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CONSERVATION AND ENVIRONMENTAL CONDITIONS IN A TEMPORARY STORAGE AREA OF PALAZZO SOLIANO IN ORVIETO Mariarosaria Di Napoli1, Laura Rivaroli1, Roberta Talone1. Alessandra Cannistrà2, Elisabetta Giani3, Annamaria Giovagnoli3, Maria Pia Nugari3, Elena Ruschioni4

1 Private restorers 2 Museo dell’Opera del Duomo di Orvieto, Piazza del Duomo, 26 - 05018, Orvieto (Tr) 3 Istituto Superiore per la Conservazione ed il Restauro, Via di San Michele, 23 - 00153, Roma 4 Istituto Centrale per il Restauro e la Conservazione del Patrimonio Archivistico e Librario Via Milano, 76 - 00184, Roma Key words: environment, monitoring, storage area, preventive conservation. ABSTRACT This work concerns a conservative and environmental study of the first floor of Palazzo Soliano, an historical building located next to the Orvieto’s cathedral which is temporarily used as a storage area by the M.O.D.O. (Museo dell’Opera del Duomo di Orvieto). The cultural properties housed in building consist of heterogeneous materials (textile, ceramics, glasses, stone materials, canvas, metals, paper). These objects are preserved in different storage units (racks, shelves and cases). The study of the storage area and of objects conservation conditions was realized by using the Environmental Data Sheet (EDS) and the Collection Data Sheet (CDS), a methodology developed by Istituto Superiore per la Conservazione ed il Restauro. The EDS is a tool that helps to highlight the features of the storage environment, by carrying out seasonal microclimate monitoring, as well as chemical air quality and entomological monitoring campaigns. Through the correlation of all these data with the information collected with the EDS and the CDS, it was possible to evaluate the conditions of the objects in relation with the environmental, structural and architectonic characteristics of the storage area. This study allowed to detect some causes, linked to the main typologies of objects decay. INTRODUCTION The present study1

is based on an analysis of the issues pertaining the preservation and the definition of a preventive conservation strategy of part of the Museo dell’Opera del Duomo di Orvieto collections, currently guarded in a temporary storage area, located on the first floor of an historical building: Palazzo Soliano. The storage area is a large rectangular-plan hall (17m wide, 37m long, 20m high) and is accessible through a large wood front door, which directly faces the west side of Piazza del Duomo (Figs. 1, 2).

The hall is provided with double rows of leaded glass windows, with a wood truss vaulted ceiling and tufaceous walls directly bordering on the outside. There are no Heating Ventilating Air Conditioning

1 For further information about the topic see M. DI NAPOLI, L. RIVAROLI, R.TALONE, I depositi del Museo dell’opera di Orvieto

studio conservativo e proposte di allestimento, 10 December 2009, B. A.’s Graduation Thesis ISCR - 59° National Exam.

Fig. 1 - Palazzo Soliano – Orvieto Fig. 2 - The map of the storage area

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(HVAC) systems and daylight is the sole source of lighting entering trough the windows. The analysis of the building started with an historic inquiry, aimed at detecting the conservative history of the housed collections, for a better understanding of the current typology of decay of the items. The collections belong to the Opera del Duomo as a part of the museum founded in 1882 and they are constituted by artistic funds coming from churches, monasteries and fraternal orders in the county of Orvieto, from town deposits, from private donations and from decorative, pictorial and sculptural works dated between XVI and XVII centuries removed from the Duomo after the restoration completed at the end of the XIX century. The knowledge of the origin, the architectural structure and the different functions of this building/storage area are indispensable elements for defining the ambient adequacy for the preservation of the artefacts. Palazzo Soliano was built at the end of the XIII century and has undergone different interventions in the following few centuries until the XIX century renovation works which defined its current features: the works finished in the 1897 and the wide hall on the first floor was used as exhibition hall. In 1989 the museum was closed and structural works began in order to obtain a better fruition of the space. Today the hall is temporary used as storage area. METHODOLOGY Complying with the Atto di indirizzo 2, it was decided to analyse the status quo of the storage area, with a double approach: the Environmental Data Sheet (EDS)3 associated to the Collection Data Sheet (CDS)4. Such instruments allow to interrelate collected data and to evaluate the items’ conservation conditions, in close relation with the environmental, structural and architectural features of the spaces in which they are stored. The EDS, was developed by the ISCR and permits to obtain an overall description of the environmental characteristics through an analysis of the physical, chemical and biological aspects. As for the methodology of the preservation inquiry, it has been applied the statistical method by filling the CDS and using of the SOS Collections®5 software. RESULTS Collections

