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Vienna University of Technology Department of Spatial Development, Infrastructure and Environmental Planning Centre of Public Finance and Infrastructure Policy In co-operation with Hon.-Prof. Dipl.-Ing. Dr. Judith Lang

SOUND INSULATION IN HOUSING CONSTRUCTION Results of an investigation commissioned by SAINT-GOBAIN – ISOVER

Project team Univ.-Prof. Mag. Dr. Wilfried Schönbäck (Project leader) Hon.-Prof. Dipl.-Ing. Dr. Judith Lang Project Ass. Dipl.-Ing. Dr. Roger Pierrard http://www.ifip.tuwien.ac.at/ Vienna, July 2006

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Vienna University of Technology

Centre of Public Finance and Infrastructure Policy Department of Spatial Development, Infrastructure and Environmental Planning Resselgasse 5/2/2, A-1040 Vienna, Austria Tel.: ++43/1/58801-26701 (Secretary) Fax: ++43/1/58801-26799 E-Mail: ifip@tuwien.ac.at Web: www.ifip.tuwien.ac.at

Judith Lang A-1090 Wien, Latschkagasse 4 Tel.: ++43 1-317 53 94 Email: judith.lang@aon.at

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Synopsis

The compilation of results obtained from environmental surveys in different European countries shows that the second most frequent source of noise pollution are one's neighbours, after road traffic noise which causes the majority of noise complaints.

In Austria, for instance, a survey conducted every 3 years as part of the microcensus found out that neighbourhood noise - after traffic noise - was the second most frequently indicated cause of strong to very strong noise disturbance until the mid-1980s. As a result of improved sound insulation in housing construction and the strict observance of standard requirements in subsidized housing construction, neighbourly noise is now perceived to be at nearly the same level as industrial noise. It is, however, slightly exceeded by "other sources of noise" (e.g. leisure facilities). In 2003, 7.7 % of the respondents who felt strongly or even extremely disturbed by noise claimed neighbourhood noise was the cause of the disturbance.

In Germany it was deduced from an inquiry about the experienced noise annoyance that 17.3 % are annoyed moderately, strongly or extremely by noise from the neighbours.

In the U.K. in 1999/2000, a National Survey of Attitudes to Environmental Noise was performed with a detailed questionnaire. 84 % reported hearing road traffic noise, 81 % hearing noise from their neighbours or other people nearby, 58 % hearing the neighbours inside their homes; 40 % reported being annoyed or bothered by road traffic noise, 37 % by the noise of the neighbours or other people nearby.

In France in 2004 41.2 % of the households felt disturbed by noise, 23.3 % by traffic noise and 19.6 % by neighbours.

In the Netherlands an investigation found that sound originating from the neighbouring flat can be heard in about 75 % of apartments, and heard every day in 40 %. In about 1/3 of all households this sound is found to be annoying, and for 13 % very annoying.

In a study in panel-block-buildings in Lithuania, Slovakia and Eastern Germany it was found that in the investigated buildings 65 %, 40 % und 36 % respectively complained of noise, the primary source of which was noise from neighbours (talking, music, DIY activities and TV).

As a result of a representative opinion poll among the population of Switzerland on the perception of and affectedness by noise, the following results were sampled. In response to a general question on the importance of the noise problem from a general point of view (Switzerland as a whole) and for the individual in particular, a ranking was made on a scale from 1 to 6 (1 = does not affect at all, 6 = strongly affects). According to the poll, road-traffic noise ranked highest with 4.2 (general view) and 3 (personal view) among the respondents. Neighbourhood noise ranked distinctly lower with 2.5 and 2 respectively. People dissatisfied with their homes assess the environmental impact of neighbourhood noise in Switzerland clearly higher (3.1) than those satisfied with their homes (2.4).

The survey of the sound insulation requirements for residential housing in European countries conducted by Rasmussen shows that different quantities are used to define the requirements (apparent sound reduction index, normalized sound level difference, standardized sound level difference with or without spectrum adaptation term for different frequency ranges, normalized impact sound pressure level, standardized impact sound pressure level with or without spectrum adaptation term for different frequency ranges) and the differences in the requirements in the various countries are very great up to 10 dB (a difference of 10 dB means about double loudness of the noise).

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A calculation to prove which sound levels are caused in the neighbouring flat with different sound insulation by different activities (conversation between 6 people with normal loudness and animated conversation with laughter, and music played with a single instrument or with 6 instruments) shows that the sound insulation required in the existing standards does not make the neighbours activities inaudible at all.

In several European countries, therefore, classes for enhanced sound insulation besides the minimum requirements dictated by building regulations have been defined in the last few years; these are based mainly on the standardized sound level difference plus spectrum adaptation term DnT,w+C (also written DnT,A ); in many cases the importance of the low frequency range (C50-3150) is pointed out and partly – especially in the higher sound insulation classes – used in the requirements. In several countries specifications of the classes are given in the form of how many persons feel annoyed by the neighbours’ noise and how many are satisfied with the sound insulation.

The impact sound insulation is mainly described by the normalized impact sound pressure level, partly with the spectrum adaptation term CI, whereby – especially for the higher classes – the low frequency range is also considered by CI,50-2500. Several specifications exist on the correlation of subjective satisfaction and required impact sound insulation.

Requirements for airborne and impact sound insulation within a flat (or a single-family house) exist only in some countries and only for the higher sound insulation classes.

In all considered countries sound insulation is planned on the basis of EN 12354-1 and -2; in many countries, calculation programmes exist for the determination of the sound insulation in the planning state and data have been published as a basis for the planning. Measurements of the sound insulation in the finished building are partly scheduled for the classification (ascertaining the acoustic class of a building or a space).

The development of sound insulation in housing construction in Austria is described in detail.

Based on calculations of the audibility of living activities on the one hand and on sound insulation classes in different countries on the other, the following requirements for airborne and impact sound insulation for 4 sound insulation classes are proposed.

Class “Music” “Comfort“ “Enhanced“ *) “Standard“ Airborne sound insulation between flats DnT,w +C (dB)

≥ 68 (C50-3150)

≥ 63 ≥ 58 ≥ 54

Airborne sound insulation between the rooms within a flat (without doors), also incl. one-family houses DnT,w +C (dB)

≥ 48 ≥ 48 ≥ 45 ≥ 40**)

Impact sound insulation between flats L’nT,w + CI,50-2500 ***)(dB)

≤ 40 ≤ 40 ≤ 45 ≤ 50

Impact sound insulation within a flat, also incl. one-family houses L’nT,w + CI,50-2500 ***)(dB)

≤ 45 ≤ 45 ≤ 50 ≤ 55

*) minimum requirements for terraced houses **) if requested ***) for a transitional period L’nT,w + CI, values decreased by 2 dB

Based on the results of measurements and calculations of the sound insulation in a number of massive residential buildings in 2 Austrian provinces (“Bundesländern”), it is shown that the standard requirements are exceeded and partly far exceeded in a considerable percentage of cases; the measures which can improve the sound insulation are also shown.

To investigate the sound insulation in wooden constructions, an example is shown of a multi-family house in Austria; furthermore, a comprehensive collection of data on the sound insulation

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(and heat insulation) of wooden constructions available on the internet is referred to. The influence of different details is shown by means of a series of wooden wall and floor constructions from a German investigation. Two investigations from the Netherlands about improvements in sound insulation in massive buildings and wooden constructions are dealt with briefly.

Various studies have put the expenses incurred by improved sound insulation at between 1 and 7% of total construction costs.

Calculations for a sample of massive constructions in the federal provinces of Upper Austria and Styria produced no significant correlation between the standard of sound insulation achieved and total construction costs. From this it can be deduced that other features have a far greater impact on construction costs than improved sound insulation, a result which is supported by other studies. At the end of the day, this represents an important argument in favour of achieving better levels of sound insulation in new constructions, as it is common knowledge that the subsequent removal of shortcomings caused by insufficient standards of sound insulation is only possible at enormous cost, if at all.

With regard to a small sample of lightweight wooden constructions in Styria, some with sound insulation levels in accordance with the requirements of ÖNORM and others with better but unspecified sound insulation in comparison with ÖNORM, no generally valid trend regarding the impact of achieved sound insulation on total construction costs could be deduced. However, it may be assumed that in particular as far as lightweight wooden buildings are concerned, the effect of improved sound insulation on total building costs is far greater than with massive constructions.

As far as externalities from neighbourhood noise are concerned, research is thin on the ground in comparison with other types of environmental noise, such as road, rail and air traffic noise. Currently only a small number of studies have been carried out which in some cases show a significant willingness to pay in order to escape disturbance from neighbourhood noise or to achieve an improved level of sound insulation in this respect. Investigations from an economic perspective, in particular cost-benefit analyses of this problem, have not been performed, and there is thus a great need for further research in this area.

However, the effects of annoyance from neighbourhood noise appear thus far to have been underestimated in comparison with other sources. A more recent study argues that annoyance from neighbourhood noise can manifest itself in the form of increased risk of illness, and goes on to show that the negative impacts of neighbourhood noise on health cannot be differentiated from those of traffic noise.

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List of contents

1 Significance of different sources of noise annoyance in residential buildings in Austria and selected European countries...................................................................................................... 1

2 Sound insulation requirements for residential buildings........................................................... 7

2.1 Which units are used to describe sound insulation and which minimum requirements must be fulfilled in the European countries? ........................................................................... 7

2.1.1 Airborne sound insulation........................................................................................... 7

2.1.2 Impact sound insulation............................................................................................ 11

2.2 Which requirements can ensure sufficient protection against noise annoyance caused by neighbours‘ activities in multi-family dwellings? Which proposals have been made? ....... 13

2.2.1 Protection against airborne sound transmission ....................................................... 13

2.2.2 Protection against impact sound ............................................................................. 24

2.3 How can the fulfilment of the requirements be ensured .................................................. 31

2.4 Sound insulation in Austrian dwellings............................................................................ 37

3 Suggested sound insulation classes for residential buildings ................................................ 44

4 Structural measures for improving the sound insulation in newly built residential houses...... 47

4.1 Residential buildings in massive construction ................................................................. 47

4.2 Lightweight construction of residential buildings (wooden structures) ............................. 63

5 The costs of improved sound insulation ................................................................................ 72

5.1 Proportion of building costs in overall construction costs ................................................ 72

5.2 Total net costs and sound insulation in massive residential constructions in Upper Austria and Styria ................................................................................................................. 76

5.3 Total net construction costs and sound insulation in lightweight wooden residential buildings in Styria ................................................................................................................. 80

6 Current thinking on the measurement of the effects of disturbance caused by noise and its reduction.................................................................................................................................. 82

6.1 Effects of noise on health ............................................................................................... 83

6.2 Social effects of noise..................................................................................................... 84

6.3 Economic effects of noise – the external costs of noise .................................................. 84

6.4 Economic effect of neighbourhood noise ........................................................................ 88

6.5 Proposals for further research ........................................................................................ 91

Literature .............................................................................................................................. 92

Standards............................................................................................................................. 96

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List of figures

Figure 1: Annoyance by noise in communities with different numbers of inhabitants.................. 2

Figure 2: Sources of strong and very strong annoyance ............................................................ 2

Figure 3: Spectrum adaptation terms for walls ........................................................................... 9

Figure 4: Third octave band level in the neighbouring room transmitted from the source room with music or talking 90 dB A-weighted for different sound insulation and background level........................................................................................................ 15

Figure 5: Comparison of regression fits to average responses versus STC ............................ 23

Figure 6: Global relation between real walking and the normalized impact sound level (spread zone is indicated by upper and lower line)..................................................... 27

Figure 7: Comparison of the A-weighted sound level for excitation with the rubber ball and the weighted normalized impact sound level for excitation with the tapping machine with the equivalent sound level of walking noise ........................................................ 30

Figure 8: Spectrum adaptation terms CI and CI,50-2500 from measurements made on timber joist floors .................................................................................................................. 31

Figure 9: Difference calculated value – measured value for measurements between rooms side by side................................................................................................................ 33

Figure 10: Difference calculated value – measured value for measurements between rooms one on top of the other............................................................................................... 33

Figure 11: Percentage of people annoyed by noise from different living activities ................... 38

Figure 12: annoyance by noise in Austrian dwellings .............................................................. 40

Figure 13: Results of measurements of airborne and impact sound insulation in residential buildings in Upper Austria .......................................................................................... 41

Figure 14: Results of sound insulations measurements in subsidized housing (built between 1990 and 1999) in the federal states of Steiermark (Styria) and Oberösterreich (Upper Austria) .......................................................................................................... 43

Figure 15: Sound level inside the building versus sound level in front of the facade with the sound insulation of the external structure according to ÖNORM B 8115-2................. 46

Figure 16: Sound transmission paths between two rooms ....................................................... 47

Figure 17: Section of the outer wall of bricks with the concrete floor and outside heat insulation ................................................................................................................... 48

Figure 18: Elastic connection of lightweight massive partition walls with the floor and the separating wall between flats ..................................................................................... 49

Figure 19: Weighted sound reduction index Rw and weighted standardized sound level difference DnT,w of outer wall and inner wall when flanking a floor of 535 kg/m2 (bare floor with grit), with floating floor with resonance frequency < 85 Hz .......................... 62

Figure 20: Example of construction of wall and floor and the relevant connections in a multi-family house in wooden construction.......................................................................... 64

Figure 21: Partition with junction to foundations and floor in the model-project in wooden construction ............................................................................................................... 70

Figure 22: Partition with junction to the outer wall and the roof in the model project in wooden construction (SBR 2003) ............................................................................................ 71

Figure 23: Comparison of the standard SIA 181 1988 and 2006 .............................................. 74

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Figure 24: Net cost per square metre and sound insulation for rooms above and next to one another ...................................................................................................................... 78

Figure 25: Net building costs per square metre and the number of residences constructed Source: IFIP, 2006 (based on the data from Table 37)............................................... 78

Figure 26: Net construction costs per square metre and sound insulation levels of massive constructions in Styria................................................................................................ 80

Figure 27: Net construction costs per square metre and sound insulation levels of lightweight wooden constructions in Styria................................................................................... 81

Figure 28: Trend over time of air-traffic noise level (LDN in dB(A)) associated with a constant proportion of seriously affected individuals of 25%..................................................... 82

Figure 29: External costs because of noise in the EU 15 Member States, in EUR million per year............................................................................................................................ 85

Figure 30: Overview of the key cost components of economic effects caused by noise ........... 86

Figure 31: Disturbance profile for noise from neighbours’ activity over a day according to Grimwood und Ling.................................................................................................... 89

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List of tables

Table 1: Noise annoyance in Austrian dwellings...................................................................... 1

Table 2: Noise annoyance from various sound sources in Germany ....................................... 3

Table 3: Perception of the neighbours..................................................................................... 3

Table 4: Proportions of respondents who heard and reported being bothered, annoyed or disturbed to various extents by general categories of environmental noise ............... 4

Table 5: Annoyance caused by noise in French households ................................................... 5

Table 6: Overview airborne sound insulation requirements in 24 European countries ........... 10

Table 7: Overview impact-sound insulation requirements in 24 European countries.............. 12

Table 8: Sound level in the receiving room for different sound levels in the source room and different sound insulation ........................................................................................ 14

Table 9: Indicative planning values for the background level in flats in residential buildings in different land use categories according to ÖNORM B 8115-2.............................. 14

Table 10: Relation between airborne sound insulation in dwellings and the expected percentage of people finding conditions satisfactory ............................................... 16

Table 11: Meaning of the sound reduction quality for dwellings............................................. 17

Table 12: Requirements for airborne sound insulation in classes A, B, C, D in DS 490 ......... 17

Table 13: Airborne sound insulation in classes A, B, C, D according to SFS 5907 ................ 19

Table 14: Perception of noise from neighbouring flats assigned to the 3 sound insulation classes SSt according to VDI 4100 ......................................................................... 19

Table 15: Subjective perception of the airborne sound insulation between rooms depending on the background level (draft SIA 181) .................................................................. 20

Table 16: standard requirements for airborne sound insulation inside the building DnT,w+C-Cv according to draft SIA 181................................................................................... 21

Table 17: Relation between impact sound pressure level and the expected percentage of people finding conditions satisfactory ...................................................................... 25

Table 18: Standard requirements for impact-sound insulation in draft SIA 181...................... 25

Table 19: Subjective perception of impact-sound insulation between rooms ......................... 26

Table 20: Results of laboratory experiment with impact sound and simulated constructions with different sound insulation below 125 Hz........................................................... 26

Table 21: Requirements for impact-sound insulation in classes A, B, C, D (DS 490)............ 27

Table 22: Proposal for impact-sound insulation requirements in residential buildings in Poland..................................................................................................................... 28

Table 23: Requirements and recommendations for impact-sound insulation in Norway (NS 8175)....................................................................................................................... 28

Table 24: Requirements for impact-sound insulation in classes A, B, C, D (SFS 5907)......... 29

Table 25: Mean values for the calculated value – measured value difference for DnT,w .......... 34

Table 26: Proposed requirements for airborne and impact sound insulation in 4 sound insulation classes .................................................................................................... 44

Table 27: Requirements for the sound insulation of the façade according to ÖNORM B 8115-2..................................................................................................................... 45

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Table 28: Maximum sound levels in rooms for living caused by a sound source outside the building ................................................................................................................... 45

Table 29: Sound insulation between adjacent rooms............................................................. 50

Table 30: Sound insulation between rooms one above the other........................................... 55

Table 31: Weighted standardized sound level difference DnT,w required for flanking elements and examples of their fulfilment................................................................ 63

Table 32: Sound insulation between adjacent flats in dwellings in wooden construction........ 66

Table 33: Sound insulation between flats one above the other in dwellings in wooden construction............................................................................................................. 68

Table 34: Sound insulation requirements in accordance with the sound insulation levels laid out in VDI 4100 ....................................................................................................... 75

Table 35: Differences in sound-insulation costs for sound insulation level II and III compared with sound insulation level I in accordance with VDI 4100, with reference to total construction costs in % ................................................................ 75

Table 36: Building costs index 2000 ...................................................................................... 76

Table 37: Sound insulation for rooms above and next to one another and costs per square metre....................................................................................................................... 77

Table 38: Maximum difference in sound insulation versus the range of cost per square metre....................................................................................................................... 77

Table 39: Net construction costs per square metre for massive constructions in Styria with sound insulation levels in line with ÖNORM or higher levels of sound insulation than laid down in ÖNORM....................................................................................... 79

Table 40: Net construction costs per square metre of lightweight wooden constructions in Styria which meet the minimum requirements for sound insulation in accordance with ÖNORM or exceed the sound insulation requirements laid down in ÖNORM .. 81

Table 41: Externalities from road traffic noise as % of GDP in selected European countries . 85

Table 42: Results from Stated Preference studies of road traffic noise; as experienced inside the dwelling................................................................................................... 87

Table 43: Ranking of sources of noise leading to complaints about neighbours .................... 88

Table 44: Significantly ODDS Ratio (OR) for diseases calculated in the WHO-LARES study 90

Table 45: Monetary Evaluation of Noise Disturbance ............................................................ 91

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1 Significance of different sources of noise annoyance in residential buildings in Austria and selected European countries

In Austria in 1970-1994, inquiries about the annoyance of people in their dwellings were performed in 3-year periods within the scope of the microcensus. In the following years the inquiries were performed at somewhat wider intervals in 1998 and 2003. So there exists a good overview of the development of annoyance by noise in Austria in the last three decades. Up to 1998 the annoyance could be specified in 3 degrees: very strong, strong and slight. In 2003 the rating of the annoyance was widened to 4 degrees: very strong, strong, medium and slight. By inserting the grade “medium” the share of the other grades was reduced. In Table 1 below, the results of the inquiries on noise annoyance since 1970 are shown according to the publications of Österreichisches Statistisches Zentralamt (now Statistik Austria).

Table 1: Noise annoyance in Austrian dwellings percentage annoyed

1970 1973 1976 1979 1982 1985 1988 1991 1994 1998 2003

in all 49.9 48.9 52.8 40.35 41.4 36.4 37.3 33.5 33.8 35.3*) 28.4 29.1

slight 26.5 23.0 29.6 20.3 21.5 17.6 18.4 15.6 16.7 17.5*) 12.5 10.0

medium 9.8

strongly 14.1 15.6 15.1 12.6 12.5 11.7 12.4 11.4 10.9 11.5*) 10.8 6.2

very strongly 9.3 10.3 8.1 7.4 7.4 7.1 6.5 6.5 6.2 6.3*) 5.1 3.2

*) Until 1988 the evaluations were performed referring to the households, while the results were evaluated referring to households until 1994; from 1994 referring to people; for the year 1994 both evaluations are stated: the upper number refers to households, the lower number to people.

Source: Lang 2006

Evidently annoyance by noise in Austria has been reduced considerably by the measures which have been taken especially to protect people against noise from road and rail traffic

The annoyance in small communities is considerably smaller than in towns, as is shown in Figure 1.

Investigation into the sources of strong and very strong annoyance identified predominantly traffic noise, with 70 to 80 %; further noise sources as factories, neighbours and others (with construction sites, leisure time activities, tourist facilities) barely reached 10 %, as shown in Figure 2.

Thus annoyance overall has been reduced considerably by measures against road traffic noise and rail traffic noise, but the share of traffic stayed unchanged on the whole.

