40234Ymi_Vaisala154 8.9.2000 20:22 Sivu 1

154/2000154/2000 Humidity, pressure and carbon dioxide measurement

The New Vaisala DMT242 Dewpoint Transmitter For Low Dewpoint OEM Measurements

Vaisala’s ppm Calculation of Moisture in Transformer Oil Using the HMP228 Transmitter

PTB210 Series Digital Barometers For Measuring in Extreme Environments

Outdoor Plant Growth Experiments

In the Elevated CO2 Atmospheres in Japan 40234Ymi_Vaisala154 8.9.2000 20:23 Sivu 2

Contents

Presidents’ Column 3

Dewpoint Vaisala has been awarded a contract by the Meteorological Low Dewpoint OEM Measurements 4 Service of Canada (MSC). Humidity Expressed as Dewpoint Temperature 6 Vaisala supplies electronic station barometers to replace U.S. National Weather Service Awards the mercury barometers Dewpoint Contract to Vaisala 8 currently used for weather observation throughout Humidity Canada. The PTB220 digital barometer is easy to maintain, Industrial Humidity Measurements 8 and can be exposed to Reliable Performance in Humid Air extremes of temperature Conditioning Applications 10 between -20 and +60 °C. Improved Maintenance for Transformers 11 Using Automated Long-Term Monitoring of Relative Humidity 13 Carbon dioxide is used to Vaisala Sensor in Radio Telemetry carbonate the beverages in the Instrumentation Systems 16 production of soft drinks. In the United States, OSHA Pressure requires that the carbon Reliable Barometric Pressure Measurement dioxide level remains at, or in All Wind Conditions 18 below, 5,000 ppm in the atmosphere of any filler room PMI20 Digital Barometer Display area. Big Springs Inc. is a - Perfect Partner for Vaisala’s Barometers 20 major soft drink manufacturer Measuring for Extreme Environments and a large local Coca-Cola franchise distributor located in Using PTB210 Barometers 21 Huntsville, Alabama. The Meteorological Service of Canada: company has successfully used Digital Barometers at Airport Locations 22 Vaisala CARBOCAP transmitters for more than a Vaisala’s Barometers Used to Track year in their bottling plant. Leakage from Nuclear Enclosures 24

Carbon Dioxide Dissolved CO Measurements 24 The Vaisala After Sales Service 2 for humidity, barometric GMM220 Series Carbon Dioxide pressure and carbon dioxide Measurement Module 26 products in Europe has Measuring Carbon Dioxide in the increased its range of services. In addition to service and Soft Drinks Industry 27 repair facilities, our European GMT220 Series Industrial Carbon Service Center offers factory Dioxide Transmitter 28 calibration facilities to customers in Europe, Israel Outdoor Plant Growth Experiments and South Africa. The first in Elevated CO2 Atmospheres 29 parameter in this factory calibration service is relative Others humidity. Services and Calibration at Standard Prices 32 Meeting the Demands of the Customer 34 Cover photo: Jussarö Lighthouse, Finland Vaisala in Brief Finnish Maritime Administration. – We develop, manufacture – We focus on market seg- Editor-in-Chief: Editors: and market products and ments where we can be Marit Finne Bellcrest Language services for environmental world leaders, the pre- Publisher: Services Oy and industrial measure- ferred supplier. We pay Vaisala Oyj Printed in Finland by ments. high attention on customer P.O. Box 26 Sävypaino, Finland satisfaction. Our main qual- FIN-00421 Helsinki – Purpose of those mea- ity discipline is Product FINLAND surements is to provide Leadership. Competitive Phone (int.): basis for better quality of advantage is enhanced by +358 9 894 91 life, cost savings, protection economies of scale and of environment, improved scope. Telefax: safety and performance. +358 9 894 9227 Internet: www.vaisala.com Design and Artwork: 2 154/2000 Non-Stop Studiot Oy ISSN 1238-2388 40234Ymi_Vaisala154 11.9.2000 08:17 Sivu 3

President’s Column

Environmental Measurements for a Variety of Needs

aisala’s Sensor Sys- the life of a transformer. Detect- In order to maintain high qual- tems Division (SSD) ing moisture in oil is an essential ity processes that can even be V specializes in a few part of a comprehensive trans- certified, measuring instru- selected parameters former maintenance program. ments must be well maintained. of environmental measure- Many Meteorological Services Instruments need to be calibrat- ment. These are many forms of are entering a new era of air hu- ed at regular intervals in order humidity, barometric pressure midity measurement and the to guarantee that operations are and gas measurements, selec- U.S. National Weather Service is of high quality. We have devel- tively. We manufacture this one of the pioneers in this area. oped our own operations to be type of equipment for demand- Delays in measuring data, even able to better face this chal- ing users, for use in various ap- in situations where the weather lenge. plications to improve produc- changes quickly, can be eliminat- We are already developing tivity, quality and safety. ed thanks to the new method. technology for working with Our aim has been to constant- Through Vaisala’s BARO- new gases and developing associ- ly expand our product range to CAP® technology, barometric ated technology. Through these, meet varying new requirements. pressure measurement has rein- in the future, we will be able to Humidity measurement solu- forced its firm standing among offer even more measurements tions already include hundreds professional meteorologists. for improving productivity and of applications. However, the Producing and using carbon safety. same product is not suited to dioxide is fundamental for living every environment. Recently, we organisms. To optimize living have launched new products es- conditions for flora and fauna, pecially for measuring low hu- the correct concentration of car- midities, where the unit of meas- bon dioxide is essential. Levels of urement is the dewpoint. Besides carbon dioxide that are too high traditional HUMICAP® tech- can be hazardous, even danger- nology, we have developed the ous, so reliable measurement new DRYCAP® technology. and stability are important. In Moisture measurement in trans- this respect, Vaisala’s CARBO- former oil is also a new area of CAP® technology has been application. The presence of given the approval of the experts. moisture in liquid transformer Measuring instruments are a Pekka Ketonen insulation plays a critical role in part of our customers’ processes. President and CEO

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New DMT242 dewpoint transmitter for Low Dewpoint OEM Measurements

Vaisala has launched a transmitter for low dew- he latest addition to urement instrument that uses point OEM measurements with unparalleled our dewpoint prod- the kind of technology that long term stability! One of the main assets of T uct range is the would not require the end user ® DMT242 transmit- of the equipment to carry out DRYCAP technology is its excellent long term ter, which is based on much maintenance. Until now, stability, and the new DMT242 incorporates DRYCAP® low dewpoint, thin the need for high maintenance DRYCAP® polymer technology. film polymer technology. The has mainly been due to the new product is geared towards long-term drift, which has OEM manufacturers, who are forced the end user to carry out looking for a dewpoint trans- maintenance on their drying Jan Grönblad, M.Sc. (Eng.) mitter with low maintenance systems, e.g. on a compressed Product Manager needs, that is simple to install air dryer, as often as twice a Sensor Systems Division and use, but who also expect the year, in order for the drying sys- Vaisala Helsinki high reliability that is synony- tem to maintain its high perfor- Finland mous with the Vaisala brand. mance specifications. The Vaisala DMT242 dew- In 1997, Vaisala launched a point transmitter is an ideal patented technology for low choice for industrial applica- dewpoint measurements, incor- tions where it is necessary to porating the DRYCAP® sensor control the dryer performance in a DMP248 dewpoint trans- in low dewpoints. The trans- mitter that had a wide range of mitter provides wide dewpoint features. The main advantage temperature measurements of the DRYCAP® technology is ranging from –60 °C to +60 its excellent long term stability. °C, with an accuracy of ±2 °C. The improvement is largely due to the fact that a polymer- DMT242 – a product based sensing material was cho- with excellent long sen, rather than the sensing term stability technology that was already on the market. The Vaisala DMT242 dewpoint The DMT242 dewpoint trans- Polymer itself is a very stable transmitter is an ideal choice for mitter was developed with the material. A polymer sensor also industrial applications where it is needs of OEM type manufac- makes it possible for so-called necessary to control the dryer turers firmly in mind, because autocalibration to be per- performance in low dewpoints. they require a very basic meas- formed at certain intervals. This

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basically means that, during au- rates. The number of transmit- to rescale the analog output tocalibration, the polymer is ter options has been minimized with a standard PC. warmed so that it is slightly to allow for a very cost effective The DMT242 product fulfils above the surrounding temper- product, but which nevertheless low dewpoint measurement re- ature and, based on widely re- provides high measurement per- quirements in a wide variety of cognized physical changes, the formance. It is, however, easy OEM applications including dry end (i.e. offset) error in the and quick to install or replace compressed air, electronics, sensor response can be detected the DMT242 as it comes with plastics, metal, as well as in and eliminated. The capacity to the IP65/NEMA4 protected other industries. The experi- correct the offset error makes connector with screw terminals, ence gathered in a wide variety the polymer technology a high- as standard. For maintenance of applications in these indu- ly competitive technology for purposes, the unit also comes stries has shown the DRYCAP® low dewpoint measurements. The DMT242 dewpoint transmitter equipped the RS232 serial line, measurement technology to be incorporates the DRYCAP polymer making it possible for the user a superior in performance. ■ Dew resistance sensor. Another advantage is that poly- out, and no recalibration is mer technology is dew resis- needed. Full recovery means tant, should condensation be a not only that process down- possibility. Also, exposing a time that would be caused by sensor to normal ambient air maintenance is avoided, but for longer periods – even to also means direct savings in re- laboratory air – can be as fatal calibration and sensor replace- as a high humidity exposure for ment costs. Also, storage in some low dewpoint sensors. normal ambient air does not When installed inside in a dry- pose a problem because poly- ing system, high humidity lev- mer technology is one of the els are not usually a problem, most common technologies but they can still be a potential used for controlling indoor air threat during startup of the dry- humidity in offices, clean- ing system or during a drying rooms and production areas. system malfunction. The new DMT242 dewpoint If dew forms on the sensor transmitter has all of these assets Electrical connection of the DMT242 element, the DRYCAP® sensor thanks to the DRYCAP® poly- dewpoint transmitter is fast and easy fully recovers after it has dried mer technology that it incorpo- thanks to its connector.

