How can cultural heritage be managed in times of climate change? Conference Bamberg, Germany, Date: February 27th/28th 2023

Long-term measurements of climate in the dome of Xanten and measurements on historic surfaces to predict damage risks on historical windows and mould risk on several historic altars in Xanten

Johannes Schubert et.al. (cathedral builder Xanten), Rolf Becker (university Rhein-Waal)  and Hans Daams

The current and future assessment of the indoor climate in Xanten cathedral and their effect on damages  of historical furnishings requires an extensive measurement strategy throughout the cathedral and on respective objects inside the cathedral. In cooperation with the university of Rhein-Waal this has been done now for more than three years. 

This paper is focusing on in-situ measurements of historical surfaces. The valuable stained glass from the Middle Ages and the historical Petrus Altar are selected as examples of measurements and risk assessment.

The impact of climate and sun on the protective glazing was measured for a period of 3 years. Data were collected for temperature and relative humidity inside the air gap, the air directly close to the historical glazing inside the church and the surface temperatures of the glazing inside the airgap and inside the church. Measurements were done using the IoT-Instrument Custos-Aeris from iXtronics GmbH, which is easily assembled within minutes and connects the data to the internet Cloud using an LTE Connection. Data analysis directly links thermodynamic risks with possible damage root causes like drying out, embrittlement, shrinkage of the gel layer and exponential increase in glass corrosion, mould and damage to the fixative. Diagrams are created for all directly measured data and the dew point. On top based on intelligent data analysis diagrams are created to show the behaviour of the system over years with respect to being in the optimum and outside the optimum thermodynamic condition. The optimum area indicates most probably no damage to the window. Outside of the optimum area new diagrams are linked to show the possible damages that can happen to the window.

 The same system is used at the Petrus Altar to measure air and material thermodynamic conditions.

But on top the system Custos-Mucoris is used to directly measure and warn the user if mould starts to grow. This system is using an objective and a camera to take pictures from the surface. Using artificial intelligence the system is able to detect mould right in the beginning of growth when the diameter is exceeding 1 mm. In order to train the convolutional neural network more than 6000 pictures of mould were used to achieve a detection accuracy of almost 100%. The system is linked to the cloud by using WLAN or an LTE-connection.  Measurements are carried out now for almost three years with permanent and automatic control of the surface of the Petrus altar. The same system is installed in the Dome of Münster inside the organ.

The full paper is available from my cloud using the following link:

https://1drv.ms/b/s!AoHAta94EDU2gYsPfnlEHN31CVUyOA?e=pxKOtJ