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Microclimate Frames

Microclimate Frames

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Microclimate frames are controlled experimental setups designed to study localized climatic conditions within a specific area. They allow researchers to manipulate and measure environmental variables such as temperature, humidity, and light, facilitating the investigation of ecological responses and interactions in a defined microenvironment.
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Microclimate frames are controlled experimental setups designed to study localized climatic conditions within a specific area. They allow researchers to manipulate and measure environmental variables such as temperature, humidity, and light, facilitating the investigation of ecological responses and interactions in a defined microenvironment.
Impact Loads of Air Pollutants on Paintings: Performance Evaluation by Modeling For Microclimate Frames
by Mikkel Scharff

2025, Journal of the American Institute for Conservation

Modeling of the transport (fluxes) of gaseous air pollutants to the surfaces of paintings installed inside six different microclimate frames (mc-frames) was performed. Mc-frames are used to protect paintings against the external... more
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Canvas-related microcracks in Danish 19th-century paintings
by Troels Filtenborg

2024, Zenodo (CERN European Organization for Nuclear Research)

This paper discusses the emergence of microcracks observed in the ground layers of paintings on canvas supports. Such cracks are visible in 50 µm resolution x-radiographs and correlate with the occurrence of microcracks as well as more... more
Figure 1. A Pergola, C.W. Eckersberg, Italy. 1814/16. Oil on canvas, 34 x 28.5 cm, Statens Museum for Kunst, KMS2059. The area shown in detail in Figure 2 is marked with white lines (SMK Photography/Jakob Skou-Hansen) METHOD
Figure 2. A Pergola, Eckersberg, Italy. 1814/16, 400 x 400 pixel (20 x 20 mm) detail of Figure 1, covering the area of Figures 3, 4 and 7 (SMK Photography; KADK Mikkel Scharff image enhancement)
Figure 5. Schematic drawing of a cross-section of canvas thread and the superimposed layers, showing a step-by-step visualisation of microcrack creation and later propagation from ground layer(s) through superimposed layers: 1a) paint, 1b) ground, 1c) thread fibres; 2) moisture absorption causes the fibres to swell, resulting in cracking of the ground where it is thinnest; 3) dried fibres, the crack remains; 4) increased forces cause stress in the paint/second ground layer; 5) paint cracks (KADK/Cecil Krarup Andersen) CONCLUSION Figure 4. X-radiograph of Figure 3, processed with a Fourier filter using nip2 software, where the microcracks in the two directions are highlighted in red and orange. The crack propagations through the paint layers are not highlighted here (SMK Photography; KADK/ Mikkel Scharff image enhancement) the paint layers.
Figure 3. X-radiograph of the same area as in Figure 2 (SMK Photography; KADK/Mikkel Scharff image enhancement)
Figure 6. Schematic drawing of the point of intersection of two threads, at the top of which the ground layer is thinnest and the stress concentration strongest, causing crack formation. The crack thus formed is shown in red (KADK/Mikkel Scharff)
Table 1. Overview of the Eckersberg paintings in the study. For the paintings highlighted in red the x-radiographs clearly showed microcracking. For those highlighted in green, the microcracks were faintly or only locally visible. Paintings without highlighting had few or no visible microcracks
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A Portable Tool for the Evaluation of Microclimate Conditions within Museum Enclosures, Transit Frames, and Transport Cases
by Sławomir Jakieła

2024, Studies in Conservation

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A Portable Tool for the Evaluation of Microclimate Conditions within Museum Enclosures, Transit Frames, and Transport Cases
by Anne Haack Christensen

2024, Studies in Conservation

Figure 1. Installation of L-PQC dosimeter (a) clamped in test frames and historical frames and (b) continuous recording in transit frame of a painting in Tate Store. Data acquisition system outside the frame.
Figure 2. Installation of L-PQC dosimeter in back of panel painting in Apsley House, London (English Heritage) Table 2 shows tne results obtained from exposure of the L-PQC dosimeters in a purpose-built frame (oil-tem- pered hardwood frame A_T) in the Tate Conservation Exposure was also performed within frames of paint- ings. PQC crystals were exposed by clamping the crystal legs between stainless steel supports or by placing them into a purpose-built holder connected to a battery operated data acquisition system for con- tinuous recording of measurements at pre-selected time intervals (Figure 1) or in an mc-frame (Figure 2). The holder is connected to a data acquisition system which is located outside the frame. This was later amended in shape to a flat rectangular holder accom- modating four crystals which allowed for operation within (mc)-frames in the PROPAINT project.
Figure 3. L-PQC dosimeters response in front and behind the panel painting Man of Sorrows and Mother of Sorrows — Epitaph on Jan Stupecki died 1509 (painter unknown c.1509) in the National Museum, Krakow, Poland. After 40 days in the mc frame, the change in the dosimeter is about 10.5% in front of the painting and up to 15% behind the painting. Tempera- ture and RH were also recorded for that period.
Table 1. Values for exposure of L-PQC crystals and lead coupons in three commercial box frames with different AERs (English Heritage). Table 2. Values for exposure of L-PQC crystals and lead coupons in oil-tempered hardwood frames with and without added materials to mitigate emissions (Tate Conservation Department).
Department. A reduction in values occurred when
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Levels of Preservation for Cultural Heritage within an Open-air Museum
by Andrea Bernath and 
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Elena Luciana Badea

2024, Studies in Conservation

Figure 1. Storage facility associated with Z.1 level of preservation. Image: °Astra Museum. Based on monthly averages, 2016-2017 may be con- sidered to be a wet period, with many values over 70% RH, which were distributed throughout the whole year. February was the wettest month, but the most Ultraviolet radiation and visible radiation were mon- itored by sensors measuring the wavelengths 250- 400 nm and 400-700 nm, respectively. Temperature and RH were monitored using Sensirion SHT25 sensors, whilst Alphasense® sensors were installed for measuring ozone, nitric oxide (NO), nitrogen dioxide (NOz) and sulphur dioxide (SO2). We could not say
Figure 2. Dretea Church, the monument where the environmental conditions were monitored for one year. Image: ©Astra Museum.
Table 1. Distribution of objects and monuments by their zones of enclosure, with different climate conditions. Property Environment for Efficient Adaptation to the Cli- matic Changes. They concerned the following par- ameters measured at Dretea Church (Figure 2): temperature, RH, ultraviolet radiation, luminosity, air- borne pollution, nitric oxide, nitrogen dioxide and sulphur dioxide. These refer to Z.2, the zone of enclosure for this ethnographic monument, where the preser- vation conditions are without climatic control. whether the software or the hardware architecture was problematic, but several data losses occurred during monitoring.
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Impact Loads of Air Pollutants on Paintings: Performance Evaluation by Modeling For Microclimate Frames
by Guillermo Fernando Ochoa Andrade

2023, Journal of the American Institute for Conservation

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Levels of Preservation for Cultural Heritage within an Open-air Museum
by Elena Badea

2023, Studies in Conservation

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Trouble in Storage?: Understanding the dynamics of airborne organic acids in storage buildings and its consequences for the air quality, energy use, and preservation of heritage collections
by Signe Hjerrild Smedemark