Dryers and other OEM applications are the typical environment for DMT242 dewpoint transmitter. PHOTO COURTESY OF ATLAS COPCO. COURTESY OFPHOTO ATLAS

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Dewpoint is one of the many widely used parameters alongside relative humidity, ab- solute humidity, mix- ing ratio and partial water vapor pressure, that show the water vapor content in air or in other gases. The fol- lowing article explains the behavior of dew- point temperature (Td) and clarifies the termi- nology used to de- scribe it. Humidity Expressed as Dewpoint Temperature

ewpoint is defined as humidity (Figure 1). This prin- pears, and this results in an in- the temperature (°C ciple is used by some instru- applicable measurement. D or °F) to which air ments with capacitive sensors must be cooled for to measure dewpoint in a gas. Pressure changes water condensation to begin, A practical example of dew- i.e. for air to become saturated point is a glass of cold liquid Dewpoint is a pressure sensitive with water vapor. At dewpoint on a warm summer day. If the parameter, because variation in temperature, the amount of temperature of the drink is total pressure changes the par- water vapor present in the air is equal to, or below, the dew- tial water vapor pressure ac- equal to the maximum amount point of ambient air, the air cording to Dalton’s law: of vapor air can hold at that close to the glass surface cools specific temperature. down and becomes saturated Ptotal=Pw+Pdry air, The capacity of air to hold with water vapor that condens- water vapor is strongly depen- es on the surface, forming Where the total pressure is dant on temperature; warmer water droplets called ‘dew’. the sum of the partial pressures air can hold more vapor. This of the gas components present: phenomenon is usually illus- Temperature changes water vapor and dry air. trated with a curve with water Pressurized air provides a vapor saturation pressure as a According to its definition, practical example of what hap- function of temperature (Figure dewpoint is related to the pens if the air at +20 °C is com- 1). At dewpoint, the partial amount of water vapor, i.e. the pressed from atmospheric pres- water vapor pressure (Pw) in air partial water vapor pressure, sure to a pressure of six bar equals the water vapor satura- and is thus not dependant on (6000 hPa). We assume that the tion pressure (Pws). In this state, temperature. This means that dewpoint of ambient air is +6°C condensation and evaporation the dewpoint of a process with (Pw=9.35 hPa), and that the are in equilibrium and take high temperature is equal to temperature remains constant place at the same rate. the dewpoint measured from a during compression. As the air Since the correlation be- cooled sample of that process is compressed, the partial water Senja Paasimaa, M.Sc. (Eng.) tween water vapor saturation gas. However, if the gas sample vapor pressure (Pw) is increased Product Engineer pressure and temperature is is taken from the process to an sixfold to Pw=56.1 hPa. The cal- Sensor Systems Division known, the dewpoint can be environment where the tem- culated dewpoint would then be Vaisala Helsinki calculated from the measured perature is below the process +34.9 °C. However, dewpoint is Finland temperature and the relative dewpoint, a dew formation ap- always less than, or equal to am-

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used. The water vapor satura- 1200 tion pressure over ice is slightly lower than that over super- 1000 cooled water, i.e. ice gives off water vapor at lower rate (Figure 800 2). This must be taken into ac- count when using a measure- 600 at 60 °C Pws (hPa) ° ment technology in which the RH = 100% T = 80 C 400 P = 198 hPa RH = 42 % dew/frostpoint is a calculated ws P = 198 hPa parameter derived from relative Td = 60 °C w humidity or from the partial 200 water vapor pressure. As frost forms, it always occurs at a frost- 0 point that is different to dew- 0 102030405060708090100 point. Temperature (°C) As in the case of dewpoint, the frostpoint can also be seen Figure 1. Water vapor saturation pressure Pws as a function of temperature. in practice by taking a package Dewpoint of a gas at 80 °C and 42 % RH. from a freezer to room temper- ature. In this case, the air close 800 to the package cools down and becomes saturated with water vapor, which forms frost in- 600 stead of dew, on the package surface. 400 Why dewpoint? T = 0 °C Pws (Pa) RH = 20 % Dewpoint is a commonly used 200 parameter to represent the Td = -20 °C amount of water vapor in dry Tf = -18 °C applications such as pressur- 0 ized air systems. In dry condi- tions, changes in dewpoint val- -40 -20 -20 -10 0 ues are much larger compared Temperature (°C) to very small changes in rela- tive humidity values, which Figure 2. Water vapor saturation pressure Pws over water (—) and ice (- - -). bient air temperature. Thus, gives dewpoint measurements Dewpoint and frostpoint of a gas at 0 °C and 20 % RH. dew formation would take place an advantage in process con- until the partial water vapor trol. For example, at room tem- pressure is equal to the water perature, change in dewpoint This fundamental measuring Capacitive instruments saturation pressure at that tem- from –40 °C to –45 °C corre- technology is widely used as a perature (23.4 hPa) i.e., dew- sponds to relative humidity calibration reference in labora- Metal oxide sensors have been point is the same as the actual from 0.81 % RH to 0.48 % RH. tories because it gives very ac- widely used in industrial pro- air temperature, +20 °C. In applications where gas curate results over a wide range cesses for the past three decades. Conversely, if a sample was pipes are installed outdoors, of dewpoints. However, it can- They have proved to be suit- taken from pressurized air dewpoint is a useful parameter, not tolerate dusty environ- able for on-line measurement (6000 hPa) with dewpoint of because of wide variations in ments due to its sensitive op- and tolerate dusty environ- +3 °C to an atmospheric pres- ambient air temperature. The tics, and thus it is less com- ments better than chilled mir- sure of 1000 hPa, the dewpoint gas should be dried to such a monly used for process control rors. However, their poor long- would then be –20 °C. high degree that dew formation purposes. term stability means there is a When using a measurement is avoided regardless of the With a chilled mirror instru- need for frequent calibration, technology that cannot be in- temperature in the pipe, which ment, dew, rather than frost, which increases maintenance stalled in the pressurized means that dewpoint of the gas may also occur below freezing costs. Moreover, relatively high process, but a sampling system should be below the gas tem- point, even down to –20 °C. humidity may destroy the sen- is needed, the dewpoint in the perature in all conditions. Before frost, dew forms due to a sor e.g. if there is a drier mal- process, which is sometimes lack of impurities on a very function in the process, or even called pressure dewpoint, has Chilled mirrors clean surface initializing the during a system ramp up. to be calculated from the meas- crystallization. This must be Recently, polymer sensors ured value. However, new tech- One traditional method to meas- noted when comparing the read- have also been introduced to nologies have enabled meas- ure dewpoint is a chilled mirror ings of instruments using differ- dewpoint applications. Their urements straight from the instrument where the mirror is ent technologies such as capaci- advantages over the metal oxide pressurized processes, thus ob- cooled down until dew forms tive instruments, in which rela- sensors are that they tolerate viating the troublesome loga- on it. The dew formation causes tive humidity or the partial condensing water and have far rithmic calculations. light to be scattered on the sur- water vapor pressure are the vari- better long-term stability. The face, and this is detected with ables measured initially. The dif- accuracy of polymer sensors has Dewpoint or frostpoint optics. At the start of dew for- ferences in the readings of the recently been improved to such mation, the temperature of the instruments may be due to the a degree that they are reliable in If dewpoint is below zero (0 °C), mirror denoting dewpoint is fact that one actually shows dew- applications with low dewpoints, ■ the term frostpoint (Tf) is often read by a thermometer. point and the other, frostpoint. even down to –70 °C.

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Jan Grönblad, M.Sc. (Eng.) Product Manager Sensor Systems Division Vaisala Helsinki Finland

Many industrial environments set specific re- quirements for humidity instrumentation. The latest addition to the Vaisala range of in- dustrial humidity transmitters is a small stain- less steel sensorhead. It offers many new ad- vantageous features for applications where a Vaisala’s HMP243 dewpoint transmitter has specially designed for reliable and fast dewpoint measurement. robust sensorhead is required. The new trans- mitter models HMP237 and HMP247, incor- porating the new sensorhead structure, are al- ready available. U.S. National Focus on reliable readings Measuring humidity in demand- ing environments is not an easy Weather Service task. First, the measurement tech- nology used must be applicable Awards Dewpoint for the particular environmen- tal conditions in a specific ap- plication. One technology may Contract to Vaisala offer certain features for good measurement, but maintenance needs can be very high. Not all he U.S. Department of Commerce/NOAA, the instruments offering the National Weather Service (NWS) has awarded a same technology have the abili- T contract to Vaisala to develop and manufacture a ty to provide reliable readings state-of-the-art meteorological dewpoint sensor. in high temperatures, very high This sensor will replace several hundred aging and high main- levels of humidity approaching tenance units originally installed in Automated Surface condensation, or in certain en- Observing Systems (ASOS) at major airports throughout the vironments where chemicals United States. are present in the measured gas. NWS selected Vaisala after more than three years of ex- Second, the mechanics of the tensive testing of standard off-the-shelf dewpoint instru- instrument, and especially ments manufactured by Vaisala and its competitors. Vaisala’s those of the sensorhead are ex- HMP243 dewpoint transmitter was the unit tested by NWS, tremely important in demand- and the core technology of this transmitter will be incorpo- ing applications. rated into the sensors to be delivered to NWS. Vaisala’s HMP243 humidity/dewpoint transmitter pro- HMP237/247 vides fast and reliable dewpoint measurement even under ex- sensorhead technology treme conditions where a combination of high humidity and rapidly changing temperature might present unwanted dew In industrial applications, the formation on the sensor head. Because the temperature of transmitter housing must be the HMP243’s sensor head is constantly higher than ambi- IP65/NEMA4 protected, to ent, the possibility of dew formation is eliminated. The result allow for plants to be spray-wa- is uninterrupted, accurate and stable dewpoint measurement tered, for example. The hous- that is unmatched by other technologies. ■ ing material can be plastic or,

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HMP247 humidity transmitter uses the recently developed small-sized metal sensorhead for the most demanding applications.

Two threaded holes on the back of the sensorhead mean that the sensorhead can be installed in process conditions.

Managing demanding customer needs in Industrial Humidity Measurements

in demanding environments, which ensures reliable measure- means that it can be installed in The new installation options, metal. The sensorhead me- ments even in conditions where different ways. On the back of a design adapted to tough envi- chanics are a little more com- dew may form. This warming the sensorhead, two threaded ronments and high perfor- plicated, because the most es- method is patented by Vaisala. holes allow it to be fixed to a mance humidity sensing with sential part of the entire instru- Both of these sensorhead types threaded pole inside the pro- HUMICAP sensors make the ment is located in the sensor- can be used in very high tem- cess and thus to be usefully lo- HMP237 and HMP247 a very head. If the mechanics and the peratures of up to +180 °C cated right in the heart of a par- attractive choice as industrial sensor protection are not well (+356 °F). ticular place, if needed. humidity transmitters. ■ adapted to the particular envir- onment that they are in, the Leak tight installation entire measurement can be im- paired or the lifetime of the in- The material of these new sen- A leak tight installation is possible for the sealing around the sensorhead cable, strument can be reduced. sorheads is stainless steel, a mate- but naturally also for sealing the connection around the metal body of the The new small-sized, ex- rial suitable for a wide variety of sensorhead. tremely robust sensorhead was applications. The robust nature developed for the most de- of this sensorhead is not its only Process wall Process wall manding customer needs. The asset, because it is also leak tight Installation b) Installation a) sensorhead was first used in the up to 1 Mpa (10 Bar/145 Psi). The HMP230 series, and the trans- leak tight installation can be fit- mitter model was then called ted around the sensorhead, but the HMP237. Later, the same also on the sealing around the Maximum pressure 1 MPa structure was developed and sensorhead cable, making the in- also added to HMP240 series stallation very flexible in applica- and called the HMP247. tions where the pressure of the The main difference between measurement space differs from these two series, the HMP230 the ambient pressure. and HMP240, is that the In addition to the traditional HMP240 series sensorheads in- duct installation kit, the design corporate a warming system, of the new sensorhead also

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The HMW61 & HMW71 Humidity Transmitters Reliable Performance in Humid Air Conditioning Applications

In response to con- he HMD/W 60/70 cerns about efficient series, Vaisala’s range T of humidity and tem- air conditioning and perature transmitters economical solutions, for air conditioning applica- reliable humidity meas- tions, has been enlarged with new additions – the wall mount- urement instruments ed HMW61 & the HMW71 play a key role in transmitters. They are designed monitoring humidity for dusty and humid air-condi- tioning applications where accu- levels in dusty and rate and stable measurement moist environments. and control of relative humidity For example, ventila- and temperature are required. Wall-mounted HMW61 & HMW71 transmitters are designed for dusty and tion in environments humid air-conditioning applications, such as indoor swimming pools. Protection against dust such as greenhouses and water spray and indoor swimming ity measurement only (U mod- with a field calibration option. pools is a challenge The transmitters are dust and els) or with both humidity and Any adjustment required can for humidity control water spray resistant and meet temperature measurement (Y be made within seconds with- IP65 (NEMA 4) requirements. models). The HMW61 has cur- out de-installing the transmitter instruments. Vaisala’s All the materials used have been rent output (loop-powered) or interrupting the measure- new wall-mounted chosen for their excellent corro- and the HMW71 has voltage ment. This feature makes main- HMW61 & HMW71 sion resistance. This makes the output, where different voltage tenance easy, rapid and cost ef- transmitters especially suitable scales can be selected with fective. Alternatively, the transmitters are specifi- for humid and wet environ- jumpers. HMK15 humidity calibrator cally designed for such ments. Applications include can be used for calibrating in demanding air condi- greenhouses, livestock farms, in- Fast, on-site calibration various levels of humidity. tioning applications. door swimming pools, various The transmitters incorporate types of storage area and any The output of the HMW61/71 the HUMICAP®180 sensor, other areas, which are regularly transmitters can be easily which has excellent stability cleaned with sprayed water. checked at the place of installa- even in high levels of humidity. The HMW61/71 transmitters tion while still operating, using The sensor is also insensitive to are available either with humid- the HMI41 humidity indicator dust and most chemicals. ■

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Vaisala’s ppm calculation for moisture in transformer oil Improved Maintenance for Transformers

The presence of mois- Irma Ylikangas, ture in liquid trans- M.Sc. (Chem. Eng.) Product Manager former insulation Sensors Systems Division plays a critical role in Vaisala Helsinki the life of a trans- Finland former. Determining the amount of mois- ture in oil is an essen- tial part of any com- xcessive moisture prehensive transformer content in oil makes maintenance program. E the insulation mate- The Vaisala micro- rials age more quick- ly and reduces their dielectric processor-based strength. In general, the me- HMP228 transmitter chanical life of insulation is re- enables continuous duced by half every time that moisture and tempera- the water content is doubled. ture measurements in The rate of thermal deteriora- Vaisala’s microprocessor-based HMP228 transmitter enables tion of the paper is proportion- continuous moisture and temperature measurements in transformer oil. transformer oil. al to its water content. continues…

The presence of moisture in liquid transformer insulation plays a critical role in the life of a transformer.

