Keeping the European organ heritage alive and well
Organs are complex musical instruments and objects of art comprised of wood, leather and metals. The components are all quite sensitive to environmental factors such as temperature, humidity and organic acids. The ‘Sensor system for detection of harmful environments for pipe organs’ (Sensorgan) project was designed to develop new real-time methods for monitoring and detection of harmful environments and subsequent damage processes with respect to pipe organs. The researchers focused on the two main threats to pipe organs, namely acetic acid corrosion inside the pipes and cracking of wooden parts due to fluctuations in ambient humidity. The latter is affected by temperature fluctuations as the heating of a church, for example, may remove moisture from the air. To address the issue of acid corrosion in the pipes, the researchers developed a dosimeter and associated software based on changes in vibrational frequency of a piezoelectric crystal. Specifically, when such crystals are coated with pipe metal (lead) and the coating starts to corrode, the frequency with which the crystals vibrate changes and that change can be detected. The researchers developed the dosimeter together with a specialised adaptor enabling the pipe to be played during monitoring. Fluctuations in humidity can cause cracks in wooden structures that not only damage invaluable wood carvings but may also make the organ unplayable. The investigators employed an innovative method of recording acoustic emission (AE) activity to trace microfracturing of wooden parts. The prototype sensor was successfully tested and a new commercial version is ready for introduction to the market. In summary, the EU-funded initiative made significant contributions to preservation of the European organ heritage via real-time monitoring as well as by pointing the way toward improved organ restoration policies and standards for conservation of cultural heritage. The results could impact European building environments and have far-reaching effects on the cultural life and health of EU citizens.
