Proceedings e report - Firenze University Press

WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
objects of interest, since no obvious building damages, but mould infection at several areas were
found.
Fig. 3: painted wooden sculpture affected by mould (Aspergillus spec.)
Criteria for the selection were no obvious structural damages, but some relevant mould damages.
Within the period from March 2004 until August 2005, air temperature and relative humidity close to
at the affected surfaces were recorded hourly with mini data loggers. During several inspections in situ
within that period, additional data have been obtained, like water activity, moisture content and
surface temperature. From critical areas, infrared thermographs were taken. To determine the mould
species, samples from infected areas were taken for laboratory investigations. To assess the hygienic
status of the indoor air, airborne spore concentration [5] was determined with a sampler (Holbach LKS
130; fig. 9).
Additionally to that work, the susceptibility of restoring materials within laboratory and field tests was
investigated and opportunities for preventive and cleaning measures have been checked. Different
paints, solidification materials, glues, lutes and wood species were selected for the investigations, in
agreement with the Heritage Preservation Trust.
As an example, Fig. 4 shows the typical curve of the indoor climate of Peter and Paul Church
Reichenbach (altar) between March 2004 and June 2005. It is conspicuous that the relative humidity
always was below 70 %. Due to the intensive infections (see fig. 1 and 3), much more humidity values
were been expected. Obviously, wood interiors may take up moisture peaks rapidly and thus buffer
relative humidity. But, this may lead to a higher moisture content of the material and thus to an
increased mould risk.
temperature [°C]
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temperature
rel. humidity
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04/03/04 05-Mai-04 07/07/04 07/09/04 09/11/04 10/01/05 14/03/05 15-Mai-05
100
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rel. humidity [%]
137
temperature [°C]
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rel. humidity
temperature
0
0
01.04.04 26.04.04 21-Mai-04 15.06.04 10.07.04 04.08.04 29.08.04
Fig. 4: Run of the interior climate at Peter and Paul, Fig. 5: Run of the interior climate at St. Marien
100
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rel. humidity [%]