The results obtained through the combined elaboration of the acquired data provided a detailed picture of the conditions of the entire collection, highlighting the “weak” points of the storage area. From the recorded data it emerges that there are approximately 2230 stored items. The collections are constituted by heterogeneous objects such as archaeological finds, paintings, sculptures, ceramics and majolica, fabrics, textiles, furniture, numismatics and graphic works

(Fig. 3).

2 Decreto Ministero Beni e Attività Culturali del 10/05/2001, Atto di indirizzo sui criteri tecnico-scientifici e sugli standard di

funzionamento e sviluppo dei musei (Art.150, comma 6, D.L.n.112/1998), in Gazzetta Ufficiale n.224 del 19 ottobre 2001 – Serie generale, Supplemento N.238, Allegato A.

3 G. ACCARDO, C. CACACE, E. GIANI, A. GIOVAGNOLI, M.P. NUGARI, Museum collections: data sheets for improve management, in Proceeding of Conference Conservation Science 2002, J.H. TOWSEND, K. EREMIN, A. ADRIAENS (eds.), Edinburgh (Scotland) 22-24 May 2002, Edinburgh 2003.

4 B. FOSSA, Une stratégie préventive pour la conservation des collections en réserve. Une expérience dans le musée archéologique national de la "Villa Giulia" à Rome. Mémoire de maîtrise, Université de Paris I-Panthéon-Sorbonne, MST en conservation et restauration des biens culturels, Paris 1995.

5 B. FOSSA, M. TRUGLIO, SOS Collections®:Un programme personnalisé au service de la conservation préventive. In “Informatique & conservation-restauration du patrimoine culturel” (8es journées d'études de la SFIIC, Chalon-sur-Saône 23-24 octobre 1997), Champs sur Marne 1997.

Fig.3 – The distribution of the item

ceramic21%

stone17%

w all painting15%

tissue14%

paintings on canvas10%

metal alloy10%

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The items are being preserved according to different storing methodologies, not always meeting the correct preservation tenets, but more often determined by needs connected to the objects’ size, in relation to the available space. As the storage area was temporary, a non-programmed development was followed, with subsequent crowding of the spaces, in which heterogeneous items have been amassed, sometimes in contact because free from wrapping material. The stocking units present in the hall are: a vertical rack with frontal sliding opening and with metal bars shelves, wooden cases in different shapes, wood cupboards with glass doors, large chest of modular shelves. Most of the two-dimensional pieces are housed, hanged or leaned, on the rack’s bars shelves. Many different items, made up of different materials, are being kept in wooden cases, not always provided with cushion material. In the wood cupboards with glass doors there is stored the collection of medieval majolica works, free from wrappings and set on different shelves. Finally, the large chest of modular shelves hosts both wrapped materials and wooden cases (Fig. 4). Other items are placed on wood platforms or on the bare floor. Such situation makes difficult the accessibility, the handling and the visual inspection of the items, raising the risk of damages.

