Research on the acoustic qualities of building materials and structures and their use for noise reduction in premises ; Statybinių medžiagų ir konstrukcijų akustinių savybių tyrimas ir panaudojimas triukšmui mažinti patalpose
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2011
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VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Tomas JANUŠEVIČIUS RESEARCH ON THE ACOUSTIC QUALITIES OF BUILDING MATERIALS AND STRUCTURES AND THEIR USE FOR NOISE REDUCTION IN PREMISES Summary of Doctoral Dissertation TECHNOLOGICAL SCIENCES, ENVIRONMENTAL ENGINEERING (04T) Vilnius 2011 Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2007–2011. Scientific Supervisor Prof Dr Habil Donatas BUTKUS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering – 04T). Consultant Assoc Prof Dr Vytautas NAINYS (Vilnius Gediminas Technical Universityiences, Environmental Engineering – 04T). The dissertation is being defended at the Council of Scientific Field of Environmental Engineering at Vilnius Gediminas Technical University: Chairman Assoc Prof Dr Raimondas Leopoldas IDZELIS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering – 04T). Members: Dr Habil Algimantas BUBULIS (Kaunas University of Technology, Technological Sciences, Mechanical Engineering – 09T), Prof Dr Habil Kazimieras RAGULSKIS (Kaunas University of Technology, Technological Sciences, Mechanical Engineering – 09T), Prof Dr Habil Petras VAITIEKŪNAS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering – 04T), Assoc Prof Dr Saulius VASAREVIČIUS (Vilnius Gediminas Technical Universityiences, Environmental Engineering – 04T).
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01 janvier 2011
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VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Tomas JANUŠEVIČIUS
RESEARCH ON THE ACOUSTIC QUALITIES OF BUILDING MATERIALS AND STRUCTURES AND THEIR USE FOR NOISE REDUCTION IN PREMISES Summary of Doctoral Dissertation TECHNOLOGICAL SCIENCES, ENVIRONMENTAL ENGINEERING (04T)
Vilnius
2011
Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2007–2011. Scientific Supervisor Prof Dr Habil Donatas BUTKUS Gediminas Technical (Vilnius University, Technological Sciences, Environmental Engineering – 04T). Consultant Assoc Prof Dr Vytautas NAINYS Gediminas Technical (Vilnius University, Technological Sciences, Environmental Engineering – 04T). The dissertation is being defended at the Council of Scientific Field of Environmental Engineering at Vilnius Gediminas Technical University: Chairman Assoc Prof Dr Raimondas Leopoldas IDZELIS(Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering – 04T). Members: Dr Habil Algimantas BUBULIS University of Technology, (Kaunas Technological Sciences, Mechanical Engineering – 09T), Prof Dr Habil Kazimieras RAGULSKIS (Kaunas University of Technology, Technological Sciences, Mechanical Engineering – 09T), Prof Dr Habil Petras VAITIEKŪNAS Gediminas Technical (Vilnius University, Technological Sciences, Environmental Engineering – 04T), Assoc Prof Dr Saulius VASAREVIČIUS(Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering – 04T). Opponents: Assoc Prof Dr Egl. JOTAUTIEN1(Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering – 04T), Prof Dr Alfredas LAURINAVIČIUS Gediminas Technical (Vilnius University, Technological Sciences, Civil Engineering – 02T). The dissertation will be defended at the public meeting of the Council of Scientific Field of Environmental Engineering in the Senate Hall of Vilnius Gediminas Technical University at 1 p. m. on 17 June 2011. Address: Saul*tekio al. 11, LT-10223 Vilnius, Lithuania. Tel.: +370 5 274 4952, +370 5 274 4956; fax +370 5 270 0112; e-mail: doktor@vgtu.lt The summary of the doctoral dissertation was distributed on 16 May 2011. A copy of the doctoral dissertation is available for review at the Library of Vilnius Gediminas Technical University (Saul*tekio al. 14, LT-10223 Vilnius, Lithuania). © Tomas Januševičius, 2011
VILNIAUS GEDIMINO TECHNIKOS UNIVERSITETAS
Tomas JANUŠEVIČIUS
STATYBINIŲ MEDŽIAGŲ IR KONSTRUKCIJŲ AKUSTINIŲ SAVYBIŲ TYRIMAS IR PANAUDOJIMAS TRIUKŠMUI MAŽINTI PATALPOSE DAKTARO DISERTACIJOS SANTRAUKA TECHNOLOGIJOS MOKSLAI, APLINKOS INŽINERIJA IR KRAŠTOTVARKA (04T)
Vilnius
2011
