Control of indoor environments in heritage buildings: experimental measurements in an old Italian museum and proposal of a methodology

This paper describes some results from an experiment carried out regarding a procedure to be adopted for temperature and R.H. monitoring of indoor spaces designed for exhibiting events, such as museums and similar institutions. The monitored data employed in this study has been collected by the Department di Ricerche Energetiche ed Ambientali of the Università degli Studi di Palermo in co-operation with the Regional Gallery ''Palazzo Abatellis'' of Palermo. The study analyses a simple method for characterising the environmental quality of museums so as to ensure the optimal conservation of works of art. This methodology is based on the procedure (where thermal and hygrometry parameters are concerned) proposed by an Italian standard rule. A new technique, firstly applied to the industrial environment, based on the passive reactive monitoring of proper coupons is also proposed for monitoring air quality in museums. The methodology adopted, has been applied to two survey campaigns which were carried out at a distance of 5 years. This shows the two aspects of thermal-hygrometry and levels of indoor air quality aimed at preserving works of art. The future developments of this work are oriented towards the definition of guidelines in support of those responsible for the conservation of works of art and improvements in the quality of environments for artwork conservation and for the comfort of visitors through the use of proper HVAC systems.     

Future thermohygrometric climate within historic houses

A simple transfer function has been used to predict indoor temperature and humidity from outdoor climate. Using downscaled output from the Hadley Model (HadCM3) changes in indoor climate through to 2100 were predicted for an idealised unheated room at a number of European sites. The potential threats to paper and the risk of salt damage were predicted using damage functions. Although paper faces an increased risk in some temperate locations, salt weathering can increase or decrease dependent on location. Many future indoor climates may already exist at other locations, so communication throughout the heritage sector offers examples for the management of future challenges. Climate change is relatively slow so there is ample time for the adoption of good practices at these locations.     

On the damage of frescoes and stuccoes on the lower surface of historical flat suspended light vaults

In many historical and monumental Italian buildings, frescoes or stuccoes of artistic and historical value are present on the lower surface of flat light vaults, made by wooden arches, reeds and plaster. These vaults are often suspended by wooden or metallic ties to the upper bearing structures. When differential settlements of the wooden arches happen (i.e.: due to a bad working of their hangings) cracks appear on these precious surfaces. This paper experimentally and numerically investigates on this issue, pointing out which constructive parameters mainly influence the cracking behaviour of the frescoed or stuccoed lower surface, and thus providing guide lines for designing compatible conservation and retrofitting interventions.     

Evaluation of the effect of phase change materials technology on the thermal stability of Cultural Heritage objects

The use of phase change materials (PCMs) in civil buildings as an effective thermal energy storage solution has been well documented in literature and proven in the field. When applied to Cultural Heritage, PCMs’ technology needs to be adapted to specific requirements. Besides the important objectives of economic return and human comfort, the indoor microclimatic conditions have to be suitable for conservation purposes. The application of PCMs’ technology to Cultural Heritage has been investigated within the European MESSIB (Multi-source Energy Storage System Integrated in Buildings) project. Firstly, several methodologies of incorporation of PCMs in different materials were studied and tested. The thermal properties of gypsum panels and silicon coatings incorporating micro-encapsulated PCMs in the form of powder and emulsion were analysed in the laboratory. Then, PCMs incorporated in gypsum panels in contact with a wooden panel were tested and their effect on the thermal behaviour of the wooden panel was evaluated under thermal cycles in a climatic chamber. PCMs incorporated in silicon coatings in contact with a painting were also tested. Moreover, gypsum panels containing PCMs were tested in the S. Croce Museum in Florence, Italy, where the microclimatic monitoring has shown thermal conditions potentially dangerous for the works of art preserved. The research performed both in the laboratory and on the field confirmed the effectiveness of the PCMs as thermal storage solutions, but also gave evidence on an important drawback when the material incorporating PCMs is in direct contact with an object of art.     

