SENSORGAN no 022695, Publishable final activity report 1/1/09
022695
SENSORGAN
Sensor system for detection of harmful environments for pipe organs
Instrument: Specific Targeted Research Project
Thematic Priority: 8.1 Policy-oriented research: Scientific Support to Policies
Publishable final Activity Report
Period covered: from 2006-01-01 to 2008-12-31
Date of preparation: 2009-03-12
Start date of project: 2006-01-01
Duration: 36 months
Project coordinator name: Carl Johan Bergsten
Project coordinator organisation name: University of Gothenburg
1(11)
Revision: draft
SENSORGAN no 022695, Publishable final activity report 1/1/09
1. Project execution
Background.
The organ belongs to the core of European culture reflecting a diverse history of traditions
and stylistic periods. The European heritage of the organ is preserved in more than 10 000
historical instruments. A major threat to this heritage is indoor harmful environments.
The organ contains many different types of materials, like different types of wood, leather,
different types of lead-tin alloys, from pure lead to almost pure tin, brass and iron.
It also contains a complex system of moving parts and the bellows, the wind channels and the
windchests need to be airtight.
This makes the organ to an object being very sensitive to microclimate changes and harmful
environments.
Organic acids, also in combination with condensation phenomena, create pipe corrosion
causing serious damage to the pipes. Harmful humidity conditions can create cracks in the
wooden parts of the organ, making the instrument unplayable.
Project objectives
The SENSORGAN project objectives are to make available new instrumentation for
monitoring and detection of harmful environments for organs through development of sensors
for real time measurement.
The sensor system contains three different parts:



Dosimeter to detect organic acids that are corrosive to metal (lead or lead/tin alloy)
organ pipes.
Sensor to indicate risk of cracks in wooden parts of organs.
Sensor to detect dew or frost formation inside organ pipes.
The sensors are designed in order to be placed in the organ without disturbing playing or
affecting the sound. The sensor system was applied in a field study in the historical organ
from 1611 in the Minor Basilica of St. Andrew the Apostle in Olkusz, Poland. The data
collected from all the sensors was analysed, microclimatic factors creating harmful
environments were studied, and conclusions were drawn for publications, mitigative
strategies, and to support the Committee for European Standardisation (CEN).
Partners
Participants in the project are
Göteborg Organ Art Center, University of Gothenburg, Sweden
School of Biological and Chemical Sciences, Birkbeck College, University of London, UK
Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences Krakow, Poland
Institute of Atmospheric Sciences and Climate, National Research Council of Italy, Padova,
Italy
The Municipal Cultural Centre, Olkusz, Poland
School of Arts, Sciences and Humanities, University of Sao Paulo, Sao Paulo, Brazil
Environmental Inorganic Chemistry, Chalmers University of Technology, Gothenburg,
Sweden
2(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
Work performed and end results
Dosimeter to detect organic acids
The results from the previous European Commission funded COLLAPSE project (Corrosion
of Lead and Lead-Tin Alloys of Organ Pipes in Europe) have shown that the escalating
problem of corrosion inside organ pipes is caused by organic acids, especially acetic acid,
emitted from the wooden parts in the organ. The organic acids in the organ wind enter into the
pipe foot and creates a corrosive environment inside the foot.
A corroded and collapsed pipe foot
When an alternating electrical field is applied on a piezoelectric quartz crystal, the quartz
crystal starts vibrating at its resonant frequency. If a coating is applied to the crystal surface
the crystal frequency will decrease.
This property is used for development of a dosimeter for detection of organic acids being
corrosive to organ pipes. A coating of pipe metal (lead) is applied to the crystal. When the
coating reacts (starts to corrode) with the organic acids, the mass of the coating increases and
a frequency shift of the crystal vibration can be detected.
The piezoelectric quartz crystal is coated with a thin layer of lead using thermal deposition.
The lead coated crystal.