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Figure 1: Annoyance by noise in communities with different numbers of inhabitants

Source: Lang, 2006

Figure 2: Sources of strong and very strong annoyance

Source: Lang, 2006

Annoyance caused by noise from the neighbouring flat was the most frequently cited after traffic noise in the inquiries in 1978, 1982 and 1985, mainly as a result of the low sound insulation in the residential buildings constructed after the war. The annoyance from neighbours then decreased with the introduction of new sound-insulation requirements and their observance for

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subsidized buildings. In 2003, 7.7 % of strong and very strong annoyance was caused by noise from the neighbours. 10.4 % of the people annoyed by noise (29.1 % of those interviewed) cited noise from the neighbouring flat as a cause. From this one can derive that 3 % of the total population are annoyed by noise from the neighbours. The share is different in Vienna, with most people living in multi-family houses, and in the provinces, where more people live in detached houses. So in 2003 12 % of the strongly and very strongly annoyed persons in Vienna specified the neighbouring flat as a cause, compared to only 4.4 % in communities with up to 20,000 inhabitants and 9.6 % in communities with more than 20,000 inhabitants (except Vienna). 15.03 % of the total of 35.2 % annoyed individuals in Vienna specified the neighbouring flat as the noise source; from this it can be seen that in total 5.3 % of all inhabitants of Vienna are annoyed by noise from the neighbours.

In Germany the Umweltbundesamt (Environmental Protection Agency) orders inquiries at intervals of two years, where apart from the level of satisfaction with environmental policy, the degree of the environmental awareness of the population, including the experienced annoyance by noise is determined. The evaluations of the inquiry in 2004 (Ortscheid et al., 2006) produce the following data (Table 2).

Table 2: Noise annoyance from various sound sources in Germany percent annoyed by noise from

sound source road traffic air traffic rail traffic industry and trade

neighbours total

not at all 40.1 67.6 79.8 80.9 57.3 37.8

somewhat 29.6 20.0 12.0 11.6 25.4 35.4

medium 20.3 7.8 5.4 5.5 11.3 18.7

strongly 6.1 3.3 2.0 1.6 4.0 6.1

extremely 3.9 1.3 0.8 0.4 2.0 2.0

Source: Ortscheid et al., 2006, translation by Lang

Road traffic noise is evidently also the most annoying noise source in Germany; the second frequently specified source is neighbourly noise.

There was also a question related to the quality of the acoustical sound insulation, which asked about the extent to which the neighbours are perceptible through partitions and floors. The results of this question are shown in Table 3.

Table 3: Perception of the neighbours perception of the neighbours percent of all interviewed percent of those which have

neighbours very good

4.3 5.6 good

8.0 10.4 mediocre

12.4 16.0 somewhat

26.7 34.5 not at all

25.9 33.5 no neighbours

22.8 --

Source: Ortscheid et al., 2006, translation by Lang

Evidently 2/3 of those interviewed who have direct neighbours perceive noise from their neighbours’ living activities, and 16% well or very well. This points to the fact that the sound insulation installed in the existing dwellings does not sufficiently protect the occupants against being heard by their neighbours and against hearing their neighbours. When comparing the results of the inquiries in 2004 and 2002 one can see that the share of those highly annoyed by road traffic (7 percent points) and by air traffic, rail traffic and industry (1-2 percent points) decreased. In contrast no decrease in the number of people highly annoyed by the neighbours can be noticed.

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When comparing at the end of 2002 the results of the inquiries from 1960 to 1988 and the inquiries carried out by the Umweltbundesamt between 1984 and 1994, it was found that no decrease in noise annoyance over time can be derived (Ortscheid, 2003).

In the United Kingdom BRE undertook a National Survey of Attitudes to Environmental Noise 1999/2000 with a detailed questionnaire (BRE, 2002). The key findings are: 18 % of respondents reported noise as one of the top five from a list of environmental problems that personally affected them. This placed it ninth in the list of 12 environmental problems. 69 % of respondents reported general satisfaction with their noise environment (i.e. liking the amount (or absence) of noise around them at home to some extent (rated according to top 3 categories on a 7 point scale from definitely don´t like to definitely do like). 84 % of respondents reported hearing noise from road traffic. 81 % of respondents reported hearing noise from neighbours and/or other people nearby. 71 % of respondents reported hearing noise from aircraft. 49 % of respondents reported hearing noise from building, construction, demolition, renovation or road works. 40 % of respondents reported being bothered, annoyed or disturbed to some extent (a little, moderately, very or extremely) by road traffic noise. 37 % of respondents reported being bothered, annoyed or disturbed to some extent by noise from neighbours and/or other people nearby. 20 % of respondents reported being bothered, annoyed or disturbed to some extent by noise from aircraft. 15 % of respondents reported being bothered, annoyed or disturbed to some extent by noise from building, construction, demolition, renovation or road works. 21 % of respondents reported that noise spoilt their home life to some extent (a little, quite a lot, or totally)

The grade of annoyance caused by the different sources is shown in Table 4. It gives the answers to the question: When you are at home, to what extent are you personally bothered, annoyed or disturbed by noise from….? Not at all – A little – Moderately – Very – Extremely.

Table 4: Proportions of respondents who heard and reported being bothered, annoyed or disturbed to various extents by general categories of environmental noise

bothered, annoyed or disturbed (%) noise category (n = 2876)

hear (%) to some extent moderately, very

or extremely very or extremely

Road traffic 84 ± 3 40 ± 3 22 ± 2 8 ± 1 Neighbours (inside their homes) 58 ± 4 18 ± 2 9 ± 1 4 ± 1 Neighbours (outside their homes) 71 ± 4 22 ± 2 10 ± 1 4 ± 1 Other people nearby 68 ± 4 20 ± 3 8 ± 1 3 ± 1 Neighbours and/or other people nearby (combined category)

81 ± 3 37 ± 3 19 ± 2 9 ± 1

Aircraft/airports/airfields 71 ± 4 20 ± 4 7 ± 2 2 ± 1 Building, construction, demolition, renovation or road works

49 ± 5 15 ± 2 7 ± 2 2 ± 1

Trains or railway stations 36 ± 4 6 ± 1 2 ± 1 1 ± 0 Sports events 34 ± 4 4 ± 1 1 ± 0 0 ± 0 Other entertainment or leisure 31 ± 4 6 ± 1 2 ± 1 1 ± 0 Community buildings 30 ± 3 4 ± 1 1 ± 0 0 ± 0 Forestry, farming or agriculture 26 ± 4 3 ± 1 0 ± 0 0 ± 0

Factories or works 23 ± 3 4 ± 1 2 ± 0 1 ± 0 Other commercial premises 23 ± 4 3 ± 1 1 ± 0 1 ± 0 Sea, river or canal traffic 16 ± 3 0 ± 0 0 ± 0 0 ± 0 Any other noise 15 ± 3 4 ± 1 3 ± 1 1 ± 0

Source: BRE 2002

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The annoyance caused by neighbours was further investigated in detail for the single sources, however not separated for the categories of neighbours; so details on the annoyance from the neighbouring flat can not be reported.

In France the annoyance caused by traffic noise and by noise from the neighbours from 1998 to 2004 was reported (Le Jeannic et al., 2005). In Table 5 some results from this investigation are shown.

Table 5: Annoyance caused by noise in French households % of households often or sometimes disturbed

1998 1999 2000 2001 2002 2003 2004 95%

confidence interval

total 20.6 38.9 39.0 42.3 40.4 40.5 41.2 40.0 : 42.4 by traffic noise 22.9 21.2 21.2 22.1 21.9 21.6 23.3 22.3 : 24.4 by neighbourly noise 19.0 18.8 18.5 21.3 19.9 19.8 19.6 18.6 : 20.6

Source: Le Jeannic et al., 2005

The table shows that annoyance caused by noise from the neighbours is about as high as that caused by traffic noise (road, rail and air traffic).

Splitting up according to the population density shows e.g. for the year 2004 the highest proportion of 29.7 in the most densely populated parts (>3500 inhabitants/m2) and the lowest proportion of 14.0 in areas with < 70 inhabitants/m2.

A similar differentiation also results for the annoyance caused by noise from the neighbours: 42.8 % of those living in sensitive town quarters (Zone urbain sensible, ZUS) are disturbed by noise from the neighbours, 24.8 % are disturbed in communities with ZUS in the parts outside the ZUS and 19.5 % in communities without ZUS (except rural communities) and 8.6 % in the rural communities.

The importance of annoyance by noise especially in urban areas is also shown in an investigation on the annoyance by noise in large towns in France (Association des maires de grandes villes de France, 2003). According to this investigation road traffic noise is important for 54 % and less important for 32 %, while noise from neighbours is important for 75 % and less important for 14 %.

In the Netherlands studies showed that both the scale and the severity of noise annoyance from neighbours is substantial and by order of size equates to the annoyance from traffic noise (van Dongen, 2001). Sounds from neighbouring dwellings can be heard in approximately 75 % of dwellings in the Netherlands and in 40 % of cases this is a daily event. In approximately 1/3 of all households (=2.2 million) at least some level of annoyance is experienced from these sounds; in approximately 13 % (=850.000 households) to a severe degree. From a diagram on annoyance versus sound insulation one can read that with a sound insulation according to Rw + C = 53 dB 10 % are severely annoyed, 11 % are annoyed and 14 % slightly annoyed. The grade of annoyance is correlated with the subjective assessment by the residents of the quality of the sound insulation and with the objective measure for the sound insulation. The main sound sources causing annoyance are special pop music, having the TV/radio/audio equipment on loud, slamming doors, walking heavily on the stairs or on floors. An increase in annoyance from noise from neighbouring dwellings can be expected if sound insulation in relation to the exterior is improved, but not in relation to adjacent dwellings. Almost all respondents (approximately 95%) said they took the neighbours into account with their own behaviour.

In a study on housing conditions and self-reported health status in panel block buildings in three cities of Eastern Europe (Bonnefoy, 2003) was found, that noise exposure is associated with both self-assessed health and mental health and affects a large part of the population. With 65 %, 40 % and 36 % of the respondents in Vilnius, Bratislava and Schwedt-Oder claiming frequent noise disturbances noise is identified as a priority challenge for housing and health. The main reason for disturbances was neighbour noise (talking, music, do-it-yourself activities, TV, etc). The level of self-assessed health status directly depended on the type of building, the

6

sound insulation of the flat (including noise from a neighbouring flat) and other influences. Noise exposure was found to be one of the most constant factors influencing the perception of health and well-being in this kind of housing.

In Switzerland a representative poll on the attitude to noise and noise annoyance has been carried out within the scope of a thesis (Lorenz, 2000). From this one can find data on noise annoyance in general and the sources. Answering the question of the relative importance of the noise problem for Switzerland in general and from a personal perspective, road traffic noise was ranked highest at 4.2 in general and with 3 in personal terms on a scale from 1 to 6 (1 = does not concern at all, 6 = concerns very strongly). Noise from neighbours was ranked clearly lower with 2.5 and 2. Persons not satisfied with their home rank the environmental pollution in Switzerland caused by noise from the neighbours clearly higher (3.1) than those satisfied with their home (2.4). The personal attitude towards noise from the neighbours is also ranked higher (3.1) by the persons who are not satisfied with their home than by those satisfied, (1.9). Evidently there exists a correlation between the problem of noise from the neighbours and satisfaction with the home. A similar result is also illustrated by the fact that 57 % of people not satisfied with their home feel disturbed by noise there, compared with only 21 % of those satisfied. Noise annoyance in the home is also connected with the sound insulation of flats and houses. 57 % of the respondents (also these not bothered by noise in their home) take the view that houses and flats should be better isolated against noise. About 53 % and 47 % respectively would like windows or walls with better insulation against external noise, about 37 % would prefer better wall insulation against noise inside the property, nearly 25 % identified better impact-sound insulation of the floors, and 54 % of the population would be prepared to pay a higher rent for a quieter place of residence.

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2 Sound insulation requirements for residential buildings

2.1 Which units are used to describe sound insulation and which minimum requirements must be fulfilled in the European countries? In principle we have to distinguish between the units to describe the sound insulation of a building element and the units to describe the sound insulation between rooms in a building (which is determined by several building elements and their combination).

In a building one has to consider the propagation of airborne sound (pressure vibrations in the air produced by some source of vibration like musical instruments, loudspeakers, people speaking, etc.), as well as of impact sound (sound created by walking on floors, moving chairs, dropping of objects, etc.) and sound caused by operating sanitary equipment and its propagating as airborne and as structure-borne sound (propagating within the building elements). In the present study only airborne sound and impact sound are covered.

All units are frequency dependent; for decades the frequency range of 100 – 3150 Hz has usually been considered; in the last years the frequency range has been enlarged to 50 Hz to lower frequencies and to 5000 Hz to higher frequencies. To simplify specifying sound insulation also single number quantities for the different units are calculated and stated.

2.1.1 Airborne sound insulation The airborne sound insulation of building elements is described by the sound reduction index R (10 times the common logarithm of the ratio of the sound power which is incident on the element to the sound power transmitted through the element) versus frequency. It is also called transmission loss (TL). From the sound reduction index versus frequency, the single number quantity, the weighted sound reduction index Rw is calculated by comparing the values with a reference curve according to ISO 717-1.

In a new edition of ISO 717-1 two supplementary spectrum adaptation terms were introduced, C for pink noise (equal levels over the whole frequency range, representing approximately living activities like talking, music, radio, TV, and railway traffic at medium and high speed) and Ctr for noise with predominantly low frequencies (representing approximately urban road traffic, many factories, disco music and so on). With the sum of Rw and the relevant spectrum adaptation term (according to the relevant spectrum) the difference of A-weighted levels may be calculated. The spectrum adaptation terms may be stated for the frequency range 100-3150 Hz (used for decades) as well as for the enlarged frequency ranges of 50-3150 Hz, 50-5000 Hz or 100-5000 Hz; the relevant frequency range has then to be stated as an index, e.g. C50-5000 or Ctr,50-5000.

The airborne sound insulation between two rooms is described using different units in different countries. Following the traditional assumption that the sound is transmitted in the building only through the separating element, the sound reduction index is also used to describe the sound insulation between two rooms; to take into account the fact that the sound is generally transmitted in a building via the separating element and the flanking elements, the sound reduction index in the building is called the apparent sound reduction index R’1. The single number quantities, weighted apparent sound reduction index R’w, and C and Ctr, are calculated and stated as described above.

1 pronounced R-dash; the dash indicates that the given sound reduction index is measured in the building.

8

To clearly differentiate between the sound insulation of a building element and the sound insulation between two rooms in a building, the sound level difference D between two rooms is stated. As the sound level in the receiving room is also determined by the sound absorption in the room (the higher the sound absorption, the lower the sound level), this sound level difference has to be referred to a standardized absorption; two units are standardized: the normalized sound level difference Dn, referred to 10m2 of sound absorption area in the receiving room and the standardized sound level difference DnT, referred to 0.5 seconds of reverberation time in the receiving room. Numerous measurements have shown that the reverberation time in living rooms is independent of the volume over 0.5 seconds and therefore the standardized sound level difference is better in practice at representing the acoustic conditions in rooms2.

The sound insulation perceived by the occupants is best described by the standardized sound level difference. E.g. in Austria it turned out after an extensive investigation into the sound insulation in dwellings based on a wide range of measurements (Bruckmayer et al., 1974) that the apparent sound reduction index is not the appropriate unit and should be substituted by the sound level difference. After some time using the normalized sound level difference referring to 10 m2 sound absorption area, the reference was changed to 0.5 seconds reverberation time (though the designation “normalized sound level difference” was kept up to 1994).

Supplementing apparent sound reduction index, normalized sound level difference and standardized sound level difference, the spectrum adaptation terms are stated.

In the practice of building acoustics one may draw a clear differentiation to describe acoustic quality:

The sound insulation of a building element is characterized by the sound reduction index; it can only be measured in a normalized test facility; the single number stated is the weighted sound reduction index Rw, and additionally the spectrum adaptation terms C and Ctr.

The sound insulation between two rooms in a building (no matter whether adjacent or one on top of the other or not directly connected to each other) is characterized by the standardized sound level difference; the single number stated is the weighted standardized sound level difference DnT,w, and additionally the spectrum adaptation terms C and Ctr.

Usually R’A is written for R´w + C. E.g. in the new regulations concerning acoustic performance of buildings in Poland, R´A1 is written for R´w + C and R´A2 for R´w + Ctr (Nurzynski, 2003). In ISO 717-1 these terms are also specified as R´A,1 und R´A,2. Likewise DnT,A is written for DnT,A,1 = DnT,w + C and DnT,A,tr for DnT,A,2 = DnT,w + Ctr, as also specified in ISO 717-1.

In the Swiss standard SIA 181, DnT,w + C is called „spektralangepasste Pegeldifferenz“ (spectrum-adjusted level difference).

The value for C is mostly -1 or -2 dB for massive building elements, for lightweight multilayered walls it may range down to -12 dB. In buildings where sound usually is transmitted via several building elements (separating element and flanking elements) partly massive and partly lightweight (e.g. flexible layers of plaster board in front of massive walls), C may range from -1 to -10 dB. In any case however always DnT,A ≤ DnT,w.

The spectrum adaptation terms of all massive and lightweight elements, which are described in Katalog für schallschutztechnische Kennwerte von Wänden (ON, 2001), are shown in Figure 3 for 60 massive und 36 lightweight multilayered walls.

2 The sound absorption area A results from the volume V and the reverberation time T by A = 0.16.V/T; evidently the sound absorption area grows with rising volume while the reverberation time remains constant independent of volume.

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Figure 3: Spectrum adaptation terms for walls a) massive walls b) lightweight multilayered walls

.

Source: Lang, 2006

The different quantities described above to prescribe the required sound insulation are used in the standards and regulations for sound insulation in European countries. As the different quantities are connected via the volume of the receiving room and the area of the separating element, the requirements cannot be compared exactly. So e.g. the most used quantities R’ and DnT are connected by the following formula:

DnT = R´-10.lg(S.0,5/0,16.V) = R’ –10.lg(3,125.S/V)

where S is the area of the separating element and V the volume of the receiving room3.

3 A statistical evaluation of 10,000 measurements in residential buildings in Germany showed that on the average DnT,w ≈ R´w + 2,4 dB and for 26 % DnT,w < R´w and in the other 74 % DnT,w > R´w (Burkhart 2005).

-14

-12

-10

-8

-6

-4

-2

0

30 35 40 45 50 55 60 65 70

Rw dB

C a

nd C

tr d

B

C Ctr

Caverage -1

Ctraverage -4

-14

-12

-10

-8

-6

-4

-2

0

30 35 40 45 50 55 60 65 70

Rw dB

C a

nd C

tr d

B

C Ctr

Caverage -3

Ctraverage -7

10

A standardization of the quantities used to express acoustical requirements is advisable. A working group EAA TC-RBA WG4 „Sound insulation requirements and sound classification – Harmonization of concepts” has been established for this purpose (Rasmussen, 2005).

In Table 6 below, an overview is given of the requirements for airborne sound insulation between flats in European countries (Rasmussen 2004).

Table 6: Overview airborne sound insulation requirements in 24 European countries4

Source: Rasmussen 2004

In Croatia the following minimum requirements are prescribed in the standard JUS U.J6.201 (1989) (Henich, 2006): partitions between flats R’w,min = 52 dB, walls between garage and flat R’w,min = 57 dB, walls between flats and business premises R’w,min = 55 dB, walls between flats in terraced houses R’w,min = 52 dB; floors between flats R’w,min = 52 dB, floors above or beneath a flat towards a room with other use R’w,min = 57 dB, floors between garage and flat R’w,min = 57 dB, floors between flat and business premises R’w,min = 57 dB.

4 The quoted literature (11) and (12) see in literature Rasmussen 2004.

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2.1.2 Impact sound insulation The impact-sound insulation of floors is described by the normalized impact sound level, i.e. the sound level which is measured in a test facility in the receiving room beneath the floor, which is excited by a standardized tapping machine. This sound level refers to 10m2 sound absorption area in the receiving room. From the sound level measured in third-octave or octave bands, a single number is calculated according to ISO 717-2, the weighted normalized impact sound level Ln,w.

In a new edition of ISO717-2 a supplementary spectrum adaptation term CI was defined. This spectrum adaptation term may be determined for the frequency range of 100-3150 Hz, which has been used for decades, and also for the enlarged frequency range of 50-3150 Hz or 50-2500 Hz; the frequency range has to be specified as an index, e.g. CI,50-2500. The sum of Ln,w and CI characterizes the linear impact sound level and corresponds better to the A-weighted sound level, produced by walking on the floor.

Floors in residential buildings mostly consist of a bare floor and a floor covering. Single bare floors do not ensure sufficient impact sound insulation. The required impact sound insulation can only be achieved with the additional impact sound insulation of a floor covering

It is therefore necessary for the planner to know the impact sound level of the bare floor and the reduction in impact sound pressure level from the floor covering to calculate the impact sound level of the entire floor. Single number quantities have been defined for the bare floor and the floor covering for this purpose: the equivalent weighted normalized impact sound pressure level Ln,eq,0,w of bare massive floors and the weighted reduction in impact sound pressure level ∆Lw for the floor covering. The weighted impact sound pressure level of a floor with covering is the equivalent weighted normalized impact sound pressure level Ln,eq,0,w of the bare massive floor less the weighted reduction in impact sound pressure level ∆Lw for the floor covering.