Environment Physical monitoring Microclimate monitoring consisted in three campaigns of data acquisition. The survey was made by continuous monitoring of temperature and relative humidity values using datalogger, Escort Data Logging Systems L.t.d.. The examined period was divided in twelve weeks and began from winter through all spring and summer. Monitoring shows that the storage temperature and humidity were not always suitable for the proper preservation of items and they were often discordant with those recommended by the Atto di indirizzo (see reference 2). A large number of items responding to different microclimatic needs is stored together. In the graph, in different colors, the ranges of recommended values of temperature and relative humidity are underlined (Fig. 5); in this ranges a large number of materials can be safety stored.

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Fig. 4 - Different stocking units

Fig.5 – Seasonal behaviour of temperature and relative humidity recommended ranges

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The graph shows that in winter (from 03/02 to 02/03/2009) the temperature remained below the threshold of the recommended values, but not reaching harmful temperatures for the objects; in spring (from 05/05 to 01/06/2009) it is mostly constant within the threshold, while in summer (from 16/07 to 08/12/2009) it reached high and unsuitable values. The daily temperature fluctuations have generally remained within an acceptable range, except for sporadic events. The relative humidity is the more critical parameters especially for hygroscopic materials (paper, textiles, etc.); in fact in the first part of the winter RH values reached 75%. In summer they sometimes reached 35%, harmful values for wood paintings and leather objects. Moreover, a further critical aspect regards the RH daily fluctuations, that reached 10%, as in winter as in spring, and 20% in summer. Chemical monitoring Together with the microclimate survey, a chemical monitoring was performed focusing on CO2 concentration and particulate matter concentration (PM10). A weekly monitoring of CO2 has been carried out by Air Flow IAQ910 for each season to cover the whole year. Measurements were acquired outside and in two different positions inside the storage area: one close to the front door (A) and the other at the end of the hall (B). The CO2 concentration outdoor increases gradually from winter to summer, and decreases during the autumn season (Fig. 6); the maximum value (485 ppm) was recorded during the summer season. During winter and spring at point A, carbon dioxide concentrations were recorded similar than the outdoor ones, while in summer and autumn higher values than outdoor were found. The CO2 concentration at point B was always lower than at point A.

This may be explained by the proximity of point A to the not air-tight door which increases the outdoor-indoor air exchanges. Seasonal monitoring of the particulate matter concentration was carried out using the Microdust PRO 880 nm Aerosol Monitor System. The measurements were performed within the storage in the same positions of CO2 monitoring. The PM10 concentration varies considerably in relation to the door opening and to the use of the storage. At point A, values are always higher, confirming the continuous air exchanges between inside and outside (Fig. 7). However the evaluation of the collected data indicates that the air quality values of Soliano storage, in all seasons, are within the recommended values; in the Atto di indirizzo the threshold for this pollutant is fixed at 30μg/m³. Biological monitoring The cataloging and conservative inventory work of the artifacts has consisted in a detailed analysis of the conservation conditions of the objects. In some cases, some biological degradation forms were observed. Microbiological investigation has been carried out; in particular specific sampling was done on a tissue paper used as packing material for some marble slabs decorated with glass (Fig. 8). The sample was analyzed under a stereomicroscope (Leica MZ16) and an optical microscope (Leica DMRB) and they showed the presence of numerous reproductive structures of an Ascomicete: the Chaetomium sp. (Fig. 9). This fungal strain has strong cellulolytic capacity and therefore it is frequent in degradation of paper and

Fig.6 – Concentration of carbon dioxide Fig.7 – Concentration of PM10

Palazzo Soliano: CO2 concentration

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Palazzo Soliano: CO2 concentration

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Fig.7 – Concentration of PM10 Fig.6 – Concentration of carbon dioxide

Palazzo Soliano: CO2 concentration

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cellulosic materials. The presence of Chaetomium is probably due to environmental conditions that present high relative humidity favorable to its proliferation.

