high reliability, accuracyand good stability of the VaisalaPTB210 and PTB220 DigitalBarometers in this comparisonproved once again that Vaisalaproducts offer excellent quality.The good performance of thePTB series barometers was oneof the most crucial factors forCMA in their selection and pur-chasing process. After compre-hensive comparison and assess-ment CMA decided to purchasePTB220 barometers. Several

hundred units have been deliv-ered to CMA.

Extensive cooperationbetween CMA andVaisalaCMA is one of Vaisala’s most

important customers in China.The various cooperation projectsbetween CMA and Vaisala traceback to the founding of Vaisala’sBeijing Representative Office in1994. A set of MILOS 500 pro-vided to CMA in August 1994

was much appreciated due to itsadvanced technology and long-term stability, proven in a 10-month test in western rural areasof Beijing. Since then Vaisala hasalso provided CMA with RS80-15G Radiosondes, RT20 Radio-theodolites, DigiCORA Sound-ing Systems with GPS wind find-ing, and a number of otherweather observation products. In1997 Vaisala provided the Qing-hai province with key hardwarefor a project called DisasterWeather Monitoring Network,with the help of a loan from theFinnish government. Vaisala’sBeijing office often arranges sem-inars on various topics to intro-duce state-of-art meteorologicaltechnologies. Vaisala also invitesexperts and officials of all levelsto visit the production plant inFinland. Their high-performanceproducts have proven thatVaisala is one of the world’s bestcompanies in the field of meteor-ology. Consequently, they havewon the confidence of Chinesemeteorological customers. �

Vaisala's PTB220 DigitalBarometers are designed formeasurements in a wideenvironmental pressure andtemperature range.

Barometers were tested on site fortheir stability,

34 160/2002

T he PTU200MIK1 Mete-orological InstallationKit allows easy outdoor

mounting and installation of thePTU200 Barometric Pressure,Relative Humidity and Tempera-ture Transmitter. The kit consistsof a protective transmitter box,support arm, a radiation shield,the SPH10 Static Pressure Head,pole attachment clamps, and apressure hose. The kit can be at-tached to any pole with diameterof either 2" or 50 mm. The boxoffers IP65 (NEMA 4) protec-tion for the transmitter. It is air-tight and connected to the staticpressure head with the pressurehose. The radiation shield pro-

tects the relative humidity andtemperature probe of PTU200and the SPH10 Static PressureHead reduces the effect of windon the pressure measurement.

Approved for SuomiNet SuomiNet is an internationalnetwork of GPS receivers, locat-ed primarily at universities. Itgenerates near real-time esti-mates of precipitable water va-por in the atmosphere, totalelectron content in the iono-sphere, and other meteorolog-ical and geodetic information.Each SuomiNet site has a dedi-cated meteorological measure-ment package (MET package)

PTU200MIK1 Meteorological Installation Kit

Easy Measurements on Site

The PTU200MIK1 offers easyinstallation of equipment at anoutdoor site.

The Vaisala PTU200MIK1 Meteorological Installation Kit is a high-quality mounting kit for outdoor use of PTU200 Barometric Pressure,Relative Humidity and Temperature Transmitter. It allows meteorol-ogical measurements to be made on site, e.g. next to a GPS antenna.The PTU200 Transmitter belongs to recommended equipment of theSuomiNet network, an international network of GPS receivers.

The Vaisala SPH10 and SPH20Static Pressure Heads are designedto minimize the errors in barometricpressure measurement caused byvariations in wind speed anddirection.

which records temperature, baro-metric pressure and relative hu-midity.

One of the approved METinstruments for the meteorolog-ical observations is the VaisalaPTU200 Barometric Pressure,Relative Humidity and Tempera-ture Transmitter. The PTU200Transmitter uses the very stable,silicon-based BAROCAP® pres-sure sensors and requires calibra-tion only infrequently. ThePTU200 central unit can be in-stalled indoors with its displayand keypad, or outdoors withthe optional PTU200MIK1 out-door installation kit. �

160/2002 35

I n the 1990s, emissions ofcarbon dioxide from fossilfuel and cement production

were, on average, 6.3 PgC (onePgC = one petagram of carbon= 1 billion tonnes of carbon) peryear (IPCC, 2001)1. The rate ofincrease in atmospheric CO2

concentration has been, on aver-age, 1.5 ppm per year, which cor-responds to 3.2 PgC per year inatmospheric storage. It is esti-mated that oceanic uptake is 1.7PgC per year. To reach a balance,there has to be a net sink of at-mospheric CO2 to terrestrial areas that amounts to about 1.4PgC per year. Land use changes,especially deforestation in tropi-cal regions, cause a net CO2 re-lease to the atmosphere that wasestimated to be about 1.7 PgCper year during the 1980s. Frominversion modeling of atmos-pheric CO2 concentrations andisotopic studies, we know thatthere is a large net sink (about 2PgC per year) to the terres-

Tuomas LaurilaSenior ResearcherFinnish Meteorological InstituteHelsinkiFinland

Surge in studies on

Carbon Cycles of the Ecosystems of the World

Figure 1. Most of the multiyear micrometeorological CO2/H2O flux sites have provided data to the FLUXNET-network, which has a Data and Information System unit at Oak Ridge National Laboratory, Tennessee.

Interest in the global carbon cycle has grown greatly in recent years.Mankind is completely dependent upon primary production and in-teracts with the biota through different activities, such as agriculture,forestry and fish farming. The production of these basic resources willbe very much affected by climate change and the growing humanpopulation.

➤

36 160/2002

induced emissions. The KyotoProtocol remained on a rathergeneral level. The negotiationsthereafter, on how to definewhich biological sinks may beconsidered in the calculations,were long and difficult at manyinternational conferences beforethe final text was approved inthe Marrakech Accord in 2001.

Many nations would like tofacilitate reduction of their emis-sion burden through using car-bon sequestration by vegetation.The problem is our insufficientknowledge of where the sinks arelocated and how they maychange in the future. Our under-standing is very much lacking inwhich land-use classes they arerelated and how forestry or agri-cultural practices may increaseor decrease the sequestration. Itis stated that the sinks should beverifiable, which is a normalcondition in international agree-ments. However, it will be a verychallenging task to develop the

tools for carbon sequestrationmonitoring, because of differentmeasurement approaches andthe limited understanding of theprocesses.

Carbon dioxide budgetmeasurementsThere are several ways to studycarbon balances at differentscales, but all of them have se-vere limitations. The global CO2

budget mentioned above isbased on the very accurate at-mospheric CO2 concentrationmeasurements, which are per-formed on global measurementnetworks. The Global Atmos-phere Watch (GAW) network,coordinated by the World Meteorological Organization(WMO), and the network runby the CMDL group in the Na-tional Oceanic and AtmosphericAdministration (NOAA) in theU.S., are the most importantsources of this data. However,the network is too scarce to pro-

vide information on CO2 bal-ances at regional level. The cal-culations are based on inversionmodeling, which has many limi-tations and relies on additionaldata.

Measurements of changes instock of biomass are a direct wayto monitor carbon uptake. It is astraightforward, though labor-in-tensive, task to measure thechanges in tree trunk biomassevery 5 years or so. Because mostof the carbon is stored in thesoil, it is a practically impossibletask to measure changes in thiscarbon reservoir.

Micrometeorologicalflux measurementmethods Micrometeorological flux meas-urement methods offer an inter-esting way to study CO2 fluxes ina scale that is comparable to thesize of a typical ecosystem, forexample 30 hectares. The core ofa standard set-up is a fast-re-

Figure 2. Flux measurement site ona field at Jokioinen in southernFinland. The soil at this site is peatand one of the objectives of the studyis to measure the decomposition rateof the peat and compare it to thecarbon uptake by the cultivatedplants. The sonic and inlet tube tothe CO2/H2O monitor is mountedon a boom on top of the short mast.The monitoring and dataacquisition computers are housed ina box on the ground. The other mastis equipped with meteorologicalsensors such as radiationcomponents, temperature andhumidity sensors. Also, soiltemperature, moisture and heat fluxto the soil are measured. During thegrowing season, CO2 efflux from thesoil uptake by plants is alsomeasured by chambers to get datafor ecosystem models.

trial biota, which is mostly locat-ed in temperate and boreal re-gions of the Northern Hemi-sphere. The reasons for this up-take are nitrogen deposition andincreasing atmospheric CO2 con-centration, which act as fertiliz-ers. Recent studies indicate thatland use changes, especially theforestation of abandoned agri-cultural land, are also importantcontributors.