Disertacija rengta 2007–2011 metais Vilniaus Gedimino technikos universitete. Mokslinis vadovas prof. habil. dr. Donatas BUTKUS Gedimino technikos (Vilniaus universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T). Konsultantas doc. dr. Vytautas NAINYS (Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T). Disertacija ginama Vilniaus Gedimino technikos universiteto Aplinkos inžinerijos ir kraštotvarkos mokslo krypties taryboje: Pirmininkas doc. dr. Raimondas Leopoldas IDZELIS(Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T). Nariai: habil. dr. Algimantas BUBULIS technologijos universitetas, (Kauno technologijos mokslai, mechanikos inžinerija – 09T), prof. habil. dr. Kazimieras RAGULSKIS (Kauno technologijos universitetas, technologijos mokslai, mechanikos inžinerija – 09T), prof. habil. dr. Petras VAITIEKŪNAS (Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T), doc. dr. Saulius VASAREVIČIUS(Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T). Oponentai: doc. dr. Egl0 JOTAUTIEN3(Lietuvos žem*s ūkio universitetas, technologijos mokslai, aplinkos inžinerija ir kraštotvarka – 04T), prof. dr. Alfredas LAURINAVIČIUS(Vilniaus Gedimino technikos universitetas, technologijos mokslai, statybos inžinerija – 02T). Disertacija bus ginama viešame Aplinkos inžinerijos ir kraštotvarkos mokslo krypties tarybos pos1dyje 20 m. birželio 7 d. 3 val. Vilniaus Gedimino technikos universiteto senato pos1džių sal1je. Adresas: Saul1tekio al. , LT-0223 Vilnius, Lietuva. Tel.: (8 5) 274 4952, (8 5) 274 4956; faksas (8 5) 270 02; el. paštas doktor@vgtu.lt Disertacijos santrauka išsiuntin1ta 20 m. geguž1s 6 d. Disertaciją galima peržiūr1ti Vilniaus Gedimino technikos universiteto bibliotekoje (Saul1tekio al. 4, LT-0223 Vilnius, Lietuva). VGTU leidyklos „Technika“ 890-M mokslo literatūros knyga. © Tomas Januševičius, 20
Introduction Problem of the work.With technical progress gaining momentum in the second half of the 20th century the cities of developed countries have become particularly noisy. Being incapable of adapting to novelties and a quick pace of changes, men have a feeling of inferiority and various stimulating means, therefore, are used more and more often. This contributes to the spread of alcoholism, toxicomania, noise mania and other evils which create the illusion of oblivion, adaptation and comfort. Noise is an urgent environmental problem causing health disorders. In many cases it causes various stress reactions of the organism from the compensatory stage to de-compensatory stage of adaptation. Consequently, the investigations of the influence of noise on the rise of various illnesses (arterial hypertension, ischemic heart disease, myocardial infarction) are important and relevant. As much as 40% of European Union population is exposed to increased environmental noise during the daytime and around 20% – at night. According to the data of the World Health Organisation (WHO), in Europe 450 million people are exposed to a noise level of 55 decibels; 3 million suffer from 65 dBA noise and 9.7 million feel 75 dBA noise. With construction traditions changing the walls and ceilings of buildings are more and more often made of cast-in-place concrete. Improvement of noise-insulating qualities of such ceilings or walls is possible upon covering them with noise-absorbing materials; however, the presence of holes or cracks in insulating materials largely reduces noise-insulating qualities. Interior walls are often built using gypsum or expanded clay tiles which are light and strong, but a single partition made of such tiles has poor sound insulation. The main sources of noise include traffic, industrial enterprises, construction work, ventilation equipment, neighbours’ activities and festive events. A number of noise sources also exist at home: TVs, musical instruments, children’s toys, vacuum cleaners, washing machines, etc. The most widely spread type of noise in cities is motor traffic – goods vehicles, buses, trolley-buses, also railway transport and civil aircraft. Traffic-generated noise accounts for 60–80% of the noise prevailing in cities. It enters dwellings, public buildings and other spaces frequented by people. The increase in noise level of 0 dB is perceived by a person as a two-time increase in loudness. Topicality of the problem.The distribution of noise dispersion within dwellings through interior walls, ceilings or facades has not been researched to the full extent. Where the reduction of noise in the sources of its spread is
