Satellite "Building Acoustics"

– towards a better understanding

Program overview


Assessment of single number ratings of airborne sound transmission through laboratory listening tests

Monika Rychtáriková, KU Leuven, Dep. of Physics and Astronomy, Division of Soft Matter and Biophysics, Laboratory of Acoustics

Abstract

Ongoing discussions on building acoustic standards have brought a number of interesting research questions that concern not only the development of more accurate simulation and measurement methods, but also suitable methodologies for the assessment of acoustic comfort through laboratory listening tests.

Validation of the proposed single number ratings in listening tests, requires not only adequate auralisation and laboratory conditions with sufficiently low background sound levels, but also appropriate psychoacoustic methods.

This contribution presents an overview of the research done in relation to laboratory listening tests used in building acoustic context. Next, the choice of the psychoacoustic method and its impact on the subjective assessment of airborne sound transmission is discussed. Finally, results on the effect of temporal and spectral features of the presented stimuli on loudness perception are presented. A comparison is made between (1) original daily life signals, auralized as they would sound after being transmitted through a wall between neighboring apartments, (2) a time reversed version of the signals, and, (3) noise stimuli filtered to have the spectrum of particular sounds.

Short Vita

Monika Rychtáriková was born in Bratislava in 1975. She studied architecture and building constructions at the Faculty of Civil Engineering at STU Bratislava, where she graduated (1998), received her Ph.D. degree (2002) and become an associated professor (2010) in the field of acoustics with a habilitation thesis on “Room acoustic simulations in multidisciplinary context”. During her research stays, she has visited TU Wien (Austria), TU Delft (The Netherlands), RWTH Aachen (Germany), TU Zagreb (Croatia) and Belgian Building Research Institute (BBRI) in Limelette (Belgium). Recently, she is active as a researcher expert at the Department of Physics and Astronomy, Laboratory of Acoustics at KU Leuven and as a docent at Department of Building Structures at STU Bratislava. Since 2002, she has been active in different fields of building physics in general and building and room acoustics, environmental and virtual acoustics and perception of sound in particular. She has contributed to 3 monographies, she is author of one book on Psychoacoustics, 4 book chapters, 3 course text books, 14 papers in peer reviewed international journals, over 25 other scientific papers, and over 100 proceeding articles. She has given more than 70 talks at conferences, of which 2 plenaries and 40 invited. Monika Rychtáriková has been involved in over 50 acoustical consultancy projects 4 wind comfort studies and 7 architectural projects.


The Relevance of Rating Low Frequency Airborne Noise in Buildings

Valtteri Hongisto, Senior Research Scientist, Adjunct Professor, Turku University of Applied Sciences, Turku, Finland

Abstract

The presentation summarizes recent Finnish outcomes in the field. The study 1 concerns a large socio-acoustic survey conducted in 28 Finnish multi-storey buildings [1-2]. Occupants were mainly annoyed by living sounds which are not primarily low-frequency sounds. R’w explained the annoyance caused by neighboring living sounds better than R’w+C50-3150. Study 2 [3] concerns a listening experiment where 59 subjects rated the annoyance of various kinds of living sounds heard through various kinds of walls. Findings suggested that it is not necessary to include frequencies 50-80 Hz to the single-number quantity (SNQ) of airborne sound reduction index used to rate the sound insulation in residential buildings. Subjective annoyance against most living sounds can be well explained by SNQs including frequencies 100-3150 Hz, such as R’w. Study 3 [4] used the data of study 2 to determine a SNQ (or reference levels Li) for the band 50-5000 Hz which best predicts the annoyance caused by neighboring living sounds. The reference levels Li of optimized reference spectrum were 10 dB smaller than for C50-5000 of ISO 717-1 within frequencies 50-125 Hz. Within 200-500 Hz, the optimized Li values conformed the Li-values of C50-5000. Above mentioned studies have provided very strong scientific evidence against the exclusive use of R’w+C50-3150 in residential environments. While the research and definition of an optimum SNQ continues, the use of R’w, or DnT,w, is justified since it seems to be a reasonably good predictor of annoyance.

References:[1] Hongisto et al. 2015, Building and Environment. [2] Hongisto et al. 2013, Proceedings of Internoise 2013. [3] Hongisto et al. 2015, Acta Acust united Ac. [4] Virjonen et al. 2016, Submitted manuscript.

Short Vita

Hongisto is a leader of the indoor environment (IE) research group focusing on acoustics and ventilation. The research involves physical modeling and measurement of IEs, modeling and development of IE products, perception of IE in laboratory conditions (psychophysics) and long-term effects of IE on humans in various environments (cognitive and environmental psychology).