2023

This Ph.D. thesis assembles the results from a three-year interdisciplinary Ph.D. project between the Royal
Layout of the ventilation system in Storage II. The system only contains internal dehumidification and a heating surface used only to dry out the building after construction. Layout of the HVAC system in Storage I with heating, cooling, humidification, dehumidification and air filtration.
The results from the laboratory and field measurements in Part I-III are summarized in Chapter 4. All data is collated into a Monte Carlo simulation in Chapter 5. The simulation examines the concentrations of formic acid and acetic acid in indoor air, and determine the fraction of organic acids that is removed through active air filtration and the fraction that deposit back onto interior surfaces. Chapter 6 contains a discussion of the methods used to control organic acids in storage buildings and their energy use. Finally the thesis ends with a conclusion in Chapter 7. Figure 1. Graphical outline of the thesis.
Figure 2. Sketch of the new storage facility using semi-passive climate control belonging to the National Museum and the Royal Library of Denmark. (© Drawing by Gottlieb Paludan Architects from https://www.gottliebpaludan.com). Large investments are now being made in heritage institutions to improve the preservation conditions in storage buildings and reduce the energy use. Examples of major storage buildings under construction in Denmark include the shared storage facility between the National Museum and the Royal Library (Figure 2) and the shared storage facility between local museums in Senderjylland (Figure 3).
Figure 3. Sketch of the new storage facility using semi-passive climate control belonging to Museum Sonderjylland. (© Visualisation by Friis & Moltke Architects and BASE Erhverv from https://www.faod.dk/friis-moltke-vinder-konkurrencen-om-magasinbygning/).
rhe concept of passive climate control is to build an airtight hygrothermal inert building envelope on an un nsulated concrete floor. The building envelope will even out daily fluctuations in the outside climate. The un nsulated concrete floor will act as a heating surface in winter and a cooling surface in summer (Christense! ot al., 2016, Padfield et al., 2018). As the storage is unoccupied, no heating to comply with human comfor ‘equirements is needed. Simulations using COMSOL Multiphysics® modelling software have shown that thi emperature in a storage building with passive climate control changes slowly from 7°C in winter up to 15°C nm summer in a temperate climate as Northern Europe (Figure 4) (Padfield, 2013). Smedemark et al. (2019a neasured a temperature from 7°C in winter up to 19°C in summer in a storage building with passive climat control in Denmark. Figure 4. Computer simulation of the temperature in a storage building with passive climate control during winter and summer in a temperature climate as in Northern Europe. (Reproduced with permission by T. Padfield (2013) based on a simulation by Bohm and Ryhl-Svendsen (2011) using the COMSOL Multiphysics® Modelling Software).
A widespread concern in connection with the application of semi-passive climate control is that the airtight building envelope in combination with emissive collections stored densely packed on movable shelves can lead to thermal stratification and a local accumulation in indoor air pollution. Figure 5 show general museum collections stored densely packed on movable shelves in a large storage room at the shared storage facility with semi-passive climate control at the Centre for Preservation of Cultural Heritage in Vejle, Denmark. Figure 5. A storage room with semi-passive climate control at the shared storage facility at the Centre for Preservation of Cultural Heritage in Vejle, Denmark. The store contains general museum collections stored closely packed on movable shelves with a large amount of collection materials in a small space.
Figure 6. Storage I seen from the outside (left). The store contains a book collection stored on compact movable shelves (right).
Figure 7. Floor plan for Storage I. The areas with movable compact shelves are marked in grey. A HVAC system with heating, cooling, humidification, dehumidification and air filtration service the storage ‘oom (Supplementary information 1). The HVAC system contain F8 particle filters as well as two consecutive activated carbon filters. A building management system (BMS) control the intake of outdoor air, the internal recirculation rate and the climate conditions. Air is supplied to the storage room to maintain a constant overpressure and reduce infiltration from outside.
Figure 8. Storage II seen from the outside (left) and the room with a mixed material collection stored on compact movable shelves seen from the inside (right).
information 2. Light sensors are activated when the storage rooms are in use. The storage room with a paper-based archival collection has two external walls as well as one wall facing a central hall and one facing another storage room. The storage room with a mixed material collection has one external wall, one wall facing a central hall and two walls facing other storage rooms (Figure 9). The entrance has a double door airlock. A detailed description of the wall construction is given in Supplementary information 2. Light sensors are activated when the storage rooms are in use. Figure 9. Floor plan for Storage II. The storage room with a paper-based archival collection is on the right and the room with a mixed material collection is on the left. The areas with movable compact shelves are marked in grey.
stored on wood packaging. Figure 10. The Monte Carlo simulations prediction of the formic acid and acetic acid concentrations in a storage building with a mixed material collection at normal indoor room conditions.
Figure 11. The Monte Carlo simulations prediction of the formic acid and acetic acid concentrations in a storage building with a mixed material collection stored on wood packaging at normal indoor room conditions.
Figure 12. The average organic acid concentration predicted from the Monte Carlo simulations together with the standard deviation.
zero. All negative values were therefore set to zero. The surface removal rate probability density plots predicted in the Monte Carlo simulations are highly right skewed and to exclude extremely unlikely values the 95% quartiles were used as the maximum rate. The Monte Carlo simulations also predict scenarios where the source strength is lower than the air exchange rate giving rise to a negative surface removal rate. This is a model error as the surface removal rate can never be below zero. All negative values were therefore set to zero. Figure 13. The Monte Carlo simulations prediction of the surface removal rate in a store with a mixed material collection at normal indoor room conditions. The collection is stored on wood packaging.
Figure 14. The Monte Carlo simulations prediction of the surface removal rate in a store with a mixed material collection stored on wood packaging at normal indoor room conditions with active air filtration.
All exterior walls in Storage I (left) have a glass facade while the interior walls of the storage area consisted of 180 mm concrete, 200 mm insulation, a vapour barrier, 50 mm insulation, 300 mm air gab and 40 mm concrete. \ll exterior walls in Storage I (left) have a glass facade while the interior walls of the storage area consisted A detail showing the construction of the interior and exterior walls in Storage I and II.
Figure 1: A state-of-the-art storage facility in the region Vejle, Denmark, for general museum collections with semi-passive climate control. What is noticeable is how the facility consists of large storage halls with museum collections stored closely packed on mobile shelving with a large loading of collection materials in a small space. Collections made of diverse materials are stored together.
Figure 2: Computer simulation of the temperature in a repository with passive climate control. The building is constructed with a well-insulat- ed building envelope with high thermal inertia placed on an uninsulat- ed concrete floor. Based on outside climate conditions in Denmark the simulation show a winter scenario where the temperature fluctuates from down to 7°C in winter (left side) up to 15°C in summer (right side). (Reproduced with permission by T. Padfield*4 based on a simulation by Bohm and Ryhl-Svendsen%? using the COMSOL Multiphysics® Modelling Software).
Figure 3: Concentration of carboxylic acids in heritage institutions as reported in literature. At the top diagram and displayed as sum of total carboxylic acids: inside a microclimate frame (yellow), display cases and cupboards (red), repositories (blue), and exhibitions (grey). Please note log scale, which is used due the large span of reported values. The bot- tom diagram zoom in on the observations from repositories and dis- plays the fractions of formic and acetic acid concentration. Only obser- vations of concentrations above the detection limit are included. In cases where a concentration was given as a range, the highest con- centration value is used. Numbers on x-axis gives the literature refer- ence. If (*) the concentration value was given as ug/m: in the original reference, but converted to ppb by this author.
Figure 4. The concentration of outdoor generated ozone and indoor generated acetic acid as a function of the air exchange rate. (Reproduced with permission from Ryhl-Svendsen et al.*?).
pollution in archives, which directly can be attributed to the collection itself. This was performed under laboratory conditions, at which the environmental conditions were controlled to mimic winter and summer indoor climate scenarios (10°C and 22°C).
FIGURE 2 A passive diffusion sampler for formic and acetic acid mounted on an aluminum rack with a metal spring clip.
FIGURE 3 The test chamber set-up. Clean air was conditioned by splitting the air stream in two, and bubbling one part of it through a washing bottle with water. The conditioned air was then supplied to the temperature controlled test chamber. The chamber’s exhaust air was passed through two impingers with an alkaline solution to collect formic acid and acetic acid from air. The emission of formic acid and acetic acid from the papers were collected in a 2.9 L glass test chamber (desiccator jar), which was ventilated continuously with clean air at a rate of 8 chamber volumes per hour. with clean air at a rate of 8 chamber volumes per hour.
FIGURE 4 Mass-specific emission rate at 22°C and 50% RH, and the pH (aqueous cold extract) of each paper sample. Each data point represents the mean value of two replicate tests.
FIGURE5 The mass-specific emission rate of the paper collections at the three storage sites, at summer and winter temperature conditions. The surface removal rate was for all locations estimated to be 2 per hour, and the ventilation rate 0.1 per hour, except for Koppel, which was 0.6 per hour. The data point in brackets indicates samplers exhausted, and that level might have been higher. The lines connecting data points are for visual aid only.