At the same time an entomological survey was conducted by passive traps. Near the two middle windows 2 sticky traps for flying insects (Bio - Trap, Bio Control s.r.l.) were placed to take advantage of the attractive effect of light to certain insect species (phototropism), while 18 sticky traps for crawling insects have been placed on the floor along edges and corners of each side of the building (Crok - trap, Bio Control s.r.l.). On the West side, since there is a book case with three shelves, at each height traps for crawling insects were placed The captured insects have been identified by stereomicroscope analyses; harmful and not harmful organisms and the prevalent typologies were detected; the results are summarized in figure 10. In table 1 the most frequent founded insects, the materials they damage and the conditions of growth are reported.

Fig.8 – Fungal attack on the packing material Fig.9 – Chaetomium at the stereomicroscope

Fig.10 – Damaging insects

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The total fauna distribution resulted homogeneous; the insects presence appeared permanent and well distributed. The insects concentration was maxima on the ground and decreases on the shelves up to be almost null in the higher levels. This fact should be determined, not only by lower number of crawling insects at high levels6, but mainly by the minimum amount of organic materials on these shelves. The

6 U. CESAREO, G. MARINUCCI, E. VECA, E. RUSCHIONI, Il monitoraggio entomologico negli ambienti di conservazione dei beni

archivistici: un'esperienza nell'Archivio di Stato di Roma, in “Bollettino ICR – Nuova Serie”, n.13, Roma 2006. .

Table.1 Harmful insects found in storage area

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detection of harmful and not harmful entomofauna is a risk index for the whole collection because it indicates a lack of appropriate barriers against the external environment and a poor cleaning and housekeeping. The entomological monitoring has also shown that elevated temperature and relative humidity (T 28-30°C, RH 65%) detected in summer have created a favorable environment to the proliferation of harmful and not harmful insects, further encouraged by the presence of organic materials (wood, paper, canvas, leather, textiles). The results of chemical, physical and biological monitoring, combined with those from the CDS have highlighted improper storage, packaging and positioning of items, threatening the entire collection. In table 2 some damages affecting the stored objects and their percentage are shown. Moreover the most affected constitutive materials by the different forms of decay are highlighted.

Table 2. Typologies of damages and classes of most affected materials

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CONCLUSIONS The study and the monitoring carried out in the storage area allowed to highlight the main interventions to improve the current environmental conditions to reach a correct preservation of the items. Palazzo Soliano could become a storage area only after solving the environmental problems including the sanitary risk connected to the presence of insects guilty for allergic appearance and cutaneous irritations7. Afterwards to minimize, or at least, to reduce the natural process of materials deterioration, some easy management improvements should be realized; for instance, to modify the main entrance door in order to control the inside-outside air exchanges for limiting the impact of external climate on internal microclimate and the diffusion of insects and chemical – biological pollutants. To drastically decrease several risks, housekeeping and disinfestations as the objects as the storage area must be planned. To achieve full correct conservation conditions for the most sensible materials, it would be necessary to build different stoking units with the possibility to have microclimate and air quality control by an active HVCA – AQ system. In any case as a parallel activity, each artefact will have to be manually prepared to be stored into the new housing; this phase will include the perfect clean-up, disinfestations, packing and restoration also to avoid to contaminate the new structures, granting proper and long lasting objects safety. Bibliography A. CANNISTRÀ, Le stanze delle meraviglie, Milano 2006 B. FOSSÀ, La Manutenzione ordinaria e straordinaria delle collezioni, in Gestione e cura delle collezioni. Dispensa del corso 27-28 maggio 2005. Museo Internazionale delle Ceramiche in Faenza, A.M.LEGA (ed.), Firenze 2005. A. GARZELLI, Musei d’Italia. Meraviglie d’Italia, Bologna 1972. UNESCO-ICCROM, Reorganization of collections in storage update; Workshop 2008.

7 E. RUSCHIONI, D. MATÈ, U. CESAREO, Aerobiologia e problemi di entomofauna negli archivi. Bollettino ICR Nuova serie

n.14, Roma 2007.