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impossible it is necessary to search for possibilities and ways of limiting noise entering inside buildings. It is necessary to search for such exterior and interior building structures which would decrease a noise level inside buildings. A big contribution to research on the noise insulating qualities of materials was made by the former Soviet Union scientists E. J. Yudin, V. N. Nikolski, G. L. Osipov. In researching noise dispersion within buildings directly via structures and via alternative routes a lot was achieved by the U.S. scientist L. L. Beranek, who earned a science award as one of the most deserving scientists of this field. A big contribution was also made by L. Craig and E. Gerretsen, while the latter did some work in formulating standards for building acoustics measurements. Lithuania’s most prominent acousticians with significant achievements in this field are D. Gužas, J. Stauskis and A. Jagniatinskis; the issues of vibro wave formation and dispersion are analysed by K. Ragulskis, A. Bubulis and other researchers of worldwide recognition. Traffic-generated noise is the main problem affecting dwellings in cities. Materials for ceilings as well as their structures are being developed and selected mainly taking account of thermal resistance. It is necessary to research whether these materials and their structures are always efficient in terms of sound insulation and to search for new structures of ceilings and facades with such sound insulation qualities which would ensure that the level of sound in buildings satisfies the sound levels established in standards and hygiene norms. Object of the work.of the work – buildings’ interiorResearch object walls, ceilings, facades and parts thereof as well as a noise suppression chamber. Aim of the work. Experimental investigations of building materials and structures, which could be used for noise reduction in dwelling and working rooms, and the evaluation of their effectiveness. Tasks of the work . analysis of building materials and structuresTo carry out a classification to be used for sound insulation between building’s interior walls, ceilings and facade in accordance with A, B, C, D, E. 2. To investigate the acoustic qualities of building materials and structures in a noise suppression chamber and under natural conditions. 3. To develop and research perspective building structures for sound insulation between building’s rooms. 4. To compare the acoustic qualities of the elements of building structures which were determined in a noise suppression chamber and under natural conditions. 5. master and adapt a modelling programme for the modelling ofTo select, the sound insulation of building interior acoustics.
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Methodology of research. Investigations of the acoustic qualities of materials and structures made of them were carried out in accordance with the testing methodologies laid down in ISO standards. This work applied methodologies for determining the sound insulation and sound-insulating indices of interior walls , ceilings, facades and parts thereof under natural conditions and in a noise suppression chamber. For theoretical calculations of the sound insulation of interior walls the formulas of the law of mass and those indicated in ISO 12354-1 standard were used. To prognosticate the sound insulation of interior walls and ceilings the modelling programme BASTIAN was used. Scientific novelty.Novelty of the work is link with a complex investigation of sound insulation in dwellings: the acoustic qualities of the existing and new building structures and their elements were investigated in a noise suppression chamber and verified directly in buildings, prospective building structures for noise absorption from interior walls, ceilings and façade structures were sought for and modelling of noise insulation in building structures was performed. In an outcome of the performed analysis of the results of sound insulation modelling and measurement the recommended noise-suppressing building structures for sound insulation between building’s interior walls, ceilings and facades were selected and recommended for use in construction. Practical value.The data of the performed measurements and modelling of noise dispersion between building’s interior walls, ceilings and facades allow a selection of such building structures for dwellings which would best suppress or retain noise dispersion between the neighbouring apartments in a building as well as noise entering inside from outside. Such results may be used when developing new structures. Defended propositions . When measuring the standardised level difference for airborne sound DnT,w in premises where the reverberation duration in the target room is T<0,4 s, the reference reverberation duration value T0 to be assumed as the has average of the reverberation duration in the target room. 2. In order to achieve acoustic comfort the unit mass of the area of monolithic interior wall materials can be prognosticated in accordance with the international standard EN ISO 2354- and modelling programmes. 3. When using sound-reducing jalousies whose slats are covered with a 3 cm layer of rock wool and when the slats are directed to the source of noise at an angle of 20º to 45º the equivalent noise level is reduced from 8 to 4 dB.