For wooden floors it is not possible to use the weighted reduction in impact sound pressure level ∆Lw. However, a special quantity for the reduction in impact sound pressure level by floor coverings on wooden floors has been defined in a new edition of ISO 717-2; this has to be determined separately by measurement on a normalized timber joist floor and stated with the single number ∆Lt,w for the impact sound pressure level on timber joist floors and ∆Ltv,w for the impact sound pressure level on vertically laminated wooden floors5. In an investigation the basis for the determination of these quantities and ∆Lt,w und ∆Ltv,w for a great number of usual types of floor covering on wooden floors was measured (Lang, 2004). The airborne and impact sound insulation of a series of timber joist floors with different floor coverings was also measured in this investigation; furthermore, a connection between impact sound insulation measured by the tapping machine and given for walking was determined by comparison with the noise of persons walking on the floors (see Figure 7).

The impact sound insulation of floors in a building is measured with the tapping machine in the same way as in test facilities. However, the sound level does not refer to 10 m2 sound absorption area but to the reverberation time of 0.5 seconds (which is usual in living rooms in practice regardless of their volume) and the result is called the standardized impact sound level L’nT and the single number weighted standardized impact sound level L’nT,w .

However, in the standards in several countries, requirements for the impact sound insulation in buildings are laid down based on the weighted normalized impact sound level L’n,w or on the weighted standardized impact sound level L’nT,w

6, in some countries with the additional adaptation term CI.

5) The index t was chosen from the English word timber, the additional index v was chosen for the English word vertically laminated. ∆Ltv,w is not defined in ISO 717-2 but only in the Austrian standard ÖNORM B8115

6) To make clear, that the number concerns sound insulation in the building a dash is added.

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A precise comparison of the different values is not possible as L’nT,w and L’n,w are connected via the volume of the receiving room according to

L’nT,w = L’n,w – 10.lg 0,032.V That means: in rooms with a volume > 31 m3, L’nT,w < L’n,w.

In Table 7 below, a survey of the requirements for impact-sound insulation between flats in European countries is given.

Table 7: Overview impact-sound insulation requirements in 24 European countries

Source: Rasmussen, 2004

In Croatia the following minimum requirements for the normalized impact sound level are prescribed in the standard JUS U.J6.201 (1989) (Henich, 2006): floors between flats Lw,maks = 68 dB, floors beneath flats above rooms for other use Lw,maks = 68 dB, floors above flats beneath rooms for other use Lw,maks = 58 dB, floors beneath flats above garages Lw,maks = 68 dB, floors above flats beneath a terrace for common use Lw,maks = 63 dB, floors in a noisy works to flats adjacent or above Lw,maks = 48 dB, floors above a flat beneath a noisy works Lw,maks = 48 dB.

Table 7 shows that the quantities used to define the requirements are different and the differences in the requirements in the various countries are considerable with a range from about 50 dB in Austria up to about 60 dB in several other countries (a difference of 10 dB represents a doubling of the loudness of the walking noise).

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2.2 Which requirements can ensure sufficient protection against noise annoyance caused by neighbours‘ activities in multi-family dwellings? Which proposals have been made?� The noise-producing living activities as well as the claim for protection against disturbing noise from the occupants of multi-family houses are very different. It will therefore hardly be possible to make all activities inaudible and to protect persons who are extremely sensitive to noise against any disturbance. In the chapter on scope in ÖNORM B 8115-2, the following sentence is essential: “In this standard requirements and indicative values for the minimum sound insulation are defined with the aim to protect people with a normal degree of sensitivity against disturbing transmission of airborne and impact sound in the case of usual behaviour”. In this ÖNORM, additional requirements for enhanced sound insulation are stated; enhanced sound insulation is especially recommended for buildings in quiet areas.

2.2.1 Protection against airborne sound transmission In order to prove which protection against airborne sound (caused by typical activities) transmitted from the neighbouring flat is given when observing the minimum standard requirements and when improving the sound insulation, calculations were made on the sound level produced in the neighbouring flat, assuming different sound sources in the flat and different levels of sound insulation against noise from the neighbouring flat. The calculated sound level was then compared with different requirements for quietness.

The following sound levels produced by living activities can be assumed according to ÖNORM S 5012: Conversation (with guests, 6 persons in a 75 m3 living room with usual furnishing) A-weighted equivalent sound level 73 dB talking with normal loudness 78 dB lively conversation with laughter maximum level 82 dB or 87 dB A-weighted music played at home (ensemble with 6 instruments in a 100 m3 living room with usual furnishing) A-weighted equivalent sound level 91 dB, maximum 98 dB music played at home (1 violin in a 75 m3 living room with usual furnishing) A-weighted equivalent sound level 78 dB, maximum 86 dB:

The last two mentioned sound levels may also be considered characteristic for playing loud music on a hi-fi in a flat.

The frequency response can be assumed with pink noise (sound level equal in all third-octave bands) for conversation and for music.

The sound level to be expected in the receiving room was calculated for different sound levels in the source room and different degrees of sound insulation between the flats. It proved that the calculation of the A-weighted sound level in the receiving room from the A-weighted sound level in the source room and the weighted standardized sound level difference plus spectrum adaptation term C was equal to the result of the detailed calculation in third octave bands.

In Table 8 the A-weighted sound levels are shown.

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Table 8: Sound level in the receiving room for different sound levels in the source room and different sound insulation A-weighted sound level A-weighted sound level in the receiving room (dB) for

sound insulation DnT,w in the source room (dB) 55 dB 60 dB 65 dB 70 dB

73 19 14 9 4 78 24 19 14 9 86 32 27 22 17 91 37 32 27 22 98 44 39 34 29

Source: Lang, 2006

The sound levels in the receiving room may be compared with the levels prevailing in this room at quiet times (learning, reading, sleeping).

According to ÖNORM B 8115-2 the background level in a room may be assumed according to the land use category, where the residential building is situated and the time of day, as shown in Table 9.

Table 9: Indicative planning values for the background level in flats in residential buildings in different land use categories according to ÖNORM B 8115-2

land use category quiet area health resort area

residential area in suburbs, rural

residential area

urban residential area, agricultural

area with dwellings

core area, (trade, offices, dwellings)

area for enterprises without

sound emission indicative values for the background level (dB) day/night

20/15 25/15 30/20 30/20

Source: ÖNORM B 8115-2, translation by Lang

The frequency response is assumed with the inverse A-weighting curve. This corresponds well with third-octave band analysis of background levels measured in practice. In Figure 4d some examples are shown: limit curves for 25 and 35 dB A-weighted, a background level measured in a flat (Nurzynski, 2003) and the background levels measured in the halls (without audience) in the Vienna Musikverein building (Berger et al., 2005).

In Figure 4a) to c) the sound levels to be expected in the receiving room are represented for some examples of different sound insulation between adjacent flats ((DnT,w = 55 to 68 dB)7 under the assumption that the A-weighted sound level in the source room is 90 dB (with a frequency analysis for music or spoken conversation). For lower sound levels in the source room the sound levels in the receiving room may be reduced by the corresponding amount.

The comparison of the values in Table 8 and Table 9 shows that the equivalent sound level of normal conversation (which corresponds also to radio and television turned down to moderate volume) is diminished to 19 dB in the neighbouring flat by the minimum required DnT,w = 55 dB and will then not be audible with respect to the background level of 25 dB; the maximum levels however may be heard. The table also shows that music at home with an ensemble of 6 musicians (may be only a theoretical case) with an equivalent level of 91 dB requires sound insulation of DnT,w = 68 dB, to reduce the sound level to the background level of 25 dB in the neighbouring room, while single peaks will exceed this. Music at home with one violin with the equivalent level of 78 dB can be reduced below the background level of 25 dB in the neighbouring flat with the minimum required sound insulation DnT,w = 55 dB; single peaks

7) DnT,w = 55 dB corresponds to the minimum requirement in ÖNORM B 8115-2, DnT,w = 68 dB corresponds to the highest sound insulation determined in a series of random measurements in subsidized residential buildings in Styria.

15

however will exceed this and will become audible. Enhancing the sound insulation above 60 dB will give sufficient protection for the neighbour.

Figure 4: Third octave band level in the neighbouring room transmitted from the source room with music or talking 90 dB A-weighted for different sound insulation and background level a) Minimum required sound insulation b) Enhanced sound insulation (Austria)

c) highest sound insulation measured d) limit value background level in subsidized residential building

Source: Lang, 2006 Here the result of laboratory experiments may be quoted on the correlation between sound insulation characterized by a single number (weighted standardized sound level difference) and speech intelligibility (Thaden, 2001 and Thaden et al., 2000). For loud speech with 80 dB A-weighted, the intelligibility in the neighbouring room was on average 0.43 and 0.6 with a sound insulation of DnT,w = 54 dB.(2 examples with different frequency shape); it was only a little smaller with 0.01 to 0.22 when the sound insulation was enhanced by 3 and 7 dB (the

16

intelligibility was dependent on the frequency shape of the sound insulation and with this on the speech level in the neighbouring room).

A laboratory experiment (Mortensen, 1999) showed that 80 to 98 % feel annoyed by music from the neighbouring room with a sound insulation of R’w 56 – 57 dB, depending on the share of the low frequencies.

If one compares the above results with the minimum requirements for sound insulation in the different countries, it does not come as a surprise that quite a significant percentage of the residents in multi-family dwellings feel disturbed by neighbourly noise. It is also no wonder that in the last few years recommendations for improved sound insulation, in addition to the existing minimum requirements were worked out in several countries.

In the following paragraphs some example studies from the literature on the connection between sound insulation and disturbance by neighbourly noise, as well as proposals for enhanced sound insulation, are discussed.

The data in Table 10 show the high sound insulation required to ensure satisfaction with the acoustical quality. When comparing the figures, one has to note that the airborne sound insulation has been described with R´w + C50-3150. Depending on the situation (volume of the receiving room and area of the separating component), the DnT,w value can either be the same, or lower by up to 1 dB, or higher by up to 4 dB than R´w

8. Please also note that C50-3150 is negative (-3 to -10 dB, depending on the building style). Thus, DnT,w ≥ 68 dB more or less corresponds to a value of R´w + C50-3150 = 63 dB.

Table 10: Relation between airborne sound insulation in dwellings and the expected percentage of people finding conditions satisfactory

% finding conditions satisfactory airborne sound insulation R´w + C50-3150 (dB) 20 40 60 80

48 53 58 63

Source: Rasmussen et al., 2003

In the Netherlands a comprehensive study has been carried out (Gerretsen, 2001) for the appropriate unit to describe sound insulation and the requirements for 5 quality classes. The requirements were deduced from an emission level of 70 dB(A) for “neighbours radio” on regularly loud moments and the difference of 12 dB for speech and music, which gives 82 dB, and an indoor reference sound level of 25 dB(A). That results in a required sound insulation of DnT,w + C = 57 dB; the comparison with the results from several social surveys with respect to sound in dwellings lead to the use of 5 classes covering the range from a just acceptable acoustic climate for existing situations (k=5) till the maximum comfort which seems to be practically achievable (k=1). The five quality classes with different numbers of occupants disturbed by the neighbours noise are shown in Table 11 9.

To quality class III an airborne sound insulation of DnT,w + C ≥ 52 dB is assigned, to class II DnT,w + C ≥ 57 dB, this would be desirable. The requirements for the different classes differ each by 5 dB, class V is described as just acceptable for existing situations, class I with DnT,w + C ≥ 62 dB as corresponding to the maximum achievable comfort in practice.

Class III corresponds to the present legal requirements (designated as “sufficient”, ”gives protection against unbearable disturbance under normal behaviour of the occupants, bearing in minds the neighbours)”.Class II would be desirable (designated as “good”, „giving normally a good protection against intruding sound without to much restraints on behaviour of the occupants) (Gerretsen, 2003).

8) see 2.1.1

9)The table is also valid for the impact sound insulation and for the sound insulation against noise from outside.

17

Table 11: Meaning of the sound reduction quality for dwellings

Source: Gerretsen, 2001

In Denmark in 2001 a sound classification for dwellings was defined in the DS 490 standard (based on a proposal from the INSTA B-committee on sound classification). Requirements for airborne-sound insulation, impact-sound insulation, noise of HVA and sound level of traffic noise intruding through the outer building elements are given for 4 classes, A, B, C and D. Class A corresponds to especially good sound insulation, where the occupants are only occasionally disturbed by noise; more than 90% judge the acoustic conditions to be good or very good. The sound insulation in class B is clearly better than the minimum requirements for terraced houses; the occupants are disturbed by noise only to a limited degree; 70-75 % judge the acoustic conditions as good or very good, less than 10 % as bad. In class C one may expect that 55 –65 % judge the acoustic conditions to be good or very good, with less than 20 % bad. Class D is for older buildings with unsatisfactory sound insulation and must not to be used for new buildings. In class D one may expect that 30-45 % of people judge the acoustic conditions as good or very good, and 25-40 % bad.

In Table 12 the requirements for airborne sound insulation are shown.

Table 12: Requirements for airborne sound insulation in classes A, B, C, D in DS 490 Room type Class A

R’w + C50-3150 dB Class B

R’w + C50-3150 dB Class C R’w dB

Class D R’w dB

Between a flat and shop or communal room with noisy activities

68 63 60 55

Between a flat and a room outside the flat 63 58 55 50

Source: DS 490, translation by Lang

For the better sound insulation classes A and B, R’w + C50-3150 is prescribed to protect the occupants against low frequency noise.

In Belgium an investigation on the required sound insulation has been carried out in connection with the transition to new quantities for sound insulation and with a higher demand for higher quality residences (Vermeir, 2003). As best qualified quantity the standardized sound level difference was chosen. As basic requirement an economic class of sound insulation, the so called „normal acoustic comfort class“ was defined. For this sound insulation class the requirement should be as severe as possible without increasing the global building cost. A further class should indicate what nowadays could be considered as a rather good sound

18

insulation that can be achieved with reasonable technical means. The requirements that should guarantee this quality, accepting an increase in building costs define the “improved acoustic comfort class” (Ingelaere et al., 2005). The basic requirement was defined with DnT,w ≥ 54 dB10 and for terrace houses when both adjacent houses are constructed at the same time and dwellings in the improved acoustic comfort class DnT,w ≥ 58 dB11 was deduced. The requirement is increased with 4 dB when a living space (living room, kitchen…) is next to a bedroom of another apartment. It is clear that an architect should avoid this kind of situation. The basic requirement DnT,w ≥ 54 dB is already fulfilled in 50 % of the cases for common walls and floors in Belgian building practice. Still in discussion is the question of low frequencies with respect to the rapid evolution of new low frequency sources inside dwellings (Vermeir et al., 2003 and Ingelaere et al., 2005).

In Sweden the 2nd edition of the SS 025267 standard not only contained the (former) requirements for minimum sound insulation, supplemented by the prescription of R’w + C50-3150 instead of R’w (class C with minimum 53 dB), but also further classes B and A requiring higher sound insulation; class B with R’w + C50-3150 ≥ 57 dB is aimed at (Hagberg, 2002, quotes R’w + C50-3150 ≥ 56 dB); that means with respect to the negative values of C50-3150 an R’w in the range of 58 to 61 dB. In class A R’w + C50-3150 ≥ 61 dB is required, which means about R’w in the range of 62 to 65 dB. Besides the requirements between flats quoted above higher values (61 and 65 dB) are also prescribed between flats and communal rooms and garages in the building.

Class A is indicated as very good sound insulation (very high acoustic quality), class B (high acoustic quality) as clearly better sound insulation than class C, which is typical for the acoustical quality of the existing buildings and corresponds to the legal prescriptions. Class D is only a low acoustical quality and is only to be used if C cannot be achieved, e.g. for refurbishing of old buildings.

In Finland an acoustic classification was introduced in the standard SFS 5907, published in 2004, concerning rooms in buildings such as dwellings, hotels and lodgings, facilities for the elderly, office buildings, schools, educational establishments, day-care centres, health care facilities and industrial workplaces. In the standard the limits are defined for airborne and impact-sound insulation and for the levels of noise caused by heating, plumbing, air-conditioning and electrical appliances inside and outside buildings and also the limits for room acoustics in 4 classes A, B, C and D. Class A is the most demanding and class D the most moderate. Acoustic class C represents the minimum requirements for new buildings. Acoustic class D only applies to existing old buildings, class D is only meant to be used when the aim is to give the acoustic qualities of an old building. The values representing classes A and B make it possible to design buildings which incorporate a higher than normal acoustic standard. The classification is performed both per space and per building.

The requirements for the airborne sound insulation are given in classes D and C for the weighted apparent sound reduction index R’w only, in classes B and A for R’w + C50-3150. Besides the requirements between flats in dwellings there are also requirements for the sound insulation between a flat and a night-club or dance restaurant or similar within the building and between a flat and a commercial space, office, restaurant or other noisy spaces and garages within the building

In the following Table 13 the requirements are shown.

10) This leads to an estimated 70 % of inhabitants that are satisfied with this sound insulation.

11) With this more than 90% of the inhabitants are satisfied.

19

Table 13: Airborne sound insulation in classes A, B, C, D according to SFS 5907 Space Class A

R’w + C50-3150

Class B R’w + C50-3150

Class C R’w

Class D R’w

between two apartments and in general between the spaces surrounding an apartment

63 58 55 49

between an apartment and a commercial space, office, restaurant, or other noisy space within the building, including a garage

68 63 60 60

between an apartment and a nightclub, dance restaurant or other similar space within the building

75 75 70 70

Source: SFS 5907

In Germany in DIN 4109, a minimum sound insulation is described with a weighted apparent sound reduction index of 53 (horizontal) and 54 dB (vertical); in addition, in VDI 4100 an enhanced sound insulation in sound insulation classes II and III with 56/57 dB and 59/60 dB is proposed12. The perception of noise from neighbouring flats, which can be assigned to these sound insulation classes, is shown in Table 14 below. For completeness the criteria for walking noise and noise from sanitary installations are also included.

Table 14: Perception of noise from neighbouring flats assigned to the 3 sound insulation classes SSt according to VDI 4100

type of noise emission perception of noise from the neighbouring flat, evening background noise 20 dB(A) provided

SSt I SSt II SSt III loud speech intelligible generally intelligible generally not intelligible speech with raised voice generally intelligible generally not intelligible not intelligible normal speech generally not intelligible not intelligible not audible walking noise generally disturbing generally not disturbing not disturbing noise from sanitary equipment

unreasonable nuisance generally avoided occasionally disturbing not or only seldom

disturbing music played at home, loud radio and TV, parties clearly audible generally audible

Source: VDI 4100

The table shows that also with sound insulation class III with a weighted apparent sound reduction index of 59/60 dB (horizontal/vertical), loud speech is audible, though generally not intelligible, as is music played at home. This agrees in principle also with the data given in Table 8.

A concept of sound insulation classes with transition to the quantity DnT,w has been proposed as follows (Burkhart, 2005):

E simple sound insulation (e.g. old buildings) DnT,w = 52 dB D minimum sound insulation DnT,w = 55 dB C enhanced sound insulation DnT,w = 58 dB B comfort sound insulation DnT,w = 63 dB A excellent sound insulation DnT,w = 68 dB

From the compilation of results measured in cases of complaints about insufficient sound insulation (expert opinions for courts, complaints from occupants) the following requirements can be deduced based on this sound insulation, above which only 15 % of complaints (especially sensitive occupants) are found (Kurz et al., 2003).

between adjacent rooms R’w ≥ 54 dB between rooms one on top of the other R’w ≥ 57 dB

12) The draft DIN 4109-10 with analogue requirements for enhanced sound insulation, in which in July 2002 the switch over from the weighted apparent sound reduction index R’w, to the weighted standardized sound level difference DnT,w had been planned, was withdrawn without any replacement.

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The difference of 3 dB in the requirements results from the use of R’w (as the area of the floor is larger than that of the partition R’w increases with the equal sound insulation). Both values may be considered as equal to about DnT,w ≈ 55 dB.

Within the scope of the current revision of DIN 4109 the transition from the weighted apparent sound reduction index R’w, which has been used for decades, to the standardized sound level difference DnT,w, which describes the sound insulation between 2 rooms more correctly, is planned; additionally, consideration of the spectrum adaptation terms and enlargement of the frequency range to the low frequencies are also proposed by experts (Schmitz et al., 2003).

A comprehensive statistical evaluation of results of a large number of sound insulation measurements in buildings shows the level of sound insulation prevailing at present in German dwellings (Burkhart et al., 2004). The weighted apparent sound insulation index R’w is ≥ 53 dB for 50% and ≥ 57 dB for 10% between adjacent flats; corresponding with this (considering the sound insulation in DnT,w) the weighted apparent sound reduction index R’w is for 50% ≥ 56 dB und for 10% ≥ 60 dB between flats one on top of the other. Thus the higher sound insulation classes mentioned above are not being achieved in practise at the time being. This may also explain the comparably widespread annoyance by noise from the neighbours reported in chapter 1.