Figure 1. Area-specific emission rates of formic acid and acetic acid from sample 1-7 at 20% RH and constant temperature (23 +2°C) as well as at 10 and 23°C with constant RH (50 +5% RH). The cross indicates measurements that are below the LOQ of 5 ug m*. A few authors have measured the emission rate from paper. Ramalho et al. [3] measured a mass-specific emission rate SERm (mass emitted per gram material, per hour) of acetic acid from paper at indoor conditions after accelerated ageing. The mass-specific emission rate was 887 ng g! h'! from a cotton rag paper and 4820 ng g! h'! from a paper made of ground-wood pulp. Smedemark and Ryhl-Svendsen [20] measured the mass- specific emission rate of formic acid and acetic acid from four paper samples from the late 19" to the 20" century at indoor conditions. The emission rate in their study ranged from 45 ng g' h"' from a book printed in 1864 up to 468 ng g' h'' from a newspaper printed in 1946. The mass-specific emission rate from the four paper samples in our study are within the same range. The mass-specific emission rate of formic acid and acetic acid ranged from 262 ng g! h'! from the book printed in 1993 (sample no. 3) up to 1692 ng g! h! from the newspaper printed in 2017 (sample no. 4). the newspaper printed in 2017 (sample no. 4).
rate with ambient (Case 3), or the surface removal rate (Case 4) on the concentrations of formic acid and aceti acid were also modelled (Figure 1). The results are compared with the resulting energy use of each case. Figure 1. Overview of the four simulations. Case | is the model storage room. Case 2-4 modelled the impact of changes in the temperature, the air exchange rate with ambient and the surface removal rate on the concentrations of formic acid and acetic acid in indoor air.
Table 1. Input data to calculate the generation rates of formic acid and acetic acid from wood and paper. 2.2 The removal mechanisms Case | modelled the concentrations of formic acid and acetic acid in the model storage room at 23°C and 50% RH. The air exchange rate with ambient was set to 0.03 h'! to imitate a storage building with semi-passive climate control [14]. The surface removal rate in the model storage room was set to 2 h'! to imitate a densely packed room with a large area of interior surfaces [13].
The results from Case 1-4 are shown in Figure 2.
Figure 2. Concentrations of formic acid and acetic acid together in the modelled Case 1-4. Results are given in bold and input data in italic below.
‘igure 3 show how the concentration of organic acids would vary in the model storage room with a paper collection as a function of the air exchange rate for normal indoor room conditions (Case 1) as well as cooler onditions (Case 2). The air exchange rate would need to be increased with 1.6 h'' in order to achieve the same eduction in concentration of organic acids as could be achieved by lowering the temperature from normal ndoor room conditions to cool conditions. Likewise, the air exchange rate would need to be increased with .8 h'! to achieve the same reduction in concentration of organic acids as could be achieved by lowering the emperature in the model storage room with a wood collection. Figure 3. Concentration of organic acids in the model room with a paper collection at normal indoor room conditions, and cool conditions, as a function of the air exchange rate. The trace of the orange arrow shows that the air exchange rate must be increased from 0.03 to 1.6 h'! for reaching the same reduction in organic acid level as could be achieved be lowering the temperature from 23 to 10°C.
5 CONCLUSIONS As shown in Figure 1, the emission rate of carboxylic acids depends on temperature. A de- crease in temperature from 23°C to 10°C reduces the emission of formic and acetic acid from the tested samples to 27-68%. In addition, a decrease in temperature led to a reduction in the total VOC emission. ee ee ee ee ee The concentration of carboxylic acids and other VOCs from all the tested museum objects reduced when temperature decreased. Although the surface specific emission rates were low, the loading of collections in repositories is usually very dense, so the total impact of the emis- sion from the collection items on the air quality may be high. With a lower temperature inside repositories, the chemical deterioration rate of cultural heritage collections will decrease, and following this, the emission of harmful pollutants must also decrease. A forthcoming field test in a Danish museum storage building will investigate this further.
The objects of this study were two storage facilities. Storage I (HVAC system) contained a 15 to 17™ century book collection from the Royal Library in Denmark. Books are stored on movable compact shelves on each side of a central passage (Figure 1). The facility was built in 2008. The storage room has no external walls. All walls are without windows and connect to services areas or other storage rooms. Light sensors turn the light on when people enter the store. The entrance has a double door airlock. One HVAC system with heating, cooling, humidification, dehumidification and air filtration serviced the storage room (596 m*). A building management system (BMS) controlled the intake of outdoor air as well as the internal recirculation rate. Air was supplied to the storage room to maintain a constant overpressure and control the RH. The RH was kept constant throughout the year while the set-point conditions for temperature was changed gradually from 6°C in winter up to 19°C in summer to reduce the energy use for climate control. There were no ventilation to comply with human comfort requirements. The energy use for Storage I was 67 kWh per cubic meter of storage space, per year, corresponding with 210 kWh m” year! (3 m height).'® Figure 1. Storage I with a 15" to 17" century book collection stored on movable shelves on each side of a central passage.
Figure 2. Storage II with a mixed material collection densely packed on wooden pallets, placed on movable shelves.
Figure 3. The distribution of measurement locations in Storage I and IL.
Figure 4. The average temperature over three weeks in August 2018 in each measurement location in the horizontal and vertical grid in Storage I and IH. Low temperatures are shown in light red and high temperatures in dark red.
Figure 5. Temporal plot of the temperature in the vertical grid in the room with archival collections (Storage ID) from January 2018 to February 2019. (The two peaks in temperature in late autumn in the middle and close to the ceiling could be due to human activities such as heritage objects being handled close to the measurement location). Figure 5 shows the temperature variation between January 2018 and February 2019 in the vertical grid in the archival collection in Storage II. The weak vertical temperature stratification is visible from late spring and increase through the summer. The largest temperature difference was 3.8°C between the floor and 5 m height. The same temperature stratification was observed within the room with mixed collections in Storage II.
Figure 6. The vertical and horizontal grid within Storage I and IT showing the air concentration of organic acid (ug m=). The colour scale shows the sum of organic acid from blue (lowest concentration) to orange (highest concentration). One measurement location in the corner of the room with mixed collections in Storage II was left out due to a large object.
Figure 7. Internal airflow between the room with archival and mixed collections in Storage II and adjacent rooms mixed collections and 43 +6.2 m° h"' from other parts of Storage II. Figure 7 shows the internal airflow between the rooms with archival and mixed collections, and the exchange with other rooms of Storage II. The airflow rate (m* h'') was ten times higher from the room with mixed collections into the rooms with archival collections than in the opposite direction. The room with mixed collections received 1 +0.1 m* h"! air from the room with archival collections and 44 +5.1 m? h'! from other parts of Storage II, whereas the room with archival collections received 11 +1.2 m? h" air from the room with mixed collections and 43 +6.2 m? h"! from other parts of Storage II.
References
Figure 1. The average increase in mass of copper, zinc and lead coupons in Storage I and II, as measured every three months from February 2018 to January 2019 (one year). Error bars display the standard deviation of each set of measurements (three coupons of each metal).
Figure 2. The increase in corrosion thickness on a 400nm lead AirCorr™ sensor measured from February 2018 to January 2019 (one year) in Storage | and II. Figure 2 shows the increase in corrosion thickness on the AirCorr™ lead sensor. The corrosion thickness increased with 5 nm within Storage I with a book collection and 13 nm in Storage II with a mixed material collection after one year’s exposure.
Figure 1. Set-up showing the measurement locations upstream and downstream of the filters as well as the passive diffusion samplers in the middle and in the corner of Storage I and II and the temperature and RH sensor. The concentration of formic acid and acetic acid were measured in the air upstream and downstream of the activated carbon filters (Figure 1). A 0.144 m? sample of air was drawn through a 0.1 M sodium hydroxide solution in a washing bottle at 100 mL min’ using a calibrated pump. The air was sampled over 24 hours. The concentrations collected in the sodium hydroxide solution were quantified by ion chromatography (IC) analysis on an 881 Compact IC pro instrument with an 863 Compact Auto sampler, using an anionic precolumr (art.-no. 6.1005.250) and a column for organic acids (art.-no. 6.1005.200) from Metrohm (Herisau. Switzerland). An acceptable baseline separation between formic acid and acetic acid was achieved with ¢ column temperature of 30°C and a flow rate of 0.4 mL min" using 0.33 mmol L" sulphuric acid as eluent anc 0.1 mol L” lithium chloride as suppressor. The method has a limit of quantification (LOQ) of 5 ug m®? for both formic acid and acetic acid. In both rooms, the formic acid and acetic acid concentrations were measured as an average over ten days using passive diffusion samplers from the Swedish Environmental Research Institute [VL. These measurements determined the impact of active air filtration on the concentration of organic acids close to sensitive collection objects within the storage rooms. The method has a LOQ of 1.4 ug m°? for formic acid and 4 ug m°? for acetic acid. Duplicate samplers were placed at shelves in the middle and in the corner of each room (Figure 1). The temperature and relative humidity were also measured in the middle of each storage room with a Gemini TinyTag View 2 climate recorder (accuracy about +0.2°C and +3% RH).
Figure 2. Set-up showing the RH controlled chamber with cellulose acetate films off-gassing acetic acid to the air stream as well as the measurement locations upstream and downstream of the desiccant silica gel rotor and the temperature and RH sensors. ‘he concentration of acetic acid was measured in the air upstream and downstream of the desiccant rotor Figure 2). The air supply to the desiccant dehumidifier was passed through a humidity-controlled chamber, n which the relative humidity was maintained at 25%, 50% and 70% RH, respectively. The temperature and elative humidity were measured in the air upstream and downstream of the desiccant rotor using a climate latalogger with an external sensor (Gemini TinyTag View 2, accuracy about +0.2°C and +3% RH). Degraded ellulose acetate film sheets were used as an emission source, releasing acetic acid at a high rate into the air upplv.