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Approbation of the scientific work.On the basis of the work results, 4 articles were published in reviewed publications included in the list of ISI Web of Science journals with Impact Factor, 2 articles – in reviewed publications on the list of ISI Proceedings, and 2 articles – in other scientific publications. The scope of the scientific work.The scientific work consists of a general characteristic of the dissertation, 8 chapters, conclusions and recommendations, a list of references, and a list of publications. The total scope of the dissertation is pages, 93 pictures, 3 tables and 30 formulas.52 Noise spread inside the building In order to ensure residents’ comfort and protection against noise, the sound insulation of interior walls, ceilings and facades is classified and normalised. Sound insulation falls into five classes in Lithuania. Ceilings, interior walls and facades of buildings are required to meet the requirements of at least sound insulation class C. Noise has an adverse effect on human health, reduces working capacity, causes fatigue and decreases attentiveness. Premises are protected against noise from outside by facades with their biggest noise conductor being windows. Windows of different structures have different sound insulation which is most frequently investigated in noise suppression chambers; however, such investigations under natural conditions are scarce. Sound spread within buildings and structures can be modelled using modelling programmes. 2 Investigations of building materials and structures in a noise suppression chamber Measurements carried out in a noise suppression chamber covered sound reduction index Rwstandardised level difference for airborne sound D, nT,Wand the frequency characteristics of the qualities of acoustic materials. The noise suppression chamber consists of two rooms divided by an interior wall in which the investigated structures were assembled. The noise suppression chamber has acoustic insulation with regard to building’s vibration and humidity. The background noise level recorded in the noise suppression chamber in a frequency range from 00 to 200 Hz varied from 8.9 to 2.0 dB, in a frequency range 250–000 Hz the value of the background noise level stood at 0 dB, and when frequencies varied from 250 to 350 Hz the background noise level reached from 0.8 to 4.6 dB. The investigations of sound reduction indices and sound reduction frequency characteristics of light materials, such as gypsum cardboard, wood chipboards, rock and glass wool, were carried out in the noise 8
suppression chamber. Investigations were also carried out of the sound reduction indices and sound reduction frequency characteristics of log, straw and clay, and expanded clay tile walls by covering them with different sound-insulating and sound-absorbing materials and searching for the ways of how can sound insulation class C required for buildings be achieved. Figure 2.a shows the expanded clay tile, log and straw and clay walls in question. Figure 2.b shows the sound reduction indices recorded for the expanded clay, log, and straw and clay walls in the noise suppression chamber. The log wall was investigated using 20 different modifications thereof. The expanded clay tile wall was investigated using 5 different modifications of the wall. No. 1 No. 2 No. 3 7060 60 55 5040 40 30 12 3 4 5 3 2 1 6 20 1 utty (2 mm); 1 – sidings (20 1 ressed straw (400 2 – plaster (10 mm); mm); mm);10 3–expanded clay tiles 2 – rock wool 2 – clay plaster (10 mm)0 „FIBO“ (3 MPa), (100 mm);No. 1 2 No. 3 No. (100×185×490); 4 – 3 – log wall (150 „Paroc“ (50 mm); mm);Strukture No . 5 – air space (50 mm); 4 – wood 6 – gypsum cardboard chipboard (10 mm) (12,5 mm) a) b) Fig. 2.1.of the experimental structures and sound reduction indicesSamples polystirene granules sawdust chaff
60 50 40 30 20 10
Frequency,Hz
Fig. 2.2.Results of sound level reduction by chaff, sawdust and polystyrene granules Figure 2.2 shows the results of the investigations carried out by using 0.2 m thick packages of bulk materials. In the presence of low frequencies of 9