Internationalcooperation to reduce emissionsTo combat global warming, sub-stantial reductions of fossil fuelemissions are needed. In Kyoto1997, nations agreed upon an in-ternational protocol that aims atworldwide reductions of CO2

emissions. To assist in reachingan agreement in negotiations, itwas decided that additional ter-restrial sinks might be partlyused to compensate for anthro-pogenic emissions, i.e. human-

160/2002 37

sponse sonic anemometer and afast-response (5-10 Hz)CO2/H2O monitor, which arelocated several meters above theecosystem to be studied. Directobservation of the flux betweenthe atmosphere and an ecosys-tem, including trees, undervege-tation and soil, is obtained at 30-min. (half-hourly) resolution asa covariance between the verti-cal wind speed and gas concen-tration variations in a turbulentflow field.

A great advantage of mi-crometeorological measure-ments is that measured fluxesmay be used in process studiesand model verification. For ex-ample, temperature response ofecosystem respiration, light useefficiency of CO2 assimilation oreffects of drought on carbon bal-ances, may be plotted from ob-servations. Water vapor fluxes,which are measured in parallel,tie hydrological processes, evap-oration and transpiration to the

carbon fluxes. Micrometeoro-logical flux measurement is theonly tool to get daily and annualbalances, which are obtained bysumming up half-hourly obser-vations. These measurementshave provided a great deal ofquite new information on the in-terannual variation of carbonfluxes and the factors behindthese variations. The drawbackof the method is the fact that toestablish and run a station is notcheap. The costs for equipping astation lies at around 100 000EUR and, usually, service visitsare needed several times a week.In addition to flux measure-ments, measurements of otherphysical and biological parame-ters have to be conducted for aprofound understanding of thefunctioning of the ecosystems.The instrumentation to obtaininformation on CO2 fluxes ofdifferent components, leaves,stems, roots, ground vegetationand soil, are also needed for

many applications. These areusually measured with differentkinds of chamber systems.

Fluxnet for globalmeasurementsAfter the development of field-proven instrumentation and dataacquisition systems for fluxmeasurements during 1990s, thenetwork of permanent sites is ex-panding. The sites are usually runby research groups at universitiesas a part of their ecophysiologicalstudies. Most of the multiyearsites are part of a global networkFLUXNET (http://www-eosdis.ornl.gov/FLUXNET/). Thereare also regional networks suchas CARBOEURO in Europe(http://www.bgc-jena. mpg.de/public/carboeur/) and AMERI-FLUX in America.

The main task of these sta-tions will be to act as referencesites to support the global en-deavor to reach a better under-standing of CO2 fluxes and an-

nual net balances. Remote sens-ing from space will be a centraltool in the verification of the Ky-oto Protocol. However, remotesensing measurements are entire-ly indirect and they have to besupported by extensive model-ing activities and ground-basedreference measurements if weaim to reach reliable net carbonbalance estimates. �

References:

1. IPCC, 2001: Climate Change 2001;The Scientific Basis, Cambridge Uni-versity Press, Cambridge, 881 pp.

Figure 3. Annual cycle of CO2 fluxes between the agriculturalfield at Jokioinen and the atmosphere in 2001. The half-hourlyflux values in winter and spring show flux upward (positivenumbers) when the peat is gradually decomposing. Barley wassown at the end of May and negative fluxes during the day(CO2 uptake) appear in June reaching their maximum in mid-July. In August, the crop ripens and the CO2 uptake graduallyceases. Harvest took place in September. Positive fluxes arehighest during nights in summer when heterotrophic effluxfrom soil and autotrophic maintenance respiration from plantshave their seasonal maximum. A typical feature of themicrometeorological observations is that the time series are notcomplete because of technical problems and an absence ofturbulence during calm periods. These gaps have to be filledbefore long-term averages are calculated, which is one source ofuncertainty. Outlayers typically result from non-ideal turbulentconditions. After gap filling the data, we can calculate theannual balances in 2001. This agricultural field on organicsoil lost 200 g C m-2 to the atmosphere and 160 g C m-2 wastransported away in harvest as grains, resulting in a totalyearly carbon loss of 360 g C m-2. We can estimate that duringthe growing season, carbon uptake by plants and respirationfrom soil were both about 550 g C m-2.