Figure 3. The formic acid and acetic acid removal efficiency of Filter A and B under normal ventilation conditions and with the fan running at full power in Storage I (light blue) and in Storage II with three mobile stand-alone filter units (dark blue). In grey is shown the acetic acid removal efficiency of the desiccant silica gel rotor at 25%, 50% and 70% RH.
Table 2. The amount and surface area of the cellulose acetate film (acetic acid source) and the adsorbent silica gel and clay brick. The clay brick was processed into a powder. Although the mass of silica gel and clay varied, the volume and exposed surface area of each material was identical and corresponded to the chamber area.
Figure 4. The test room with an adsorbent clay brick wall to the left. The concentration of acetic acid was measured in four locations: one at the emission source, one in the middle of the room and two at the clay brick wall. The temperature and RH were measured in one location. Floor dimensions were 2.7 x 2.4 m. The acetic acid concentration was measured as an average over three weeks using passive diffusion samplers (as described in 3.3). The concentration was measured in four locations within the room; one close to the emission source, one in the middle of the room and two close to the adsorbent wall about 10 cm from the wall surface. 25 g of degraded cellulose acetate film sheets (0.12 m’) were used as the emission source. The temperature and relative humidity were measured with a Gemini TinyTag View 2 climate sensor (accuracy about +0.2°C and +3% RH) in the middle of the room.
Table 1. Information about Storage I and the two rooms in Storage II. The information is collected in Table 1.
Table 2. The Monte Carlo simulation model parameters and input data. The Monte Carlo simulation ignores the contributions of formic acid and acetic acid from construction materials, building interior and people’s activities. The simulation only accounts for the formic acid and acetic acid emissions from heritage collections.
Table 3. The nine scenarios modelled in the Monte Carlo simulation. distribution was therefore assigned to each variable in this study. 5.3 Results and discussion
Table 4. The minimum and maximum organic acid concentration predicted in the Monte Carlo simulations for the nine scenarios. The 95% quartile and the average concentration predicted together with the standard deviation are also given. All nine probability density plots have a similar shape. They are all clearly right skewed. To exclude extremely unlikely high concentrations the 95% quartile were used as the maximum concentration expected. Table 4 show the average predicted concentrations and the standard deviation. The average concentration indicates where the distribution is centered. The standard deviation show the large concentration interval obtained from the Monte Carlo simulations and thereby the uncertainty in the predictions.
Table 5. The simulated surface removal rate of formic acid and acetic acid onto interior surfaces in a room with a paper and a mixed collection.
Table 1 The characteristics of the six paper samples. pH values with an asterisk were determined with own measuring according to TAPPI T509 and differed slightly from the manufacturer’s specifications. Two papers are modern standard test papers produced by Klug Conservation (Immenstadt, Germany): Novo Test Paper 1 contains mechanical wood pulp including 17% lignin, and Novo Test Paper 2 is a wood-free paper made from 100% bleached cellulose pulp. The four other samples are naturally aged historic papers, covering a period of almost 70 years of the 19th and 20th century. They originate from a test sample collection of the Royal Library in Denmark. The exact composition of the historic papers was not established, except for the presence of lignin, which was identified by the phloroglucinol spot test (TAPPI T401, 1992). The aqueous cold extract pH of the samples was Six paper types were selected to represent the variation of paper types found in a typical library collection.
Table 3. Mass-specific emission rate of paper samples from climate chamber measurements, in ng acid emitted per gram of paper, per hour, at normal room temperature, cool, and at dry conditions. The values given are the average of two measurements, plus-minus one standard deviation.
Table 1. Description of the eight samples. *Sample no. 1 was dated based on watermark identification. **The archaeological wood was treated with PEG from October 2013 to July 2016 and then freeze-dried from August 2016 to January 2017. The area-specific emission rates of formic acid and acetic acid were quantified for four naturally aged paper samples (samples no. 1-4) together with two naturally aged wood samples (samples no. 5-6) and a newly produced wood packaging (sample no. 7) used to transport and store heritage collections in storage buildings. As an example of a well-known highly emissive material, the acetic acid emission from a cellulose acetate photographic negative (sample no. 8) was measured as well (Table 1).
Table 2. Surface area, mass and loading factor of sample 1-8. 2.2.2 Active air sampling and analysis
Table 3. Concentration of organic acids (sum of formic acid and acetic acid) in one storage building with mechanical ventilation (1), two rooms in another storage building with semi-passive climate control (II) and outdoor. The measurements were conducted in winter and summer. Table 3 shows the concentration of organic acids (sum of formic acid and acetic acid) outdoor and inside Storage I and the two rooms in Storage II in winter and summer. The concentration outdoor was below the LOQ in winter and summer. The concentration of formic acid and acetic acid were larger inside the storage buildings than outdoor. It is assumed that internal sources as the heritage collections themselves contribute to the concentrations of formic acid and acetic acid inside the storage buildings as the storage rooms contain non- emissive construction materials and building interior such as concrete and metal that would not contribute significantly to the concentrations of formic acid and acetic acid.
Table 4. Temperature (monthly average) in all three storage rooms in winter and summer. 3 in both rooms. Within the same period the temperature increased 7-8°C whereas RH variations remained within the uncertainty of the sensor (43% RH). A study by Krupinska et al. [19] showed a similar trend where the concentration of formic acid and acetic acid increased 5-6 times from winter to summer, and Smedemark and Ryhl-Svendsen [20] showed an 3-8 times increase in the concentration of formic acid and acetic acid with a 7°C increase in temperature from winter to summer within three storage buildings with archival and library collections in Denmark. Our study demonstrated how the emission rates of formic acid and acetic acid as well as the concentration in air inside real storage buildings with heritage collections depend on the temperature. as the concentration in air inside real storage buildings with heritage collections depend on the temperature.
_ Table 5 shows 36 VOCs detected as emissions during chamber tests from the four paper samples (no. 1-4). The recycled newspaper printed in 2017 emitted the largest number of VOCs. Almost all VOCs detected from the paper samples were measured in trace concentrations below 10 pg m® (shown in light blue in Table 5). Identified substances released by the four paper samples detected in chamber air correspond with the VOC profile from paper made of rag and ground-wood pulp found in previous studies [1, 3, 6-7, 27-31]. Compounds as toluene, ethylhexanol, nonanal and decanal were detected as emission substances from all four samples. Gibson et al. [1] detected the same compounds as emission substances from books.
Table 5. VOCs detected in chamber air from the four paper samples at 23°C and 50% RH. The blue colour indicates the presence of the specific compound (light blue indicates trace concentrations and dark blue concentrations above 10 pg m’). In addition, the right column contains references to other studies detecting the same VOC off-gassing from paper.
Table 2. Overview of the input data used to calculate the concentrations of formic acid and acetic acid in the model storage room (Case 1), and the impact of the temperature (Case 2), the air exchange rate (Case 3) and the surface removal rate (Case 4) on the concentration of organic acids in indoor air. The input data for the air exchange rate in Case 3 was taken from [14] and [15], and for the surface removal rate in Case 4 from [13].
Table 3. The energy use (kWh m® year") for Case 1-4. The energy use for each case is collected in Table 3.
The input data to calculate the heat loss through the building envelope and air exchange with ambient was taken from [16].
References
Table 2. Concentration of air pollution in summer and winter in Storage I and II. Organic acid is the sum of formic acid and acetic acid concentrations. <LOD indicate measurements below the limit of detection (ozone < 2.0 ng m°, nitrogen dioxide < 0.4 ug m°, acetic acid < 1.4 ug m°? and formic acid < 1.0 pg m*). Table 2 shows the concentration of ozone, nitrogen dioxide and organic acids in Storage I and II. The concentration of ozone was below detection limit in both stores except for Storage IJ in summer. The concentration diminished indoors to less than 5% of the ambient level. Also, the concentration of nitrogen dioxide was below detection limit within both stores in summer. In winter, the concentration diminished to 9- 4% of the ambient level. 4% of the ambient level.
the corrosion rate of an AirCorr™ monitoring system, when using a copper sensor. The increase in corrosion thickness was associated with both the temperature and RH. In Storage I with a book collection, the corrosion rate increased from 0.1 to 0.8 nm per month when moving from winter to summer. In Storage II, with a mixed material collection, the corrosion rate increased from 0.3 nm in winter to 2.1 nm per month in summer. Prosek ef al. (2013) also found a correlation between the increase in temperature, RH and the corrosion rate of an AirCorr™ monitoring system, when using a copper sensor. Figure 3. Increase in corrosion thickness of the AirCorr lead sensor per month together with the monthly average temperature and monthly average RH from February 2018 to January 2019. Increased colour intensity means higher values.
heritage environments. All filters were new. The formic acid and acetic acid removal efficiency of the activated carbon filters were calculated using Equation 1. Table 1. The product name and cost of the two activated carbon filters, their classification and energy class. *Both filters have been classified as F7 according to EN 779:2012, now replaced by ISO 16890:2016, and the performance tested by ISO 10121-1:2014 and ISO 10121-2:2013. **Filter A and B have been certified as energy class E according to EUROVENT with A+ having the lowest energy use and E the highest (Ecob, personal communication).
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Quantification of formic acid and acetic acid emissions from heritage collections under indoor room conditions. Part I: laboratory and field measurements
by Signe Hjerrild Smedemark