An investigation on a sensible gradation of classes of the sound reduction index in requirements for airborne sound insulation has been carried out within the scope of the “Enhanced sound insulation” working group in the Room and Building Acoustics committee of the Deutsche Gesellschaft für Akustik (DEGA) (Alphei et al., 2006). Starting from a sound source with pink noise in the source room with an A-weighted equivalent sound level of 70 dB (corresponding to typical levels in speech and music as background noise), the loudness in the receiving room was calculated for a background level of 15 to 25 dB with a frequency response of a 6 dB/octave decrease with different insulation using a heavy and a lightweight wall. From the results the step in sound insulation which corresponds to a halving of loudness in the receiving room was deduced. With the lowest background level of 15 dB considered in the receiving room, a functional gradation resulted for R’w 48.3 – 53 - 57.5 - 64.2 dB for a massive separating element (C50-5000 = -3 dB) und nearly equal 48.0 – 53 – 57.5 – 63 for a lightweight separating element (C50-5000 = -5 dB).

In Switzerland a new SIA standard, 181, draft 2003, has been worked out using the quantity DnT,w +C to describe airborne sound insulation; the standard also indicates at which sound insulation level a certain number of the neighbours’ activities are audible and to which degree (see Table 15).

Table 15: Subjective perception of the airborne sound insulation between rooms depending on the background level (draft SIA 181)

spectrum corrected weighted standardized sound level difference DnT,w + C (dB)

speech intelligibility for normal conversation

background level 20 dB(A) background level 30 dB(A) 64 54 scarcely audible 54 44 audible but not understandable 49 39 partly understandable 39 29 well understandable

Source: draft SIA 181

In this draft standard 3 classes of requirements are distinguished

Standard requirements correspond to the state of the art, offer a grade of sound insulation for which it can be assumed that a large number of the occupants feel comfortable with respect to the acoustic conditions. With this degree of sound insulation fulfilled, one can expect only a small minority to be unsatisfied.

Minimum requirements ensure a sound insulation which only is able to protect against considerable disturbance. With this degree of requirement one has to expect a clear minority to be unsatisfied.

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Special requirements have to be defined and agreed upon for special use or for claims for special protection.

If, especially in rooms with low background level (below 25 dB (A)), a high level of protection against noise is to be achieved, an increase in the standard requirements of 5dB is recommended.

In Table 16 the standard requirements are shown. It is interesting that these are graded according to the noise in the source room and the noise sensitivity in the receiving room. The minimum requirements are 3 dB lower.

Table 16: standard requirements for airborne sound insulation inside the building DnT,w+C-Cv

13 according to draft SIA 181

Noise exposure small moderate great very great*)

Examples for emitting room and use (source room)

low noise use: reading room, waiting room, patients room, medical service room, archive

normal use: living room, bedroom, kitchen, bath-room, WC, corridors, staircase, office, conference room, classroom, laboratory

noisy use: home mechanics room, canteen, assembly room, heating, garage, lift shaft, machinery room

intensive noisy use: works, room for practising music, gymnasium, restaurant and rooms belonging to it

noise sensitivity required values**)

low 44 dB 49 dB 54 dB 59 dB medium 49 dB 54 dB 59 dB 64 dB high 54 dB 59 dB 64 dB 69 dB *) special arrangements for special use (see……) **) special arrangements for accesses (see…..)

Source: draft SIA 181

The requirements in the right column, e.g. room for practising music, show in combination with high noise sensitivity similarly high values to those deduced in Table 8. The requirements in Table 16 also show that the minimum sound insulation DnT,w = 50 to 55 dB usually stated in standards is only sufficient for low noise use or normal use in living or bedrooms with low or medium noise sensitivity; when comparing the values one has to take into account also that the requirements refer to DnT,w + C, which is at least 1 to 2 dB smaller than DnT,w, which means the corresponding values of DnT,w still have to be higher than the values given in the table to ensure equal sound insulation.

In the SIA 181 standard, published on 1 June 2006, the requirements are (diverging from the draft standard) only distinguished into minimum requirements and enhanced requirements. The values for the minimum requirements are 2 dB lower than those given in Table 16 above (out of the draft) and the enhanced requirements are 1 dB higher than those given in Table 16 above.

In France apart from the legal sound insulation requirements (DnT,A = DnT,w +C = 53 dB), there exists the "Certification Qualitel"14 (www.qualitel.org). According to this association, buildings need to fulfil certain quality criteria with respect to sound insulation (interior and exterior sound), thermal insulation (winter and summer), HVAC engineering, expenses made for the operation, and accessibility for handicapped people (which is an optional criterion). Concerning sound insulation, the association identifies 2 classes with requirements that exceed the legal stipulations. With respect to airborne sound insulation, a value of DnT,w + C ≥ 53 dB is also demanded for class CQ (Certification Qualitel). For class CQCA (Certification Qualitel Confort Acoustique), the value DnT,w + C ≥ 55 dB is required for multi-family dwellings and DnT,w + C ≥ 58 dB between row houses. Sound insulation between side rooms should be DnT,w + C ≥ 50 dB for both classes. Between flat and works a higher sound insulation DnT,w +C ≥ 58 dB is required for both classes. 13) According to draft SIA 181, CV has to be inserted for rooms with a volume ≥ 126 m3, so it is only of minor importance for dwellings; it is calculated by CV = 5.lg(V(100) and rounded to an integer. According to the standard published in June 2006, CV is for rooms with a volume ≥ 200 m3 ≠ 0.

14 Formerly "Label Qualitel"

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In England, new sound insulation requirements were published in 2003. They were based on listening tests and a comparison between the subjective acceptability and the different single-number ratings for sound insulation against dance music with "pounding bass beat". The requirements were fixed using the measurement unit DnT,w + Ctr. However, the correlation with DnT,w + Ctr,50-5000 would have been even better (Seller, 2005). DnT,w + Ctr ≥ 45 dB must be fulfilled for both floors and walls. No higher requirements were called for.

Also in Poland, new units for sound insulation were introduced in compliance with ISO 717, resulting in new requirements (Nurzynski, 2003). The apparent sound reduction index R'w + C was chosen as a suitable unit. The requirement to be met by residential houses was fixed at R´w + C ≥ 50 dB. For terraced houses R´w+C ≥ 52 to 55 dB is stated. Additional safety factors have been introduced. If the value of single number index obtained in laboratory measurements is used in designing works it should be adjusted. The adjusted value is called “calculation value” and designated by RAR =RA – 2 dB. This factor is intended to take into account the accuracy of laboratory measurements and the quality of workmanship. It is also emphasized, that low frequencies should be taken into consideration, but introduction of sound insulation indicators that include low frequency bands need more empirical experience due to concern about precision and relation between laboratory and field behaviour of partitions.

In Hungary at present the requirements as shown in Table 6 exist. A switchover from R’w ≥ 52 dB to R’w + C ≥ 51 dB is being prepared. It is also planned for the future to give recommendations for higher-quality insulation (Reis, 2006).

In Spain, new sound insulation requirements for residential buildings were worked out (Esteban et al., 2004). At this time there was a switch from the original demand for building elements with a sound insulation level measured in a test facility to the demand for the sound level difference with spectrum adaptation term DnT,w + C in the building. This was fixed at a value of ≥ 50 dB between living and bedrooms. In Canada an investigation on acceptable values for party wall sound insulation was carried out (Bradley, 2001). A total of 600 subjects were interviewed in 300 pairs of homes in 3 Canadian cities. The 300 common walls had apparent STC ratings (i.e. including possible flanking paths) varying from 38 to 60 with a mean of 49,8 dB15. The responses of subjects asked how satisfied they were with the building in which they lived were significantly related to measured STC values. Also a significant correlation was found when subjects were asked if they would like to move from their present home. Subjects´ responses concerning how considerate their neighbours were, were also significantly related to measured STC values and also the responses to the question how often they were awakened by noises from neighbours in their building. The evaluation of the answers showed, that for lower STC values the responses do not vary with STC, but for higher STC > 50dB the responses systematically decrease with increasing STC, similar for the different sources. However for music related sounds the sound insulation must be greater than about STC 55 to reduce its impact on residents. Figure 5 compares the curves that were fitted to each set of average responses. It shows for most types of sound that the benefits of sound insulation only occur when the STC rating of the wall is substantially above STC 50; however for music related sounds the sound insulation is more effective, if the party wall has an STC rating well over STC 55. Two of the average responses reduce to a score of about 1 at STC 60 indicating that at this point residents would not hear these sound from their neighbours at all and they were not at all annoyed by them. The other two average responses in the figure are greatly reduced for a mean sound insulation rating of STC 60 suggesting that walls with STC 60 would practically eliminate problems related to inadequate sound insulation. STS 55 is therefore recommended as a realistic goal for

15) The sound insulation is given in values of STC for the apparent sound reduction index R’; from comparative calculations one can show, that in most cases the STC-value for the apparent sound reduction index corresponds to the value for the weighted apparent sound reduction index and eventual deviations are mainly in the range of ± 1 dB.

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acceptable sound insulation and STC 60 as a more ideal goal that would practically eliminate the negative effects of neighbours noises.

Figure 5: Comparison of regression fits to average responses versus STC

Source: Bradley, 2001

Several studies point out the importance of the 50-80 Hz frequency range, which is presently not considered in the calculation of the single-number rating. In a laboratory test in Denmark (Mortensen, 1999), 25 test persons were asked to assess the music transmitted from a neighbouring room that had a different level of sound insulation for the low frequencies (below 160 Hz). While music, transmitted through a solid wall with a spectrum adaptation term of C50-

3150 = -1 to - 2 dB was found to be disturbing by 80 to 83 % of the test persons, 98 % of them found it disturbing when transmitted through a wall of C50-3150 = -7 dB although in both cases the weighted apparent sound reduction index only differed by 1 dB. The investigation in Poland also indicated the importance of considering the spectrum adaptation terms and pointed out that the low frequencies should be considered, but that the experience was still lacking, especially with reference to the precision of measurements.

To sum up, it can be said that, based on the studies conducted in many countries over the last few years, a rather clear recommendation can be derived - both with respect to a well-suited unit for describing airborne sound insulation and with respect to the required value.

The most suitable unit of description is the standardized sound level difference with the additional spectrum adaptation term DnT,w + C. It would be useful to also include the low frequencies, i.e. to apply the value C50-3150. However, we do not yet have sufficient experience concerning the appropriate value for C50-3150. For this reason, the below-listed values for DnT,w + C should be valid for DnT,w + C50-3150 after a transitional period that still needs to be fixed.

DnT,w + C ≥≥≥≥ 54 dB can be regarded as a standard requirement. This level protects only people with a normal sensitivity against noise disturbance caused by normal neighbourly activities. On the other hand, the residents themselves need to cut down their activities (children, music-making) out of consideration for their neighbours.

Classes for enhanced sound insulation should be defined. They can be based on the requirements specified in Switzerland: depending on the sound emission during use on the one hand, and on the noise sensitivity or people's need for quietness on the other (see Table 16). Furthermore, the Scandinavian classes A and B as well as the Dutch sound insulation quality classes I and II can be employed.

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Netherlands class I: DnT,w + C ≥ 62 dB class II: DnT,w + C ≥ 57 dB Finland, Denmark: class A: DnT,w + C50.3150 ≥ 63 dB class B: DnT,w + C50.3150 ≥ 58 dB Switzerland: moderate noise exposure: high noise sensitivity: DnT,w + C ≥ 59 dB medium noise sensitivity: DnT,w + C ≥ 54 dB great noise exposure: high noise sensitivity: DnT,w + C ≥ 63 dB medium noise sensitivity DnT,w + C ≥ 58 dB

It will thus be possible to define a class of "Enhanced sound insulation" with DnT,w + C ≥≥≥≥ 58 dB and a "Comfort" class with DnT,w + C ≥≥≥≥ 63 dB. In any case, a further class should be created which allows music-making in a flat without disturbing your neighbours. This class could be defined as "Music" with DnT,w + C50-3150 ≥≥≥≥ 68 dB16 (see Table 8 and Table 16). The sound insulation class that needs to be fulfilled by a building or individual building parts must then be defined as early as in the planning process.

Requirements for the airborne-sound insulation within a flat only exist in some countries:

in the Netherlands in the N 1070 standard, a minimum requirement for the sound insulation between living rooms within a flat for the 5 quality classes is stated as DnT,w + C ≥ 52, 42, 32, 22, 12 dB (unless the rooms are connected or separated by a wall with a door). This requirement also applies between rooms on 2 storeys in the same flat.

In Belgium in the new standard DnT,w ≥ 35 dB is required between two rooms within a flat (if at least the function in one of these rooms is sensitive against the noise from the other room) and DnT,w ≥ 43 dB for the class with the improved sound insulation.

In Finland R’w + C50-3150 = 48 and 43 dB is required in classes A and B between at least one room and the other rooms within a flat.

In Sweden R’w = 44 and 40 dB is required in classes A and B between at least one room and the other rooms within a flat.

In Spain DnT,w + C = 30 dB is proposed “on trial” for the sound insulation between rooms within a flat (Pena, 2002).

As guide values for the functional insulation between the rooms within a flat data in the SIA181 draft in Table 15 can be cited. With a minimum requirement of DnT,w + C ≥≥≥≥ 40 dB speech from the neighbouring room is still well intelligible or partly intelligible. If one expects that speech from the neighbouring room is not intelligible (and thus less disturbing) an enhanced sound insulation with DnT,w + C ≥≥≥≥ 45 dB is required at any rate; for comfort sound insulation DnT,w + C ≥≥≥≥ 48 dB can be stated. With this, conversational speech from the neighbouring room is audible but hardly or even non-intelligible depending on the level of background noise.

2.2.2 Protection against impact sound For decades now, it has been the objective of various studies to find an appropriate method for describing impact sound insulation. Other methods than the one using a standard tapping machine have been repeatedly proposed - also in view of the demand that the method for describing impact sound insulation must well be able to describe the insulation against footfall sound (walking noise). Nevertheless, the tapping machine method was accepted for international standardization (ISO 140-6) and also for all national standards as it is comparatively easy to apply and delivers well reproducible values. In addition, the requirements to be met were specified, together with single-number ratings according to ISO 717-2. Several investigations were carried out on the correlation between the standardized impact sound level and the A-weighted level of footfall sound caused by persons wearing different shoes. A more

16) For this case it is important to also consider the low frequencies. For a transitional period (until there is sufficient experience with low frequencies) the value required for DnT,w + C should be valid.

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recent study (Hagberg, 2001) found that the single-number rating L’n,w + CI,50-2500 correlates well with the subjective assessment of walking noise, with

L’n,w + CI,50-2500 = 73.4 - 3.80 S, where S stands for the subjective assessment on a scale of 1 to 7 (with 7 being the best rating)17.

The quantity L’n,w + CI,50-2500 is at present only used in Sweden for the definition of the requirements for impact-sound insulation (in Norway it is recommended). With the Swedish requirement L’n,w + CI,50-2500 ≤ 56 dB in class C, which corresponds to the building regulations, a subjective assessment of 4.4 is achieved; the best rating S = 7 would be achieved with L’n,w + CI,50-2500 ≤ 47 dB (this is given with the recommendation in class B in the Norwegian standard and in class A in the Swedish standard with L’n,w + CI,50-2500 ≤ 48 dB). In the classes A and B with enhanced sound insulation qualification recommended in the Scandinavian countries, the requirements are based on L’n,w + CI,50-2500 (see Table 21 and Table 24). The most stringent requirement in the best class A in Finland L’n,w + CI,50-2500 ≤ 43 dB (see Table 24) would give a subjective rating of S = 8.

From a study on the subjective assessment of impact sound (Nilsson et al., 2001) it can be deduced that the rating of impact-sound insulation by means of the tapping machine is quite similar to the assessment of the walking noise produced by test persons.

A correlation between the normalized impact sound level and satisfaction with the acoustic conditions in shown in the following Table 17.

Table 17: Relation between impact sound pressure level and the expected percentage of people finding conditions satisfactory

% finding conditions satisfactory Impact sound pressure level L´n,w + CI,50-2500 (dB) 20 40 60 80

63 58 53 48

Source: Rasmussen et al., 2003

In Switzerland requirements in SIA 181 draft are based on the quantity L’nT,w + CI. The value L’n,w + CI ≤ 50 dB given in Table 7 corresponds to the requirement for normal use and sensitivity. In the Swiss draft standard requirements are distinguished in standard requirements and minimum requirements for impact-sound insulation as well as for airborne sound insulation; for the standard requirement a classification according to the use of the room and the noise sensitivity is given, as shown in the following Table 18.

Table 18: Standard requirements for impact-sound insulation in draft SIA 181 Noise exposure small moderate great very great*)

Examples for emitting room and use (source room)

archive, reading room, waiting room, balconies

living room, bedroom, kitchen, bath-room, WC, office, heating and air condition room, corridor, staircase, arcade, garage, terrace

restaurant, hall, gymnasium, work-shop, rooms for practising music and rooms belonging to it

kinds of use defined in class “great” , if these occur also during night 22.00 - 6.00 h

noise sensitivity requirements low 60 dB 55 dB 50 dB 45 dB medium 55 dB 50 dB 45 dB 40 dB high 50 dB 45 dB 40 dB 35 dB

Source: draft SIA 181

The minimum requirements are 5 dB higher.

17) The values for L’n,w + CI,50-2500, on which this correlation is based, were in the range of 51-65 dB.

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CI is in the range from 0 to 4 dB for floors with floor covering; thus the requirement L’nT,w +CI ≤ 50 dB corresponds approximately to the Austrian requirement L’nT,w ≤ 48 dB (the most stringent requirement in the European countries according to Table 7).

In the SIA 181 standard, which was published on 1 June 2006 (differently from the draft) minimum requirements and enhanced requirements are distinguished. The required values for the minimum are 3 dB higher than the values stated in Table 18 above (for the draft) and the enhanced requirements are equal to the values given in tTable 18.

In the SIA 181 draft, data on the subjective assessment of the impact sound insulation between rooms are stated, as shown in Table 19.

Table 19: Subjective perception of impact-sound insulation between rooms Spectrally adapted and weighted standardized impact sound level L'nT,w + Cl in dB

Background level 20 dB(A)

Background level 30 dB(A)

Normal walking wearing walking shoes or slippers

Running children, walking barefoot

Moving furniture, several romping children

65 75 very well audible extremely audible extremely audible 60 70 well audible very well audible extremely audible 55 65 audible well audible extremely audible 50 60 scarcely audible audible very well audible 45 55 inaudible scarcely audible well audible 40 50 inaudible inaudible audible 35 45 inaudible inaudible scarcely audible 30 40 inaudible inaudible inaudible

Source: draft SIA 181

The table shows that “not audible” for very loud impact load in quiet surroundings can be expected only with a weighted standardized impact sound level of L’nT,w + CI ≤ 30 dB.

In the Netherlands when deciding on the acoustic quality classes for dwellings (see Table 11) the quantity L’nT,w +CI was chosen, and for class III L’nT,w +CI ≤ 53 dB and for class II L’nT,w +CI ≤ 48 dB were defined (Gerretsen, 2003).

In an investigation in Denmark (Rindel, 2003) it turned out that the low frequencies have to be adequately considered to describe the impact sound especially for lightweight floors and the quantity L’n,w + CI,50-2500 is much more appropriate than the quantity L’n,w . Table 20 shows the different assessment.

Table 20: Results of laboratory experiment with impact sound and simulated constructions with different sound insulation below 125 Hz

Source: Mortensen, 1999

Evidently the disturbance caused by impact sound is very different depending on the share of low frequencies, which is described by CI,50-2500. Table 20 also shows that even with L’n,w + CI,50-

2500 = 54 dB, 20 % are disturbed by walking and 47 % are disturbed by children.

The requirements for impact-sound insulation in classes A and B from the 4 sound insulation classes (see Table 12 and the notes to the 4 classes) therefore are based on L’n,w + CI,50-2500 as shown in Table 21 below.

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Table 21: Requirements for impact-sound insulation in classes A, B, C, D (DS 490) Type of room class A

L’n,w + CI,50-2500 (dB)

class B L’n,w + CI,50-2500

(dB)

class C L’n,w (dB)

class D L’n,w (dB)

In living rooms and kitchens in business premises or communal rooms with noisy activities

38 43 48 53

In living rooms and kitchens from other flats or communal rooms 43 48 53 58

In living rooms and kitchens from staircase, corridor, balcony, and from toilet and bath in other flats

48 53 58 63

Source: DS 490, translation by Lang

As for airborne-sound insulation, for impact-sound insulation the protection against low frequency noise is also specially considered with the spectrum adaptation term CI,50-2500 in the classes with enhanced sound insulation.

The new standard in Belgium stipulates a limit value of L’nT,w ≤ 58 dB for the weighted standardized impact sound level (54 dB to a bedroom or studio) for the “normal acoustic comfort class”, whereas L’nT,w ≤ 50 dB is valid for the “approved acoustic comfort class”. Based on information obtained from literature a general correlation can be established between the A-weighted sound level of walking noise and the normalized impact-sound level (Vermeir, 2003); this is shown in Figure 6.

Figure 6: Global relation between real walking and the normalized impact sound level (spread zone is indicated by upper and lower line)

Source: Vermeir, 2003

Evidently a weighted normalized impact sound level below 39 dB (at best) or 47 dB (on average) is required to reduce walking noise below 30 dB and a weighted normalized impact-sound level below 31 dB or 39 dB to reduce walking noise below 25 dB.