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Water in mineral oil trans- formers creates the risk of bub- ble formation, when desorption of water from the cellulose in- creases the local concentration of gases in the oil. Accurate moisture measurements can also provide warning of leaks in the oil systems, as the water is absorbed from the surrounding air.

Reliable sensors technology

The HMP228 transmitter in- corporates the latest version of the Vaisala capacitive thin film polymer sensor. It operates by measuring changes in its capacitance as the thin film absorbs water molecules from the oil.

Principle measured and calculated values

Water activity is the principle measured value. Water activity immediately indicates whether the oil is too moist. The mea- surement remains proportional Moisture levels in oil are affected by temperature cycling of a transformer. The extent to the saturation level of water to which oil is water soluble is dependant on temperature: the more the temperature in each individual oil, indepen- rises, the more soluble it is. dent of the aging or tempera- ture of the oil. Traditionally, the trans- former field has used ppm val- ues. Thus, Vaisala offers the Calculation Model with Average Coefficients for miner- al transformer oils and the Calculation Model with Oil Specific Coefficients for miner- al and silicon based oils. All sili- 20 con based transformer oils 18 need to use the Calculation 16 Model with the Oil Specific Calculation Model. 14 12 HMP228 identifies servicing requirements 10 8 In the electrical industry, mois- 6 ture measurements indicate the condition of transformer oil 4

and identifies servicing require- Maximum error of the reading (%) 2 ments. This HMP228 Moisture and Temperature Transmitter, 0 improves the maintenance of 0102030405060708090100 transformers, and enables reli- Temperature (deg C) able and continuous measure- ment of their transformer oil The maximum number of errors caused by deviation of mineral oils using moisture and temperature. ■ Average Calculation Model.

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Terry Willems Senior Materials Scientist

and

Howard Kanare Principal Scientist Construction Technology Laboratories Inc. Skokie, IL, USA Figure 1. CTL staff have been using Vaisala’s HMI41 hand-held moisture meters and HMP44 measurement probes for relative humidity measurement in concrete slabs.

Investigating floor moisture problems Using Automated Long-Term Monitoring of Relative Humidity

In recent years, CTL has focused on the prob- ince 1993, Construc- tance from our home office, the lems caused by excessive moisture in floors. To tion Technology La- hand-held meter requires sepa- S boratories, Inc. (CTL) rate trips to the jobsite. We investigate moisture problems affecting floor staff have become in- need to drill holes and place coverings in buildings, CTL staff have been creasingly involved in troub- probes, then a return trip to using Vaisala’s HMI41 hand-held moisture me- leshooting moisture problems take readings at least three days in concrete floors with mois- later after the probes have equi- ters and HMP44 measurement probes for rela- ture-sensitive floor coverings. librated in the concrete. To re- tive humidity measurement in concrete slabs. Resilient floorings such as vinyl duce travel costs and to collect sheet, vinyl composition tile, more detailed data, we decided linoleum, and vinyl-backed car- to begin using automated data pet are all susceptible to prob- logging instruments and to lems when excessive moisture leave probes in place for several and alkalies from concrete months. react with adhesive or cause Data logging of relative hu- plasticizer breakdown. midity levels in the concrete provides a method to obtain Professional solutions accurate readings and to track changes with time. Calibrated Since many of the projects we probes are installed into the evaluate are a considerable dis- drilled concrete holes. The

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The authors of the article: Howard Kanare (left) and Terry Willems.

probes are linked to a data log- sion. The probes were placed at By contrast, the elevated slab 1999 and began to maintain a ger that reads, averages, and depths of 1, 2, and 3 inches (25, had 70–75 % RH at the same steady internal RH after that records the relative humidity at 50, and 75 mm) and connected depth. Humidity below 85 % is date. By contrast, the elevated preset intervals up to many to an ACR SmartReader Plus generally considered acceptable slab continued to dry at a fairly months. seven channel data logger. This for floor coverings. Above this constant rate. (The steep rise in compact, self-contained logger level a host of problems can the curves seen from 2–6 Thorough studies of has a 10-year lithium battery occur, including mold and November is due to the probes vinyl-backed carpet tiles and can be unplugged from the mildew, adhesive degradation, reaching equilibrium with the data collection system and plasticizer breakdown, and di- surrounding concrete which Vinyl-backed carpet tiles had mailed to our laboratories for mensional changes of flooring takes 3–4 days after placement.) been installed in a medical fa- downloading data. Humidity such as curling and shrinkage. cility on two concrete sub- readings were averaged every These forms of distress cause Cost-effective approach strates: a slab-on-ground and eight seconds and recorded maintenance problems and can to monitoring an adjacent elevated light- once every hour for approxi- lead to trip-and-fall hazards. weight concrete slab cast on mately two months. A second result from the data Upon excavation of a portion of ribbed steel deck. Carpet tiles was knowledge that the elevat- the concrete floor, we deter- installed on the elevated light- Revealing RH results ed slab was drying while the mined that the granular layer di- weight concrete were well- slab-on-ground was actually be- rectly below the slab contained bonded and did not exhibit Two useful results came from coming wetter, even though 7 % moisture (by weight), suffi- distress. However, carpet tile the data collected over two the floor was nearly two years cient to replace the moisture was curling and debonding on months. First, the results (see old! The data indicated that the lost from drying the slab during the slab-on-ground. The slab- Figure 5) indicated that in the concrete slab-on-ground was construction, before flooring on-ground consisted of a 5- area of distressed carpet on the reaching equilibrium with the was installed. We calculated that inch (125-mm) thick, normal slab-on-ground, moisture levels wet sand below. the slab-on-ground would take weight concrete slab cast on 7- were very high, averaging about The Figure 5 shows the slab- many years to dry sufficiently inch (175-mm) sand layer on 97 % RH at two-inches (50 on-ground was gaining mois- for moisture-sensitive floor cov- top of an 8-mil (0.2-mm) plas- mm) below the top of the slab. ture until the end of November erings. Therefore, we recom- tic vapor retarder. The vapor re- tarder sheet should have kept moisture from entering the floor system from below, but WEST EAST 5 moisture was somehow getting 1A 1B 1C 2A 2B 2C to the underside of the carpet

through the concrete. Vaisala 3,5” HMP44 relative humidity 2”

LIGHT WEIGHT 5” NORMAL WEIGHT probes were selected to study CONCRETE METAL DECK the situation. CONCRETE VAPOR RETARDER 7” SAND LAYER CTL placed HMP44 probes (PLASTIC SHEET) in six locations, three in the slab-on-ground and three in Figure 2. CTL placed Vaisala’s the lightweight concrete slab HMP44 probes to six locations, three (see Figure 2). Six probes were (2A, 2B, 2C) in slab-on-ground and ‘match calibrated’ together to three (1A, 1B, 1C) in the lightweight SECTION provide the best possible preci- concrete slab. 2 NTS

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Figure 3. A typical problem of adhesive failure mended to the facility owner lesson about how to prevent caused by excessive moisture in concrete. Some that the existing flooring should this sort problem from occur- water-based adhesives are re-emulsifiable and can be replaced with less-moisture- ring by careful architectural de- become gummy losing adhesion between the concrete sensitive flooring. tailing in new construction. and the vinyl-backed flooring. Data logging wiring cannot be installed everywhere in a Important building due to the traffic pat- investigative tool terns, uses of the facility, and cost. In addition to logging The combination of accurate with several probes, we also relative humidity measurements placed probes in several remote and long-term monitoring is an locations throughout affected important tool for investigating areas of the building and read floor moisture problems. Now, those with the HMI44 hand- we can document drying histo- held meter. Results of the moni- ry, look for changes due to am- toring program indicated po- bient conditions, relative differ- tential problems existed in ences between different por- other parts of the building as tions of the building, and pre- well. After reviewing the data, dict slab drying times. the construction contractor The amount of data record- agreed to replace the carpet ed results in a high level of con- tiles with a more breathable fidence in our predictions. By floor covering and monitor the establishing moisture profiles building for future problems. within the slab, trends are easi- We presented the findings to ly seen. While monitoring of a meeting of architects and concrete relative humidity is construction contractors who just one part of our investiga- were able to see graphically tion, the advantages of data how moisture was moving into, logging has led us to new un- and out of, the floors they had derstanding of long term mois- built. They learned a valuable ture levels within concrete. ■

Figure 4. Carpet tile was curling and debonding on the slab-on-ground.

Relative Humidity in Carpeted Concrete Floor Slabs 50 CTL – Professional solutions for mois- 55 1-inch ture problems 60 Construction Technology Laboratories, Inc. (CTL) 65 perform research, testing and consulting on a wide 70 2-inch range of construction ma- suspended slab terials. With a 75-year on metal deck history, CTL is known 75 worldwide for its solu- 3-inch tions of construction or 80 performance problems. The company has its 85 main office and laborato- Relative Humidity, percent Humidity, Relative 1-inch ries in Skokie, Illinois, with 90 130 staff, including chemists, geologists, ce- 95 2,3-inch ramists, architects and slab-on-ground civil and structural engi- neers. 100 30-Oct 6-Nov 13-Nov 20-Nov 27-Nov 4-Dec 11-Dec 18-Dec 25-Dec 1-Jan

Figure 5. Results of data collected over two months, related to relative humidity is carpented concrete floor slabs.

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Vaisala Sensors in Radio Telemetry Instrumentation Systems

Hanwell Instruments specializes in radio telemetry systems for monitoring anwell Instruments and control in a wide range of environments, ranging from historic build- Ltd. was established H in 1990 and is based ings to industrial processes. Since 1998, the company has used Vaisala hu- at two sites in midity sensors for all relative humidity monitoring due to their stability Southern England. The compa- and rapid response characteristics. Vaisala’s carbon dioxide sensors are also ny specializes in radio teleme- try systems for monitoring and incorporated in a Hanwell transmitter unit for measuring carbon dioxide control in a wide range of envi- gas concentration. ronments. The applications range from historic buildings to industrial processes. Hanwell is using Vaisala humidity and car- bon dioxide sensors in their radio telemetry applications.