Approach to environmental risk analysis for the main monuments in a historical city

The analysis of environmental risk in historical cities facilitates the development of conservation strategies that can minimize the deterioration of historical heritage sites. Risk maps built with GIS software provide information about the probability of the main hazards in a region, and is a very useful tool to identify, evaluate and prioritize the restoration budget of a city in order to manage preventive conservation. In this paper, new methodologies are applied based on the vulnerability matrix and its relationship with static and structural factors, climate conditions, air quality and social agents. This technique has some obvious advantages in the application of risk analysis for cultural heritage conservation, such as the capability of simultaneous risk assessment and geographical references. The vulnerability study implies an on-site diagnosis analysis and requires an adapted protocol for archaeological heritage. The validation of this methodology was carried out in the historical town of Merida (Spain) with a GIS application (ArcGIS software), where the main monuments of this UNESCO World Heritage site were studied.     

An advanced church heating system favourable to artworks: A contribution to European standardisation

The European project Friendly-Heating (FH): comfortable to people and compatible with conservation of artworks preserved in churches addressed the problems caused by the continuous or intermittent heating of historic churches, which disturbs the microclimatic conditions to which the building and the artworks preserved inside have acclimatised. As thermal comfort and the preservation of artworks often conflict with each other, a balance between the two needs is necessary. The proposed heating strategy is to provide a small amount of heat directly to people in the pew area while leaving the conditions in the church, as a whole, undisturbed. This novel heating system is based on some low-temperature radiant emitters mounted in a pew to provide a desirable distribution of heat to the feet, legs and hands of people occupying it. Due to little heat dispersion, this novel system not only significantly reduces the risk of mechanical stress in wooden artworks and panel or canvas paintings, fresco soiling and cyclic dissolution-recrystallization of soluble salts in the masonry, but is energy-efficient. The detailed environmental monitoring was conducted in the church of Santa Maria Maddalena in Rocca Pietore, Italy over a 3-year period to verify the performance of the novel heating system in comparison to the warm-air system that was active earlier in the church. The methodology and results of this comprehensive and multidisciplinary study were included in three draft standards of the European Committee for Standardisation intended for use in the study and control of environments of cultural heritage objects.     

历史文化名城保护的信息技术方法研究进展与趋势

面向中华文化复兴与时空大数据时代,首先梳理了历史文化名城保护的4种需求,分析了信息技术应用的4个特征:数据获取的全面与动态、数据挖掘的定量与定性、信息展示的直观性、信息应用的便捷性。在此基础上,通过文献梳理了历史文化名城保护的信息技术方法研究进展,包括信息获取技术应用进展、保护状态评价应用进展、保护规划设计应用进展,以及动态变化监测应用进展。最后,展望了历史文化名城保护智慧化发展的3个趋势:数字孪生名城的理念引领、名城信息模型的技术支撑,以及智慧名城大脑的智慧保护。     

Risk assessment: A comparative study of archive storage rooms

The goal of preventive conservation is to provide the correct maintenance of our cultural heritage in order to enrich our future. The Canadian Museum of Nature developed a risk model for preventive conservation that has proven useful in application to a Portuguese archive. This work applies this model to compare the magnitudes of specific risks estimated for this same archive collection when located in either of two pairs of storage rooms. These rooms are in two different parts of this building: two are in an older part and two are in a recent addition. It was, therefore, necessary to assess the building itself, both structurally and environmentally, as well as analyse its common human practices. In terms of the overall risk magnitude, the best room was found to be in the recent building and the worst in the older building. However, risks related to water problems were found to be higher in the new building. In this work cost-free measures and easy to implement recommendations are given in order to improve the quality of the storage rooms. A final comment on the method itself is also given.     

Identification and assessment of engineered road heritage: A methodological approach