In Poland the standard requirement L’n,w ≤ 58 dB is comparatively high. A study found that with this level of impact-sound insulation approx. 60 % of the residents hear their neighbours walking (Izewska, 2005). Even with an impact sound insulation of L’n,w = 50 dB the residents felt strongly disturbed by impact sound, particularly in combination with a low background noise level. Especially in the low frequency range from 50 to 250 Hz the sound level of walking noise is clearly (more than 10 dB) above the background level. In a proposal for modifying the standard, 3 classes as well as 3 different levels of ambient noise are recommended, as shown in Table 22 below (Izewska, 2005).

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Table 22: Proposal for impact-sound insulation requirements in residential buildings in Poland Impact sound classification

of dwellings Maximum weighted normalized impact sound level L’n,w (dB)

depending on LA,eq (dB) of background noise Day ≥ 40, night ≥ 30 Day = 35, night = 25 Day ≤ 30, night ≤ 20

Class I (minimum) 58 53 48 Class II (medium quality) 53 48 43 Class III (comfortable) 48 43 38

Source: Izewska, 2005

In Norway comprehensive studies on impact sound insulation were carried out, in particular of timber floors and in this context also the low frequent impact sound. The studies confirmed the high importance of considering low frequencies and of introducing the spectrum adaptation term CI,50-2500 (Homb, 2005). In the following Table 23 requirements and recommendations in classes A, B and C for impact-sound insulation in Norway are stated (in total 4 classes were defined)

Table 23: Requirements and recommendations for impact-sound insulation in Norway (NS 8175)

Impact-sound insulation between flats L’n,w (dB) L’n,w + CI,50-2500

class C minimum-requirement ≤ 53 legally required

recommended, but not normative ≤ 53

class B recommended - ≤ 48 class A - ≤ 43

Measurements made on wooden floors in the laboratory resulted in normalized impact sound levels L’n,w in the range of 42 to 52 dB, with spectrum adaptation terms C I,50-2500 in the range of +4 to +10 dB. The values for L’n,w + CI,50-2500 were in the range of 46 to 57 dB. This shows the essential importance of considering low frequencies in the 50 to 80 Hz range. Measurements made on wooden floors in buildings showed similar values for L’n,w in the range of 46 to 52 dB and for L’n,w + CI,50-2500 in the range of 54 to 60 dB. Values in the range of +5 to +8 dB resulted for CI,50-2500 . In the case of massive floors, the frequency range below 100 Hz is not so important: the normalized impact sound level L’n,w for the tested massive concrete floors ranged from 46 to 55 dB; the value L’n,w + CI,50-2500 ranged from 47 to 55 dB. The values measured for CI,50-2500 were in the range of 0 to +2 dB for massive floors. For a lightweight concrete aggregate element with ceiling and a resilient floor the values were clearly higher in the range from +3 to +10 dB.

In Finland the required impact-sound insulation level was tightened in 2000 from L’n,w ≤ 58 dB to L’n,w ≤ 53 dB. In a study (Sipari, 2002) with measurements on a great number of different kinds of floors it was shown that this requirement can be fulfilled by massive floors with adequate floor coverings and also with timber floors with adequate floor coverings. Considering the spectrum adaptation term CI,50-2500 with values of 0 to 2 dB for massive floors shows that also L’n,w + CI,50-2500 ≤ 53 dB can be fulfilled. Though CI,50-2500 for timber floors is in the range of 0 to + 7 dB L’n,w + CI,50-2500 ≤ 53 dB can be fulfilled also with timber floors with an adequate floor covering.

In the SFS 5907 standard, published in 2004, the following requirements are defined in the 4 classes A to D apart from the value L’n,w ≤ 53 dB required in the building regulations (corresponding to class C); there are also requirements for the insulation of flats against rooms with higher impact load in the same building (see also the explanations related to the classes above Table 13).

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Table 24: Requirements for impact-sound insulation in classes A, B, C, D (SFS 5907) Space class A

L’n,w + CI,50-2500

class B L’n,w + CI,50-2500

class C L’n,w

class D L’n,w

From the spaces surrounding an apartment to an apartment or a kitchen in general1)

43 49 53 63

From a commercial space, office, restaurant, or other noisy space within the building, including a garage. to an apartment

43 43 49 49

From a night-club, dance restaurant or other similar space within the building to an apartment

33 38 43 43

1) Use of the spectrum adaptation term CI,50-2500 is recommended also in class C.

Source: SFS 5907

In Sweden L’n,w or L’n,w + CI,50-2500 ≤ 48 dB is in class A, L’n,w or L’n,w + CI,50-2500 ≤ 52 dB in class B and L’n,w or L’n,w + CI,50-2500 ≤ 56 in class C as defined in the SS 25267 standard.

In Germany the normalized impact sound level is given as L’n,w ≤ 46 and 39 dB for the sound insulation classes II and III in the criteria for enhanced sound insulation in VDI 4100; according to Table 14 the perception “generally not disturbing” and “not disturbing” is assigned to these values.

A concept of sound insulation classes has also been proposed for impact sound insulation by keeping the quantity normalized impact sound level for the requirement (Burkhart, 2005) with the following values:

E Low sound insulation (e.g. old buildings) Ln,w = 53 dB D Minimum sound insulation Ln,w = 48 dB C Enhanced sound insulation Ln,w = 43 dB B Comfort sound insulation Ln,w = 38 dB A Excellent sound insulation Ln,w = 33 dB

In fields of experts the inclusion of the spectrum adaptation term and the frequency range to be considered is also being discussed for airborne sound as well as for impact sound.

In France in addition to the legal requirement L’nT,w ≤ 58 dB, the fulfilment of L’nT,w ≤ 55 dB has been demanded for the criterion CQ (Certification Qualitel) and L’nT,w ≤ 52 dB for the criterion CQCA (Certification Qualitel Confort Acoustique).

In Spain, a weighted standard impact sound level of L’nT,w ≤ 65 dB is required.

In Hungary it is planned to switch from L’n,w to L’n,w+ CI.

As the requirements for impact-sound insulation can only be fulfilled with an acoustically adequate floor-covering design on the bare floor, methods which also use single numbers to describe and measure the improvement of the impact sound insulation with floor coverings have been developed and standardized. Though these can be used very well to describe the impact sound insulation of a floor covering on all massive bare floors, these can not be used for lightweight timber floors. A separate method for the measurement and a deduced single number for the improvement of impact sound insulation on timber floors therefore has been developed and standardized (see 2.1.2). In a comprehensive investigation with measurements on 16 different types of floor coverings on a standardized timber joist floor the details of the method were established and data for the impact sound insulation of the floor coverings determined (Lang, 2004).

Additional measurements were also carried out with the “heavy/soft impact source”, which was developed in Japan and included in ISO 140-11: This impact source is a rubber ball with 180 mm diameter and a mass of 2.6 kg dropping from a height of 100 cm; its impact is typical

30

for jumping of children. The measurements with the standardized tapping machine and those with the rubber ball showed that the low frequencies prevail in impact sound18. Therefore it is recommended to carry out impact sound measurements from 50 Hz and to use L’nT,w + CI,50-2500 for defining requirements for impact sound insulation; with this a good correlation with the sound level produced by the rubber ball (characterising the jumping of children) is also achieved.

Furthermore, in this investigation, the sound level of the walking noise below 6 different timber joist floors was measured to prove the suitability of measurement results gained with the tapping machine and with the rubber ball for the subjective assessment of the impact sound insulation of floors. In Figure 7 the A-weighted equivalent sound level of the walking noise (mean value of 3 different shoes worn by different persons) is compared to the weighted normalized impact sound level19 Ln,w and Ln,w + CI and the maximum A-weighted sound level caused by excitation with the rubber ball. The values for Ln,w correspond quite well to the spread zone described in Figure 6. Figure 7 shows that a normalized impact sound level Ln,w = 48 dB corresponds to an equivalent sound level of about 33 dB and walking with this impact sound insulation can thus be clearly audible. In order to reduce the walking noise to less than 30 dB the weighted normalized impact-sound level would have to be below 40 dB.

Figure 7: Comparison of the A-weighted sound level for excitation with the rubber ball and the weighted normalized impact sound level for excitation with the tapping machine with the equivalent sound level of walking noise

Source: Lang, 2004

To sum up, the investigations carried out in many countries over the last years as well as the recommendations given for higher impact sound insulation confirm that it is essential - especially for lightweight wooden floors - to consider the low frequencies. Thus, it will also be possible to cover the subjective perception of disturbance caused by the walking noise. For this reason, the prescription of requirements for impact sound insulation in residential buildings should always be based on the unit L’n,w + CI,50-2500. This hardly changes the requirement to be met by massive floors, but is important for wooden floors in order to avoid disturbance caused by the "drum sound" that residents frequently complain about. The Austrian requirement L’nT,w ≤ 48 dB should be extended to L’nT,w + CI,50-2500 ≤≤≤≤ 50 dB. Higher requirements can be described

18) The great amount of very low frequencies in the impact sound, which is caused by walking on timber floors is also claimed as subjectively very disturbing by residents in buildings with timber floors.

19) The spectrum adaptation term CI,50-2500 could not be evaluated, as the measurements with the tapping machine had been carried out only from 100 Hz.

35

40

45

50

55

60

65

70

75

80

85

25 30 35 40 45

A-weighted equivalent sound level of walking noise dB

A-w

eigh

ted

soun

d le

vel o

r nor

mal

ized

impa

ct

soun

d le

vel

dB

soft/heavy impact source Lnw Lnw+CI

31

with L’nT,w + CI,50-2500 ≤≤≤≤ 45 dB, and very high requirements (comfort class) with L’nT,w + CI,50-2500 ≤≤≤≤ 40 dB. At present, there is however still a lack of experience in handling unit CI,50-2500 in Austria and other countries. Therefore, a transitional period would have to be set during which measuring experiences can be gained. Until the necessary measuring and planning experience is available, the above requirements could be used, decreased by 2 dB for L’nT,w + CI. The CI values for solid floors only slightly differ from 0; for wooden floors they are in the range of 0 to 4 dB. Figure 8 shows the spectrum adaptation terms CI and CI,50-2500 that have been obtained from measurements on 23 timber joist floors with different types of floor coverings.

Figure 8: Spectrum adaptation terms CI and CI,50-2500 from measurements made on timber joist floors

Source: Lang, 2006

Few requirements have been defined for the impact sound insulation within a (2-storey) flat. In the Netherlands, standard NEN 1070 specifies a weighted normalized impact sound level of LnT,w + CI ≤ 53, 63, 73, 83 93 dB for each of the 5 quality classes. The sound level required for steps is 5 dB lower. In Finland, impact-sound insulation is only required for classes A and B and only for at least one room in one and the same flat. However, the required values of LnT,w + CI ≤ 53, 63, 73, 83, 93 dB are quite high. In Sweden as well, impact-sound insulation is required for classes A and B for at least one room of the flat which, at a level of LnT,w ≤ 64 and 68 dB, is even higher than the Finnish. In Switzerland, the appendix to the standard recommends L’ ≤ 55 dB (level 1) and L’ ≤ 50 dB (level 2) for separating elements within a flat.

Frequent complaints have been made about insufficient impact sound insulation in 2-storey flats, particularly in one-family houses, for which no special requirements exist in Austria. Consequently, a requirement should be fixed that corresponds to the one applicable between the flats of a multi-family house or which possibly allows 5 dB higher levels. As wooden floors are often installed in both split-level flats and one-family houses, it is important that the requirements for these types are also based on the quantity L’nT,w + CI,50-2500.

2.3 How can the fulfilment of the requirements be ensured

For the fulfilment of the requirements, it is absolutely essential to consider appropriate sound insulation measures as early as possible in the planning phase. As a basis for the planning, the following are necessary:

0

2

4

6

8

10

12

14

30 35 40 45 50 55 60 65 70 75 80

Ln,w dB

CI,

CI,5

0-25

00 d

B

CI CI50-2500

CI,50-2500 average 7 , range 1 to 13 dB

CI average 2, range 0 to 4 dB

32

- data on the acoustic properties of building elements and building materials given in the physically correct quantities

-- weighted sound reduction Rw for building elements measured in a test facility

-- weighted normalized impact sound pressure level Ln,w for floors

-- equivalent weighted normalized impact sound pressure level Ln,eq,0,w for bare massive floors

-- weighted reduction of impact-sound pressure level ∆Lw by floor coverings

-- weighted reduction of impact-sound pressure level ∆Lt,w by floor coverings on lightweight floors

-- dynamic stiffness s’ for materials used under floating floors in dwellings

- standardized calculation procedures for the determination of the sound insulation between rooms side by side or one on top of the other (airborne and impact sound insulation) in the building.

Furthermore, to ensure the required sound insulation in the construction, the following are also required:

- specification to the details of correct construction work

- measurements of airborne and impact sound insulation at random samples between rooms side by side as well as one on top of the other after finishing the construction work.

Standards published by ISO or EN exist which define methods to be used for measurements of building elements and building materials in test facilities as well as for measurements of airborne and impact sound insulation in buildings.

The statement of the acoustic properties of building elements and building materials is mainly the task of producers (or importers). It is however also advisable to establish and publish catalogues containing all the acoustic properties as stated by the producers. It is also a main task of suppliers of building material, e.g. producers of isolating materials, plasterboard etc. to specify all details for correct installation of their materials.

In Austria a catalogue of acoustic data for building elements has been published by the Austrian Standards Institute with measurement results for the sound reduction index of walls, windows and doors. A comprehensive data bank with a catalogue of wooden building elements examined with respect to building physics and ecology has been established on the internet (www.dataholz.com) by the Fachverband der Holzindustrie Österreichs. The basis for the planning of sound insulation is ÖNORM B 8115-4 containing the simplified calculation procedure according to EN 12354-1 and EN 12354-2 and guiding values for the weighted sound reduction index of building elements, the improvement of sound insulation using acoustical linings, the equivalent weighted normalized impact sound level of bare floors, and the weighted reduction of impact sound pressure level with floor coverings and floating floors and floor coverings on timber joist floors and vertical laminated timber floors. An example of a calculation according to EN 12354-1 is enclosed. Tables show which flanking elements are permitted or required according to the type of separating element to fulfil the prescribed standardized sound level difference between rooms side by side and one on top of the other.

In some provinces (“Bundesländern”) the fulfilment of the required sound insulation according to ÖNORM B 8115 has to be proved for subsidized buildings at the planning stage before the start of construction work and by measurement with random samples in the finished building.

The applicability of the new calculation procedure according to EN 12354-1 for the Austrian types of construction system was proven before its integration into ÖNORM by a comparison of results of measurements of sound insulation in dwellings with the results of the calculation according to EN 12354-1. Results of measurements of the standardized sound level difference between rooms side by side (26 cases) and rooms one on top of the other (36 cases) in 28 residential buildings carried out in the years 1995-1999 were made available for the

33

comparison. The comparison between the results of the measurement and the calculation for each of the cases is shown in Figure 9 and Figure 10 (Lang, 2001).

Figure 9: Difference calculated value – measured value for measurements between rooms side by side

Source: Lang, 2001

Figure 10: Difference calculated value – measured value for measurements between rooms one on top of the other

Source: Lang, 2001

Furthermore, measuring results for 17 rooms one on top of the other and 6 rooms side by side were available from an investigation (Lang, 1985); for these the calculations were also carried out for comparison.

The mean values of the calculated value - measured value difference for all comparisons are given in Table 25.

-5

-4

-3

-2

-1

0

1

2

3

4

5

55 55 56 57 57 57 58 58 58 58 58 59 60 60 60 60 61 61 61 62 63 64 64 65 66 67

measured value DnT,w dB

calc

ulat

ed v

alue

- m

easu

red

valu

e d

B

-5

-4

-3

-2

-1

0

1

2

3

4

5

54 54 54 55 55 55 55 55 56 56 56 56 57 57 57 57 57 57 58 58 58 58 58 58 58 58 58 59 59 60 60 61 62 62 63 68

measured value DnT,w dB

calc

ulat

ed v

alue

- m

easu

red

valu

e d

B

34

Table 25: Mean values for the calculated value – measured value difference for DnT,w Measurement Difference calculated value – measured value

(mean values) dB Measurements in years 1995-1999 Between rooms side by side Between rooms one on top of the other Measurements 1985 Between rooms side by side Between rooms one on top of the other

- 0,4 0,6

0,3 0,3

Source: Lang, 2001

Within the scope of the investigation calculations were also carried out with the Bastian program to compare the calculated results; they showed that the program used with the simplified method yields the same results as the manual calculation. It gives the results very quickly, and also conveniently separated for the single sound transmission paths; thus the planner can identify immediately which sound transmission path plays a decisive role in sound transmission and therefore may require improvement. The program is used in several institutions in Austria to plan sound insulation.

In Belgium new building guidelines are established in several research projects to assist building industry to create new products and building systems taking in account the new requirements. When establishing the new standard it was decided, that the requirements should concern the finished building only, but that the project should chose building elements and techniques to obey these requirements, eventually using calculation models as can be found in the EN 12354-series of standards or by using specific building prescriptions. The project should not take into account the measurement tolerances; indeed to take in account uncertainties in the prediction models and limitations in precision of the measurement techniques a tolerance is included in the standard: measurement results up to 2 dB lower than the requirement are still said to comply with the standard (Ingelaere et al., 2005)

In Germany a revision of DIN 4109 is being worked out which will also make data available for massive constructions as well as for lightweight methods of construction as a basis for the calculation of sound insulation in the building from the properties of the elements according to EN 12354. Investigations of the reproducibility of measurements of the sound reduction index of massive building elements showed considerable differences determined by the different loss factors in the test facilities and standardized conditions were proposed. Details are still under discussion. The applicability of the calculation procedure according to EN 12354 for the types of construction usual in Germany has been tested (Metzen, 1999; Blessing, 2001; Späh, 2001). The calculation procedure according to EN 12354 was extended to enable application for massive double walls (Metzen et al., 2002).

How far the method according to EN 12354 is applicable for the planning of airborne and impact sound insulation in wood-construction buildings was also tested or a new method developed (Metzen et al., 2005). A comprehensive data bank was established for the sound reduction index (including spectrum adaptation terms) and flanking level difference (including spectrum adaptation terms) of wall constructions and the sound reduction index and normalized impact sound level (each including spectrum adaptation terms) of wooden floors. The comparison of results from calculations and measurements of the airborne sound insulation in buildings yielded differences ≤ 2 dB for the calculation with the simplified method in EN 12354 in most of the cases. Differences ≤ 4 dB resulted for impact-sound insulation of wooden floors when calculating with the newly developed method, where the larger differences were also determined by defects in the installation of the floating floors (Scholl et al., 2004).

In the Netherlands the guideline NPR 5070 has been established; in this flanking elements appropriate for connection with separating elements are shown in detail. It is the responsibility of local authorities to give permission to construct buildings and they will do so if it is made plausible that the building will fulfil the requirements (fulfilling requirements stays the responsibility of the builder/project developer). Local authorities will check the design of the building using NEN guidelines (NPR 5070) and general knowledge (EN 12354 may be used but

35

it is not mandatory). Local authorities may check afterwards by measurements, but nowadays this is seldom done, only a few localities still do it to promote and demonstrate good workmanship. There is a system of a kind of insurance in case of buying houses; in that case measurements are performed if in doubt about the promised acoustic quality (Gerretsen, 2006). From various studies it shows that nowadays normally the legal requirements are met for new built houses. The guideline NPR 5070 specifies also constructions for the higher quality class II and gives also information for the correct design of floating floors (Gerretsen, 2003).

In Spain with the new draft standard (codigo tecnico de la edificacion CTE) not only new requirements for the sound insulation in the building (instead of the former laboratory requirement to each construction element) were introduced but also in situ measurements and checking in the design stage. Sound transmission models are developed to provide architects and designers with effective tools in their attempt to guarantee the acoustical requirements from the very first stage of the building. Especially the required data for the use in EN 12354 shall be established, taking into account the special methods of construction usual in Spain (hollow bricks and beam and block floors) (Esteban et al., 2004). For that purpose multiple in situ loss factor measurements were performed on several different hollow floors and walls used in Spain and supplements for the calculation procedure proposed in order to approve the accuracy of EN 12354´s calculations (Esteban et al., 2004). To make a calculation programme on basis of EN 12354 available for the planners the Acoubat software (developed by CSTB) was adapted to Spanish constructions and for easiness of use. Training courses in building acoustics are being carried out to spread that knowledge. Once the new building regulation will be applicable and architects and building designer used to work with prediction models or other tools to fulfil in situ requirements acoustic classification schemes will be implemented as exists currently for thermal insulation. To check the accuracy of the calculation procedure according to EN 12354 for constructions used in Spain the results of measurements and calculations (with the simplified and with the detailed model) in several buildings were compared (Esteban et al., 2005). 24 real different situations have been studied concerning the airborne sound insulation in vertical and horizontal directions. The average sound level difference DnT,w was in the range from 32,5 to 59,5 dB. The average of the difference measured value - calculated value was 0,5 dB (standard deviation 1,9 dB) for the detailed procedure and –0,6 dB (standard deviation 3,2 dB) for the simplified model. In the conclusions a strong dependency between the prediction accuracy and the reliability of the input data is emphasized. A further detailed comparison measurement – calculation was carried out in a building (Andrade et al., 2005); it showed that the prediction models can be applied with good agreement to the Spanish constructions in the case of single layer elements.