2023, Heritage Science

The area-specific emission rates of formic acid and acetic acid from heritage objects made of wood and paper were quantified for normal indoor room conditions (23 °C, 50% RH) as well as for cooler (10 °C) and drier (20% RH) conditions. At... more
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A Portable Tool for the Evaluation of Microclimate Conditions within Museum Enclosures, Transit Frames, and Transport Cases
by Jorgen Wadum

2023, Studies in Conservation

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Mass-Transfer Air Pollution Modeling in Heritage Buildings
by Signe Hjerrild Smedemark

2023, Heritage

Two simple mass-balance models for estimating the concentration of air pollutants inside buildings are presented for pollutants originating from outdoors or generated indoors. The models can be used to establish average pollution loads on... more
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Levels of Preservation for Cultural Heritage within an Open-air Museum
by Márta Guttmann

2023, Studies in Conservation

Figure 1. Storage facility associated with Z.1 level of preservation. Image: °Astra Museum. Based on monthly averages, 2016-2017 may be con- sidered to be a wet period, with many values over 70% RH, which were distributed throughout the whole year. February was the wettest month, but the most Ultraviolet radiation and visible radiation were mon- itored by sensors measuring the wavelengths 250- 400 nm and 400-700 nm, respectively. Temperature and RH were monitored using Sensirion SHT25 sensors, whilst Alphasense® sensors were installed for measuring ozone, nitric oxide (NO), nitrogen dioxide (NOz) and sulphur dioxide (SO2). We could not say
Figure 2. Dretea Church, the monument where the environmental conditions were monitored for one year. Image: ©Astra Museum.
Table 1. Distribution of objects and monuments by their zones of enclosure, with different climate conditions. Property Environment for Efficient Adaptation to the Cli- matic Changes. They concerned the following par- ameters measured at Dretea Church (Figure 2): temperature, RH, ultraviolet radiation, luminosity, air- borne pollution, nitric oxide, nitrogen dioxide and sulphur dioxide. These refer to Z.2, the zone of enclosure for this ethnographic monument, where the preser- vation conditions are without climatic control. whether the software or the hardware architecture was problematic, but several data losses occurred during monitoring.
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Levels of Preservation for Cultural Heritage within an Open-air Museum
by Elena Luciana Badea

2022, Studies in Conservation

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Monitoring the accumulated water soluble airborne compounds deposited on surfaces of showcases and walls in museums, archives and historical buildings
by Peter Brimblecombe (ENV)

2022, Heritage Science

Background: Cultural heritage objects are subject to the deposition of a multitude of airborne pollutants even when kept inside museums, archives, historical buildings or showcases. Some of the pollutants are quickly deposited onto any... more
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A Portable Tool for the Evaluation of Microclimate Conditions within Museum Enclosures, Transit Frames, and Transport Cases
by Guillermo Andrade

2022, Studies in Conservation

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Voc Emissions from Canvas and Acetic Acid Deposition to Canvas and Glass
by Terje Grøntoft

2022

The protection of paintings and other objects in collections is a major concern for museum administrators, conservators and national authorities. Artwork may get damaged by accumulation of air pollutants inside protective enclosures due... more
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Monitoring the accumulated water soluble airborne compounds deposited on surfaces of showcases and walls in museums, archives and historical buildings
by Kaare Lund Rasmussen

2022, Heritage Science

Background: Cultural heritage objects are subject to the deposition of a multitude of airborne pollutants even when kept inside museums, archives, historical buildings or showcases. Some of the pollutants are quickly deposited onto any... more
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Derivation of a Model for the Calculation of Impact Loads of Air Pollutants to Paintings in Microclimate Frames
by Terje Grøntoft

2022

of gaseous pollutants on paintings installed in microclimate frames (mc-frames), and some examples of modelling results, is presented. The model can be used to study how basic design properties of microclimate frames, such as their air... more
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The air quality inside the showcase containing the remains of the Danish King St. Knud the Holy (+AD 1086)
by Lilian Skytte

2022

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Syddansk Universitet The Showcase containing the remains of the Danish King St . Knud the Holy ( + AD 1086 )
by Lilian Skytte

2022

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Air pollutant depositions in museums
by Janusz Czop

2021

Provides an overview of the possible dangers of air pollution to works of art, using the collection of the National Museum in Cracow, Poland, as a reference. Control strategies and preventive methods are discussed on materials including... more
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IAP Copenhagen 2001
by Maarten van Bommel

2021

While the external climate has strongly influenced planning in the past, today modern technology creates the desired microclimate inside buildings with powerful systems to heating, ventilating, air conditioning (HVAC), and lighting. While... more
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Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI®dosimetry
by Monica Garrido

2021, Studies in Conservation

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air... more
Figure 1 The measurement sites (photos: Google maps, Wikipedia).
Figure 2 MEMORI measurement locations in English Heritage sites. (A) Apsley House, plate, and china room. (B) Ranger’s House, bronzes room, showing the centre showcase (desktop) in foreground, the alcove case back left, and the corner case back right (photos: © English Heritage 2015). A MEMORI dosimeter was mounted inside one of the three Francis Bacon frames (Fig. 3) and removed after three months (6 January — 7 April 2014). The frame was then provided with a sheet of carbon cloth, of the same area as the (non-traditional) panel support and placed next to its reverse side, to act as a pollution adsorber, and a new MEMORI dosimeter inserted behind this for three months (7 April — 7 July 2014). In each case, the dosimeter was placed in the space between the back of the panel and the Melinex covered backboard, located so that air could circulate over both surfaces of the dosimeter. Except for the installation of the sorbant, the frame was in all other respects unchanged from the first MEMORI The boxes were specifically designed for the storage of these materials, but constructed with different types yf high impurity. chemically unstable. low-grade
Figure 4 MEMORI measurement locations in the National Archives of Norway. (A) store room, (B) archive solid board boxes, (C) measurement in box without documents, and (D) measurement in box with documents. MEMORI dosimeters were mounted in a storage room and inside two high-lignin-content solid board boxes, one with and the other without documents, located in the storage room (Fig. 4). The storage room had mechanical ventilation with temperature The MEMORI technology consists of a dosimeter, a small dosimeter reader, and the MEMORI web naagec for evaluation of reaulte and information on
Figure 3 (A) Fixing the MEMORI dosimeter close to the verso of the panel inside the middle Bacon Frame (sitting face down ona table) using spacers on either side to ensure air circulation. The backboard was placed on top and attached to the frame edges. (B) Inserting carbon cloth over the verso of the panel in the Bacon frame before positioning the second dosimeter, as shown (photos: © Tate 2015).
Figure 5 The MEMORI dosimeter.
Figure 6 Measuring of the MEMORI dosimeter.
Figure 8 MEMORI results from measurements in the Tate locations, with colour evaluation for sensitive pigments anc varnishes; inside the Francis Bacon frame without carbon filter (g) and with carbon filter installed (h). The MEMORI technology Innovation for Conservation
high relative humidity. However, the measured RH values, of consistently less than 75% in the bronzes room in Ranger’s House, are unlikely to cause cor- rosion of copper alloys if acetic acid concentrations are below 3000 pug/ m’, or if formic acid concentrations are below 2000 ug/m°* (Cano & Bastidas, 2002; MEMORI-2, 2015). Investigations into this risk are ongoing, with monitoring of acetic and formic acid concentrations and of the copper corrosion rate (Prosek et al., 2014). The unglazed biscuit porcelain in the showcase is known not to be affected by organic acid. The yellow risk category in the high relative humidity. However, the measured RH
Table 1 EWO levels typical for general types of cultural locations in Europe
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Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI®dosimetry
by Monica Garrido