Roads built by civil or military engineers from the 18th century onwards form an essential part of our heritage, but currently considered on a very infrequent basis. They represent one of the main turning points in the development of the transport system and serve to gain a better understanding of the historic construction of many landscapes and their current arrangement and operation. Their consideration as heritage has to be made on a territorial scale. This approach regards landscape as a cultural artifact, which is undergoing constant design, construction and transformation, where the road is considered as an axis that shapes the landscape and that contains individual elements such as associated structures or buildings. One of the most important characteristics of historic roads undoubtedly lies in the fact that they are a heritage that is still in use. Many of the roads built for carriages or the first automobiles have, in fact, served to trace the current network of roads and motorways. For this reason, many historic routes have undergone considerable modification and a large percentage of their heritage has disappeared. Likewise, their original or more intact sections, that is to say those that were replaced during their gradual adaptation to the automobile in the 20th century, are not always easy to identify. The distinction and undoubted documental value of historic roads, together with the neglect and vulnerability of these assets, makes it essential to define specific strategies with some degree of urgency in order to appraise this heritage. In this respect, the purpose of this article is to establish a methodology with which to identify sections of historic roads that were replaced by new alignments. The decision to focus the work on these sections is based on the fact that the infrastructure of these and particularly the older sections, have undergone a smaller degree of change and subsequently retain their original routing and geometry and a far higher number and variety of heritage elements more intact. This has made it possible to ascertain the diversity of elements composing the heritage of historic roads and enables the classification of the same. The identification methodology has been applied to a significant proportion of the Spanish main road network on selecting some 15 sections of historic roads of very different characteristics. Files have been prepared for each of these sections on the basis of cartographic analysis and detailed field work, these files including data related to location, characteristics and inventory of historic elements forming the road's heritage and will subsequently include references to road layout (both longitudinal and cross-sectional), structures (essentially drainage works), auxiliary elements (signalling) and associated buildings (inns, roadworkers’ houses…). Finally, and on the basis of the experience gained during the research, an initial proposal is laid out for the heritage assessment of these assets, considering aspects such as historic, technological and documental singularity which will depend on the degree of transformation and definition of the section in question.     

基于数字技术的历史街区空间更新与文化价值活化设计 ——以南京南捕厅历史街区为例

以南京市南捕厅历史街区为例,通过综合运用三维地理信息系统、多元异构时空数据分析、历史信息比对等技术手段,展示了复合历史空间导向的数字化保护与更新实践.通过无人机倾斜摄影测量技术,对历史街区的大场景进行纹理数据采集,构建整个历史街区的三维数据模型.在历史研究的基础上,为历史街区更新构建合理的历史空间形态框架,并对历史街巷...     

Conservation of stained glass windows with protective glazing: Main results from the European VIDRIO research programme

The methodology of protecting the European stained glass windows against environmental risk (e.g. meteorological factors, air pollution, microorganisms) by means of an external glazing is not new. In spite of many scientific studies carried out in the last 20 years, some questions were still up for discussion. The European VIDRIO (2002–2005) project gave an answer to these questions. The research carried out by the different project partners established a new multidisciplinary approach aimed at evaluating the efficiency of the protective glazing systems and their effects on stained glass windows conservation, and finally at assessing the most appropriate strategy to preserve stained glass windows. Scientific results showed that the so-called isothermal glazing (i.e. ventilation by the air coming from the inside of the building) protected efficiently the ancient stained glass window from environmental attack (i.e. rain, pollutants, condensation, thermal shocks) with very limited secondary effects. The scientific research highlighted that its efficiency was strongly related to the technical design of the protective system. In particular, the ventilation and the size of the interspace had to be carefully considered. The research developed within the VIDRIO project was turned into general recommendations to the owners and practitioners on the best practice for the stained glass windows future conservation.     

An architectural assessment method for new exterior additions to historic buildings

The design approaches of new exterior additions to historic buildings have been among the ongoing debates in the field of architectural conservation. The aim of this study is to develop an assessment method, which can be used to determine the compatibility in architectural expression of the new addition in relation to the characteristics of a historic building. This method is based on the architectural analysis, which includes environmental relations, building-lot relations, mass relations and the facade composition of the historic building both before and after the new addition in relation to the value of a historical building. In this study, a selected group of historic buildings in ?zmir, Turkey with new exterior additions was analysed with regard to their exterior architectural characteristics in order to evaluate the compatibility of the new addition, by employing the use of contemporary conservation principles. The importance of this study is to guide architects to form the basis of a decision for developing an integrated approach in designing new additions in the course of the actual design process. On the other hand, the proposed method can be evaluated as a contribution to the emerging field of heritage impact assessments as well as scientific assistance to local governments to criticize specific projects of cultural heritage assets submitted for appraisal. Analysis results showed that the value of the historic building should first clearly be identified and a new addition should bear the identity of its own period. However, instead of altering the scale or form of the historic building, a new addition should complement and contribute to the sense of proportion, disposition and historical pattern.     