The fulfilment of the regulation can be achieved checking the design with: - using “approved solutions” (i.e. combination of floors, walls. etc., known to work) - calculation according to EN 12354.

At present the ministry is working on those “approved solutions” and each regional government will decide how to check the correct design and workmanship.

Substantial work has been done adapting EN 12354 to Spanish constructions and developing a Spanish version of Acoubat software (named Acoubat-dBMAT) together with CSTB (Esteban, 2006).

A simply to use software to predict acoustic insulation in buildings in accordance with EN 12354 including the necessary data was also described (Pena et al., 2002).

In Sweden the new standard on sound classification explicitly advises, that a building acoustic documentation should be presented at an early stage of a project based on calculations or measurements. Measurements in the building are often required. A database of sound insulation of typical constructions suitable for the calculation of sound insulation in situ according to EN 12354 has been established including data for suitable renovation measures (Simmons, 2004). For calculations the programme Bastian was used. With respect to the introduction of the spectrum adaptation terms in the standard with the prescription of R’w + C50-

3150 for airborne sound insulation and L’n,w + CI,50-2500 for impact sound insulation the results of

36

calculations (with Bastian) and measurements for 4 typical building constructions were compared with the requirements (Hagberg, 2002). For the constructions with heavy floors and heavy walls or with heavy floors and lightweight walls the calculated and measured values seem to give satisfactory correspondence, the requirements for class B can be achieved. For the lightweight constructions with steel frame or wood frame floor structure with layers of gypsum board it was not possible to calculate with the program. The measurements yielded partly to low sound insulation, especially for impact sound. It was noticed, that the use of the Swedish classification standard has ended up with more activity in the field of building acoustics and it is sure that the building technique will be developed further to optimize different building structures to various classes in the standard. A database has been established as input data to EN 12354 and the influence of flanking conditions and structural reverberation were proved (Simmons, 2001). A detailed investigation of uncertainty of measured and calculated sound insulation in buildings was carried out. In an inter-laboratory comparison 8 laboratories made sound insulation measurements on 7 partitions located in the same building; all values of the standard deviation were in the range given in ISO 140-2. About 40 calculations of sound insulation between rooms in real buildings (concrete floors) were made according to EN 12354 and the calculated values were compared to field measurements. Safety margins were deduced 2 dB for R’w and L’n,w and 3 dB for R’w + C50-3150 and L’n,w + CI,50-2500. These values are applicable when input data are documented properly and the quality of workmanship is high (Simmons, 2005).

The fact, that in Sweden buildings largely are constructed with a higher sound insulation (class B) than the minimum requirement was partly explained as follows (Simmons, 2006): „The main reason for the change of building practice in Sweden, was the political change made to the system for subsidizing dwellings, in 1992. In the same time, forced limitations on allowable rents of dwellings were removed. As a result, prices were then set by the market, less dwellings were built, and there was a severe inflation in prices. But also, the dwellings built had to please "rich" people, e.g. middle-aged who sold their house and wanted to move to a high-standard apartment. These clients demanded better quality than basic, considering the prices they had to pay. There was also a consensus on the standard constructions used to that day, that these were not up-to-date and there were severe complaints. The change from "habitant", being allocated to a dwelling, to "client" buying one, meant a big step for the industry.”

In Finland according to the standard a building or space can only be stated as belonging to one of the acoustic classes defined in the standard, if the values defined in the classification have been verified by acoustic field measurements performed in the finished building. The classification can be achieved for an individual space or for an entire building. When ascertaining the acoustic class of a building the size of the samples for measurements of airborne and impact sound insulation is 5 % of the structures separating spaces, however the minimum to be measured is always two.

In France, in Référentiel Qualitel (a comprehensive handbook), besides the requirements on airborne and impact sound insulation for the Certification Qualitel, detailed specifications are given on how to fulfil these requirements for airborne sound insulation with the different types of constructions. Additionally, “prefabricated” combinations of separating and flanking elements (for standardized room dimensions) are quoted in large numbers, as well as the procedure for calculating the sound insulation of any combination. The possibilities of by-paths by air conditioning systems and similar installations are considered in detail. Tables for the determination of R’w + C are given at the end. Precise data are also given to fulfil the required impact sound insulation in vertical as well as horizontal and diagonal directions. The impact sound insulation for stairs is also dealt with in detail.

In Poland a study on the verification of the calculation method in EN 12354-1 was carried out and found, that the differences between the measurements and the calculations are to a large extent dependable on the input results for the calculation (Szudrowicz, 2001).

In England constructions are to be tested to improve compliance with the requirements and fulfil the Pre Completion Testing (PCT) since revision of the Approved Document (with raised standards DnT,w + Ctr ≥ 45 dB). 2004 Robust details were introduced which have a demonstrated

37

performance of at least 47 dB DnT,w + Ctr . These constructions are exempt from PCT requirements provided that the development is registered and approved Robust Detail methods are used. A number of robust details are available for separating walls from masonry, timber, steel and for separating floors from concrete, timber, steel-concrete composite. Each robust detail has its own site work checklist. These are designed to help builders to ensure that building work is carried out exactly in accordance with the robust details specifications. Trade associations, manufacturers or other interested parties may wish to submit proposals for new robust details. Before an application is made evidence is required to demonstrate that the proposed design is likely to meet the required performance criteria. This requires the proposer to undertake some initial sound testing before. The robust details must be practical to construct on site and be reasonably tolerant to workmanship. The robust details handbook includes the robust details specification sheets and site checklists to help builders and building control bodies to ensure that separating walls and floors are built properly. To ensure that the registered constructions are correct installed in all details seminars and interactive training aid is offered. The system is also clearly legally covered (www.robustdetails.com).

In Hungary when the building is ready, local authorities don't need any document about sound insulation. But the contractors, or the main organisation of building regularly orders sound insulation measurements, for any case, only for control. Producers of building materials and elements deliver their products with the required acoustic information to construct buildings according to the standards (Reis,2006).

To sum up, from this overview it follows that in nearly all the considered countries the planning of sound insulation is carried out based on EN 12354 and relevant programs (after having established the applicability for the respective usual types of constructions). In several countries a database with the required input data has been or is being established. An examination of the planning is only compulsory in a few countries, and also sound insulation measurements in the finished building are only carried out in a few countries. Partly comprehensive collections of “appropriate constructions” are available, which may ensure the required sound insulation in the building (provided that workmanship is of high quality).

2.4 Sound insulation in Austrian dwellings

Sound insulation in building construction has a long tradition in Austria. In 1936 ÖNORM B 2115 “Building construction – Protection against sound and vibrations” was published and in 1949 ÖNORM B 8115 “Building construction – sound insulation and room acoustics” according to the state of the art at that time. In 1959 a new edition followed.

Determined by the growing volume in 1981 the standard was divided into 4 parts: Part 1 with the definitions, Part 2 with the requirements, Part 3 with the basic room acoustics, Part 4 with measures to fulfil the requirements on sound insulation.

While parts 1 and 2 were reedited several times, part 4 was not newly published until 1992. It already considered the new knowledge on the sound transmission in buildings via separating and flanking elements. In 2001 a new edition had to be published, especially with respect to the adoption of EN 12354-1 and EN 12354-2 into Austrian standards, as these European standards replaced parts of ÖNORM B 8115.

The basis for the development of building acoustics in Austria was the results of research work carried out from 1970-1973 (Bruckmayer et al., 1974) proposing guidelines for the application of economic measures for sound insulation in housing construction. There the required sound insulation in dwellings was deduced from a comprehensive inquiry into satisfaction with the living conditions and measurements of the sound insulation in flats of selected interviewed persons. Relevant information on how to install sound insulation was developed from numerous measurements with selected examples of “right and wrong”. In a series of examples the extent to which good sound insulation requires higher building costs was tested.

38

The inquiry, which evaluated about 10,000 questionnaires, showed a comparably high percentage of people disturbed by noise in multi-family buildings; this was clearly different in buildings constructed in different construction periods, as can be seen in Figure 11.

Figure 11: Percentage of people annoyed by noise from different living activities

.

Source: Bruckmayer et al., 1974, translation by Lang The result showed that the sound insulation in houses erected after 1945 was essentially worse than in houses erected before the war.

There was also a question in the questionnaire about whether people would be willing to pay higher costs for better sound insulation in their flat. Nearly all (96 %) would probably have been willing to pay 2-3 % more and 66 % of the persons feeling strongly annoyed in their flat would definitely have been willing to do so. Also nearly all of those disturbed would probably have been willing to pay, and 57 % definitely.

The weighted apparent sound reduction index R’w between flats side by side (separating walls) was in the 42-56 dB range and between flats one on top of the other (separating floors) in the 46-59 dB range, thus from very low to very good.

The comparison of sound insulation measurement results with the statements of the occupants on the annoyance by the neighbours’ noise showed that talking, radio and TV are not or nearly not audible and do not disturb at a weighted apparent sound reduction index of in average 52 dB.

With a weighted apparent sound reduction index of 57 dB this is ensured in nearly all cases. Thus it turned out that the sound insulation required in the standard is sufficient; but the great number of annoyed people is caused by the fact that the requirements are not fulfilled. The 57 dB required for separating walls for buildings erected using the reconstruction funds under the decree of the Federal Ministry for Trade and Reconstruction was sufficient in any case.

It was deduced from the result of the investigation that an obligatory prescription of the requirement and a check of its fulfilment are essential. Furthermore it was deduced that the fulfilment of the required sound insulation has to be considered early in the planning stage. Only the timely consideration of the sound insulation aspects and their integration into the planning can ensure a building with high-quality sound insulation without additional costs. An additional requirement to the correct planning is careful workmanship, which has to be ensured by regular inspection and measurements. A list of proposals for legislative measures to ensure the required sound insulation in dwellings was established. These proposals were introduced for subsidized dwellings e.g. in the province of Styria, and with this suitable sound insulation was

39

ensured. Sound transmission in the flanking elements was already considered as essential and for the first time the adequate flanking elements to be combined with separating elements depending on their construction were specified.

The comparison of the results for walls and floors also showed that declaring the sound insulation using the apparent sound reduction index R’w was not functional, as this quantity does not describe the real sound insulation between two rooms. Therefore the transition to the normalized sound level difference was proposed and integrated into the standard. In this way not only was a quantity defined which better describes the sound insulation between two rooms; the fact that the sound reduction index specifies the sound insulation of an element, but the normalized sound level difference indicates the sound insulation between two rooms, which not only depends on the sound insulation of the separating element but also on that of the flanking elements, was also clearly and understandably expressed for the planners.

In 1981 a proposal for a comprehensive table with separating elements and appropriate flanking elements based on the first data deduced from the research work on the influence of the flanking elements was published for the first time. In addition, a calculation procedure was published which enabled the planners to calculate the sound insulation between two rooms from the separating and the flanking elements. The easily to be used table was accepted quickly in practice and was the basis for the data on separating elements and adequate flanking elements in the standard.

In further research work in 1984-1985 on economic measures to fulfil the required sound insulation according to the standard, the sound insulation in a great number of dwellings was measured, especially to deduce general laws on sound transmission by separating and flanking elements. With the detailed measurements a calculation procedure was deduced and its suitability proved (Lang, 1985). The sound insulation in the examined buildings was, more than 10 years after the first major series of measurements, far higher, the normalized sound level difference was in the range from 52-65 dB between rooms side by side and in the 55-58 dB range between rooms one on top of the other. The measures which had been put into action after the aforementioned research work, especially the indication of the importance of the flanking elements with the simple description in a table, had entered the planning practice.

The calculation procedure and the (extended) table were included in the ÖNORM B 8115-4 standard as the correctness and usefulness of the planning procedure, taking into consideration the flanking elements dependent on the separating element, had been proved. A simple computer program based on the procedure was developed and frequently used.

When the procedure according to EN 12354-1 was worked out in the CEN working group, the basics of the procedure were already well-known and used in Austria; the introduction of EN 12354-1 in Austria, therefore, only required a transition to the new values for the vibration reduction index and somewhat adjusted formulae. Before the new procedure was introduced in the Austrian standard a series of calculations was carried out to prove the suitability for the types of constructions common in Austria and the correlation with the results of sound insulation measurements in existing buildings. The result of these comparisons was positive (see Figure 9 and Figure 10) and EN 12354-1 was therefore introduced into the national standards in Austria (as the first country in Europe).

The fulfilment of the sound insulation requirements is prescribed for subsidized dwellings20, and - depending on the respective Austrian province – airborne and impact sound insulation has to be proved in the planning stage and/or in the finished building by random measurements. This has led to a visible improvement in the sound insulation in Austrian dwellings; this is also to be seen from the results of the microcensus in 3-year periods with questions related to the noise annoyance in dwellings (see Figure 12).

20) Most of the multifamily houses in Austria are erected with subsidies.

40

Figure 12: annoyance by noise in Austrian dwellings

a) annoyance in general

b) share of the neighbouring flats in the sources of strong and very strong annoyance

Source: Lang, 2006

Evidently noise from the neighbours had increased considerably as a source of annoyance with the construction of new residential buildings in the years 1970-1980; it decreased again in the following years with the increasing observation of the standard requirements and their fulfilment21. The increase again in 2003 may have been caused by the increasing share of

21) The greater share in Vienna may be caused by the fact that the share of multifamily houses in Vienna is higher than in the provinces, where the share of single houses is higher.

0

10

20

30

40

50

60

1970 1975 1980 1985 1990 1995 2000 2005

year

perc

enta

ge a

nnoy

ed b

y no

ise

total strongly and very strongly

0

2

4

6

8

10

12

14

16

18

20

1970 1975 1980 1985 1990 1995 2000 2005

year

perc

ent

Austria Vienna

41

privately-financed dwellings, for which a test of the sound insulation before the start of construction work and a measurement after finishing the construction is not required.

In the province of Styria, for subsidized buildings the fulfilment of the sound insulation regulations has to be proved by a calculation before the start of construction work and measurements are carried out in the finished building shortly before the delivery of the flat. With this the following results were achieved:

1997: 216 measurements, requirements fulfilled: 97.9 % for impact sound insulation L’nT,w ≤ 48 dB und 92.3 % for airborne sound insulation DnT,w ≥ 55 dB 1999: 137 measurements, requirements fulfilled: 93.8 % for impact sound insulation and 100 % for airborne sound insulation

There are no complaints about noise annoyance by the neighbours in those dwellings where measurements have been carried out.

In the province of Upper Austria, the workmanship of builders of multi-family houses is supervised with respect to the quality of the sound insulation. In any year about 70 housing areas are supervised with respect to the legally required acoustic properties of the building. This is about half of the subsidized buildings erected in Upper Austria. With this it is ensured that every builder is tested at least once a year. As a result of this supervision of the acoustic quality using measurements, over more than two decades the sound insulation in the subsidized dwellings has clearly increased. Unfavourable developments in some building materials are quickly discovered and appropriate countermeasures can be taken.

The results of measurements in Figure 13 show that the sound insulation has stabilised at a high level in the last few years. This is valid for the sound level difference between flats side by side and between flats one on top of the other, as well as for the impact-sound insulation.

Figure 13: Results of measurements of airborne and impact sound insulation in residential buildings in Upper Austria

a) Airborne sound insulation between flats side by side (1988 – 2005) Mean value of the standardized sound level difference DnT,w

year

42

b) Airborne sound insulation between flats one on top of the other (1988 – 2005) Mean value of the standardized sound level difference DnT,w

year

c) Impact-sound insulation (1988 – 2005) Mean value of the standardized impact sound level L’nT,w

year

Source: Land OÖ, Abteilung Wohnbauförderung, 2005

The sound insulation measured in 28 subsidized residential buildings (62 measurements in total) within the scope of the comparison of measured and calculated values is shown in Figure 14 with the frequency distribution of measured values. The percentage of buildings fulfilling the minimum required value of DnT,w = 55 dB (according to the Austrian standard), the enhanced sound insulation DnT,w = 58 dB (stated in the standard) and a proposed more stringent “comfort sound insulation” DnT,w = 63 dB is marked.

It is obvious that a high percentage of the flats far exceeds the required minimum sound insulation and also the higher recommended value.

43

Figure 14: Results of sound insulations measurements in subsidized housing (built between 1990 and 1999) in the federal states of Steiermark (Styria) and Oberösterreich (Upper Austria)

Source: Lang, 2006

sound insulation between adjacent flats

0

10

20

30

40

50

60

70

80

90

100

50 52 54 56 58 60 62 64 66 68 70

standardized sound level difference DnT,w dB

perc

enta

ge fu

lfilli

ng

100%

77%

23%

sound insulation between flats one on top of the other

0

10

20

30

40

50

60

70

80

90

100

50 52 54 56 58 60 62 64 66 68 70

standardized sound level difference DnT,w dB

perc

enta

ge fu

lfilli

ng

100%

50%

5%

44

3 Suggested sound insulation classes for residential buildings

The different investigations show that the minimum sound insulation required in the countries, which in some of them is also legally stipulated, only offers protection against noise caused by normal living activities and for persons of normal sensitivity. At these levels of sound insulation, the occupants of multi-family houses still complain about disturbance by neighbourly noise and also about the need to restrict their own activities in order to protect their neighbours from noise. In the last decade, several countries have therefore also worked out requirements for an improved sound insulation and published sound insulation classes.

All buildings can be assigned to one of these classes, depending on their sound insulation. When selling the building, this classification can be praised as an asset. Studies have shown that there is a willingness to pay a higher price when the insulation is (provably) higher.

The proposals derived in section 2 and 3 from the investigations presented in this study have been put together in Table 26 below for 4 sound insulation classes.

Table 26: Proposed requirements for airborne and impact sound insulation in 4 sound insulation classes

Class “Music” “Comfort“ “Enhanced“ *) “Standard“ Airborne sound insulation between flats DnT,w +C (dB)

≥ 68 (C50-3150)

≥ 63 ≥ 58 ≥ 54

Airborne sound insulation between the rooms within a flat (without doors), also incl. one-family houses DnT,w +C (dB)

≥ 48 ≥ 48 ≥ 45 ≥ 40**)

Impact-sound insulation between flats L’nT,w + CI,50-2500 ***)(dB)

≤ 40 ≤ 40 ≤ 45 ≤ 50

Impact-sound insulation within a flat, also incl. one-family houses L’nT,w + CI,50-2500 ***)(dB)

≤ 45 ≤ 45 ≤ 50 ≤ 55

*) minimum requirements for terraced houses **) if requested ***) for a transitional period L’nT,w + CI, values decreased by 2 dB

Source: Lang, 2006

In some standards – also in Austria – separate, more stringent, requirements are defined for the sound insulation between terraced houses. Separated requirements for terraced houses in the classes A to C do not seem necessary. However, class C should be defined as the minimum requirement for terraced houses.

A building may be assigned to a class by measurement of the sound insulation; an assignment is only possible if all requirements of the respective class are fulfilled: airborne sound insulation between flats side by side and between flats one on top of the other, airborne sound insulation for at least one room within a flat, impact sound insulation from a room outside the flat, also from the staircase, and impact sound insulation within a flat (split-level or single family house).

In multi-family houses at least two measurements for any of the requirements are necessary; if there are more than 40 flats in one building, measurements have to be carried out for 5 % of the flats (randomly chosen).

The sound insulation against noise intruding from sound sources outside the building through the external elements is to be designed according to the requirements for the resultant sound reduction index + Ctr (resultant from the sound reduction index of window and opaque external element) in ÖNORM B 8115-2. These requirements are staggered according to the sound level in front of the façade. To prove the fulfilment, the rating level in front of the facade has to be stated for day and night (according to a measurement or calculation, or taken from a noise map

45

or a strategic noise map), and the sound insulation of the façade has to be measured (2 measuring sites or 5 % of the flats).

In Table 27 the requirements for the resultant apparent sound reduction index R’w + Ctr are shown versus the sound level in front of the façade.

Table 27: Requirements for the sound insulation of the façade according to ÖNORM B 8115-2 Rating level22 in front of the facade (dB)

day night

≤ 50 ≤ 40

51-55 41-45

56-60 46-50

61-65 51-55

66-70 56-60

71-75 61-65

75-80 65-70

R’res,w + Ctr (dB) 28 33 33 38 38 43 48

Source: ÖNORM B 8115-2, translation by Lang

These values also correspond approximately to the requirements of the Swiss SIA 181 standard for medium noise sensitivity.

In Figure 15 the sound level in the room is shown which results from the A-weighted sound level in front of the building and the sound reduction index required in ÖNORM B 8115-2. For this example a 30m3 room is assumed with an area of the outer element of 6 m2. For comparison, the indicative planning value for the background level in the room is marked for the land use category which is assigned to the sound level in front of the façade (see Table 9). These levels inside the building can be compared with maximum levels defined for the design of the sound insulation of the façade as given in other countries, e.g. in Finland and in Denmark (see Table 28).

Table 28: Maximum sound levels in rooms for living caused by a sound source outside the building class A B C D Finland maximum sound level LA,eq (dB) day 7 – 22.00 night 22 – 7.00

25 20

30 25

35 30

35 30

Denmark maximum sound level LA,eq,24h (dB)

20

25

30

35

Source: Lang, 2006

22) The rating level is determined from the A-weighted equivalent continuous sound level plus a possible adaptation value (e.g. railway bonus – 5 dB).