2021, Studies in Conservation

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air... more
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Indoor air pollution impact on cultural heritage in an urban and a rural location in Romania: the National military museum in Bucharest and the Tismana monastery in Gorj County
by Octaviana Marincas

2021, Heritage Science

Assessment was performed of the air quality related risk to the conservation of cultural heritage objects in one urban and one rural indoor location in Romania, with expected different air quality related conservation challenges: the... more
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Predicting Future Condition and Conservation Costs from Modelling Improvements to the Indoor Environment: The Monumental Munch-Paintings in the University of Oslo’s Aula Assembly Hall
by Terje Grøntoft

2021, Journal of Conservation and Museum Studies

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Indoor air pollution impact on cultural heritage in an urban and a rural location in Romania: the National military museum in Bucharest and the Tismana monastery in Gorj County
by Terje Grøntoft

2021, Heritage Science

Assessment was performed of the air quality related risk to the conservation of cultural heritage objects in one urban and one rural indoor location in Romania, with expected different air quality related conservation challenges: the... more
Fig. 1 The measurement locations in the National Military Museum. 1a In the warehouse for foreign uniforms, 1b in a melamine fibreboard storage wardrobe in the warehouse, 2b in a wooden historic storage chest in the probative objects storage room, 3a ina contemporary history room in the main museum building, and 3b in a display showcase in the contemporary history room. No photo was available of the samplers at location 2a in the probative objects storage room
Fig. 2 The Tismana monastery in Gori County, Romania, and its iconostasis. Photos of the exact measurement locations in the icons and textiles, and book, rooms were not available. Photo courtesy: Tismana monastery
Fig. 3 a The Memori-EWO (PPO) synthetic polymer dosimeter in an aluminium holder. Four dosimeters can optionally be mounted in the holder for simultaneous parallel measurements. b A passive pollution IVL (Swedish environmental institute) type badge sampler, as was used to measure acetic and formic acids. In Fig. 1, the dosimeters and samplers are seen placed at the measurement locations
Fig. 5 The measurement results for the locations in the National military museum and the Tismana monastery presented in the three remaining of seven (out of 22) Memori material risk evaluation diagrams, where some risk (red or yellow) were indicated (see the Fig. 4 caption)
Fig. 6 The measurement results for the National military museum and Tismana monastery locations compared with ranges of EWO response for five categories (1 to 5) of “typical museum locations” as found in the EU MASTER project [23, 28], and with approximate risk levels for the formic + acetic acid concentration (see “Methods” chapter). For the location outside of the rooms in the Tismana monastery the EWO dosimeter measurement was not performed
Table 1 The values for the air quality measured with EWO-PPO dosimeters and the passive badge samplers for acetic and formic acid, in the locations in the National military museum and the Tismana monastery a a a I eS at Fig. 4 The measurement results for the locations in the National military museum and the Tismana monastery presented in the seven (out of 22) Memori material risk evaluation diagrams, where some risk (red or yellow) were indicated are given in this figure and in Fig. 5. In the top diagram, for lead, the measurement locations are described by the circular results point markers. The circular point markers give the measurement results for the EWO (photo-oxidizing effect) on the horizontal axis, and the results for the acetic + formic acid measurements, represented by the GSD (Glass slide dosimeter) values (see “Methods” section), on the vertical axis. The locations are repeated for all the materials diagrams below the first diagram for lead. For the location outside of the rooms in the Tismana monastery, “T-in corridor outside of rooms’, the EWO dosimeter value (photo-oxidizing effect) was not measured (Table 1), and the value on the x-axis is therefore not determined (see Table 1).“Green” indicates that, within the constraints of present knowledge, it is unlikely that the materials will change significantly within a period of perhaps 30 years. ‘Red’ indicates that damage is likely to occur to objects within 3 years and that damage will require active conservation. ‘Yellow’ indicates a situation in between
Table 2 Memori risks results summary diagram for the measurement locations in the National military museum and Tismana monastery
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Impact Loads of Air Pollutants on Paintings: Performance Evaluation by Modeling For Microclimate Frames
by Terje Grøntoft

2021, Journal of the American Institute for Conservation

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Assessment of indoor air quality and the risk of damage to cultural heritage objects using MEMORI®dosimetry
by Joyce Townsend

2021, Studies in Conservation

Air pollution is one of the environmental influences that degrade cultural heritage objects situated indoors. Other essential influences, such as temperature, relative humidity, and light are often well monitored. The presence of air... more
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Colour measurement of acid-detector strips for the quantification of volatile organic acids in storage conditions
by Stephen Hackney

2021, Studies in Conservation

Stephen Hackney (2016) Colour measurement of acid-detector strips for the quantification of volatile organic acids in storage conditions, Studies in Conservation, 61:sup1, 55-69, Acid-detector (A-D) strips were originally developed to... more
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Impact Loads of Air Pollutants on Paintings: Performance Evaluation by Modeling For Microclimate Frames
by Guillermo Huayama Andrade

2019, Journal of the American Institute for Conservation

Modeling of the transport (fluxes) of gaseous air pollutants to the surfaces of paintings installed inside six different microclimate frames (mc-frames) was performed. Mc-frames are used to protect paintings against the external... more
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Monitoring air pollutants in showcases by proton-transfer-reaction mass spectrometry and passive samples tubes
by Stefan Röhrs

2015

Air pollutants which originate from volatile organic compounds like organic acids and solvents are a threat to objects of various materials displayed in a showcase. Proton-transfer-reaction mass spectrometry (PTR-MS) is a new approach... more
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IMPACT LOADS OF AIR POLLUTANTS ON PAINTINGS: PERFORMANCE EVALUATION BY MODELING FOR MICROCLIMATE FRAMES
by Michał Obarzanowski and 
2 more
Guillermo Andrade
susana lopez-aparicio

2014

Modeling of the transport (fluxes) of gaseous air pollutants to the surfaces of paintings installed inside six different microclimate frames (mc-frames) was performed. Mc-frames are used to protect paintings against the external... more
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Improved Protection of Paintings during Exhibition, Storage and Transit Final Activity Report
by Michał Obarzanowski and 
1 more
Janusz Czop