Daily natural heat convection in a historical hall

The use of numerical simulation methods for the Cultural Heritage is of increasing importance for the analysis, conservation, restoration and appreciation of works of art. This is particularly important when their preservation and planned maintenance is the primary aim. Today museums, and particularly historical buildings converted to museums, should be considered as places where precious artefacts should have first-rate protection and conservation. It is a question of solving the compromise between protection, conservation and comfort for works of art and/or visitors, with the consequence that preservation and planned maintenance criteria must prevail over use requirements. Refurbishment and conservation of a building, and requirements for visitor presence and works of art need different thermo-physical indoor parameter values. The present paper concerns the thermal and air velocity analysis of the Salone dei Duecento (the Hall of the Two Hundred of the Palazzo Vecchio (Old Palace)) in Florence. In this paper an appropriate transient 3D model by Computational Fluid Dynamics (CFD) software based on the finite element method (FEM) was used. Variations and interaction between indoor and outdoor microclimatic conditions, and thermo-physical behaviour of the building connected to lighting, visitor presence and cooling–heating fan coils system were considered. The 3D modelling method provided by the present paper can be applied to several situations where there is interaction between outdoor and indoor climate variations and the building structure. It can be very useful for defining measures to preserve tapestries, understanding deterioration processes, and developing new conservation techniques and strategies for care and exhibition.     

Using heritage risk maps as an approach to estimating the threat to materials of traditional buildings in Tainan (Taiwan)

Academic studies concerning how climate influences Asian heritage are rare. The object of this study was to utilize the concept of heritage climatology together with a spatial analysis approach that includes respective climate parameter risks to cultural heritage sites. The study area, Tainan City, Taiwan, is in a subtropical zone south of the Tropic of Cancer. Tainan has nearly 300 hundred years of rich history and a multicultural background. This study used maps to gain information about potential climactic threats to Tainan's cultural-historical legacy. There are four kinds of map that use ArcGIS to analyse and demarcate regions not only by climate parameters but also by risk to heritage. These four types of map are climate maps, heritage climate maps, heritage maps and heritage risk maps. Climate maps give the short- to medium-term general status of the climate in Tainan City and thus served as the foundation of the other maps used in this study. Heritage climate maps give data concerning index factors that influence wood and stone materials. Heritage maps show locations of cultural heritage sites on an administrative map and categorize them according to their historic value. Heritage risk maps use accumulated calculations to superimpose the heritage climate map onto the heritage map in order to evaluate the risks to heritage sites in certain areas and categorize the levels of risk. Heritage sites in mountainous areas generally need to be protected from heavy rain, whereas downtown city environments, due to the urban heat island effect, require better protection against heat and cracking. By comparison of our field study results and climate risk maps, we found that in urban areas wooden materials have a higher risk of structural cracking, colour fading and bio-degradation, while coastal areas have a higher risk of weathering of stone materials.     

Mapping the impact of climate change on biomass accumulation on stone

Several climate parameters affect the growth of organisms and, hence, their capacity to accumulate biomass. In the present research, we analyse the influence of two parameters, temperature and precipitation, on biomass accumulation on stone substrate, and propose a function to estimate it in temperate areas. The expression is subsequently used for the first time to evaluate the impact that climate change would have in biomass accumulation in Europe. The models on climate change predict an increase in temperature and precipitation in northern areas of Europe for the far future (2070–2099), which would lead to a higher accumulation of biomass. Otherwise, a significant reduction in precipitation is expected in southern areas of Europe, associated with a lower biomass accumulation in such areas.     