Rating Impact Noise

JeongHo Jeong, Fire Insurers Laboratories of Korea

Abstract

More than 50% of the housing in Korea consists of multi-story residential buildings and Koreans customarily do not wear shoes in their houses. Floor impact noise is regarded as the most irritating noise among all noises in multi-story residential buildings. In 2005, the Korean Government enacted building regulation on floor impact noise. The building regulation was consisted of 4-grade classification system and established based on the field measurement data and some survey results.  In order to improve floor impact noise isolation performance and to increase the sound comfort in apartment building for the occupants, regulations based on an objective and easily understood measurement and evaluation method are required.

The Rubber Ball was known to have similar impact characteristics to a child’s running and jumping. Laboratory and field measurement method using the Rubber Ball was standardized in ISO standards. However single number quantity was not proposed in ISO. As a SNQ for bang machine impact sound, Li,Fmax,Aw and L-index based on L-curve are used in Korea and Japan respectably. However, researches reported that other SNQs such as Loudness, Li,Favg,Fmax and LiA,Fmax show better correlation with subjective responses than Li,Fmax,Aw and L-index.

Recently, acoustic classification scheme for dwelling is being standardized in ISO/TC 43/SC 2 building acoustics. In the draft of acoustic classification scheme for dwelling, classification system on the Rubber Ball was not included. For the evaluation of low frequency impact sound isolation performance, classification for the Rubber Ball should be included.

In order to propose SNQ and classification scheme for the Rubber Ball, previous studies on the subjective response of heavy/soft impact sound should be reviewed. In addition, research on the verification should be conducted. In this paper, Korean studies on the subjective responses and classification on heavy/soft impact sound are reviewed. Also research plans to verify the SNQ and develop a classification for the Rubber Ball will be discussed.

 

 

Short Vita

Dr. Jeong is a researcher at the Fire Insurers Laboratory of Korea. His research focuses on fire safety, specifically on evacuation signals and human behaviour, and on building and room acoustics. Dr Jeong received his PhD from the Hanyang University of Seoul in 2004 in the field of Architectural Acoustics, and has since also been very active in the Korean and ISO Standards Committees related to acoustics. He is currently the Vice Chairman of the Building Committee and ISO/TC 43 committee in the Korean Society for Noise and Vibration, Project Leader of TC43/SC2/WG18 on Measurement of sound insulation in buildings and building elements and member of the ISO SC /TC 43 & SC 1 Acoustics & Noise Technical Committee of Ministry of Environment.


Equipment Noise Ratings and their Implementation

Christian Simmons, Lulea University of Technology, Luleå

Abstract

The Swedish regulations state limits on LAeq, LAFmax and third octave band Leq 31-200 Hz from service equipment. Whether these measurands are the most appropriate should be researched in depth. Many sources are nowadays time variant which complicates the acoustic planning. In this talk, examples will be given on predictions, measurements and assessments of structure-borne sound from a washing machine and a household freezer respectively. Participants will be invited to discuss, how the ISO standards should be applied, which frequency and time resolution should be used.

Short Vita

Christian Simmons has made applied research, consultancy and standardization work within the field of building acoustics for more than 25 years. The main focus has been on sound classification of multi-family residential buildings. Sound insulation has been in focus, but noise from road traffic as well as service equipment is now getting more attention. Much work remains in this field, to gain experience with predictions, measurements and ratings of the variety of types of noise, especially with respect to tonality and time variant sources.


Predictions for lightweight constructions

Michel Villot, CSTB, Center for Building Science and Technology, Grenoble, France

Abstract

The subject of this lecture is focused on predicting the acoustic performance of lightweight buildings (typically steel or wood framed lightweight elements as opposed to heavier masonry or concrete elements) from the performance of elements, i.e. using measured data which characterize direct or flanking transmission by the participating building elements. The corresponding CEN and ISO standards exist but their application has been so far mainly restricted to heavy buildings. Using recent European R&D work on lightweight constructions, these existing standards on prediction and associated measurements have been (or are being) revised with greater details for application to lightweight constructions and over a frequency range possibly extended to 1/3 octave 50 Hz. The corresponding and necessary modifications, the underlying physical principles and the resulting limitations are presented in this lecture, where both airborne and impact sound insulation as well as sound levels due to service equipment are considered.