25 to 200 Hz all three types of materials displayed nearly identical reduction of the sound level. In a frequency range from 250 to 500 Hz the sound level was reduced up to 30 dB by chaff, poorer sound reduction qualities were characteristic of sawdust which decreased the sound level to 25 dB, while polystyrene granules reduced the sound level least, up to 20 dB. Chaff has a bigger density than sawdust, while polystyrene granules are the lightest. In addition, chaff is composed of finer particles resulting in the formation of a large surface area, which absorbs and disperses the sound that falls into it. The acoustic qualities of the structure composed of perforated tin with rock wool filler which is intended for noise reduction in working premises with a large content of dust were investigated in the noise suppression chamber. Research was also done on the sound reduction qualities of the bulk materials which are used to fill air spaces in structures. A special structure was designed for the investigations of the sound reduction qualities of bulk materials. 3 Natural experimental investigations of facades and their parts Facades are composed of elements having different sound insulation characteristics such as windows, vents and walls. Different structures of windows and facades have different sound insulation capacities and therefore this chapter analyses the sound insulation investigations of different windows and facades, as well as facades with and without balcony structures. The sound insulation of windows was measured according to the element ’ methodology, the apparent sound reduction index R45° was analysed: ’ R45º = L1,s– L2+ 0 lg (S/A) – .5, (3.) where: L1,sof sound pressure to test surface, dB; L– medium level 2– medium sound pressure level in the target room, dB; S – sample area, m2; A =0.1T63Varea in the target room, m– equivalent sound absorption 2; V – room volume, m3; T – reverberation duration, s. The sound insulation of facades was measured according to the standardised level difference for airborne sound DTnw,lsm,,2, (LST EN ISO 40-5). Where sound frequencies are low, from 50 to 250 Hz, resonances formed in a frequency range of 25 to 200 Hz which was predetermined by the sound reduction qualities of windows. Resonance in a frequency range of 25 to 200 Hz formed in a façade having windows of different sizes. Where frequencies are low, to 400 Hz, sound insulation increases to 35–38 dB, while 10
with a further increase in frequencies from 500 to 8000 Hz sound insulation grows insignificantly, i.e. by –2 dB for oktave (Fig. 3.). It has been determined that the size and sound reduction qualities of windows predetermine the total sound insulation of facade. Where facades have several different windows with different sound insulation and different resonance frequencies, the sound reduction index of such facades is lower. 1 2 3 55 50 45 40 35 30 25 20
Fr equency, Hz Fig. 3.1. ation of facades’ standardised level difference forResults of the investi airborne sound Dls,2m,nTw – facade with 4 m: 12glued wood balcony door; 2 – fa ade with 4 m2glued wood balcony door and 1 m2window; 3 – facade with 3.2 m2glued wood balcony door It has been determined that plastic frame windows with glass packages have by up to 5 dB better sound reduction qualities than glued wood frame windows with glass packages. 4 Natural experimental investigations on sound insulation of building’s interior walls In order to ensure sound insulation of premises with regard to other general use or living premises it is important that interior walls correspond to the required sound insulation. Therefore, investigations of the sound insulation of the interior walls of different structures were carried out in the rooms where they are assembled. The investigations covered the standardised level difference for airborne sound DnT,W apparentand the sound reduction index R´w, as well as the insulating capacities of the structures in the event of different frequencies. During investigations of the sound reduction index it was noticed that where the room volume exceeded 50 m3, a difference of up to 4 dB between the apparent sound reduction indices R´wand DnT,Whad formed (Fig. 4.). 11