Radio telemetry and data logging systems

Accurate sensors are, of course, a vital component of any mea- surement system but the practi- calities of data collection and presentation are of equal im- portance. Where continuous monitoring is necessary, this task is traditionally performed by hard wiring sensors back to a central data collection point or by using stand-alone data logging equipment. Both ap- proaches can have their disad- vantages in specific applica- tions. Stand-alone data loggers re- quire regular human interven- tion and this inevitably leads to a variety of problems, especial- ly if logging is required at re- mote sites. Lost or corrupted data can be expensive and time consuming to rectify. Wired systems are better. However, on sites where cables can be easily damaged or regular changes need to be made, the connec- tion and re-routing of cables can be a problem. Indeed in many circumstances it may be impossible or very expensive to install cabling in the first place. Hanwell’s relative humidity and temperature Radiolog transmitters with the base station receiver and computer. Since Radio telemetry systems 1998, Hanwell has used Vaisala’s humidity sensors for all humidity monitoring due to their stability and rapid response offer a solution in principle to characteristics. many of the problems outlined

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Due to the historic nature of pation varies strongly from these buildings wiring is often time to time. By proper ventila- impossible or prohibitively ex- tion on demand it is possible to pensive. The size and substantial make essential energy saving. construction of these buildings In this application the stability can also affect the quality of of the CO2 sensors is of vital radio links, but Hanwell tech- importance. nology has overcome these problems. It is now used in Examples of recent many of the world’s major cul- applications tural institutions including the Dr. Martin Hancock Louvre and the British Museum. Air Force One, the plane of the Technical Director and President of the United States Founder of The Hanwell Radiolog of America is, of course, Hanwell Instruments Ltd. system and Vaisala packed with sensitive electronic United Kingdom sensors systems. When the plane is on the ground, the internal envi- The Radiolog telemetry system ronment is carefully controlled above, but, in practice, users of has many enhanced software from an external air condition- the wet bulb globe temperature such systems have often been and calibration features and is ing plant. Traditionally wired from the incoming radio data. disappointed. There are many now being used in a diverse sensors were trailed into the air- This gives an indication of the reasons for this, the most im- range of applications. Increasing- craft but these have now been heat stress on a body when portant being that the radio ly, customers need verifiable replaced with Hanwell humidi- working in hot environments. telemetry link has traditionally humidity and temperature sen- ty and temperature radio units. Modern energy efficient been designed independently sors for use in a wide range of The radio data is converted at buildings require independent from the sensors, logger and operating conditions. Over the the receiver to 4–20 mA signals verification during commission- data processing software. years, Hanwell has evaluated which directly control the air ing to ensure that design specifi- Hanwell Instruments have many manufacturers of humid- conditioning while the soft- cations are being achieved. A taken a holistic approach to the ity sensors, but since 1998 has ware continues its normal complete investigation might design of the telemetry sensor used the Vaisala Humichip and monitoring functions. This ap- require the short-term monitor- systems. The radio transmitter is very happy with its perfor- proach has eliminated the con- ing of temperature, humidity, is fully integrated with the sen- mance and reliability. The tinual problems experienced flow speeds, differential pres- sor technology and robust error telemetry sensor transmitter is with cabling. sures and energy consumption correction software ensures the battery powered, so low power Laboratories conducting en- in a variety of locations. All of integrity of data. consumption is important. vironmental testing on a range these variables can be gathered When readings are taken the of products from food to phar- with minimal disruption to the Monitoring for sensor has to be capable of ac- maceuticals require a flexible day-to-day operation of the optimum conditions curate measurement after a very method for adapting their moni- building. short warm up period. This, toring systems as needs change. If implemented properly, The Hanwell system was origi- combined with the sensor sta- The Hanwell system offers an radio telemetry can be of great nally designed for monitoring bility, makes the Humichip an ideal solution, providing meas- help to the instrumentation en- the environment in historic ideal choice for the Radiolog urements that can meet the gineer. The list of applications buildings, museums and gal- system. high standards required by leg- continues to grow and it seems leries, where optimum condi- Hanwell also uses the Vaisala islation. The same technology obvious that the popularity of tions have to be maintained to carbon dioxide CARBOCAP® can also be readily applied to wireless sensor systems will in- preserve valuable artifacts, paint- sensors for measuring the am- high technology manufacture crease dramatically in the com- ings and the internal fabric of bient gas concentration in pub- where quality control proce- ing years. ■ the building. Accurate control lic buildings and offices. Since dures insist on documented en- of such variables as relative hu- people exhale carbon dioxide, vironmental data. midity, temperature and light the CO2 concentration is a Comfort within office build- levels is vital. In such applica- good indicator of human pres- ings or heat stress monitoring tions sensors must be unobtru- ence in a room. Based on the in industrial environments is of sive and capable of mounting in outputs the ventilation can be growing importance. Hanwell different locations, because lay- controlled so that the air quali- have implemented a system outs often change. ty is good despite of the occu- that automatically calculates

Networked PC Control interface Receiver Sensors

Master PC Architect2 Repeater Controller Modem connection

The flexibility of a typical radio telemetry system. The radio data is readily exported as analogue or digital data from the base station, providing a highly flexible solution to a wide range of instrumentation and control problems.

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Vaisala’s new SPH10/20 static pressure heads, ideal for outdoor installations, were designed to eliminate the effects of wind on barometric pressure readings.

Vaisala has launched its new Effects caused by buildings SPH10/20 static pressure Wind-induced effects are, per- heads designed to eliminate haps, the main source of errors the effects of wind on baro- in the barometric pressure meas- metric pressure readings. urement. Wind can be both a Effects caused by wind lead direct and an indirect source of error to the measurement. to major errors in the baro- Based on the patented princi- metric pressure measure- ple, Vaisala’s new SPH10/20 ment. According to WMO static pressure heads are used to minimize wind-induced errors. recommendations, meteor- Indirect influence means ological measurements must changes in the pressure field account for these wind-in- around an object, which can, for duced effects. instance, be a building. When moving air encounters an object it will cause an over pressure or under pressure around it. Neither the pressure inside a building is immune to the wind surrounding it. Potential sources of error are due to pressure fluc- tuation inside the building caused by wind, as well as by the building’s possible air condition- ing. Therefore, buildings should not be used as ‘static pressure heads’. Direct influence means dy- namic pressure changes to the pressure intake of the instru- ment, caused by wind. A barometer will not give a true reading of the static pressure, if it is affected by gusty wind. Instead, its reading will fluctu- ate with the speed and direction SPH10/20 static pressure heads for of the wind. This effect on the pressure reading may be in the order of several hectopascals. These effects are also dis- Reliable Barometric cussed in the WMO1 guide. Minimizing a wind- induced error Pressure MeasurementMeasurement A preferable location for a barometer would be an open field without any obstacles in All Wind Conditions close to the barometer, which

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were designed in co-operation head is installed vertically, and to zero. Therefore the pressure with the Laboratory of Aero- is generally relatively close to inside the pressure head closely dynamics at the Helsinki Uni- the ground. Pressure heads usu- corresponds to the static pres- versity of Technology (Finland), ally tend to have some offset at sure of a free air flow, regardless and their wind tunnel was used their pressure coefficient which of the wind speed. for testing the prototypes2. is usually negative, even at an- Figure 1 also shows that with A static pressure error is de- gles close to zero. This means SPH heads, the pressure error fined as the difference between that part of the kinetic pressure is below 0.3 hPa at all angles the measured static pressure always remains as a pressure measured, (WMO recommen- (through the pressure head) measurement error in the dation for operational network and the actual static pressure. barometer output at all wind station barometers1) and below Timo Ranta-aho, Tech. Lic. Results can be presented as speeds. this limit also at a flow of 20 Product Manager pressure differences in pressure In SPH heads the geometry m/s between angles of Sensors Systems Division units (hPa), but also as a pres- sets the pressure coefficient be- –20…+20 °. The results are the Vaisala Helsinki sure coefficient C , which is tween the plates as slightly pos- same, regardless of the hori- Finland p useful in comparing the results itive. This is then adjusted to zontal direction of the air flow. of different pressure heads, and zero by allowing the air to leak In many pressure heads this is the measurement made at dif- to a lower pressure region. not the case due to some sup- could disturb it. In strong and ferent air flow speeds. Figure 2 shows that with SPH porting arm or other structure gusty winds, the direct effects The pressure coefficient Cp heads at the angle of zero the breaking the symmetry of the can be cancelled out by using a is defined as: pressure coefficient is also close head. Also, the pressure coeffi- static pressure head to ‘filter out’ the effect of dynamic pres- Cp = static pressure error sure1. This type of head needs kinetic pressure to be designed carefully and thoroughly. where In addition to having the properties to minimize wind-in- kinetic pressure = 0.5 x (density of the air) x (wind speed)2 duced error, several other factors must also be taken into account in the design of a pressure head. For example, a pressure coef- 0.50 It should preferably be small ficient of 0.1 means that 10 % with a hardy structure. It should of the kinetic pressure is still 0.00 not contain channels that could left as a pressure error in the easily become blocked due to pressure reading. Positive sign -0.50 rain or condensed water. All means measuring too high, and 10 m/s 20 m/s

channels should also remain negative sign means measuring dP [hPa] open in snowy and icy condi- too low a pressure through the -1.00 30 m/s tions. The structure should be pressure head. As the static such that the head is easy to re- pressure error is comparable to -1.50 move for service and cleaning. the square of the wind speed, it All of these things have been cannot be numerically com- carefully considered in the de- pensated with a constant coef- -2.00 -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 40.00 sign of the new Vaisala ficient. Proper compensation SPH10/20 static pressure would require a compensation Angle of Air Flow (∞) heads. The structure of the coefficient for vertical and hor- pressure heads consists of two izontal wind speed and direc- convex plates with openings to tion, making numerical com- Figure 1. The pressure error (dP) measurements in a wind tunnel through the pressure channel at the axis pensation a very complicated SPH heads as a function of the angle of the attacked airflow. bar between the plates. The task. structure is both vertically and horizontally symmetrical, mini- Measured pressure 0.1 mizing any effects due to the difference and pressure wind direction. The lower plate coefficient 0 has openings on its base to allow rain and condensed water Figures 1 and 2 show the meas- -0.1 to flow out. The plates are ured pressure error and pres- 10 m/s

made of PC plastic and the bar sure coefficient of SPH heads CP 20 m/s is made of sea aluminum, so as as a function of the angle of at- -0.2 30 m/s to be corrosion resistant. tack of the air flow. At an angle of zero, the air flow comes di- -0.3 Two versatile models rectly from the side of the head. In negative angles the air There are two different models flow hits the pressure head -0.4 available: the SPH10 is a basic from above and, in positive an- -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 40.00 version and the SPH20, is a gles, from below. Angle of Air Flow (∞) heated version to ensure reli- The most important aspect able operation in snowy and of the graphs is the angles close Figure 2. The pressure coefficient (Cp) measurements in a wind tunnel through icy conditions. The SPH heads to zero, because the pressure SPH heads as a function of the angle of the attacked airflow.

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cient in the vertical direc- tion often behaves asym- The PMI20 Digital Barometer Display is a metrically.

