gianfranco cellai | Università degli Studi di Firenze (University of Florence) (original) (raw)

Papers by gianfranco cellai

Building Acoustics, Sep 1, 2016

The aim of this work is the definition of a methodology to analyze the number of buildings expose... more The aim of this work is the definition of a methodology to analyze the number of buildings exposed to every noise level band, to estimate the required facade sound insulation for indoor comfort, and to evaluate the acoustic classes that would characterize existing building facades adopting the proposal for a new International Organization for Standardization standard. In particular, a relationship based on a statistical approach is analyzed between outdoor noise, determined according to the European Noise Directive, and the limit values for the acoustic classification of buildings that are going to be implemented in the proposed International Organization for Standardization standard. Building exposure to noise is described through the indicator L den as reported in the noise maps elaborated, according to the European Noise Directive, with reference to some major Italian towns. As a result of the application of the proposed methodology, the facade insulation required to obtain an adequate indoor comfort is determined.

Environments, Mar 5, 2018

The correlation between exposure to traffic noise and students' performance and annoyance has bee... more The correlation between exposure to traffic noise and students' performance and annoyance has been investigated in literature mainly considering the relationship between indoor equivalent A-weighted sound pressure level (L Aeq) and students' cognitive impairment. Annoyance is frequently related to the effect of short-duration noise events characterized by high sound pressure levels, such as those due to aircraft flyover and pass-by of buses, heavy trucks, motorcycles, or street sweepers. These noise events are often described, over specific measurement periods, in terms of maximum A-weighted sound pressure level, L Amax , or statistical levels, such as L A1 or L A10. This aspect is not considered in the noise maps drawn in accordance with the European Environmental Noise Directive, as they provide the L Aeq only, determined over day, evening, and night periods. In this paper, students' exposure to road traffic noise is analyzed by means of regression equations obtained by the authors between L Aeq and A-weighted maximum and statistical levels due to road traffic noise. The traffic noise of 28 urban streets was monitored during the opening period of Italian schools. A method is described to estimate students' exposure to noise from data made available on noise maps by the municipalities of metropolitan areas. The application of this method to the case study of Florence shows that almost 60% of students from municipal primary and lower secondary schools could be exposed to the maximum sound pressure level (SPL) inside the classroom greater than 55 dB(A) every hour, probably exceeding the typical background noise in classrooms by more than 10 dB.

Applied Acoustics, Nov 1, 2017

The paper deals with the effect of outdoor noise mainly due to traffic and façade sound insulatio... more The paper deals with the effect of outdoor noise mainly due to traffic and façade sound insulation on indoor noise level and speech intelligibility in classrooms. Results refer to the complete building stock of the Italian school buildings based on a census of the Italian Ministry of Education. The selected school sample consists of more than one hundred Italian schools of all levels (from nursery to upper secondary school) located in three Italian regions, built in different time periods and with different building techniques. The selected sample is representative of typical Italian schools. The façade sound insulation and the reverberation time of each school have been measured. The average outdoor noise level of about half the investigated schools has been measured and, for each school, the age of the building and the main characteristics of the façade have been listed (kind of glass, kind of ventilation, windows size, etc.). Based on these data, the correlations between both the main characteristics of the façades and the year of construction and the façade sound insulation have been investigated. Moreover, the influence of the noise coming from outdoor on the indoor noise level, speech intelligibility and speech to noise ratio have been analysed with reference to the situations both before and after the works carried out to improve the acoustic performances of façades. Results show that the indoor sound pressure level due to traffic noise is considerably reduced after the improvement of the façade acoustic insulation, while further treatments to indoor surfaces should be necessary to reduce internal reverberation time and to improve speech intelligibility.

Buildings, Nov 14, 2018

This paper reports the acoustic issues of open plan office environments. According to a detailed ... more This paper reports the acoustic issues of open plan office environments. According to a detailed research based on the scientific literature of the most suitable acoustic descriptors recommended for the open plan offices analysis, the main typological-functional configurations of these environments have been analyzed in order to identify six spatial typologies. The variation of acoustic parameters of these typologies has been evaluated by using a sound pyramid tracing software. The analysis procedure was calibrated in a case study of an office environment, where a measurement campaign was carried out. Results point out that the acoustic improvement of open plan offices can usually be achieved by introducing a sound absorbing false ceiling and dividing panels between working positions, but there are different issues depending on spatial geometries of the office. Better results are referred to office typologies characterized by reduced height and equal plan dimensions.