Continuous monitoring of wooden works of art using fiber Bragg grating sensors

In recent years the control and monitoring of works of art has gained more and more importance. In particular, works partially or totally realized with wood, such as polychrome sculptures, painted panels or Crucifixes, are highly sensitive and delicate and thus need a particular attention. The wooden support is, in fact, an essential element for the stability of pictorial layers: the color lies on a preparation, which in turn, is anchored to the wood. Wrong conservation methods, i.e. in an environmental climate that is not controlled, or intrinsic mechanical stresses, can warp such structures, and the effects can be irreversible and destructive to the painted layer. The use of fiber Bragg grating (FBG) sensors for the quasi-distributed, in situ measurement and continuous monitoring of deformations in painted wood panel is proposed. In order to demonstrate the applicability of FBG sensors to painted wood panels, a wooden support, made using the same 15th–16th century techniques, was prepared in the Opificio laboratories. A number of Bragg grating sensors were affixed in several critical points, on the back and front sides and on the strengthening cross-beams, in order to detect deformations in the panel dependent on the variations in the environmental relative humidity (RH). Measurements during the removal of the cross-beams are also reported. The results of measurements have shown the applicability of FBG sensors for the continuous in situ monitoring of valuable wooden objects and works of art.     

Laser cleaning of stained glass windows. Overview on an interdisciplinary project

The German Federal Foundation for the Environment (Deutsche Bundesstiftung Umwelt) is one of Europe's largest organizations of its kind. It supports innovative, exemplary projects for the protection of the environment and of national historic monuments and cultural landscapes. All projects are set up to provide a platform for researchers, craftsmen and restorers to find a common solution to difficult problems in conservation practice. More than 360 projects have been funded since 1990. Two recent projects deal with laser cleaning, one for stone and the other one for stained glass windows, the latter being presented here. This publication gives an overview on cleaning problems on stained glass windows and the project methodology. The interdisciplinary approach of the project provides the possibility of including experts in different fields to examine perspectives and limits of laser cleaning for stained glass windows. Two other publications in this issue (LACONA III) give selected results on cleaning experiments achieved within this project.     

A multilevel approach for the damage assessment of Historic masonry towers

In the paper some case studies of damaged towers in Italy are presented: the Tower Masserano of Palace Ferrero - La Marmora at Biella, the bell tower of the Collegiata of San Vittore at Arcisate, and three medieval towers in Alba. A methodology is put forward for combining laboratory and nondestructive testing methods with monitoring systems in order to reach the goal of evaluating the state of conservation of historic towers and its evolution in time.     

Teodelinda's tales at Monza Cathedral: A physico-chemical diagnosis of the pictorial cycle

The pictorial cycle “Teodelinda's Tales” at Monza Cathedral, painted by Zavattari and his sons in 1444–1446, has been investigated by optical and SEM-EDS microscopy and microFT-IR spectroscopy. Paint layers, gildings and other metallic decorations have been analysed to elucidate the execution technique, the state of conservation and the possible retouchings in consequence of deterioration processes. Organic binders, coatings and adhesives have been also identified especially by microFT-IR spectroscopy applied directly to the sampled powders or fragments and to their solvent–soluble fractions. The obtained data offer a correct and satisfactory knowledge of the original organic and inorganic materials and those used in the subsequent retouches and restorations, their state of conservation and the painting techniques (fresco, mezzo fresco and secco).The physico-chemical investigations allowed to identify the nature and sometimes the provenance of the employed materials (i.e. ultramarine blue pigments) and some decay markers, particularly useful in understanding and describing the cycle realised by the authors and the modifications suffered along the centuries, and also to propose an integrated methodology for the scientific study of the mural paintings.     

Determining treatment priorities for ecclesiastical textiles using significance and conservation assessments

The Benedictine monastic community at New Norcia, Western Australia needed an assessment of their historic textile collection as a preliminary step in gaining financial support to preserve the garments. The textiles were grouped according to functional use with sampling controlled by random number generation of the registers. The highest significance and conservation rankings were rated at 5 and the lowest in the categories was given values of one. The numbers in each category fell logarithmically as the significance values increased. The number of hours of work required to stabilise the objects increased logarithmically as the conservation ranking increased from 1 to 5. Analysis of the conservation needs indicated that nearly 84% of the collection, the sum of the level 1 and level 2 textiles can be stabilised with simple preventive conservation methods practised by trained volunteers, leaving the most significant items in the care of experienced conservators. Multiplication of the conservation and the significance values provides a treatment priority score to guide collection managers in determining which objects are treated by conservators. Data is also provided on the impact of light exposure on the deterioration of the coloured fabrics of the vestments.