Ideal for outdoor installations Perfect Partner for Vaisala’s

The new pressure heads SPH10 and SPH20 are easy Digital Barometers to install and easy to disas- semble for service and cleaning, even at the instal- lation site. The plates are made of ultra violet stabi- Vaisala’s new PMI20 lized PC plastic to ensure that the head maintains its Digital Barometer correct shape in all outdoor Display is ideal for conditions. The axis bar is manned weather sta- made of corrosion tolerant tions and laboratories sea aluminum. The warmed SPH20 contains a thermo- and offers extensive stat to switch on the warm- possibilities, as it con- ing power at temperatures fers additional proper- where there might be a risk of freezing. In addition to ties to barometers. minimizing the wind error, The PMI20 is a baro- SPH heads also protect metric display which against rain and condensed can be connected di- water, preventing capillary condensation of a water rectly to Vaisala’s column in the pressure barometers. channel, which would lead to a pressure error. The new Vaisala PTB210 here are several vital Digital Barometer can be requirements for directly installed on top of T barometers used in the SPH heads. All other meteorological in- barometers can be connect- stallations. They include good display, the display may be used ed to the SPH head with accuracy and long term stabili- as an in-house remote display for pressure tubing. SPH10 ty, as well as stability over varia- a barometer installed outdoors at and SPH20 are the perfect tions of ambient temperature. the actual measuring site. The pair to complement all Additionally, the barometer display can easily be installed in Vaisala barometers, as they should provide quick and easy a standard panel cutout. Five ensure an accurate and reli- readings and should also, programmable, open collector- The PMI20 Digital Barometer able measurement in all preferably, indicate the trend of type control outputs allow the Display is ideal for laboratories. weather conditions. ■ pressure changes. The new display to also be used as a con- PMI20 barometric display is trol unit and to control external ideal for these purposes. relays, for instance. code simultaneously. Further- more, a height-corrected pres- Remote display with Various displayed values sure (HCP) can be calculated control outputs and displayed for ±40 meters. The PMI20 digital barometer dis- This enables the measured pres- The PMI20 Digital Display is play is easy to use and the whole sure to be reduced to a reference compatible with all of Vaisala’s operating menu can be controlled altitude level – for example, the current barometers with a serial with one knob. The PMI20 has a surface of the runway at an air- output, as well as with the large backlit display with 150 x 32- port or the sea surface level in PTU200 Pressure, Temperature pixel resolution. The measured the case of a ship installation. and Humidity Transmitter. The data can be outputted either in The display of the PTU200 PMI20 can be connected direct- metric or non-metric units and transmitter shows all three meas- ly to a barometer. The display au- the pressure unit can be selected ured parameters at the same 1] World Meteorological tomatically identifies the type of from eleven different alternatives. time; i.e. pressure, humidity and Organization (WMO), Guide unit connected and sets the seri- Display settings can be secured by temperature. The user can also to Meteorological Instruments and Methods of Observation, al communication parameters. setting a key code, which prevents select the PMI20 special mode Sixth Edition, WMO-No. 8, The PMI20 is ideal for all changes to the unit and stops it as wished to show a dew point 1996. manned weather stations and from being switched off without (frost point) value. laboratories. It has both an the code. The PMI20 has a battery se- 2] Palomäki P., Measurement RS232 and an RS485 connec- The barometric display shows cured memory which stores the of Barometric pressure in the tion to the barometer and to a the current pressure output of data measured over the last 24 Wind, Master’s Thesis (in PC. As the RS485 allows for a the barometer, the calculated hours. The user can view data on Finnish), Helsinki University distance of up to one kilometer three-hour pressure trend and the display as graphical trends or of Technology, 1999. between the barometer and the the WMO pressure tendency download it to a PC. ■

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PTB210 Series of Digital Barometers Measuring for Extreme Environments

Ideal for outdoor in- aisala’s selection of stallations, Vaisala’s digital barometers has V been expanded by new PTB210 series of the new PTB210 se- digital barometers can ries. The configurable PTB220 monitor a wide range digital barometer family gained of pressure and tem- great market success after its in- The PTB210 series of digital barometers can be integrated with a weather station. troduction in 1995. The PTB220 perature. Due to their provides several options, includ- RS232C (also available as TTL The housing of the PTB210 compact structure, the ing a local display, and two or level bidirectional output). The provides an IP65 (NEMA 4) barometers can be in- three pressure sensors, incorpo- optional RS 485 output also al- protection for the barometer rated for double or triple redun- lows longer distances between electronics against dust and tegrated with weather dancy, for the most demanding the barometer and the host sys- water. The ruggedness and cor- stations and other data users. tem. rosion resistivity of the housing monitoring systems. enables the PTB210 to be in- The rugged corrosion- Accurate measurements Wide pressure range stalled outdoors. Direct integra- tion with Vaisala’s static pres- resistant housing, The PTB210 series of basic digi- Serial output models offer two sure head facilitates accurate combined with the tal barometers with different different measuring accuracy and reliable measurements in PTB210’s compact measuring ranges and output classes for the range 500...1100 all wind conditions. size, facilitates easy in- options is the newest member hPa. The higher accuracy class, of Vaisala’s barometer product the class A barometer, is fine- BAROCAP® sensor stallation and ensures family. All the barometers are adjusted and calibrated against technology a long service lifetime. characterized and adjusted at a dead weight tester, while the several temperature and pres- class B barometer is calibrated The PTB210 barometer incorpo- sure levels. The numerical com- against electronic working stan- rates the BAROCAP® silicon ca- pensations enable high accura- dards. A wider measuring range pacitive absolute pressure sensor cy over the full operating tem- 50...1300 hPa is also available developed by Vaisala for profes- perature range. with a serial output. Analog sional meteorological instru- The barometers are available output models can be supplied ments. The sensor is known for its in two basic configurations – with different pressure output excellent hysteresis and repeata- with serial or analog output. scalings between 500...1300 hPa bility characteristics and outstand- The standard serial output is for either 0...5 V or 0...2.5 V. ing long-term stability. ■

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Meteorological Service of Canada (MSC)

Marit Finne Digital Barometers at Editor-in-Chief Vaisala News Vaisala Helsinki Airport Locations Finland

Vaisala has been awarded a contract by the Meteorological Service of Canada (MSC). Vaisala sup- plies electronic station barometers to replace the mercury barome- ters currently used for weather observations throughout Canada. The new digital barometer is easy to maintain, and is not susceptible to expo- sure to temperature extremes which may vary from -20 °C to +60 °C.

Electronic weather The key persons involved with the contract at MSC from the left: Harry Lamb, Louise Smith, Dennis Wickiam, station PTB220 Gerie Lynn Lavigne, Dave Dockendorff and Rodica Nitu (Rod Prior and Peter Bowman are missing). barometers

The Meteorological Service of of all passengers flying in and and prediction services. The will be used at all hourly avia- Canada (formerly known as out of Canada for years to Meteorological Service helps tion and synoptic weather ob- the Atmospheric Environment come. Canadians adapt to their envi- serving stations in Canada. Service) is a Service under the For approximately seven ronment in ways which safe- “The new and reliable digital Department of Environment years Vaisala’s ceilometers and guard their health and safety, barometers are needed to elimi- located in Toronto, Ontario. upper air equipment have also optimize economic activity and nate human error in reading The Meteorological Service of been used operationally in enhance environmental quality. mercury barometers, transcrib- Canada (MSC) is the country’s MSC’s weather networks. It is the goal of Environment ing readings and calculating source for meteorological in- Canada to help make sustain- various atmospheric pressure formation. Vaisala was selected MSC in a nut shell able development a reality in values; specifically, altimeter to supply electronic station the country, and, by doing so, setting and mean sea level pres- PTB220 barometers for weath- The MSC traces its history to make the country an example sure. The use of digital barome- er monitoring throughout the very beginnings of Con- to the world. ters will allow us to automate Canada. federation. For over 125 years, the barometric monitoring pro- Delivery of the barometers the Canadian government has Need for digital gram in Canada,” MSC repre- began in the fall of 1999. The provided its citizens with barometers sentatives say. project to replace all the mer- weather and other atmospheric cury barometers will continue environmental information and Vaisala’s PTB220 digital barome- Evaluation process through the year 2001. When predictions. ters will be integrated to AWOS and testing completed, this project will The mission of the MSC is to (Automated Weather Observing eliminate the potential health anticipate and respond to the Systems) and also to PCs used The PTB220 was one of seven risk to observation personnel evolving needs and expectations by human weather observers to barometers approved for opera- and the potential contamina- of Canadians and their institu- generate and communicate vari- tional use by the Meteorological tion of the environment, as well tions for meteorological, hydro- ous types of weather and climate Service of Canada, and allowed as helping to ensure the safety logical and related information observations. These barometers to take part in the bid. The

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PTB220 was the only digital Vaisala’s PTB220 digital barometer which met the strin- barometers will be integrated to gent requirements of the MSC. AWOS (Automated Weather “Laboratory tests were con- Observing Systems) and also to PCs ducted over a period of more used by human weather observers to than twelve months. They con- generate and communicate various sisted of periodic calibration types of weather and climate checks (for evaluation of long observations in Canada. term stability), operating envi- ronment tests, storage and shipping environment tests, communications tests and power tests. They were de- signed to simulate the extreme conditions the barometers would be subjected to if used operationally at any of the sta- tions in our observing net- works,” MSC experts explain. tion errors associated with mer- One reason why Vaisala’s cury barometers and humans. barometers were selected was a In addition, the multiple redun- cost/value ratio. In addition, dancy in the Vaisala barometers the unique PTB220 digital combined with a special emer- barometer design incorporates gency back-up power supply the three-cell redundancy re- provides an added margin of quired to give the necessary safety and reliability. level of confidence in the meas- urements. Multiple redundan- PTB220 barometers cies were required by NAV with AWOS CANADA, MSC’s main avia- tion data recipient/client. MSC representatives explain: “Other than our design process- Environmental and es, we have not had any experi- One of Vaisala’s PTB220 digital barometers installed at London, Ontario, safety issues ence to date. We are designing a Canada. Vaisala supplies electronic station barometers to replace the mercury new digital pressure instrumen- barometers currently used for weather observations throughout Canada. Mercury barometers pose a risk tation for our AWOS which will to both the environment and replace older dual pressure ana- to personnel using them. The logue technology. The multiple- posure to temperature extremes cleaning and calibration of mercury barometers in use at cell redundancy in the PTB220 (-20 °C to +60 °C) or damage mercury barometers is also observing stations are up to 70 version which we are using is ex- brought about by routine com- eliminated. This is very labor- years old. There is therefore an pected to provide more reliabili- mercial shipping. When trans- intensive and these services are increasing risk of both human ty and an extra margin for safe- porting mercury barometers, becoming very difficult and exposure and of environmental ty than the current module.” they require special handling pro- costly to obtain. contamination to leaking mer- It is also planned to add cedures, packaging and permits Using PTB220 barometers, cury. Mean Sea Level (MSL) pres- to comply with Transportation of MSC will benefit by more The pressure measurements, sure, pressure tendency and Dangerous Goods regulations. timely and accurate atmospher- performed by observing per- density altitude reporting capa- This is especially significant with ic pressure and altimeter setting sonnel at airport locations are bility to the AWOS. remote weather stations which values and a reduction in both used to compute altimeter set- are accessible only by aircraft. the time required for training tings, which are used by pilots Benefits using digital When using digital barome- and performing atmospheric for aircraft landing and take-off barometers ters, the need for periodic observations. ■ purposes. An incorrect altime- ter setting could have disas- According to MSC, the bene- trous consequences. It could fits using PTB220 barometers Several key persons participated into mean that the pilot believes the include long-term stability, the contract process at MSC. aircraft which he/she is flying is RS232 and RS485 compatibili- Dave Dockendorff, Manager, National Weather higher above the ground than ty and three independent trans- and Climate Operations Division it actually is. When combined ducers. Peter Bowman, Barometry Technical Authority with conditions of poor visibili- The back-up power supply will Rod Prior, Manager, Technical Operations ty and/or low cloud cover, this extend the operation of the could result in an airplane acci- barometer in the event of a power Harry Lamb, Electronics Systems Engineer dent. For this reason, there can failure. It also provides better im- Rodica Nitu, Head Operational Engineering be little or no tolerance for al- munity to electromagnetic inter- Dennis Wickiam, Procurement Quality Assurance Auditor timeter setting errors. ference and power fluctuations. Louise Smith, Chief, Electronics and Engineering Procurement, Public The use of digital barometers Unlike the mercury barometer Works and Government Services Canada should eliminate incorrect al- it is replacing, a PTB220 barome- timeter settings due to reading, ter is easier to maintain, and is Gerie Lynn Lavigne, National Meteorological Systems’ Technologist computational and transcrip- not particularly susceptible to ex-