Applied Sciences

The assessment of indoor air quality (IAQ) in museums is a complex issue. In this study, a compre... more The assessment of indoor air quality (IAQ) in museums is a complex issue. In this study, a comprehensive investigation methodology was defined and applied to a museum to be validated. This methodology includes the analysis of exposed objects, the optimal conditions for conservation, the building features and the HVAC systems, and the indoor thermo-hygrometric and air quality conditions. In 2019, a survey in the Uffizi Gallery of Florence, one of the most important museums in the world, was carried out to assess the IAQ conditions in the museum, and the workers and visitors’ well-being, by focusing on some representative rooms (nine) of the museum complex in terms of visitor turnout and HVAC systems, including rooms closed to the public. Since IAQ is related to the possible presence and concentration of chemical and biological pollutants, these indicators, as well as thermo-hygrometric parameters, were monitored. The monitoring results were analyzed, evaluated, and compared with thos...

According to the European directive 2002/92/CE, degree 311/2006, as from July 2009 all the existi... more According to the European directive 2002/92/CE, degree 311/2006, as from July 2009 all the existing buildings must equipped with an energetic certification to be shown when sold or rented. Probably this disposition, together with economic incentives made available for improvement interventions of the energy performances, will lead to a remarkable reduction in the consumption of energy attributable to the existing buildings. In Italy, around 40% of residential buildings were built before 1957, and about 78% of them are inhabited by at least one person. Therefore, for these kind of buildings it is necessary to either reduce energy consumption and to have them certified. The use of simplified procedures is therefore important for two main reasons in order to meet the above requirements: on one hand, to reduce the costs relevant to the issuance of the energy labeling (we count about 800.000 transactions per year, excluding rents), on the other hand to obtain indications regarding the consumption of energy which could promote improvement interventions to the existing real estate. Considering the variety of the stock building, it is therefore difficult to define simplified methods for the energy certification unless the buildings are first subdivided into homogeneous groups based on the period of construction and typology. This paper presents the investigation which has been carried out on medieval and renaissance buildings and which are still inhabited nowadays in the cities of Pisa and Pistoia. The aim is to define a correlation between the geometrical and energy parameters, representative of the identified typology. Such correlation and its subsequent classification is based on the investigation of the thermo-physical characteristics of the external walls and flooring, and on the modeling of the energetic behaviours resulting from the data deriving from the investigations performed on a number of flats.

38° convegno nazionale AIA, 2011

57° Congresso Nazionale ATI, 2002

L'edificio scolastico deve assicurare la salubrità degli spazi ed il benessere ambientale delle p... more L'edificio scolastico deve assicurare la salubrità degli spazi ed il benessere ambientale delle persone, ottemperando al contenimento dei consumi energetici necessari per il suo utilizzo, sia in regime invernale che estivo. I requisiti suddetti fanno riferimento alle seguenti classi esigenziali: benessere termoigrometrico, benessere acustico, benessere visivo, benessere respiratorio olfattivo e qualità dell'aria. La memoria riporta una analisi dei requisiti fisico-ambientali espressi da valori limite cogenti raccomandati, suddivisi, ove possibile, per il recupero o la nuova costruzione.

Rebuild The european cities of tomorrow, 1998

If the design, installation and maintenance of HVAC systems does not follow suitable standards, t... more If the design, installation and maintenance of HVAC systems does not follow suitable standards, they can give rise to several problems, such as: excessive installation and maintenance costs as well as hygienic problems for dust deposition and accumulation. The paper deals with the state of the art duct contamination. The paper also presents the used methodology and the obtained preliminary results of a study carried out on ten hospital buildings. Finally some considerations about the effectiveness of some cleaning methods are presented.

E3S web of conferences, 2022

In museums, poor indoor air quality combined with unsuitable thermal and hygrometric conditions c... more In museums, poor indoor air quality combined with unsuitable thermal and hygrometric conditions can affect the visitors and staff wellbeing as well as cause the deterioration processes of the exhibit objects. In order to assess indoor air quality of the museum, a survey was carried out in some rooms of the Uffizi Gallery of Florence by the researchers of the Laboratory of Environmental Physics of the University of Florence. Indoor temperature, relative humidity, chemical and microbiological pollutants were sampled, and the results analyzed and discussed. To do that a general methodology of investigation and evaluation of the results was defined and applied to several rooms of the Gallery. The presence of critical pollutant concentration was underlined and proper investigations on the HVAC system were scheduled. In this paper the results regarding a representative room are shown and discussed.