3(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
For validation and calibration purpose the dosimeter was exposed to corrosive environments
with defined different temperatures, humidities and acetic acid concentrations.
The dosimeter response was measured in real time and the dosimeter coating was evaluated
and analyzed before and after exposure by different methods such as Raman and impedance
spectroscopy.
A miniaturised holder containing the necessary electronics for driving the crystals was
developed. The holder was used both for exposures in the laboratory and in the field study.
Crystal holder with built in electronics. Socket for
three crystals (1 reference and 2 measuring crystals).
For the application of the dosimeter in the organ an adaptor was designed and built. The
adaptor ensures that the pipe can be played also during the monitoring and that the dosimeter
is exposed to the organ wind flowing into the pipe foot.
Adaptor and holder inserted
between pipe and windchest.
The dosimeter and adapter applied in the historical
organ at St. Botolph, London.
In addition to the electronics in the crystal holder a unit containing electronics and software
for data storage and readout was developed.
4(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
Sensor to indicate risk of cracks
Fluctuations in ambient relative humidity are considered to be one of the main factors which
contribute to the deterioration of wooden cultural objects. Wood responds to these
fluctuations by gaining moisture when the humidity is high or losing moisture when the
surrounding air is dry. Wood shrinks as it loses moisture and swells when it gains moisture.
When wood is restrained in its movement, it can experience high stresses within the material,
which can cause significant damage. Cracks in the wooden parts of the organ can cause
serious damages making the instrument unplayable. The organ facade, often containing
invaluable art handicraft like wood carvings and sculptures, can also be damaged by a harmful
environment.
Crack in wooden sculpture
A new and innovative method of recording acoustic emission (AE) activity has been
employed to trace microfracturing of wooden parts of the organ thereby constituting an early
warning for emergence of cracks in the wood. When a microcrack develops, a sound pulse is
emitted from the wood. This sound is not in the audible frequency range but it is detected by
the sensor.
Recording of acoustic emission activity in the organ. Note the
AE sound pulses caused by rapid relative humidity changes.
5(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
A prototype sensor including signal acquisition system and software to process and evaluate
the data have been developed and successfully tested. A new version of the sensor system
adapted for the market is ready for commercialization and will be introduced into the market
soon after the project end.
Sensor system
6(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
Sensor to detect dew or frost formation
Several available sensor types for detection of condensation have been tested. Because of
application limitations for the tested sensors and the demanding application (limited space in
the pipes and harsh environmental conditions) development of a new type of dew sensor
based on fibre optics has been performed.
The principle of the Dewing-Frosting Detector is based on the change in reflectivity of an
optical fibre, following the formation of a water layer on its end surface. When this occurs the
reflectivity decreases, and the fraction of the transmitted light being reflected drops.
Principle of the Dewing-Frosting Detector
The sensor consists of an array of three optic fibres. The fibre ends are placed inside the pipe
foot, in contact with the pipe metal surface, and will thereby detect early formation of water
or ice in the pipe. To obtain a secure position of the fibres inside the pipe foot at the same
time as the pipe can be played without any risk for wind leakage an adaptor was developed.
The adapter is inserted between the pipe and the windchest and is holding the fibres in
position.
Fibres mounted in the adapter.
Pipe standing on the adapter with the
fibres inserted in the pipe foot.
The prototype sensor end electronics has been successfully tested in different environments.
7(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
Field study
A field study was performed where the developed sensors were applied in the historical organ
from 1611 in the Minor Basilica of St. Andrew the Apostle in Olkusz, Poland.
The field study organ
The dosimeter to detect organic acids installed in the organ
Detection of possible microcrack development in the wooden windchest
8(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
The dewing-frosting detector
installed in a pipe.
The detector electronic unit (white box) connected to a
data logger and gsm modem allowing measurement
data transfer via the gsm mobile phone net.