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Biotechnologie–Kempe incorporates Vaisala’s Barometers Dissolved CO2 Used to Track Measurements Leakage from or over 15 years Bio- lism of micro- organisms. For ex- technologie Kempe ample, a high concentration of F GmbH has been sit- carbon dioxide leads to a delay Nuclear uated in Berlin and in budding of Saccaramyces has been active mainly in the cerevisiae, so the reproduction field of measuring and regulat- of yeast is influenced negatively. Enclosures ing technology for biotechnolo- Further, the negative effect gy and environmental protec- of a very low carbon dioxide tion at the international level, concentration on the metabo- Vaisala’s PTB101C analogue barometers where our export share is about lism during aerobic substrate- 90 per cent. Our workshops limited yeast fermentation is are being used by the French Electricity produce measuring technology, well known and results in a Company in their program to track electrical components, scientif- yield loss. Also, the formation leakage from nuclear power plant en- ic instruments and machines, of products and by-products in closures. and, in order to control fer- the fermentation processes fre- mentation procedures, we have quently depends on the con- a self-owned programming tent of carbon dioxide in the hanks to fruitful co-operation between technology department at our medium. Gianelli Mesures and Vaisala SA, some sixty disposal. T of Vaisala’s PTB101C analogue barometers A major field of achievement On-line monitoring of have been delivered to the French for Biotechnologie Kempe dissolved carbon dioxide Electricity Company (Electricité de France, or EDF). GmbH is our development of The PTB101C has been installed in an instrument measuring probes (EU and US Continuous detection of carbon cabinet with a 220V power supply by Gianelli Mesures, patent), as well as systems for dioxide by the presented mea- a company located close to Valence, France. the registration of measure- suring system is realized by the The resulting unit is being used in EDF’s SEXTEN ments. This results in the op- combination of a silicone tubing program, designed to track leakage from nuclear power portunity to develop customer- probe and a Vaisala GMM220 plant enclosures. oriented, personalized automat- carbon dioxide probe. Vaisala’s The PTB100 series of analogue barometers is de- ing concepts, thus achieving GMM220 series modules incor- signed both for accurate barometric measurements at highly economical production. porate enhanced CARBOCAP® room temperature and for general environmental pres- Biotechnologie Kempe’s new tehcnology. Many advanced fea- sure monitoring over a wide temperature range. The probe incorporates Vaisala’s tures enable trouble-free control excellent long-term stability of the barometers mini- GMM220 series carbon dioxide of carbon dioxide levels in ex- mizes or even removes the need for field adjustment in sensor. The GMM220 series treme environments. many applications. sensors are based in CARBO- ® The SEXTEN system measures the atmospheric CAP technology, enabling The CO2 measurement is car- pressure inside nuclear enclosures with high precision trouble-free control of CO2 lev- ried out as follows: and stability. These enclosures are maintained at a els in demanding environments. slightly higher pressure than the atmospheric pressure, • directly in the fermentation in the range 900 to 1100 hPa. The value of the outside Carbon dioxide in broth, where carbon dioxide atmospheric pressure is also measured by the Vaisala biotechnology is formed and where the barometer and compared with the inside pressure. The micro-organisms are affected allowed rate of leakage from each enclosure, propor- Carbon dioxide is a product of by CO2. tional to the difference between the inside and outside the respiratory and fermenta- • in the gas stream pressures, is calculated from these two sources of in- tive metabolism of micro-or- • both above and below the formation. ganisms. During fermentation carbon dioxide saturation All of the French nuclear power plants in the 900, the carbon dioxide emission achieved under atmospheric 1300 and 1450 megawatt range have been equipped correlates with the biomass pressure with this system. ■ concentration and substrate • without any preparation of consumption. the exit gas Depending on the concentra- • with high stability tion, carbon dioxide may influ- • with a short response time ence the growth and metabo-

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Vaisala’s GMM220 series sensor

Biotechnologie Kempe’s new probe is equipped with Vaisala’s modular carbon dioxide GMM220 series sensor. The GMM220 series ® CO2 modules incorporate the CARBOCAP technology. The sensor’s operation is based on the NDIR Single-Beam Dual-Wavelength princi- ple. Its main advantages are long-term stability and a long life.

Yeast cells

Vaisala’s CO2 probe GMM220

Eberhard Kempe, (Dipl.Eng.) Managing Director Biotechnologie-Kempe GmbH Berlin, Germany

Double membrane (Silicone + Teflon) Biotechnologie Kempe’s silicone tubing probe for dissolved carbon dioxide.

Silicon tubing probe far from the equilibrium concen- tration, so permeation back into The silicone tubing probe was the broth is negligible. developed by Biotechnologie The carrier gas control and Kempe GmbH (EU and US the signal converter are located patent) and is steam sterilizable. inside a separate box. The probe, which is inserted into the broth, consists of a sili- Signal processing cone coated channel through which is passed a carrier gas. The gas is measured by absorp- Carbon dioxide permeates tion of infrared radiation inside through the silicone membrane the CO2 sensor located in the and is carried to the CO2 sensor. housing of the ST probe. The The measuring principle of infrared radiation emitted by a the system is based on the linear lamp passes through a filter relationship between the partial working at the selective wave- pressure of carbon dioxide inside length which is characteristic Protecting tube the broth and the amount of car- for absorption by carbon diox- bon dioxide permeating through ide. If there is carbon dioxide the membrane. The concentra- inside the measuring cell, the tion of CO2 in the carrier gas is intensity of light decreases in

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relation to the actual CO2 con- mentation; a probe which cov- centration. ers a range of 0–500 % satura- The ST probe described here tion, for use during pressurized is equipped with Vaisala’s mod- fermentations, is also available. ular CO2 sensor. The CARBO- CAP® sensor is silicone based Carbon dioxide and operates on the NDIR applications Single-Beam Dual-Wavelength principle. Based on this new Carbon dioxide is a product of measuring principle, its main the cellular metabolism of advantages are long-term stabili- micro-organisms used in bio- ty and a long life – the main technology. During fermenta- reasons why we chose Vaisala’s tion the carbon dioxide con- product for our carbon dioxide tent is the result of carbon application. dioxide formation by the The Vaisala GMM220 series CO 2 measurement The output of the sensor micro-organisms and its trans- modules based on CARBOCAP® technology. (Signal Converter Module) is 0 port by aeration. By means of (4) – 20mA and a serial inter- the CO2 probe it is possible: face RS-232 is available. Additional signal processing • to detect the carbon dioxide GMM220 Series is realized by connecting the concentrations which inhi- CO2 probe to a measuring bit the metabolism and computer FMC-MINI LCD. growth of micro-organisms, Carbon Dioxide This is a modification of an ex- so the user is able to start isting measuring computer compensating measures – which is successfully used in for example, aeration. Measurement Module biotechnology to detect volatile • to obtain information about organic compounds. The sys- he Vaisala GMM220 series CO2 measurement modules tem for measuring carbon diox- the growth and activity of incorporate the enhanced CARBOCAP® technology. ide is a new development by micro-organisms during fer- T The transmitters have been optimized for integration Biotechnologie Kempe. mentation. into equipment for greenhouse control, incubators, fer- The carbon dioxide concen- • to realize the control of mentors, safety alarms and integrated systems. tration in the carrier gas is anaerobic fermentations. Many advanced features enable trouble-free control of CO2 lev- shown as % Vol. after process- els, even in demanding applications and harsh environments. ing by the computer. Carbon dioxide also plays an The GMM220 series transmitters provide both time and tem- Based on the detected con- important role as a quality pa- perature stability thanks to the CARBOCAP® sensor’s constant ref- centration in the carrier gas, the rameter in the beverage and erence measurement. computer calculates the partial brewery industry and can be Fully interchangeable probes make the GMM220 series trans- pressure of CO2 in the fermen- detected by the measuring sys- mitters very versatile. The probes do not only simplify calibration tation broth. The next step is tem in order to ensure the qua- and field service, but they also make it easy to alter the measure- the calculation of the dissolved lity of the final product. ■ ment range. Different power supply voltages and output options as ■ CO2 by means of the addition- well as different probe attachments are also available. ally measured temperature. The influence of other compounds on the solubility of CO2 can be Typical calibration curve for C02 probe compensated for with the com- 20 puter program. The measuring computer realizes the collec- 18 tion of values, processing, cali- 16 brations and graphs. 14 Measuring range 12 Several CO2 probes are offered 10 for measuring the dissolved car- bon dioxide concentration by 8 the described principle, in ac- cordance with the measuring 6 range. (mA) Output of Probe 4 The measuring range is fixed by the carrier gas flow rate, 2 which, in turn, depends on the nozzle being used. Depending 0 on the chosen nozzle, a meas- 01234567 uring range of 0–50 % or 0–100 % of saturation can be realized. Dissolved carbon dioxide conc. in the liquid (g/l) These probes are offered for using during no-pressure fer- Calibration curve (related to a beverage industry application).

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Measuring Carbon Dioxide in the Soft Drinks Industry

Carbon dioxide is used to carbonate the bever- ig Springs Inc. is a Safe levels of CO2 in the ages in the production of soft drinks. In the major soft drink workplace B manufacturer and a United States, OSHA requires that the CO2 large local Coca- Carbon dioxide is used to car- level remains at, or below, 5,000 ppm in the at- Cola franchise distributor lo- bonate the beverages in the mosphere of any filler room area. Big Springs cated in Huntsville, Alabama, production of soft drinks. Inc. is a major soft drink manufacturer and a USA. John M. Wilkinson, the While the containers are being Administrative Manager, who filled during the bottling process, large local Coca-Cola franchise distributor locat- has worked for 28 years in the large volumes of carbon diox- ed in Huntsville, Alabama. The company has company, is in charge of ide are emitted from the fillers successfully used Vaisala’s CARBOCAP trans- Facility Maintenance. He also into the filler room atmosphere. mitters for more than a year in their bottling oversees the Human Resources As high concentrations of Department. CO2 are clearly hazardous, plant. There is a growing need for re- most countries, including the liable measurement of carbon USA, have set workplace expo- dioxide in bottling plant envi- sure limits. In the United States, ronments. The lack of reliable the exposure limit is 5,000 parts and inexpensive instruments has per million (ppm). Occupations made CO2 measurement diffi- where carbon dioxide can rise to Marit Finne cult and costly. Cooperation be- dangerous levels include brew- Editor-in-Chief tween Big Springs Inc. and ing and carbonated drink indus- Vaisala News Vaisala began when Wilkinson tries. Vaisala Helsinki found Vaisala’s CO2 products In the United States, OSHA Finland through the Internet. (Occupational Safety & Health

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The carbon dioxide exhaust fans in the filler room are capable of 15 air changes per hour at Springs Inc., which is a major soft drink manufacturer and a large local Coca-Cola franchise distributor located in Huntsville, The GMT220 series transmitters are designed to measure Alabama. CO2 in demanding environments.