38 160/2002

T he Vaisala GM70 Hand-held Carbon DioxideMeter is a versatile meter

for measuring carbon dioxidegas concentration. The GM70Hand-Held Carbon DioxideMeter GM70 can be used in vari-ous spot-checking applicationsincluding laboratories, green-houses and mushroom farms.The GM70 can also be used inHVAC applications. In addition,the meter can be used as a cali-bration check instrument forVaisala’s GM20 and GM220 Se-ries fixed carbon dioxide instru-ments. The GM70 is small andlightweight, yet rugged, andtherefore is an ideal choice foreven the most demanding of ap-plications.

The GM70 has a versatileeasy-to-use menu based user in-terface, a clear graphical backlitLCD display and a data-loggerfunction, all of which make han-dling measurement data easy.The GM70 is configurable and

has a wide selection of measure-ment ranges, from low concen-trations up to 20% of CO2. Dueto its short warm-up time, theGM70 is ideal for spot-checkingmeasurements. The meter can al-so be used as a tool for checkingVaisala’s fixed GM20 andGM220 Series CO2 transmitters.In addition, the GM220 Seriestransmitters can be adjusted us-ing the GM70. Optional, ready-to-use Windows® software pro-vides an easy way to handlemeasurement data in a PC envir-onment. A built-in power savingfeature extends battery opera-tion time during data-logging,making it possible to collectCO2 data in locations withoutmains power.

The GM70 Meter uses thesame interchangeable probes asVaisala’s GM220 Series industri-al transmitters. By plugging dif-ferent probes into the GMH70Handle the user can easilychange the measurement range

from low concentrations to highconcentrations. This featuremakes the GM70 extremely suit-able for various CO2 measure-ment applications. �

Christer HelenelundProduct Line ManagerSensor Systems DivisionVaisala HelsinkiFinland

GM70 Hand-Held Carbon Dioxide Meter

Versatile Carbon Dioxide Meter for Professional Use

The Vaisala GM70 Hand-Held Carbon Dioxide Metermeasures carbon dioxide accurately and is available forseveral measurement ranges between 0...2000 ppm and0...20% CO2. The GM70 can be used in various spot-check-ing applications, including laboratories, greenhouses andmushroom farms, as well as HVAC applications. The GM70incorporates Vaisala's advanced CARBOCAP® Sensor,which enables reliable and stable measurement.

The GM70 is small andlightweight, yet rugged. It is an idealchoice for even the most demandingof applications.

160/2002 39

M easurement instru-ments must be cali-brated regularly to

ensure accuracy, since the physi-cal and electrical properties ofmaterials do not remain con-stant. Calibration means com-paring the reading of an instru-ment to a valid reference value.If the reading is not in line withthe reference value the instru-ment needs to be adjusted. Inadjustment, the reading of theinstrument is changed to corre-spond to the reference value.The calibration interval depends

on the instrument, the requiredaccuracy and the environmentwhere measurement takes place.

Effortless but efficientcalibration The calibration reminder pro-gram allows customers who useVaisala relative humidity, dew-point, material moisture, baro-metric pressure, carbon dioxideand ammonia measurement in-struments to easily have their in-struments calibrated. After join-ing the program they get notifi-cation to remind them in ad-

vance of the approaching timefor calibration.

There are many ways to jointhe calibration reminder pro-gram. All new instrumentsshipped from Vaisala include aregistration card where the usercan fill in product details andtheir contact information andreturn it to Vaisala. Customerscan also register on the Vaisalawebsite. Confirmation will besent to those who register andthen, when it’s almost time forthe recommended calibration,they will receive a reminder of

the need to calibrate the instru-ment along with instructions onhow to proceed. The instru-ments are sent to a Vaisala serv-ice center for calibration. To ver-ify the results, customers receivetwo calibration certificates: onethat is produced before the ad-justment and one after. This al-lows for the monitoring of theinstrument’s performance. Cali-brated products will also bemarked with a sticker indicatingthe date of calibration and rec-ommended date for the next cal-ibration.

A service to meet customers' needsTwo levels of calibration serviceare available to cater for differ-ent customer needs: standardservice calibrations and accredit-ed calibrations from an accredit-ed laboratory. Janne Kivilaaksoof Vaisala, Sensor Systems Divi-sion, who is responsible for theservice product line, says that inessence the calibration reminderprogram is about making cus-tomers’ lives easier. They nolonger need to worry about re-membering calibration and in-stead can concentrate on theircore operations. Using theVaisala calibration service meansthey don't need to invest in theequipment or staff needed forcalibration. The calibration re-minder program offers an easy-to-use calibration service withstandard pricing where costs arealready known. Traceability tointernational standards is alsoeasily available using the service.We are also offering optimizedservice contracts, including cali-bration and maintenance, tomeet the needs of customerswho use a large number ofVaisala products. �

Calibration reminder program helps to

Maintain Lifetime Measurement Accuracy Besides providing high-performance products, Vaisala aims at sup-porting the lifetime accuracy of the instruments by making regularcalibrations easy and affordable. The calibration reminder and serviceprogram offers both standard and accredited calibrations, enablingcustomers to get the best possible performance out of their products.