The results from the field study show that the environmental situation in and around the organ
was rather satisfying during the monitoring period: No high concentrations of organic acids in
the pipe, low microcrack activity in the windchest and no condensation situation detected in
the monitored pipe. This could be one factor contributing to the 400 years old organ well
preserved condition.
Expected impact
The results from the project will contribute to
 preserving European organ heritage
 developing improved organ restoration policies
 EU policies that bring socio-economic, environmental and technological approaches
together
 scientific grounds to assist the CEN in setting normative standards for conservation of
cultural heritage, especially the microclimate inside churches
 a general understanding of microclimatic factors that create harmful environments for
organs, whose impact on European building environments will contribute directly to the
quality of life and health of the members of the Community
 detecting harmful environments and assessing methods to impede them, e.g. organ
restoration, church restoration, installation of friendly heating systems
 supporting and improving organ builders’ restoration practices
Project homepage: http://www.goart.gu.se/sensorgan
9(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
2. Dissemination and use
Dosimeter to detect organic acids that are corrosive to metal organ pipes.
Result description
When an electric field is applied to a piezoelectric quartz crystal, it starts to vibrate. This
property is used for development of a dosimeter for detection of organic acids which are
corrosive to organ pipes. When a coating of pipe metal, applied on the crystal surface, reacts
with organic acids the mass of the coating increases and a frequency change of the vibration
can be detected. The dosimeter is located direct below the pipe, exposed to the organ wind
flowing into the pipe foot
Possible market applications
The application field includes situations where there is a need for environmental monitoring
regarding the detection of organic acids being harmful to cultural heritage objects (and
especially corrosive to metal organ pipes).
Stage of development
Prototype working in field application.
Contact details
School of Biological and Chemical Sciences, Birkbeck College, University of London, UK
Dr. Marianne Odlyha (m.odlyha@bbk.ac.uk)
Sensor to indicate risk of cracks in wooden parts of organs.
Result description
A new and innovative method of recording acoustic emission activity has been employed to
detect microfracturing of wooden parts of the organ thereby constituting an early warning for
emergence of cracks in the wood. When a microcrack develops, a sound pulse is emitted from
the wood. This sound is in the high frequency range, not audible for the human ear, but it is
detected by the sensor.
Possible market applications
The application field includes all situations where there is a need for monitoring and
supervision of wooden objects from a preservation and protection perspective (e.g. organs,
museums).
Stage of development
Industrial product.
Collaboration
A license agreement has been signed between the Institute of Catalysis and Surface
Chemistry, Polish Academy of Sciences and one of the world leading companies in the
production and sale of equipment for monitoring preservation conditions for of works of art.
The sensor system will be commercialized in 2009.
Contact details
Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences Krakow, Poland
10(11)
SENSORGAN no 022695, Publishable final activity report 1/1/09
Dr. Lukasz Bratasz (ncbratas@cyf-kr.edu.pl)
Sensor to detect dew or frost formation inside organ pipes.
Result description
The working principle of the Dewing-Frosting Detector is based on the change in reflectivity
of an optical fibre, following the formation of a water layer on its distal end surface. When
water or ice form on the surface where the core is truncated, the reflectivity decreases, and the
fraction of the transmitted light being reflected drops. The fibre end is placed inside the pipe
foot in contact with the pipe metal surface and will thereby detect early formation of water or
frost in the pipe. This is the first time a sensor responds either to dew or frost occurrence. It is
very small, adaptable to the shape of any surface under investigation.
Possible market applications
The sensor is potentially useful in a number of applications, e.g. cultural heritage, agriculture,
industry, traffic.
Stage of development
Prototype working in field application.
Collaboration
Intellectual Property Rights, protection measures and potential commercialisation (either
direct or licensing) will be jointly considered by CNR-ISAC and CNR-IFAC after the on-site
testing.
Contact details
Institute of Atmospheric Sciences and Climate, National Research Council of Italy, Padova,
Italy.
Dr. Dario Camuffo (d.camuffo@isac.cnr.it)
11(11)