2013, propaint.nilu.no

Examples of passive diffusion gas samplers for a) A range of gases depending on preparation of absorbing medium. b) Volatile Organic Compounds (VOCs) and c) Formaldehyde.
The main dosimeters used in the PROPAINT project: A. The NILU EWO (Early Warning dosimeter for Organic materials). B. The Birkbeck PQC (Piezoelectric Quartz Crystal) dosimeter and C. The Fraunhofer ISC GSD (Glass Slide Dosimeter). Dosimetry can be thought of as the inverse of parameter monitoring. In parameter monitoring the potential for deterioration is inferred from environmental measurement. We assume we are measuring all the relevant parameters and may have to employ a range of techniques to do so. In dosimetry some form of sacrificial material that responds similarly to the materials of interest is exposed to the environment, and from its deterioration, the quality of the environment is inferred. Dosimetry has the advantage that a generic and synergistic integrated effect of all or a part of the different environmental factors (parameters) present in the environment (e.g. climate, light, pollutants) is usually measured.
5: The EWO dosimeter developed at NILU, exposed at Statens Museum for Kunst, Copenhagen, DK. Upper Right; the holder for up to four dosimeters, below the miniaturised holder for one dosimeter. In the EC funded project MASTER (2003-2006; MASTER project, 2009) an Early Warning dosimeter for Organic materials (EWO) was developed by the Norwegian Institute for Ait Research (NILU), (Figure 4A and Figure 5). The EWO dosimeter is a synthetic polymer sensitive to NO2 and O3, and to SO2 only at high humidity and concentrations, usually emitted outdoors and ventilated or infiltrating to the indoors. It is also sensitive to the climate parameters of temperature and UV light, and it has indirectly been calibrated for RH using RH - T isoperm values (Sebera, 1994). The effects of the environment on the EWO dosimete1 was initially measured in 120 periods of 3 months, in 30 locations in 10 European museums, during one year campaign in the EU project MASTER (Grentoft et al., 2006). Calibration of the dosimeter response against the environmental influences has also been performed. Further, evaluation of tolerable response levels for the EWO, as compared to effects on organic cultural heritage objects, was performed. The evaluation was based on reported degradation impacts of single environmental parameters on heritage objects (Tétreault, 2003) and suggested environmental standards for indoor cultural heritage locations as reported in the literature (ASHRAE, 2007). Tolerable impact levels were suggested for indoor cultural heritage locations with different degree of protection against the outdoors, ranging from archives to outside stores with no control (Figure 6). Tolerable response levels for showcases were set to one level lower than the indoor location.
re 7: The PQC dosimeters for continuous operation, developed by Birkbeck, exposed at Statens Museum for Kunst, Copenhagen, DK. eight PQC-dosimeter crystals (four RM-PQC and four L-PQC), two to four crystals clamped between steel plates were suspended within the microclimate frames. The frequency shift for the PQCs was measured before and after the exposures, and was calculated as the % change in frequency or (Hz/kHz) shift in frequency. L-PQC values are only compared between themselves, as are RM-PQC values, and the different units can be compared to results in Odlyha et al. (2005) and SENSORGAN (2009). High values of change correlated with the presence of high levels of photo-oxidising agents (RM-PQC crystals) and high levels of volatile organic acids (L-PQC). A new miniaturised prototype for measuring the frequency shift of the crystals in real time has been developed within the PROPAINT project for use within the restricted environment of the microclimate frames (Figure 7). 3.3.2.4 The Glass Slide Dosimeter
Figure 8: The Glass Slide Dosimeter developed by Fraunhofer ISC, exposed at the National Museum in Krakow, Poland. treatments, MI, M2, and M5), were exposed. The dosimeter type that was found to be best suited for indoor museum room and showcase measurements over the last 15 years (M1.0 with fire polishing finish), and showed the best sensitivity and linear behaviour, was used in PROPAINT.
Environmental Glass Slide Dosimeters (type M1.0 and MI): range of exposure results (4E-values) and related evaluation criteria after 3 month exposure (see also Figure 14). In Figure 9, the range of possible and observed Glass Dosimeter results (AE-values) ar shown together with related evaluation criteria for environmental risk potential regardin: artworks.
igure 10: Environmental Glass Slide Dosimeters: correlation of AE-values (3 months exposure) after acetic acid exposure vs. acetic acid concentration (all available data).
yure 11: Three dosimeters: 1. Early Warning Organic (EWO) dosimeter 2. Resin Mastic (RM-PQC) and Lead Piezoelectric Quartz Crystal (L-PQC) and 3. The Glass Slide Dosimeter (GSD), mounted inside the “modern” SIT-Artyd microclimate frame (A) and a “historic” frame adapted to microclimate frame at English Heritage, Apsley House, London, UK (B). C: Glass enclosure for painting (National Museum in Krakow). D: Showcase (Uffizi Gallery). Two general types of microclimate frame designs were tested: “Modern” new microclimate frames purpose built by the SIT-Artyd Company and “historical” microclimate frames adapted to existing picture frames (Figure 11 and Table 3). In location no. 12 (Table 3) the painting was placed in a more open purpose built glass enclosure with glass (front and sides) fitted to the wall (Figure 11C). Measurements were also performed in a showcase located in the Uffizi Gallery, Florence, Italy (Figure 11D).
Figure 12 shows exposure locations in the end-user institutions. The measurements in PROPAINT were divided between a general measurement campaign and different case studies. In addition to the dosimeters, passive diffusion gas samplers and climate measurements, the air exchange rates of the microclimate frames were measured in the general campaign. The general measurement campaign included all locations (Table 3). The case studies focused on specific concerns and were carried out at selected locations (see Chapter 4.6). (Results for four additional frames located in the SIT workshop are given in Appendix 1).
Figure 13: The Dosimeters placed outside the microclimate frame with a painting made by Edvard Munch, Nasjonalmuseet for Kunst, Arkitektur og Design, Oslo, Norway.
4 Dosimeter results obtained inside and outside microclimate frames for paintings with (A): The Resin Mastic POC dosimeter (f/ F, = relation between the frequency shift and the original coated crystal frequency, KHz). For SMK2 measurement was not performed outside the microclimate frame. The standard deviation for the measurements ranged from 0.66 to 1.0 with unit 1000*f/Fo. (B): the Lead PQC dosimeter (Change (%) in frequency or mass). In the case of SMK2, EH.K and SIT-Artyd, measurements with L-PQCs were not performed in the rooms. For the other rooms no response was detected. The standard deviation for the measurements of the L-PQCs ranged from 0.12 to 0.22 %. (C): The EWO dosimeter (average of two parallel exposures, except in GNM room. The EWO response is in absorption units at 340 nm). SMK = SMK1. Number in brackets are tolerability location levels [11] (at RH = 55%): [1]: Archive store, [2]: Purpose built Museum Gallery, [3]: Historic House Museum, [4]: Open display in open museum, [5]: Outside store with no control. (D): The Glass Slide Dosimeter. (AE - Extinction values measured as IR absorption at 3300 cm"). (SMK = SMK1, “Rubens frame” = SMK2).
gure 15: Results from exposures of the EWO, GSD. L-PQCs and RM-PQCs inside and outside the SMK2 microclimate frame (Table 23). The units for the L-PQC and RM-PQC are % change and 1000*f/F (= relation between the frequency shift and the original coated crystal frequency), respectively.
Figure 18: Concentrations of NO2 and O3 measured inside and outside microclimate frames. For location abbreviations see Table 3 and table in Figure text 12. Sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), organic acids (acetic and formic acids), formaldehyde and VOCs (Volatile Organic Compounds) were measured. Inorganic gases, such as NO, SO and Os, are formed mainly outdoors and infiltrates to the indoor environment, and into microclimate frames. NO2 and 03 were measured inside nearly all the microclimate frames, varying between 1 and 5 pg m®, and 1 and 7 pg m°®, respectively (Figure 18). SO2 concentrations inside microclimate frames were generally very low (<0.5 pg my’).
Figure 17: Correlation between dosimeter responses in microclimate frames and rooms. A: EWO and RM-PQC with locations tolerability levels (Figure 14C and A). B: GSD and L-PQC with impact levels (Figure 14D and Figure 15B).
Figure 19: Total concentration of volatile organic compounds (TVOC), acetic acid, formic acid and formaldehyde measured inside and outside microclimate frames. For location abbreviations see Table 3 and table in Figure text 12. compounds are emitted by materials commonly used in the construction of microclimate frames and from the objects inside the frames. Measurements inside the microclimate frames showed acetic acid concentrations varying from 30 to 2000 ug m™®, formic acid between 3( an 500 pg m®, formaldehydes between 1 and 6 pg m® and TVOC between 100 and 5000 pc m’? (Figure 19).
Figure 21: Mean temperature measured inside and outside the microclimate frames for paintings. For location abbreviations see Table 3 and table in Figure text 12.
Figure 22: Mean relative humidity measured inside and outside the microclimate frames for paintings. For location abbreviations see Table 3 and table in Figure text 12.
Figure 23: Air exchange rate of PROPAINT-microclimate frames. For location abbreviations see Table 3 and table in Figure text 12.