Administration, U.S. Depart- Office. He and the technical ment of Labor) requires the av- staff worked with me to create erage exposure limit of CO2 in the system that we are current- GMT220 Series weight to remain at, or below, ly using.” 5,000 ppm during an eight hour working shift. Mr. Wilkinson ex- Benefits of reliable CO2 plains: “We purchased Vaisala’s measurement Industrial Carbon CARBOCAP transmitters to monitor the levels of CO2 in Mr. Wilkinson says that they the filler room. The informa- have generally been satisfied Dioxide tion from the transmitters is with the CO2 transmitters. “The transmitted to the ABB Chart fact that we don’t have to cali- Recorders. The chart recorders brate the CARBOCAP trans- monitor and log these levels. mitters saves time. The system Transmitter When they sense levels over simply runs by itself and re- 4,900 ppm, an exhaust fan sys- quires little or no maintenance. he Vaisala GMT220 is the first range of CARBO- tem is activated to remove the I do not believe that there is an- CAP® transmitters available for a wide range of CO2 from the filler room. The other company that could T CO2 applications including greenhouses, fruit stor- fans turn off once the level re- match the efficiency and relia- age, safety alarms and demand-controlled ventila- turns to 1,000 ppm.” bility of Vaisala’s products, sales tion in mushroom farms, livestock husbandry and car park and services.” ■ garages. The GMT220 series transmitters are designed to meas- Cooperation began ure CO2 in harsh and humid environments. The housing is through the Internet dust and water proof to IP65/NEMA4, and the materials have been chosen to be particularly resistant to corrosion. According to Mr. Wilkinson, The transmitter is easy to install and use. The GMT220 se- Big Springs Inc. has worked to- ries transmitters have a modular structure, which includes a gether with Vaisala for more separate mounting plate to facilitate installation. than a year. “Research on the The probes of the transmitter make field maintenance Internet led me to Vaisala’s straightforward, because they are fully interchangeable. The Boston Office. After studying probes can either be replaced by newly calibrated probes or the company, I discovered that separate ones that can be used as reference probes for check- Vaisala has a long history of ing calibration. This minimizes the downtime and eliminates quality products and reliable the need for expensive calibration equipment. ■ services. Not only that, but the transmitters did not require cali- bration either. The products of most other companies require constant calibration. Another reason for choosing Vaisala’s products was Mr. Richard Kershaw, from the Boston

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Outdoor plant growth experiments in

Elevated CO2 Atmospheres

A silent giant, Mount Iwate, The Forestry and Forest Products Research Institute studies plant guards the peaceful surroundings of the Tohoku Research Center on the growth in elevated carbon dioxide environments in Japan. At the northern mainland of Japan. end of 1999, Dr. Mori started a four-year project to study the effects of carbon dioxide and soil nutrient content on young trees. Vaisala is involved in this project, providing essential carbon dioxide measurement instruments for the outdoor growth chambers.

From left, Mr. Gaku Hitsuma, Mr. Tatsushiro Ueda and Dr. Shigita Mori on location at the open top chambers.

Shigeta Mori, Ph.D. now silent giant, Tohoku Research Center Mount Iwate, guards Forestry and Forest Products A the peaceful sur- Research Institute roundings of the Tohoku Research Center on Tatsushiro Ueda the northern mainland of Environmental Equipment Japan. The volcano’s fiery pre- Section historic past, is a strong re- Hokkaido Dalton Co., Ltd. minder of how our environ- ment is undergoing constant Juhana Häkkänen, M.Sc. (Tech.) change. Since the birth of Business and Process ‘Iwate san’, mankind has Development Manager emerged and evolved into an Vaisala Tokyo increasingly influential compo- nent of our planet’s ecosystem. Kennichi Ishimoto, L.L.B. For the first time in Earth’s his- Technical Consultant tory, it seems that a single Vaisala Tokyo species is capable of altering Japan the entire climate system.

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Vaisala CO2 instruments by a grant for the ‘Development in forest study of detailed methods to evaluate CO2 budgets in forest and The consequences that global ocean ecosystems’, funded by warming has on nature are still the Ministry of Agriculture, largely unknown. Japan is at Forestry and Fisheries in Japan. the forefront of a global effort If all goes well, Dr. Mori’s study to study the phenomenon, and will eventually provide new in- to try to minimize its impact. formation on the physiological Proof of this is the United changes that plants undergo in Nations’ Kyoto Protocol aimed Vaisala’s CO2 measurement instruments are modified atmospheres. These at a worldwide reduction of car- used in the outdoor growth chambers. changes, e.g. different allocation bon dioxide and other green of chemicals within the plant, house gas emissions. could alter their resistance to the The Japanese high authority plan to ensure the well being of small country in terms of sur- pests mentioned above. It is es- in forestry issues, the Forestry the Tohoku forests in the fu- face area, it stretches right sential to comprehend these and Forest Products Research ture. It is possible that the ef- through the forest zone of the basic mechanisms in order to Institute (FFPRI), has played fects of global warming can al- Northern Hemisphere. Japan’s understand the nature of plant an active role in assessing the ready be seen in various trees in southernmost islands and the behavior in changing environ- effects of rising temperature the forests of Tohoku. It seems island of Kyushu are in a sub- ments. and carbon dioxide (CO2) con- that the slight climate change tropical forest zone and the is- Since his projects in Siberia, centration. The FFPRI, with its and rising concentration of car- land of Hokkaido in the north one of Dr. Mori’s partners has five research centers around bon dioxide in the atmosphere is in a cool-temperate forest been Hokkaido Dalton Co. Japan, is currently carrying out are allowing some pests to zone. As most areas of Japan Ltd., a company specializing in numerous research projects on spread more easily from the also have high mountains, the designing and manufacturing the subject. One of these in- south. The complicated migra- variety of domestic types of for- professional equipment for re- volves studying plant growth in tion patterns of forest pests are est is remarkable.” search and experiments. Once elevated carbon dioxide envir- one example of the new chal- Dr. Mori has led innovative again, the expertise of Mr. onments. Vaisala is also in- lenges that the research center research projects not only in Tatsushiro Ueda from Hokkaido volved in this project, provid- is facing. Japan, but also in Siberia and Dalton was needed. Under the ing essential CO2 measure- Dr. Shigeta Mori has been Indonesia. Few researchers guidance of Dr. Mori, sixteen ment instruments for the out- conducting research projects have had the opportunity to open top chambers (OTCs) in door growth chambers. for Tohoku Research Center experience such a wide range of total were designed and built on over the last two years. Before different forests, from equatori- the test grounds of the Tohoku Tohoku Research Center Morioka, he spent four years at al tropical rain forests to huge Research Center. The growth of the FFPRI Hokkaido Research larch forests in the permafrost identically cloned cuttings of a The FFPRI Tohoku Research Center. He has a doctorate in of northern Russia. hybrid larch, a cross between Center in Morioka is responsi- agriculture from the Nagoya Japanese larch (Larix kaempferi) ble for forest preservation and University Graduate School of Open top growth and Dahurian larch (Larix research in Tohoku, covering Agriculture and Forestry, and chambers gmelinii), is monitored in these an area of almost 67,000 km2, has participated in numerous chambers. The cuttings are over two thirds of which is for- research projects in different At the end of last year Dr. Mori grown in four different environ- est. The majority of the forests parts of Japan. “Japan is a started a four-year project to ments: two with different atmos- are owned either by national or unique country for a forest re- study the effects of carbon diox- pheric carbon dioxide levels and local government. The research searcher,” explains Dr. Mori. ide and soil nutrients on young two with different levels of soil center is creating a long-term “Although it is a moderately trees. The project is supported nutrients.

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CO2: 360 ppm CO2: 720 ppm low nutrients oil low nutrients oil

CO2: 360 ppm CO2: 720 ppm high nutrients oil high nutrients oil

Figure 1: Four different growth environments are monitored.

After four years of growth used them in several projects. monitoring, the small trees will “Everyone involved in produc- be cut down and analyzed ing important environmental thoroughly. In the growth measurements knows Vaisala,” chambers, the plants are sub- says Dr. Mori. Up until now, ject to outside temperature, hu- Vaisala products have been midity and rainfall. As an OTC used by the institute to meas- is closed in at the sides by ure more traditional weather transparent plastic film, the air parameters, including baromet- that circulates around the ric pressure, humidity and tem- plants can be enriched with a perature. In these new cham- particular gas; in this case, car- bers, Vaisala’s innovative CAR- bon dioxide. BOCAP® technology has been harnessed for research uses. CARBOCAP® technology This was only natural because for research use dependability and good long- term stability were the decisive Juhana Häkkänen To provide sufficiently reliable factors in the choice of the data for a scientific project, sets CO2 transmitters. of four chambers all have the same gas and soil composition. Continuing the search Therefore, a total of sixteen for clues chambers was needed (Figure 1). The carbon dioxide concen- It will be several years before tration of each chamber is meas- final conclusions will have ured by individual Vaisala CO2 been made in Dr. Mori’s and transmitters fitted in the cham- Mr. Ueda’s current project. In bers. Half of the chambers are the meantime however, the maintained at near atmospher- Forestry and Forest Products ic background concentration of Research Institute will actively 360 ppmvol and the rest at an search for answers. One of their enriched environment of dou- ambitious targets is to calculate ble background concentration, the carbon dioxide balance of 720 ppmvol. The Hokkaido the entire Japanese forest sys- Dalton control system and car- tem, by 2002. bon dioxide bottles needed for Just as there are many factors the enrichment are in a small involved in causing global hut adjacent to the chambers. warming, many answers are The control system not only also required to solve the puz- precisely regulates the CO2 lev- zle. The joint efforts of the els of the OTCs, but is also FFPRI research centers are equipped with data logging for making a difference in this cru- all important parameters. cial issue, and Vaisala is pleased Dr. Mori and Mr. Ueda were to offer any assist it can. ■ previously familiar with Vaisala instruments, as the FFPRI has

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Service and Calibration at Standard Prices

The Vaisala After Sales Service for humidity, Jori Valli, European Service barometric pressure and carbon dioxide prod- Manager. It is recommended that humidity instruments be ucts in Europe has increased its range of ser- calibrated on a regular basis. vices. In addition to service and repair facilities, “The calibration interval de- our European Service Center offers factory cali- pends on the instrument, the bration facilities to customers in Europe, Israel required accuracy and the meas- urement environment. The av- and South Africa. The first parameter in this fac- erage calibration interval for tory calibration service is relative humidity. humidity products is normally Päivi T. Laitinen, one year.” B.Sc. (Env. Eng.) Calibrations can be divided Technical Writer into two categories: one-point Sensor Systems Division Calibration – an integral and multi-point calibrations. Vaisala Helsinki part of maintenance The user can perform a one- Finland point calibration, and it is used he Vaisala After Sales Since the physical and electri- for frequent spot checking of Center in Europe cal properties of materials do instruments on the field. This T has changed its ser- not remain constant, measure- field calibration can usually be vice pricing princi- ment instruments have to be carried out without disconnect- ples for humidity, barometric calibrated regularly for them to ing the instrument, by using a pressure and carbon dioxide maintain their accuracy. As a recently calibrated portable in- products. As of April 3, 2000, part of After Sales Services in strument, such as the Vaisala After Sales has used standard Europe, Vaisala offers factory HMI41 digital indicator, as a pricing for repairing and cali- calibration services. The first reference. One-point calibra- brating Vaisala products. The parameter included in this cali- tions can also identify instru- Vaisala’s European Service Center standard price for repairs and bration system is humidity. ments that need further adjust- provides full service for its calibrations includes trans- “Humidity was chosen be- ment. customers. The after sales facilities portation, service and calibra- cause of Vaisala’s particular ex- include calibration, service, spare tion work and spare parts. In pertise in the area,” says Mr. parts and transportation at Europe, the service is based in standard prices. The European the European Service Center in Service Center is located in Helsinki. Helsinki.