Short Vita

Michel Villot was born in Dijon France in 1948. He received his engineering degree in mechanics from Ecole Centrale de Lyon in 1971. Two years later he joined the Acoustics Group of CSTB (Center for Building Science and Technology), where he worked for almost 20 years on new measuring techniques such as Acoustical Intensity, Time Delay Spectrometry, and Nearfield acoustical holography. In 1993 Michel became leader of the CSTB Building Acoustics and Vibration Team. His work was mainly in the field of measurement and prediction methods in building acoustics with a focus on structure borne noise and ground borne vibration. After retiring in 2016 he began as a consultant. Currently and throughout most of his carrier Michel has worked for CEN and ISO standardization. He is the convener of CEN/TC126 WG2 (Prediction in building acoustics) and WG7 (Lab characterization of building equipment), and active member in ISO/TC42/SC2 WG17 (Lab characterization of flanking transmissions) and in ISO/TC108/SC2 WG8 (ground borne vibration from railways). Michel is also the Associate Editor of Acta Acustica.


Input data for the prediction of sound insulation in timber buildings

Stefan Schoenwald, Laboratory for Acoustics/Noise Control, Empa Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland

Abstract

The lecture focuses on experimental methods to determine the necessary input data in buildings or in the laboratory for the prediction of direct and flanking transmission of airborne and impact sound in lightweight buildings according to the revised EN 12354. In the latest draft of this standard and the draft of ISO 10848 with the related measurement methods more detailed information is given on the application to lightweight buildings systems, such as solid or framed timber construction.

Both methods of ISO 10848, the so-called direct and indirect method, will be outlined and discussed for the special case of building junctions made from framed and solid timber floors and walls. With the indirect method, the sound reduction index of a single flanking path is determined from the sound pressure level difference between rooms, by suppressing all other path by adding shielding. With the direct method the structure-borne sound transmission at a junction is determined from the velocity level difference measured at coupled building elements. To predict the flanking sound insulation in this case, further input data, i.e. the resonant sound reduction index for direct transmission through the coupled elements, is necessary. Hereby the radiation efficiency for airborne and structural excitation plays a key role to obtain the resonant transmission component below the coincidence frequency. The classical approach, where the radiation efficiency is determined from the radiated sound power in the room, as well as a more advanced measurement method, where the radiated sound power is calculated from the velocity distribution on the element surface, will be presented and compared.

Short Vita

Dr. Stefan Schoenwald leads the building acoustic research activities of the Laboratory for Acoustics/Noise Control at Swiss Federal Laboratories for Materials Science and Technology since 2013. He is expert on direct and flanking sound transmission through building elements and building structures - in particular specialized on lightweight construction.

He finished his studies in Building Physics at the University of Applied Sciences in Stuttgart, Germany, in 2001. Afterwards he gained field experience as a consultant engineer in building physics. In 2008 he was awarded a Ph.D.-degree by the Eindhoven University of Technology, The Netherlands, on his research on prediction of flanking sound transmission through lightweight framed double leaf walls using statistical energy analysis (SEA). From 2008 to 2013 he worked as a scientist in the building acoustics group of the National Research Council (NRC-CNRC) in Ottawa, Canada. There he conducted, amongst others, research on low frequency impact sound transmission in timber frame buildings and lead the building acoustic research in a multidisciplinary project with the goal to increase the allowable building height of wooden buildings in Canada.

Dr. Stefan Schoenwald is lecturer on building acoustics at the ETH Zürich, Switzerland, and active member of European and International technical committees and standardization workgroups.


Predicting and measuring sound transmission in buildings at low frequencies

Carl Hopkins, Acoustics Research Unit, School of Architecture, University of Liverpool

Abstract

In recent years there has been a debate about the importance of considering low-frequencies in the rating of airborne and impact sound insulation. However, in order to consider regulatory requirements that include low-frequencies in the rating it is first necessary to assess what is currently achievable in terms of measurement and prediction. This presentation will review low-frequency sound fields in rooms and link this to what is achievable in laboratory and field measurements of sound insulation according to current International standards. In terms of predicting direct and flanking sound transmission, models using analytical approaches, finite elements, statistical energy analysis will be used to illustrate what is feasible, and the associated uncertainty.

Short Vita

Carl is a Professor in Acoustics and Head of the Acoustics Research Unit at the University of Liverpool in the UK which focuses on the provision of full- and part-time PhD and MPhil study through research. He is a Fellow of the Institute of Acoustics and a chartered engineer. In 2012 Carl was awarded the Tyndall Medal by the Institute for his achievements and services in the field of acoustics.

His research considers both sound and structure-borne sound in the built environment for which he has published a sole-author book on sound insulation in buildings and over 130 journal and conference papers.