jure 24: The position of the L-PQC dosimeter (crystals in flat silver holder) is shown using the arrow (left). The green and black traces show the change (%) in the crystals on exposure. The change occurs over the first 10/15 days. After 20 days the conditions in the microclimate chamber were changed (RH,T) (Right). Sa Ee eee ae Se Se a ee eee A a ee en a ae a es a a follows: The frame inside was secured using Aluminium foil 3M (nr 425) and it had a poly-carbonate back plate. Temperature, RH, pressure, CO2, acoustic emission and dimension sensors were also included. The frame was placed into a microclimate chamber. The strong increase in the rate of change of the L-PQC was observed after about 5 and 7 days lasting for about 5 and 15 days respectively (black and green curves in Figure 24). The total change over this period was about 12 % (Which was higher than the value (6.75 %) obtained for the English Heritage frame C (Case 2) with a similar air exchange rate and piece of oak wood (80 g) enclosed, after exposure for 3 months). After about 20 days an increase in temperature and RH seemed to cause a further change in the crystals (up to 20%) which remained a steady level despite further changes in RH and T.
jure 26: Back of Rossetti painting with hardboard backing removed. Top right hand corner shows crystals mounted in steel frame and top left corner shows lead coupon and A-D strip (Left). Reverse of Rossetti painting showing deposits on brass plates (Right).
Figure 27: Dosimeters exposed in store room of the National Research Institute for Cultura Properties, Tokyo, Japan.
Figure 28: EWO results at the National Research Institute for Cultural Properties, Tokyo, Japan.
Figure 29: Above: preparation of the varnish samples. Below: envelope containing a set of varnish samples. Figure 29 shows the preparation of the varnish samples.
Figure 30: The exposure chambers at NILU. Accelerated ageing of the varnish samples were carried out in the exposure chambers at NILU (Figure 30). 1.3.2 Accelerated ageing
Figure 31: Tate Britain, London (UK). Inside the frame. The varnish samples are exposed to light. No photos are available from outside the frame; - they were exposed to light. Figure 31 to Figure 36 show the exposure sites, also explaining if the varnish samples were exposed in the darkness or in the light.
Figure 33: Museo de Bellas Artes de Valencia (ES). Inside (left) and outside (right) of the frame. The varnish samples were exposed in the darkness.
Figure 34: National Museum in Krakow (PL) “Leonardo”. The varnish samples are exposed to light.
Figure 39: Amount of free terpenoids extracted from the natural varnish samples that were exposed on site, inside and outside the frames.
Figure 41: Thermogravimetric graph for MS2A (continuous line) and relative derivative (dashed line).
Figure 43: Comparison of the relative amounts of monomers, dimers and macromolecular fraction evaluated as the sum of peak areas in chromatograms corresponding to the thermal desorption at 130 °C, at 250 °C and pyrolysis at 500 °C, respectively.
Figure 44: GC-MS chromatograms of MS2A resin of the varnish sample NO2-80-59 desorbed at 130°C.
The softening temperatures of resin mastic films on steel were measured by DMA and compared with that of the control sample. Shifts to higher temperatures indicated the formation of a more cross linked film. Highest values and evidence of a more damaging effect were observed in resin mastic films exposed to ozone at low RH (20 %). The temperature shift was about 30°C and this could be correlated with an increase in the ratio of mass fragments (523/409) in the MALDI-TOF spectra. The rationale for using this ratio was based on previous work (Scalarone, 2005) where the mass fragment at 523 was attributed to the possible formation of the oxidation product oleanic aldehyde and fragment 409 was attributed to dammardienol, the unoxidised part of the material. Figure 45 shows the effect of ozone exposure on resin mastic and the dominance of fragments in the 520 region. Figure 45: MALDI-TOF spectra for resin mastic sample exposed to an O3 dose of 117.4 ppm* day at 20 % RH.
The results obtained for the onset of softening of resin mastic films are discussed in terms of the environmental conditions, mainly the levels of inorganic and organic pollutant gases measured at the sites. The effect of ozone is most evident in the sample exposed in the museum in Mexico. Figure 46 shows values for Tg for resin mastic strips exposed in frames and in rooms. The sample in the room in the Museum in Mexico was exposed to a higher than recommended level of O3 (19.9 ug/m®) (Figure 47). The sample exposed inside the microclimate frame in Mexico city had the highest Tg value. The frame appeared not to offer any protection as the Tg in the frame was equally high as in the room (Figure 46 and Figure 49). Measurable levels of O3 (1.4 ug/m*) were present within the frame and may together with acetic acid, and light have been a contributing factor. Figure 46: Tg values for resin mastic in frames (deep red) and resin mastic in rooms (blue).
Figure 48: Acetic acid concentrations i1 frames. “igure 49: Tg values of resin mastic films in frames.
igure 51: NO2 concentrations of strips in rooms.
Figure 52: Graph shows the plot of Tg (°C) vs. sites. IN = Inside microclimate frames. OUT = outside microclimate frames. Tg values for dammar strips exposed at the sites are shown in Figure 52.
Figure 55: Temperature and relative humidity recorded inside the microclimate frame for the painting “La Nana” In the Picasso Museum, Barcelona, Spain.
Microclimate frame sealed (left); Front of frame (right)
Figure 60: Microclimate frame for “epitaph of Jan Stupecki” (section).
mainly from traffic emissions (Mexico City, MNA, Oslo, NG, London, Tate B, and Valencia, MBV). In contrast, the pollution load inside the microclimate frames was found to be worse than for the unprotected (by the microclimate frame) room situation, in a more rural area (Germanic National Museum, GNM), for a room with good environmental control (Tate Store) and for a microclimate frame with high inside emission of organic acids (English Heritage, Kenwood). The SIT 1 microclimate frame was a test case with a specially constructed high emitting inside environment.
reverse of the frame (fig. 1). No sorbent material is added; the buffering role of the panel is considered sufficient. A cclimatisation of the painting in the correct relative humidity is critical for the conditions in the microclimate box. Over the course of many years it has been observed by conservators in the Mauritshuis that hazy deposits regularly form on the inside of the glass. This has also been observed in other museums which glaze their paintings. These hazy deposits, often referred to as ghost- transferred- or mirror images, are disturbing and can severely obscure the art work. Often these deposits are associated with the image, hence the term mirror images (Williams 1988; Skaliks 1999). The hazy deposits are greasy in nature and depending on thickness, are greyish or whitish in appearance. In the Mauritshuis they are removed periodically by the framing technician, first with water and green soap” using a micro-fibre cloth, followed by wiping with ethanol and damp paper. Concern has developed as to the recurring nature of the deposits and the long term effect on paintings. The reoccurrence of deposits has implications for the microclimate box design and climate conditions in certain locations in the museum. Regular removal of the deposits has furthermore significantly increased the work load for the technical staff: since 2001, when cleaning of the glass began being recorded, hazy deposits on more than 200 paintings have been removed.
Resultaat: Het spectrum van de aanslag op het glas vertoont absorptiebanden die overeenkomen met absorptiebanden in het referentiespectrum van natriumstearaat (een natriumcarboxylaat). Specifieke absorptiebanden in het referentiespectrum van natriumstearaat zijn: 1555 — 1469 - 1439 - 1418 - 719 - 698 cm?
Fig. 9. Temperature and relative humidity measurements from a test painting in microclimate box exposed to direct sunlight, 22 January 2005. (The anomalous low relative humidity of the air in the box (35%) in the lower spectrum was due to insufficient conditioning of the test painting prior to placement in the microclimate box (from Baan and Van Duijnhoven 2005, p. 51)).
re 6: Table for interpretation of environmental quality for cultural heritage in different locations based on EWO dosimeter results. (Grentoft et al., 2006).
The locations for exposures in microclimate frames in PROPAINT fable 3: The locations for exposures in microclimate frames in PROPAINT * M = “Modern” new built. H = “Historic” modified. O = Open microclimate enclosure. **Glass in microclimate frames and rooms is not included. (-) = not available. ~ Measurements were also performed in a showcase in the Uffizi, Italy and in a storeroom Japan (Figure 12).
| Light measurements at the sampling locations, obtained by light dosimeter (LightC heck©) and/or sensors. The dose values were normalized to 1 year dose exposure.
3.6.4 Case 3: Continuous monitoring in Experimental Frame The L-PQC dosimeter with continuous recording facilities (battery operated) was set up for testing in the experimental frame prepared in the laboratories of the National Museum in Krakow (Figure 24). The frame had the following dimensions: 65 cm x 59 cm x 9.4 cm
8: Exposure of L-PQC in the back of the frame of Rossetti’s painting. In this Case Study two L-PQC crystals, a lead coupon, and an A-D strip were placed at the back of a wooden frame with oil-tempered hardboard back which was covered with thin Melinex. The painting inside the microclimate frame was Dante Gabriel Rossetti’s painting “Sancta Lilias” (Tate Store, acquisition no. N02440, oil on canvas 483 x 457 mm frame: 815 x 795 x 105 mm) (Figure 26). Table 8 gives the results from the L-PQCs.
Table 11: Sites and durations for field exposures of varnish samples in PROPAINT.
Table 13: Values of Tg for accelerated aged samples of dammar and dammar and tinuvin.
Table 1-1: Results from the dosimeter measurement in PROPAINT.
Table 1-2: Results from the passive diffusion gas sampler measurement in PROPAINT.
With mockpainting and separated dosimeters. 7 With mockpainting and dosimeters together. > New empty frame. “New empty - "bad" materials. ° New empty - good" materials
*) at the time of PROPAINT project, c. 2008 Table 3-1: Microclimate frame characteristics
Table 3-2: Microclimate frame inner dimensions.
Table 3-3: Artefact dimensions.
Table 3-4: Total frame + artefact. Dimensions.
Table 3-5: Site characteristics.
Table 3-6: Room volume and air exchange.
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