VAISALA NEWS

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Multi-point calibrations are Trained personnel consisting of A product calibrated using best suited to regular calibra- seven service technicians and the Vaisala calibration service tions in stable indoor condi- one test engineer perform facto- will receive a calibration sticker tions. The Vaisala HMK15 is a ry calibrations in a controlled showing the date when the de- multi-point humidity calibra- environment. To verify the re- vice was calibrated. In the fu- tor based on saturated salt sults, two calibration certificates ture, a customer can also take baths. When a multi-point cali- are issued per calibrated instru- part in the Vaisala calibration bration is performed, the in- ment. The first calibration cer- reminder program. The partici- strument is checked at two or tificate is produced before the pants of this program will re- more stable points of relative adjustment and the second after ceive a letter, on a yearly basis, humidity; for instance, up to the adjustment. This two-certifi- reminding them of the recom- three humidities can be gener- cate system makes it possible, mended calibration and re- ated using the HMK15 calibra- amongst other things, to conti- questing them to send the in- tor. This naturally means high- nually monitor the operation strument to Vaisala to be cali- er accuracy over the whole level of the calibrated product. brated. This service will be measurement range than with launched at the end of the year one-point calibration. Traceable to the NPL 2000. ■

Reliable and Vaisala’s factory calibration is professional calibrations carried out using a batch cali- bration system based on a com- For a customer, the easiest way puter controlled humidity gen- of handling multi-point calibra- erator, with software. According European Service Summary tions is to send the instrument to Mr. Valli, the advantages of The standard price for calibration includes: to Vaisala. Our factory calibra- batch calibration methods are • free transportation by courier tion is carried out using five cali- capacity and speed: “The batch • calibration work and certificate bration points. This makes cali- calibration system allows for • wearing parts (e.g. filters) bration more reliable. As Mr. higher accuracy than salt cali- Valli notes: “Sensors seldom be- bration. The whole calibration The standard price for repair and calibration includes: have in a purely linear way. Five process is also rapid due to the • transportation by courier calibration points and very ac- short stabilizing time of the cali- • service work and spare parts (e.g. sensors) curate references give us more brator.” The batch calibrator • calibration work and certificate. accurate data from the middle also provides traceability direct- of the measurement area.” ly to the National Physical The standard price does not include probes and probe cables. The Vaisala After Sales Service Laboratory (NPL) in the United for humidity, barometric pres- Kingdom. In some quality sys- sure and carbon dioxide is led by tems traceable calibration cer- After Sales Manager Jaakko tificates are a requirement. Laurikainen and European Service Manager Jori Valli.

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Mike Johnson Boston Service Center’s number one goal Laboratory Manager and Kim Vacca Customer Service Manager Meeting the Demands Vaisala Boston USA of the Customer

At the beginning of ver the years, the in- Calibration of humidity and Boston has continually im- 2000 the Vaisala O dustry’s focus on temperature equipment can be proved upon all aspects of customer service and carried out anywhere. It is up after-sales support. The success Boston Service Center customer support to the customer whether to re- of this improvement can be conducted a survey has intensified to a degree that turn the unit to Vaisala for ser- measured in many ways, and entailing a variety of companies have begun to dis- vice. With competition for this most obviously from a survey tinguish themselves by this par- business increasing, the need to of actual customer responses. questions covering the ticular aspect. Companies have continually improving one’s At the beginning of 2000 the entire after-sales begun to understand the need capabilities is essential. Being Vaisala Boston Service Center process. The survey for offering more than just a able to support the product conducted a survey entailing a quality product. The after-sales that has been sold is a crucial variety of questions covering showed that 98 % of process is now just as impor- role for a Service Center. the entire after-sales process. 61 customers were either tant as the sales process. When Vaisala has taken the necessary out of the 150 surveys were satisfied or highly sat- it comes to making a business steps to ensure that accurate completed and returned. The isfied with Vaisala’s grow, keeping existing cus- testing and support for prod- results were extremely positive tomers satisfied is just as im- ucts can be carried out at each and showed that the direction products, with the ma- portant as finding new cus- Service Center. The Boston we are taking has proved to be jority being highly sat- tomers. Service Center provides cali- correct. isfied. The survey also There are several facets to bration traceable to the The survey showed that 98 % showed that 96 % of customer service and customer National Institute of Standards of customers were either satis- support. First and foremost are and Technology (NIST). fied or highly satisfied with those who responded quick and accurate answers. We also continue to support Vaisala products, with the ma- expressed their satis- Whether there are technical in- and service our older-genera- jority being highly satisfied. The faction with Vaisala’s quiries, status of order requests, tion products. survey also showed that 96 % or just general questions, an- of those who responded ex- service. swers must be prompt and to Improved after-sales pressed their satisfaction with the point. In almost all cases, support Vaisala’s Service, and 46 % of the question or inquiry needs these were highly satisfied. The to be answered immediately, Over the last several years, The survey allowed customers to and we make a point of provid- Vaisala SSD Service Center in voice their comments, and ing our customers with answers on the same day, even if we simply acknowledge the ques- Laboratory Capabilities tion and inform the customer 200 that we are working on it. 150 Customer service orientation 100

50 The Vaisala SSD Service Center Low Range in Boston has worked extreme- High range ly hard over the years to offer 0 customers better service than -50 that provided by all of our com- petitors. Each member of the -100 team understands the need to RH T °C Td °C T °C reflect this attitude at all times Traceability Traceability Traceability Expanded and work in accordance with Testing the guidelines that have been set out and which put us above The SSD Calibration Laboratory includes equipment that will allow for the industry standard. testing at various temperatures, dewpoints and humidities.

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From the left, Kim Vacca (Customer Service Manager) and Lori Summerlin (Customer Service Representative from the Customer Service Department in Boston. They handle all customer inquiries on service, repair, expediting and tracing

PHOTOS BY KIM VACCA, VAISALA BOSTON. VAISALA KIMPHOTOS BY VACCA, orders, and any problems with orders or shipments.

most were very positive about two or three day event in desig- the sales staff and customer ser- nated regions of the United vice personnel. Comment such States that will combine a de- as trust, confidence and relia- tailed presentation with a bility appeared several times. hands-on working session. The automotive industry has Flexible internet access toughened its requirements on the quality system of its ven- In today’s market, end-users are dors. This industry has adopted presented with several choices QS 9000, which means that all when they need calibration or suppliers must be ISO Guide service. Providing something 25 accredited (soon to become that is better than the rest can ISO Guide 17025). The SSD Mike Johnson, Laboratory Manager make the difference. This does Calibration Laboratory is look- not mean simply talking about ing to attain accreditation service and support, but fol- through third party assessment. lowing through the actual The implementation and docu- process. It is even easier to ac- mentation of accreditation will cess us via our web-site further improve the calibration (www.vaisala.com/inc/ssdcat) process, which will be of great for technical support, order in- benefit to most customers. This quiries or field returns. The is yet another way in which standard turn-around time is, Vaisala is committed to meet- on average, between two to ing all of the demands of a three days for all repairs per- changing industry. formed in the Boston Office. The Vaisala Service Center We also offer an express has evolved into a highly suc- turnaround, which allows ser- cessful operation. Meeting the viced products to be shipped demands of the customer is the back within two days. Our number one goal. We have pur- Rejane Smith, Senior Service Technician Calibration Reminder Program chased equipment that will is made up of over 3,900 pieces allow for testing at various tem- of equipment. As part of the peratures, dewpoints and hu- program a reminder is sent out midities. We are able to simu- a month before the calibration late most processes on the field is due. This allows customers to so that those products can be keep track of their equipment tested as close to the condi- to ensure that it is calibrated at tions of their environment as regular intervals. possible. We are committed to serving our customers with the Developing customer best turn-around time without training reducing quality. ■

To further improve the after- sales process the Vaisala SSD Service Center is working on developing a training course to The staff of the SSD Calibration/Service Laboratory in the educate customers on prod- group picture. From the left, (seated) Gary Francisque, Ed ucts, theory, calibration and Mehu and Chang Pyun, (back row), Paul Joyce, Linda Hall, measurements. The training Patsy Wheeler, Rejane Smith and Mike Johnson. course will take the form of a

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www.vaisala.com

Europe North America

VAISALA Oyj VAISALA Inc. P.O. Box 26, FIN-00421 Helsinki 100 Commerce Way FINLAND Woburn, MA 01801-1068 Phone int.: +358 9 894 91 USA Telefax: +358 9 894 9227 Phone int.: +1 781 933 4500 http://www.vaisala.com Telefax: +1 781 933 8029

Vaisala Malmö Vaisala Inc. Drottninggatan 1 D Boulder Operations S - 212 11 Malmö 8401 Base Line Road SWEDEN Boulder, CO 80303-4715 Phone int.: +46 40 298 991 USA Telefax: +46 40 298 992 Phone int.: +1 303 499 1701 Phone from Sweden: Telefax: +1 303 499 1767 0200 848 848 Telefax from Sweden: VAISALA Inc. 0200 849 849 Columbus Operations 7450 Industrial Parkway VAISALA GmbH Plain City, Ohio 43064-9005 Postfach 540267 USA D-22502 Hamburg Phone int.: +1 614 873 6880 GERMANY Telefax: +1 614 873 6890 Phone int.: +49 40 851 7630 Telefax: +49 40 850 8444 VAISALA Inc. Handar Business Unit VAISALA GmbH 1288 Reamwood Ave. Stuttgart Branch Sunnyvale, CA 94089-2233 Zweigniederlassung USA Pestalozzi Str. 8 Phone int.: +1 408 734 9640 D-70563 Stuttgart Telefax: +1 408 734 0655 GERMANY Phone int.: +49 711 734 057 Asia and Pacific Telefax: +49 711 735 6340 VAISALA KK Vaisala GmbH 42 Kagurazaka 6-Chome Bonn Office Shinjuku-Ku Adenauerallee 46 a Tokyo 162-0825 D-53110 Bonn JAPAN GERMANY Phone int.: +81 3 3266 9611 Phone int.: +49 228 912 5110 Telefax: +81 3 3266 9610 Telefax: +49 228 912 5111 VAISALA KK Osaka Branch VAISALA Ltd 1-12-15, Higashimikuni Newmarket Office Yodogawa-Ku, Osaka 532-0002 Suffolk House JAPAN Fordham Road Phone int.: +81 6 6391 2441 Newmarket Telefax: +81 6 6391 2442 Suffolk CB8 7AA UNITED KINGDOM VAISALA Pty Ltd Phone int.: +44 1638 674 400 3 Guest Street Telefax: +44 1638 674 411 Hawthorn, VIC 3122 AUSTRALIA VAISALA Ltd Phone int.: +61 3 9818 4200 Birmingham Operations Telefax: +61 3 9818 4522 Vaisala House A.C.N. 006 500 616 349 Bristol Road Birmingham B5 7SW VAISALA Beijing UNITED KINGDOM Representative Office Phone int.: +44 121 683 1200 Wangfujing Grand Hotel Telefax: +44 121 683 1299 Room 518-520 57, Wangfujing Street VAISALA SA Beijing 100006 2, rue Stéphenson (escalier 2bis) PEOPLE’S REPUBLIC F-78284 Saint-Quentin-En- OF CHINA Yvelines Cedex Phone int.: +86 10 6522 4050 FRANCE Telefax: +86 10 6522 4051 Phone int.: +33 1 3057 2728 Telefax: +33 1 3096 0858 VAISALA Regional Office Malaysia VAISALA Dimensions SA 2nd Fl. Wisma Chinese Chamber 7, Europarc Ste-Victoire 258 Jalan Ampang F-13590 Meyreuil 50450 Kuala Lumpur FRANCE MALAYSIA Phone int.: +33 4 4212 6464 Phone int.: +60 3 457 1376 Telefax: +33 4 4212 6474 Telefax: +60 3 459 1176 ISO 9002 Sävypaino /Offset-kopio Oy 2000