The calibration reminder programoffers an easy-to-use calibrationservice with standard pricing.

Europe

VAISALA Oyj P.O. Box 26, FIN-00421 HelsinkiFINLAND Telephone: +358 9 894 91Telefax: +358 9 8949 2227

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Vaisala GmbHBonn OfficeAdenauerallee 46 aD-53110 BonnGERMANYTelephone: +49 228 912 5110Telefax: +49 228 912 5111

Vaisala GmbHBremerhaven OfficeBuchtstrasse 4527570 BremerhavenGERMANYTelephone: +49 471 170 1655 Telefax: +49 471 170 1755

Vaisala GmbHStuttgart OfficePestalozzi Str. 8D-70563 Stuttgart GERMANYTelephone: +49 711 734 057Telefax: +49 711 735 6340

Vaisala LtdBirmingham OperationsVaisala House349 Bristol RoadBirmingham B5 7SWUNITED KINGDOMTelephone: +44 121 683 1200Telefax: +44 121 683 1299

Vaisala LtdNewmarket OfficeUnit 9, Swan LaneExningNewmarketSuffolk CB8 7FNUNITED KINGDOMTelephone: +44 1638 576 200Telefax: +44 1638 576 240

Vaisala SA2, rue Stéphenson (escalier 2bis)F-78181 Saint-Quentin-en-YvelinesCedexFRANCETelephone: +33 1 3057 2728Telefax: +33 1 3096 0858

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North America

Vaisala Inc. 100 Commerce WayWoburn, MA 01801-1068USATelephone: +1 781 933 4500Telefax: +1 781 933 8029

Vaisala Inc. Columbus Operations7450 Industrial ParkwayPlain City, Ohio 43064-9005USA Telephone: +1 614 873 6880Telefax: +1 614 873 6890

Vaisala Inc. Boulder Operations8401 Base Line RoadBoulder, CO 80303-4715USA Telephone: +1 303 499 1701Telefax: +1 303 499 1767

Vaisala Inc.5600 Airport Boulevard Boulder, CO 80301-2340USATelephone: +1 303 443 2378 Fax: +1 303 443 1628

Vaisala Inc. Sunnyvale Operations1288 Reamwood Ave. Sunnyvale, CA 94089-2233USATelephone: +1 408 734 9640Telefax: +1 408 734 0655

Vaisala-GAI Inc.2705 East Medina RoadTucson, Arizona 85706, USATelephone: +1 520 806 7300Telefax: +1 520 741 2848U.S. Toll Free 1 800 283 4557

Vaisala Inc. Regional Office CanadaP.O. Box 2241, Station "B"LondonOntario N6A 4E3CANADATelephone: +1 519 679-9563Telefax: +1 519 679-9992

Asia and Pacific

Vaisala KK42 Kagurazaka 6-ChomeShinjuku-Ku Tokyo 162-0825JAPANTelephone: +81 3 3266 9611Telefax: +81 3 3266 9610

Vaisala KKOsaka BranchThick Land Building 12032-3-5 Nanba Chuo-ku, Osaka 542-0076, JAPANTelephone: +81 6 62123954Telefax: +81 6 62123955

Vaisala Pty Ltd3 Guest StreetHawthorn, VIC 3122AUSTRALIATelephone: +61 3 9818 4200Telefax: +61 3 9818 4522ABN 58 006 500 616

Vaisala Beijing Representative OfficeWangfujing Grand HotelRoom 518 - 52057, Wangfujing StreetBeijing 100006PEOPLE'S REPUBLIC OF CHINATelephone: +86 10 6522 4041+86 10 6522 4050+86 10 6522 4151Telefax: +86 10 6522 4051

Vaisala Regional Office MalaysiaLevel 36, Menara Citibank165 Jalan Ampang50450 Kuala LumpurMALAYSIATelephone: +60 3 2169 7776Telefax: +60 3 2169 7775 C

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