46

Figure 15: Sound level inside the building versus sound level in front of the facade with the sound insulation of the external structure according to ÖNORM B 8115-2

a) day

b) night

Source: Lang, 2006

0

5

10

15

20

25

35 40 45 50 55 60 65 70

A-weighted sound level in front of the facade dB

A-w

eigh

ted

soun

d le

vel i

nsid

e th

e bu

ildin

g dB

indicative planning value for A-weighted background level inside

sound level inside LA,eq or Lr

0

5

10

15

20

25

30

35

45 50 55 60 65 70 75 80

A-weighted sound level in front of the facade dB

A-w

eigh

ted

sou

nd le

vel i

nsid

e th

e b

uild

ing

dB

sound level inside LA,eq or Lr

indicative planning value for A-weighted background level inside

47

4 Structural measures for improving the sound insulation in newly built residential houses

4.1 Residential buildings in massive construction In order to obtain an overview of the presently existing sound insulation in residential buildings and of the required measures for planning improved sound insulation, the results of a detailed investigation were consulted. This investigation was carried out within the framework of a research project on the acoustic insulation in 27 subsidized residential houses built in Styria and Upper Austria. The results give an overview of the construction methods customary in the second half of the 1990s, the sound insulation achieved and the contribution of the single sound transmission paths.

The basis for the definition of measures to improve the sound insulation is knowledge of the sound transmission paths in the buildings, as shown in Figure 16.

Figure 16: Sound transmission paths between two rooms

Source: Lang, 2001

Thus the sound is transmitted by the separating element (path Dd) and by the (usually) 4 flanking elements, following 3 paths within each: path Ff (the flanking element is excited by the sound in the source room and the flanking element radiates sound in the receiving room), path Fd (the flanking element is excited by the sound in the source room and the separating element radiates sound in the receiving room) and path Df (the separating element is excited in the source room and the flanking element radiates sound in the receiving room). The sound energy is transmitted via the junction where flanking element and separating element are connected, whereby the ratio of the masses of the two elements defines the vibration reduction index.

The standardized sound level difference between two rooms results from the sum of the values for the standardized sound level difference for the single transmission paths. The calculation procedure is defined in EN 12354-1 in a simplified and a detailed model. In Austria the simplified model is used. In the investigation mentioned above the standardized sound level difference was calculated for numerous examples according to this procedure and it was shown that the simplified model is well suited to the calculation of the sound insulation which has been measured (see the results of this comparison in Figure 9 and Figure 10).

The calculation procedure yields the contribution of each of the building elements (separating element and flanking elements) to the sound transmission and thus identifies the element that mainly defines the sound transmission and predominantly has to be improved to reduce the sound transmission.

In Table 29 and Table 30 below, the measured sound insulation (standardized sound level difference) between rooms side by side and between rooms one on top of the other is stated for the 27 analysed residential buildings, together with the structure of each of the separating and flanking elements and the standardized sound level difference achieved by each. In addition to

48

the measured value in parentheses, the calculated value for the (total) standardized sound level difference is stated, which may differ somewhat from the measured value (see Figure 9 and Figure 10). The minimum sound-level difference achieved by one of the separating or flanking elements, which essentially defines the total sound level difference, is marked in green.

The results in Table 29 and Table 30 are grouped according to the sound insulation classes proposed in chapter 3. The grouping is based on the assumption that for massive elements C= -1 and thus DnT,w + C = DnT,w -1. Altogether the tables show that the sound insulation required in the Austrian standard and much better sound insulation can be achieved in massive buildings.

The tables with the sound level difference for every single sound transmission path show that in most of the cases, the separating element achieves a sufficiently high level of sound insulation and the sound transmission between the rooms is not determined by the separating element but by the flanking elements. Consequently, the important flanking elements (those which achieve the lowest sound level difference) must be improved in order to improve the sound insulation between the rooms. Comparative calculations show that when eliminating the element with the lowest standardized sound level difference, which in many cases is the outer wall from vertically perforated clay blocks, the total standard sound level difference can be increased by 2 to 4 dB. It is thus possible to fulfil the conditions for next higher requirement class.

Recent investigations into this topic show that the flanking transmission in the outer walls alongside the floor can be reduced if the solid reinforced concrete floor slab is installed over the entire thickness of the outer wall instead of using (lightweight) clay blocks at ceiling level. With the use of a continuous heat insulation layer on the outside of the outer wall, the necessary heat insulation is ensured. Figure 17 shows a section.

Figure 17: Section of the outer wall of bricks with the concrete floor and outside heat insulation

Source: Wienerberger Ziegelindustrie GmbH

The description of the sound transmission through individual building elements in Table 29 and Table 30 also shows that lightweight partition walls made of 10 or 12 cm thick hollow bricks can considerably influence the sound insulation. By contrast, the sound transmission through partition walls made of gypsum plasterboard is negligible. By ensuring an elastic connection between the lightweight, non-load-bearing massive partition walls and the floor above or below, it is possible to improve the flanking transmission insulation in the massive partition walls. In Figure 18 an example of the elastic layer in the connection between the light partition and the floor or the separating wall is shown in a vertical and horizontal section

49

Figure 18: Elastic connection of lightweight massive partition walls with the floor and the separating wall between flats

Source: Wienerberger Ziegelindustrie GmbH

A comparison of the results of sound insulation measurements between rooms one on top of the other in dwellings with and without elastic layers beneath the load bearing and non-load-bearing partition walls showed an essential increase in sound insulation between rooms one above the other due to the elastic layer. Several measurements yielded values for the weighted standardized sound level difference of 54 to 59 dB (on average 56 dB for 6 measurements) without an elastic layer and 61 to 64 dB (on average 62 dB for 4 measurements) with “Pronuovo-Wandlager” (test report EMPA 92-11-04).

50

Table 29: Sound insulation between adjacent rooms Construction of separating and flanking elements and contribution to sound transmission Class DnT,w = 55 to 58 dB

dwelling DnT,w (dB)*) separating wall outer wall floor/floor covering inner wall

Rum (55) 54,6

25 cm hollow bricks 5 cm Roofing mineral wool 1.3 cm plaster board 62.1

3 cm isolating plaster 30 cm hollow bricks 5.5 cm isolating plaster 57.9

floating floor 18 cm concrete slab 66.8 73.1

10 cm hollow bricks 60.2

Leonding (56) 59.3

20 cm concrete 3.5 cm mineral wool 1.5 cm plaster 65.7

25 cm hollow bricks mineral wool facade from fibre-cement 64.1

6 cm floating screed 3 cm AWAKUST-polystyrene 2 cm loose fill 20cm reinforced concrete slab 71.0 75.4

10 cm hollow bricks 64.9

Wels (57) 57.4

25 cm sound insulating bricks 3.5 cm mineral wool 1.5cm plaster 63.0

38 cm hollow bricks 61.6

6 cm floating screed 3 cm AWAKUST-polystyrene 6 cm fill 20 cm reinforced concrete slab 68.5 72.7

staircase wall as separating wall 63.5

Linz-Ko (57) 55.8

30 cm sound insulating bricks 58.7

30 cm hollow bricks 5.5 cm external thermal insulating composite system (ETICS) 61.7.

7 cm floating screed 3 cm AWAKUST-polystyrene 5 cm fill 18 cm reinforced concrete slab 67.7 71.6

10 cm hollow bricks 63.5

Linz-Par (57) 55.2

25 cm hollow bricks 5 cm mineral wool 1.3 cm plasterboard on adjusting bar 60.0

40 cm hollow bricks 62.1

6 cm floating screed 3 cm AWAKUST-polystyrene 6 cm fill 20 cm reinforced concrete slab 67.1 71.3

10 cm hollow bricks 59.4

Oberzeiring (58) 58.9

25 cm hollow bricks 1.5 cm plaster 4 cm mineral wool 3 cm airspace 1.3 cm plasterboard on adjusting bar 64.3

30 cm hollow bricks 6 cm polystyrene 61.2

6 cm floating screed 3 cm mineral wool TDP 8 cm fill 20cm reinforced concrete slab 71.7 75.3

10 cm plaster board stud wall ----

51 Class DnT,w = 55 to 58 dB (continued 1)

dwelling DnT,w (dB)*) separating wall outer wall floor/floor covering inner wall

Gleisdorf (58) 56.7

25 cm sound insulating bricks 1.5cmplaster 5 cm mineral wool 1.3cm plaster board 66.9

38 cm hollow bricks 58.5

6.5 cm floating screed 2.5 cm mineral wool TDPT 9 cm fill glued. 18 cm reinforced concrete slab 67.1 76.2

12 cm hollow bricks 64.7

Graz-St (58) 60.8

25 cm sound insulating bricks 1.5cm plaster 7 cm mineral wool 1.3cm plasterboard on adjusting bar 65.3

38 cm hollow bricks 64.9

6cm floating screed 2.5cm mineral wool TDP 7.5cm fill 18 cm reinforced concrete slab 70.8 75.2

10 cm plaster board stud-wall staircase wall as separating wall 70.0

Bruck/Mur (58) 58.5

25 cm sound insulating bricks 1 cm plaster 5 cm mineral wool WF 50 1 cm air space 1.3cm plasterboard 67.6

38 cm hollow bricks 60.3

6 cm floating screed 2.5 cm mineral wool TDP 9.5 cm grit 18 cm reinforced concrete slab 72.1 75.5

12 cm hollow bricks 66.4

52 Class DnT,w = 59 to 63 dB

dwelling DnT,w (dB)* ) separating wall outer wall floor/floor covering inner wall

Graz-Gri (59) 59.8

25 cm Durisol wood-concrete finshed overlay 25/18 1.5 cm plaster 4 cm mineral wool 3 cm air space 1.3 cm plaster board 66.6

30 cm Durisol wood-concrete modular chimney blocks DS30 Wood concrete at inner side passes separating wall; if it would be separated by the separating wall. then DnTw 68 62

6 cm floating screed 2.5 cm mineral wool. TDP 8.5cm grit 18 cm reinforced concrete slab 75.2 75.8

12 cm hollow bricks 68.8

Graz-Ze (60) 60.0

25 cm sound insulating bricks 2.3 cm EPS-T 10 cm hollow bricks, with elastic layer separated from walls and floors 69.6

38 cm hollow bricks 62.6

6 cm floating screed 5 cm mineral wool TDPS 55/50 8.5cm fill 18 cm reinforced concrete slab 76.1 77.7

12 cm hollow bricks 65.2

Graz-Zel (60) 60.5

25 cm hollow bricks 1.5 cm plaster 5 cm mineral wool 2 cm air space 1.3 cm plaster board on adjusting bar 63.3

30 cm hollow bricks 6 cm Polystyrene 65.7

6 cm floating screed 3 cm mineral wool TDP 8 cm grit 18 cm reinforced concrete slab 69.8 73.9

12 cm hollow bricks with 3 cm mineral wool separated from walls and floors ----

Graz-Zel (61) 60.9

as above 63.7

as above 66.1

as above 70.2 74.3

----

Frojach (60) 59.4

25 cm Leca-concrete block 1.5 cm plaster 6 cm mineral wool 1.3cm plaster board 62.8

38 cm Leca-concrete block 2 cm heat insulating plaster 64.9

6 cm floating screed 2.5 cm mineral wool 7.5 cm gravel 16 cm reinforced concrete slab 68.0 73.1

staircase wall as separating wall 70.9

Frojach (61) 59.9

as above 63.8

as above 65.9

as above 66.3 74.1

as above 71.9

53 Class DnT,w = 59 to 63 dB (continued 1)

dwelling DnT,w (dB)* ) separating wall outer wall floor/floor covering inner wall

Linz-Par (60) 56.0

25 cm hollow bricks 5 cm mineral wool 1.3 cm plaster board on adjusting bar 58.6

40 cm hollow bricks 61.3

6 cm floating screed 3 cm AWAKUST-polystyrene 6 cm grit 20 cm reinforced concrete slab 65.7 69.9

---

Gleisdorf (61) 58.9

25 cm sound insulating bricks 1.5cm plaster 5 cm mineral wool 1.3cm plaster board 67.5

38 cm hollow bricks 60.8

6.5 cm floating screed 2.5 cm mineral wool TDPT 9 cm grit glued 18 cm reinforced concrete slab 74.0 75.7

12 cm hollow bricks 67.0

Graz-Wi (62) 62.5

25 cm sound insulating bricks 1.5 cm plaster 7 cm mineral wool 1.3 cm plaster board on adjusting bar 64.0

38 cm hollow bricks in room for measurement only French window ---

6 cm floating screed 2.5 cm mineral wool TDP 6 cm grit 18 cm reinforced concrete slab 69.6 73.1

10 cm plasterboard stud-wall ----

Graz-Gh (63) 62.4

25 cm hollow bricks 1.5 cm plaster 5 cm mineral wool 1.3 cm plaster board 65.1

38 cm hollow bricks (only in one of the two rooms) 75.1

6 cm floating screed 2.5 cm mineral wool TDP 7.5 cm gravel 18 cm reinforced concrete slab 69.0 73.6

chimney on 12 cm hollow bricks 71.9

54 Class DnT,w ≥≥≥≥ 64 dB

dwelling DnT,w (dB)* ) separating wall outer wall floor/floor covering inner wall

Linz-Schu (64) 65.3

22 cm concrete 3.5cm mineral wool TDPS 2 cm plaster 69.8

30 cm hollow bricks 6 cm external thermal insulating composite system (ETICS) 70.7

6 cm floating screed 3 cm AWAKUST-polystyrene 8 cm grit 20 cm reinforced concrete slab 75.1 78.3

25 cm hollow bricks 72.3

Graz-Lü (66) 65.2

1.3 cm plaster board 1 cm air space (glue) 22 cm concrete 4 cm wood wool-cementboard 860kg/m3 1.5 cm plaster 67.8

1.5 cm plaster 5 cm three layered woodwool- board 21 cm concrete 4 cm Heraklith-board for permanent concrete formwork system 1.5 cm plaster 70.3

6 cm floating screed mineral wool 9.5 cm grit 18 cm reinforced concrete slab 75.2 78.1

12.5 cm plaster board stud wall ----

Graz-Lü (64) 63.1

as above, identical rooms, adverse direction of sound transmission

as above

as above

as above ----

Graz-Be (65)**)

63.0

20 cm ISOSPAN-wood-concrete- modular chimney blocks 3.5 cm mineral wool 1.5 cm plasterboard 64.4

25 cm Durisol wood-concrete modular chimney blocks in the rooms for measurements no massive outer wall ----

6 cm floating screed 3 cm mineral wool TDPS 5 cm gravel 18 cm reinforced concrete slab 69.9 74.5

1.3 cm plaster board stud wall ----

Graz-Be (67)**)

64.8 as above 66.2

as above

as above 71.8 76.4

as above ----

*) Measured value in parenthesis, all other values are calculated **) The difference between the results of the two measurements with identical construction of separating and flanking elements is caused by the different volumes of the receiving rooms.

Source: Lang, 2006 (based on calculations carried out in the scope of the investigation Lang (2001))

55

Table 30: Sound insulation between rooms one above the other Construction of separating and flanking elements and contribution to sound transmission Class DnT,w = 55 to 58 dB

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Bruck/Mur (54) 58.4

6 cm floating screed 2.5 cm mineral wool TDP 9.5 cm grit 18 cm reinforced concrete slab 66.2

38 cm hollow brick 61.9

25 cm hollow brick 70.7

12 cm hollow brick 67.3

25 cm pillar from bricks. chimney 78.8 65.6

Graz-Bauernf. (54) 55.5

6 cm floating screed 2.5 cm mineral wool. TDP 8.5 cm grit 18 cm reinforced concrete slab 66.1

38 cm hollow bricks 2 cm heat insolating plaster 57.0

25 cm hollow bricks 67.7

12 cm hollow bricks. 64.1

Graz-Bauernf (54) 55.5

as above 66.1

as above 57.0

as above 67.7

as above 64.1

Graz-Bauernf (55) 55.4

as above 66.2

as above 57.1

as above 61.7

Graz-Bauernf (55) 55.4

as above 66.2

as above 57.1

as above 61.7

Graz-Bauernf (58) 60.0

as above 66.2

as above 63.4

25 cm hollow bricks 65.7

25 cm sound insulating bricks (separating wall) 73.9

Aussee (55) 57.3

6 cm floating screed 2.5 cm mineral wool. TDP 7.5 cm grit glued 16 cm reinforced concrete slab 64.1

38 cm hollow bricks 60.3

25 cm hollow bricks 67.0

12 cm hollow bricks 66.6

installation shaft 69.0

Leonding (55) 58.0

6 cm floating screed 3 cm AWAKUST.polystyrene 2 cm grit 20 cm reinforced concrete slab

25 cm hollow bricks mineral wool facade from fibre cement 63.5

10 cm hollow bricks. 61.7

staircase wall 20 cm concrete 68.3

56 Class DnT,w = 55 to 58 dB (continued 1)

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Leonding (57) 57.9

as above 65.2

as above 63.2

as above 61.2

20 cm concrete (separating wall) 70.7

Graz-Hie (55) 58.9

6 cm floating screed 2.5 cm mineral wool 8.5 cm grit 18 cm reinforced concrete slab 66.1

38 cm hollow bricks 62.7

25 cm hollow bricks 69.5

10 cm hollow bricks 64.0

Graz-Hie (58) 56.6

as above 66.1

as above 59.0

as above 61.6

Graz-St (56) 59.7

6 cm floating screed 2.5 cm mineral wool TDP 7.5cm grit 18 cm reinforced concrete slab 65.2

38 cm hollow bricks 63.5

25 cm hollow bricks. 66.7

25 cm sound insulating bricks (separating wall) 70.3

Graz-St (57) 57.2

as above 65.2

as above 58.7

as above 66.2

10 cm plasterboard stud wall ----

Graz-Ze (56) 56.3

6 cm floating screed 5 cm mineral wool TDPS55/50 8.5cm grit 18 cm reinforced concrete slab 66.2

38 cm hollow bricks 59.3.

12 cm hollow bricks 60.3

Bruck/Mur (56) 56.2

6 cm floating screed 2.5 cm mineral wool.TDP 8.5 cm grit 18 cm reinforced concrete slab 65.7

30 cm floating screed 5 cm Polystyrene 58.6

10 cm hollow bricks 61.3

Bruck/Mur (56) 56.0

as above 65.7

as above 59.2

as above 60.7

staircase wall 25 cm hollow bricks 67.4

Bruck/Mur (57) 58.0

as above 65.6

as above 60.6

as above 64.4

25 cm hollow bricks (separating wall) 70.5

57 Class DnT,w = 55 to 58 dB (continued 2)

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Graz-Wi (57) 59.4

6 cm floating screed 2.5 cm mineral wool TDP 6 cm grit 18 cm reinforced concrete slab 65.1

38 cm hollow bricks 61.5

25 cm sound insulating bricks (separating wall) 69.0

10 cm plaster board stud wall ----

Unterpremstätten (57) 57.4

6 cm floating screed 2.5 cm mineral wool TDP 7.5 cm grit 16 cm reinforced concrete slab 64.6

38 cm hollow bricks 61.4

25 cm hollow bricks 69.1

12 cm hollow bricks 62.6

staircase wall 38 cm hollow bricks 71.6

Unterpremstätten (58) 57.0

as above 64.7

as above 61.6

as above 69.1

as above 65.8

chimney 62.5

Zeltweg (58) 58.7

6.5cm floating screed 2.5 cm mineral wool .TDP 9 cm grit 18 cm reinforced concrete slab 68.2

38 cm hollow bricks 59.7

25 cm hollow bricks 68.8

St. Georgen (58) 57.7

6 cm floating screed 3 cm mineral wool TDPS 6 cm sand 18 cm reinforced concrete slab 65.2

30 cm Durisol-wood-concrete modular chimney blocks DSs 30 60.6

25 cm Durisol finished overlay 25/18 70.7

staircase wall 25 cm DMI finished overlay with plaster board on 4 cm mineral wool and 3 cm air space 80.6

chimney 63.4

Wels (58) 58.7

6cm floating screed 3 cm AWAKUST.polystyrene 6 cm grit 20 cm reinforced concrete slab 65.5

38 cm hollow bricks 63.5.

