Anna Magrini

Churches as Auditoria: Analysis of Acoustical Parameters for a Better Understanding of Sound Quality.

At the present time, music performances frequently take place in ancient religious buildings, and significant problems related to acoustic quality may occur. Measurement results obtained in 10 historically significant churches in the city of Genova, are examined. Experimental data obtained from research literature on auditoria and churches has been compared with the experimental results. A survey of the available theoretical models of the spatial distribution of the most significant acoustical parameters has been conducted, and the models most suitable for religious buildings have been applied to the churches selected. A comparison between theoretical models and experimental data is presented. A case study on the effects of permanent and non permanent acoustical treatment, without significantly changing the architectural characteristics, is presented for one of the churches selected. The results of the measurements, at various phases of the acoustical treatment, and some software simulations are presented.

Models of the Influence of Coupled Spaces in Christian Churches

Ancient religious buildings usually contain articulated environments, such as lateral chapels, in which the effect of multiple acoustically coupled spaces can influence the sound field in the central volume. By introducing absorbent materials in a lateral chapel, the acoustic response of the whole church can be altered. If the effects of coupled spaces are described by geometrical acoustics, inaccurate results may be obtained since reverberation time is influenced by mutual power interactions through the coupling areas or separating walls. Two methods are considered, to determine the simplest way to obtain accurate values of reverberation time for these situations. The results of the simulations are compared with experimental values and indicate areas of applicability of the tested methods.

A simplified model to evaluate noise reduction interventions in the urban environment

Traffic noise is a major problem in all large cities. The surface acoustical characteristics (e.g. referred to roads, pedestrian traffic areas, building façades, building surfaces, in general) affect the noise propagation in the urban environment. Through a better outdoor design and management (e.g. by means of green areas, porous asphalt, speed control), or building refurbishment actions (acoustic plaster, absorbing shading devices), the increasing of surface absorption could be useful to mitigate noise environmental pollution, and therefore to reduce the sound levels in the proximity of the building façades for their entire height. The reduction of the noise levels outside the buildings would determine lower indoor noise levels, and therefore a better situation, without direct actions on the building walls. Through a series of noise propagation calculations in urban environments, by means of a three-dimensional simulation model, the influence of some configurations and the potential impact of some intervention solutions are quantified. In the first stage of the research, the analysis of a simplified model is conducted, to evaluate the influence of noise on the building façades, based on a simplified geometry of the urban environment and of the surface acoustic features. The same analysis is validated by means of a more detailed model, corresponding to the configuration of an existing built area, to verify if the analyses performed by means of the simplified model can be extended to more complex layouts. Successively, calculations are developed to quantify the noise levels that occur with different acoustic (absorption of façades, soil, asphalt, or green elements) and geometric (road width, buildings height, presence of balconies, etc.) characteristics to show the potential reduction given by some interventions. Solutions that can lead to a more significant reduction of the noise in correspondence of the façades are then summarized. The simplified geometrical model appears to be suitable for preliminary investigations as the maximum error found for narrower roads is equal to 17%.

Measurements of Acoustical Properties in Cistercian Abbeys

The work reports the results of measurements of acoustical parameters obtained in six abbeys of the Cistercian order (XIIth century). Three of them, Silvacane, Senanque and Le Thoronet, are in the South of France. They have the original layout both outside and inside the building, and are finished in local stone. The values of the reverberation time RT, measured in these abbeys, are higher than in other religious buildings of almost the same volume. The other three abbeys, at Tiglieto, Morimondo and Chiaravalle, in Northern Italy, have similar characteristics as regards the plan and the simplicity of the interiors, but their inner surfaces are of bricks and stones, in different proportions. The measured RT values are lower than those of the French abbeys. In the abbey at Le Thoronet, the RT values are higher at low and middle frequencies, which corresponds to the range of liturgical and mainly Gregorian choral music, played in Cistercian abbeys without musical instruments. This effect could have been the aim of the Cistercian architects, experienced in architectural acoustics, or is the consequence of the use of a special kind of stone, that has lower absorbing properties than the materials used in the other churches.

Thermal Behaviour of Historical Buildings, Materials and Components: Methodological Framework, Calculation, Results

The refurbishment of building opaque envelope of historical buildings represents an important contribution for the reduction of their energy consumption. Starting from the known or expected layer composition of the existing structures, the hygrothermal behaviour analysis is necessary to define the effective heat transfer, its reduction potential, and the moisture transfer. In this chapter, after a brief definition of the main thermal and hygrometrical parameters, the analysis of some wall typologies, common in historical building construction, is carried out. This represents a starting point for the evaluation of the most suitable envelope insulation interventions. The incidence in terms of energy performance is tested considering a case study.

Guidelines for Eco-efficiency in the UNESCO Site of Cinque Terre: An Example of Good Practice

The paper discusses the results of a recent research focussed on the formulation of criteria of landscape and architectural compatibility to set up Guidelines to achieve eco-efficiency and install renewable energy source applications for domestic or agricultural use in the rehabilitation of traditional rural buildings within the World Heritage Property of Cinque Terre, Porto Venere and the Islands. The research was commissioned by the Regional Directorate of Liguria to the Universities of Genoa and Pavia and faces a new challenge for this type of sites due to the highly sensitive landscape and heritage values in place. Two factors oriented the research: a continuous passage of scale, from the territorial level to building detail and the continuous exchange among specialists within a trans-disciplinary team. The results of theoretical models of calculation of energetic behaviour and requirements applied by experts in Building Physics have been compared with the evaluation of the actual state of conservation of the buildings, with the local conditions of weather and sun exposure, with the data on relative climatology and on superficial and profound geology, with the possible energetic exigencies and with the reasons for heritage preservation and protection so as to select the possible solutions able to respond to all identified needs.

Opaque Building Envelope

The refurbishment of building opaque envelope represents an important approach for the reduction in global European energy consumption as prescribed by the Directive 2010/31/EU. Therefore, the knowledge of existing housing stock and their hygrothermal behaviour is necessary to define effective energy conservation measures. In this chapter, starting from the definition of the main thermal and hygrometrical parameters, a systematic analysis of the most common wall typologies in European construction is carried out for the definition of a structure catalogue. Moreover, for a set of envelope insulation interventions, the hygrothermal behaviour is evaluated and some diagrams for the assessment of the optimal intervention are defined. Finally, the incidence in terms of energy performance is tested considering a case study.

Energy Performance of Buildings: A Comparison of Standard Assessment Methods

Regarding energy performance assessment of existing building, the European Standards EN ISO 13790 and EN 15316, adopted at national level in Italy by Technical Standards UNI/TS 11300 (part 1 and 2), allow different approaches and simplification levels for defining some representative input parameters determining uncertainties in the results. Therefore, the reliability of calculated energy performance could be affected. The analysis has been supported applying a set of refurbishment actions on some representative cases of common national residential building stock, comparing the energy performance obtained with different calculation methods allowed by National Technical Standards and laws. The results show how these differences can lead to uncertainties about the class definition.