10 cm hollow bricks 64.7

25 cm sound insulating bricks (separating wall) 68.4

staircase wall 25 cm sound insulating bricks 68.7

Wels (58) 59.0

as above 65.4

as above 63.4

as above 64.6

as above, with 3.5 cm mineral wool and plaster 76.6

as above 68.6

58 Class DnT,w = 55 to 58 dB (continued 3)

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Linz-Par (58) 59.3

6 cm floating screed 3 cm AWAKUST-polystyrene 6 cm grit 20 cm reinforced concrete slab 65.7

40 cm hollow bricks 66.7

10 cm hollow bricks 64.0

25 cm hollows bricks (separating wall) 65.4

Linz-Par (58) 59.4

as above 65.6

as above 66.1

as above 62.9

25 cm hollow bricks 5cm mineral wool with plaster board on adjusting bar(WTW) 69.1

59 Class DnT,w = 59 to 63 dB

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Graz-Gh (59) 59.4

6 cm floating floor 2.5 cm mineral wool TDP 7.5 cm gravel 18 cm reinforced concrete slab 65.1

38 cm hollow bricks 63.5

12 cm hollow bricks 64.4

25 cm hollow bricks 5 cm mineral wool 1.3 cm plaster board (separating wall) 77.8

staircase wall as separating wall 81.1

Linz-Schu (59) 60.8

6 cm floating screed 3 cm AWAKUST-polystyrene 8 cm grit 20 cm reinforced concrete slab 66.2

30 cm hollow bricks 6 cm external thermal insulating composite system (ETICS) 67.1

10 cm hollow bricks 65.9

25 cm hollow bricks 70.4

staircase wall 22 cm concrete 73.0

Linz-Schu (62) 60.8

as above 66.2

as above, a part with additional plaster board on mineral wool 66.5

as above 64.8

22 cm concrete 3.5cm mineral wool TDPS 2 cm plaster 75.3

Graz-Szy (60) 59.1

6 cm floating screed 2.5 cm mineral wool 8 cm grit glued 18 cm reinforced concrete slab 65.9

38 cm hollow bricks 63.5

10 cm hollow bricks 65.1

25 cm hollow bricks 69.0

25 cm sound insulating bricks (separating wall) 70.7

Öblarn (60) 58.7

6 cm floating screed 3 cm mineral wool TDP 8 cm grit 18 cm reinforced concrete slab 65.6

25 cm hollow concrete blocks 6cm Polystyrene 61.8

25 cm hollow concrete blocks 68.7

12 cm hollow concrete blocks 65.4

Öblarn (63) 61.7

as above 65.6

as above 66.6

as above 69.3

plaster board stud wall ---- 12 cm hollow concrete blocks (shaft wall) 72.4

staircase wall 25 cm hollow concrete blocks mineral wool with plaster board 79.6

60 Class DnT,w = 59 to 63 dB (continued 1)

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Oberzeiring (61) 60.4

6 cm floating screed 3 cm mineral wool TDP 8 cm grit 20 cm reinforced concrete slab 66.1

30 cm hollow bricks 6 cm Polystyrene 62.7

25 cm hollow bricks. 69.6

25 cm hollow bricks 4 cm mineral wool 3 cm air space 1.3 cm plaster board on adjusting bar 76.8

12 cm plaster board stud wall ----

Frojach (62) 60.7

6 cm floating screed 2.5 cm mineral wool. TDP 7.5 cm gravel 16 cm reinforced concrete slab 64.7

38cm Leca-concrete blocks 2 cm heat insulating plaster 64.5

25 cm Leca concrete blocks (separating wall) 68.8

staircase wall 25cm Leca-concrete blocks 5 cm mineral wool 1.2 cm plaster board 76.2

12 cm plaster board stud wall ----

61 Class DnT,w ≥≥≥≥ 64 dB

dwelling DnT,w (dB) * ) separating floor outer wall inner wall inner wall inner wall

Graz-Be (68) 64.8

6 cm floating screed 3 cm mineral wool TDPS 5 cm gravel 18 cm reinforced concrete slab 65.2

no massive outer wall in the rooms where measurements were performed (only glass) ---

20 cm ISOSPAN wood-concrete modular chimney blocks 3.5cm mineral wool 1.5 cm plaster board (separating wall) 75.4

12.5 cm plaster board stud wall ----

*) Measured value in parenthesis, all other values are calculated.

Source: Lang, 2006 (based on calculations carried out in the scope of the investigation Lang (2001))

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The survey in Table 29 and Table 30 shows the importance of the flanking elements to the sound insulation between rooms located next to or on top of each other. Therefore a general condition was derived for the standardized sound level difference to be fulfilled by the flanking elements in order to meet the required standardized sound level difference between rooms located on top of each other. As a basis, a separating floor between flats was assumed, consisting of a 20 cm reinforced concrete slab with 5 cm loose fill and a floating screed with a resonance frequency below 85 Hz. This is a building style commonly used in Austrian housing construction today. According to ÖNORM B 8115-4, a weighted sound reduction index of 66 dB can be assumed for this type of construction. When assuming a room of 3 x 4 m² floor space and 2.5 m room height, a volume of 30 m³ under the separating floor results for the receiving room. In this case, the separating floor produces a standardized sound level difference of DnT,w = 65,0 dB.

The standardized sound level difference that can be achieved with solid inner and solid outer walls flanking this separating floor was calculated according to ÖNORM B 8115-4, based on the values for the vibration reduction index in compliance with EN 12354-1. It was calculated for an inner wall with a mass of 100 to 400 kg/m² and an outer wall with a mass of 200 to 600 kg/m². On the simplistic assumption that all flanking elements deliver the same sound insulation level, the following requirements for flanking elements result, as shown in Figure 19.

Figure 19: Weighted sound reduction index Rw and weighted standardized sound level difference DnT,w of outer wall and inner wall when flanking a floor of 535 kg/m2 (bare floor with grit), with floating floor with resonance frequency < 85 Hz

Source: Lang, 2006

Usually there are 5 sound transmission paths, the separating and 4 flanking elements. All 5 transmission paths have to yield the required sound insulation to fulfil the requirements. On the simplistic assumption that all flanking elements deliver the same sound insulation level, the following requirements for flanking elements result (see Table 31 below).

30

35

40

45

50

55

60

65

70

75

100 150 200 250 300 350 400 450 500 550 600

mass per m2 for outer wall or partition wall kg/m2

DnT

,w fo

r th

e fl

anki

ng w

all

dB

inner wall outer wallDnT,w

Rwcalculated according mass minus 2 dB

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Table 31: Weighted standardized sound level difference DnT,w required for flanking elements and examples of their fulfilment Required DnT,w (dB) between rooms

located on top of each other Required DnT,w (dB) to be met by the

individual flanking elements Can be fulfilled for example by:

55 62 Inner wall ≥ 100 kg/m2 Outer wall ≥ 200 kg/m2

59 66 Inner wall ≥ 300 kg/m2 or gypsum plaster boards Outer wall ≥ 420 kg/m2

64 71 Inner wall gypsum plaster boards Outer wall with additional flexible lining of plaster board

69 76 Inner wall gypsum plasterboards Outer wall with additional flexible lining of plaster board

Source: Lang, 2006

The values shown in Figure 19 are calculated for the ratio volume to area of separating floor V/S = 2.5. If this ratio is increased the values for DnT,w are increased.

The requirements for the flanking elements are similar, if the wall between flats is the separating element. If the separating wall is a multilayer construction of plasterboards and the flanking elements are totally separated by the separating wall or are also multilayer walls from plaster board, no additional requirements exist; for a massive outer wall in this case an inner flexible layer on the outer wall is necessary.

In the Netherlands in 1996/1997 an sample project was carried out with 14 flats with enhanced sound insulation compared to the minimum sound insulation in a 5-storey block of flats in massive construction with 233 flats altogether (SBR, 2000). Two versions were planned for the wall separating the flats: a one-layer concrete wall and a two-layer concrete wall. The single concrete wall was improved from 23 cm thickness (506 kg/m2) to 27 cm (594 kg/m2) in the reference case. The double wall from 2 x 16 cm concrete with 2 cm PS-foam (704 kg/m2) in between was the same in both cases; the flanking floor was in the reference case only covered with a cement floor covering (534 kg/m2), in the improved case with a floating floor on 25/20 mineral wool (564 kg/m2). The load-bearing inner walls were 16 cm concrete (352 kg/m2) in both cases; the non-load-bearing inner walls from 7 cm gypsum were isolated from floor and ceiling for the improved case.

With these measures for improvement, the airborne sound insulation in the horizontal direction was improved for the single wall from DnT,w + C = 54 and 56 dB to 57 and 58 dB and for the double wall from 55 and 56 dB to 56 and 57 dB (this may be caused by the reduction in the flanking transmission by the floor covered with the floating floor). The airborne sound insulation in the vertical direction was improved by means of the floating floor by 3 to 5 dB to DnT,w + C = 55 to 59 dB. The impact sound insulation was, as expected, significantly improved using the floating floor to Ln,w + CI = 42 to 49 dB. The additional costs for the measures were HFL 3500 per flat (including living room, 2 bedrooms, kitchen and bath).

The results show that in massive buildings in the Netherlands, sound insulation was achieved as “enhanced sound insulation”, which is usually achieved or exceeded in Austrian massive buildings (see Table 29 and Table 30). Also the floating floor on mineral wool (or another elastic insulating layer) is the regular construction in Austria.

4.2 Lightweight construction of residential buildings (wooden structures) In the last few decades, a growing number of multi-storey apartment houses have been built in Austria using timber constructions. When measuring the sound insulation of these buildings, it was found that with proper workmanship (particularly for the wall and floor connections) a high level of sound insulation can be achieved. For instance, when measuring the sound insulation in

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a multi-family house where the walls and floors had been constructed according to Figure 20, the following weighted standardized sound level differences were found: DnT,w = 69, 64 und 60 dB23 between adjacent rooms and 56 dB between rooms located on top of each other.

Figure 20: Example of construction of wall and floor and the relevant connections in a multi-family house in wooden construction

a) Connection between wall separating flats and floor (vertical section)

b) Connection between outer wall and wall separating flats (horizontal section)

c) Connection between outer wall and floor (vertical section)

Source: Amt der Steiermärkischen Landesregierung, Abteilung für Wohnbauförderung

Also with wooden constructions it is necessary to consider the sound insulation of the separating and flanking elements and their junctions. ÖNORM B 8115-4 and EN 12354-1 do not 23 The value differences are partly due to different partition wall areas and volumes. In one case, they are due to an additionally installed chipboard on the partition wall.

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provide any information on how to calculate the standardized sound level difference for buildings in lightweight construction. In a comprehensive study, including the calculation and measurement of sound insulation in several residential buildings with timber construction, a calculation method was used (Scholl et al., 2004). Based on the comparison of calculated and measured results, it was found to be suitable. This method makes use of the weighted sound reduction index of the separating and flanking elements. For flanking sound transmission, it uses the values for the weighted normalized flanking level difference according to DIN 4109, supplement 1, or a value of Dn,t,w = 75 dB when the flanking elements are completely interrupted by the separating element.

At www.dataholz.com, the weighted sound reduction indices for numerous types of wall and floor constructions have been compiled. They show that a very high sound insulation can be achieved. In addition, this website provides illustrated examples of suitable structural connections between floor and wall elements.

The detailed calculations presented in the above-mentioned report (Scholl et al., 2004) also give insight into which sound insulation can be achieved and how the flanking elements influence the sound insulation. In Table 32 and Table 33 below, the results of the measurements and the calculations are shown. Here – and better suited for the comparison – the apparent sound reduction index is stated as given in the report. The standardized sound level difference is influenced by the area of the partition and the volume of the receiving room at each of the measuring positions and thus the comparison is distorted. The converted value for the standardized sound level difference is given in parentheses by the measured value of the apparent sound reduction index. The results show that high-quality sound insulation can be achieved in the wooden dwellings.

When comparing the sound insulation for the different versions of adjacent rooms one can see that the connection between the partition and outer wall has an important influence. With a total separation of outer wall and partition at the junction, an apparent sound reduction index of 60 dB is achieved, and only 56 dB if there is no total separation. The separation can be substituted by a shield (e.g. lining from plaster board) on the inner side of the outer wall, which is interrupted by the partition.

The comparison of the results of the measurements of the sound insulation between rooms one above the other shows also the influence of the outer wall. Even with the better sound insulation of the separating floor, the sound insulation achieved is determined by the flanking outer wall. The construction with an inner shielding on the outer wall is clearly advantageous.

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Table 32: Sound insulation between adjacent flats in dwellings in wooden construction No Weighted apparent sound

reduction index (dB) Separating wall (SW) Outer wall (OW) OW-SW-junction Ceiling Floor Inner wall

1 measured 60 (DnT,w = 61)

calculated 60.6

1.0+1.25 cm GF 14 cm MW, in it separated studs 60/60, space 62.5cm 1.0+1.25 cm GF header joist separated 66

1.5 cm MD 16 cm MW, in it wood studs 60/160, space 62.5cm 1.3 cm HW 68.1

walls totally separated, no bridges by screws, header joist or frame of the partition

1.25+1.25 cmGKP on spring hanger, separated by partition 67.7

HSP on 2.5 cm MW separated by partition 65.7

wooden stud wall separated by partition 75.1

2 56 (DnT,w = 60)

58.1 differing from measuring caused by installation in wall

as above 66

as above 61

separated studs connected header joist

as above 67.4

as above 65.4

as above 76.0

3 60 (DnT,w = 61) 60.5

as above 66

as above 68.4

walls totally separated, no bridges by screws, header joist or frame of the partition

as above 67.4

as above 65.4

as above 75.4

4 60 (DnT,w = 63) 61.6

as above 66

1.5 cm MD 16 cm MW, in it wood studs 60/160, space 62.5cm 1.3 cm HW 2.5 cm MW 1.25 cm GF on spring hanger 68.1

inner layer continuous, facing shell on spring hanger, separated by partition

as above 67.7

screed on mineral wool screed and MW separated by partition 70.7

as above 75. 1

No Weighted apparent sound reduction index (dB)

Separating wall (SW) Outer wall (OW) OW-SW-junction Ceiling Floor Inner wall

5 61 (DnT,w = 61) 62

as above 66

no outer wall ----- Pitched roof with insulation between rafters 1.25 GKP with 18 cm MW on top separated by partition 75.3

HSP auf 2.5 cm MW separated by partition 65.3

2 inner walls separated by partition 75.8 und 75.8

67 GF fibre reinforced gypsum panel GKP plasterboard MW mineral wool MD medium hard board HW composite board

Source: Lang, 2006, from data in the report Scholl et al. 2004

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Table 33: Sound insulation between flats one above the other in dwellings in wooden construction No Weighted apparent sound

reduction index (dB) Separating floor Outer wall (OW) OW-floor

connection Inner wall Inner wall inner wall

6 measured 64 (DnT,w = 63)

calculated 64.6

5 cm cement screed 3 cm MW impact sound ins.board 2.2 cm chipboard 22 cm timber joists, in-between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 70

1.5 cm MD 16 cm MW, in between wood studs 60/160, space 62.5 cm 1.3 cm HW 2.5 cm MW 1.25 GF 68.2

inner shielding board separated by floor

wooden stud wall separated by floor 75.2

wooden stud wall separated by floor 75.2

outer wall 1.5 cm MD 16 cm MW, in between wood studs 60/160, space 62.5 cm 1.3 cm HW on the floor 75.2

7 60 (DnT,w = 59) 60.3

5 cm cement screed 3.5 cm MW impact sound insul. 4 cm concrete blocks as load 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 79

non rectangular ground plan 2 outer walls as above 68.1 and 70.3

inner shielding board separated by floor

separating wall wooden stud wall with separated studs 62.3

wooden stud wall separated by floor 75.1

non rectangular ground plan 2 walls wooden stud walls 75.1 and 75.1

8 61 (DnT,w = 60) 57.5

5 cm cement screed 6 cm (2x32/30) MW impact-sound insulation board 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 71

2 outer walls 1.5 cm MD 16 cm MW, in between wooden studs 60/160, space 62.5 cm 1.3 cm HW 60.7 and 60.9

wooden stud wall separated by floor 74.7

wooden stud wall separated by floor 74.9

9 67 (DnT,w = 66) 66.3

5 cm cement screed 1.5 cm MW impact-sound insulation board 3 cm bulk filling Trickling protection/Protective foil 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 68

3 outer walls wooden construction no further data 76.9, 76.9 und 77.3

outer wall separated by floor

wooden stud wall separated by floor 77.3

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No Weighted apparent sound

reduction index (dB) Separating floor Outer wall (OW) OW-floor-

connection Inner wall Inner wall inner wall

10 57 (DnT,w = 56)

56.1

2.2 cm cement-bound chipboard 2 cm MW impact sound ins.board 6 cm bulk filling Trickling protection 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.4 cm lathing 1.25 cm plaster board 61

2 outer walls 1.5 cm MD 16 cm MW, in between wooden studs60/160, space 62.5 cm 1.3 cm HW 60.9 and 61.1

no data wooden stud wall separated by floor 74.9

wooden stud wall separated by floor 75.1

11 63 (DnT,w = 62)

63.8

5 cm cement screed 1.5 cm MW impact-sound insulation board 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 69

3 outer walls 1.5 cm MD 16 cm MW, in between wooden studs 60/160, space 62.5 cm 1.3 cm HW 72.1, 72.1 and 68.5

outer wall separated by floor

wooden stud wall separated by floor 75.5

12 63 (DnT,w = 62)

63.1

as above 69

2 outer walls as above 68.4 and 68.0

no data wooden stud wall separated by floor 75.4

wooden stud wall separated by floor 75.0

13 67 (DnT,w = 66)

63.5 differing from measurement caused by rooms one above the other shifted and elastic layer under floor

5 cm cement screed 3 cm MW impact sound ins.board 3 cm bulk filling Trickling protection 2.2 cm chipboard 22 cm timber joists, in between 10 cm mineral wool 2.7 cm spring hanger 1.25 cm plaster board 73

2 outer walls as above 67.5 and 68.1

no data wooden stud wall separated by floor 75.1

wooden stud wall separated by floor 74.5

14 62 (DnT,w = 61)

60.4

5 cm cement screed 3 cm MW impact sound ins.board 4 cm bulk filling Trickling protection 12 cm stacked-plank floor, glued 68

as above 61.9

no data wooden stud wall separated by floor 74.1

wooden stud wall separated by floor 74.1

wooden stud wall separated by floor 75.9

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In the Netherlands in 2000/2001 a model project was constructed with terraced houses with three storeys in wooden construction with a sound insulation level clearly higher than the minimum requirement (SBR, 2003). A weighted standardized sound level difference between adjacent flats in the range of DnT,w + C 60 to 68 dB was measured with the improved separating wall (see Figure 21).

Figure 21: Partition with junction to foundations and floor in the model-project in wooden construction

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To achieve the better sound insulation between adjacent flats the double-leaf outer wall was constructed with an inner leaf from plaster board on wooden studs and an outer leaf consisting of a 10 cm brick wall with a separating joint at the position of the partition (see Figure 22). Besides the sound insulation of the partition the horizontal impact sound transmission and the sound insulation in the air inlet and air outlet ducts were especially considered by installing silencers.

Figure 22: Partition with junction to the outer wall and the roof in the model project in wooden construction (SBR 2003)

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5 The costs of improved sound insulation

A precise determination of the costs of improved sound insulation, and in particular the proportion of total costs accounted for by sound insulation, requires a bottom-up analysis for a broad range of various types of construction, building methods, insulation materials and alternatives for implementation. However, such an approach would go far beyond the limits of this particular study. Consequently, in this chapter, results taken from literature on this subject are primarily quoted.

Finally, however, for the small sample of massive structures shown in Tables 29 and 30, the assumption that the proportion of total construction costs attributable to various types of sound insulation is far exceeded by that of other features, and therefore that improved sound insulation is not a priori directly reflected in higher total construction costs, will be shown to be correct.

In addition to this observation of massive structures, the situation for lightweight wooden constructions will also be examined.

5.1 Proportion of building costs in overall construction costs Klemp (2005) estimates the proportion of costs represented by good sound insulation in a newly constructed residential building at 2-3% of the overall construction cost, whereby no further definition of what is to be understood by good sound insulation is provided. Furthermore, it is found that measures to improve sound insulation in existing buildings can be implemented only at considerably higher cost.

These findings are confirmed by Kötz und Blecken (1999), who note that the subsequent repair of deficiencies in sound insulation is often connected with serious problems, either because such deficiencies cannot be eliminated at all or because of the great effort and high cost involved in rectifying them.

Just how comprehensive such measures can be is illustrated by several examples:

1. The two leafs of a double leaf brick wall are connected by mortar bridges.However, only a small number of such badly placed acoustical bridges cause a drastic reduction in sound insulation. The necessary rectification of such defects is carried out by using a large stone-sawing strand - which separates the two leafs at great expense. This problem could easily have been avoided by a more careful construction of the masonry or the inclusion of an insulation layer.

2. If masonry of insufficient gross density is used, the wall will not provide enough sound insulation. Subsequent facing of the wall with a flexible leaf attachment is necessary to provide that degree / level of protection against airborne noise which is required. The damage can only be repaired at high cost and with a loss of living space. The use of masonry with the requisite stone density would have resulted in only minimal additional costs.

3. In the case of a flight of stairs made of reinforced concrete, the corbels were not correctly placed on the platforms, which meant that acoustical bridges developed in the grouting. A neoprene bearing (at a cost of around EUR 50 per flight of stairs) would have resulted in the damage being avoided. Subsequent elimination of this problem is impossible, and the residents must live with the foot fall sound produced by users of the stairs. This deficiency leads to a 10% reduction in rental or sales value.

4. As a consequence of the poor planning of a terraced-housing construction (continuous foundations and floor slabs for both houses), sound transmissions to the neighbours are inevitable. Subsequent improvements in the sound insulation are only possible with costly additional constructions, namely floating floor screed on the ground floor, as well as flexible

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shell attachments. The separation of the foundations of these houses, which is far more effective in sound insulation terms, would have been possible at only minimal additional expense.

These examples illustrate clearly that only minor shortcomings in planning and execution can lead to major deficiencies in sound insulation. As a rule, the correction of such inadequacies results in substantial additional costs (Kötz, Blecken, 1999).

An unpublished study commissioned by the Swiss Ministry of the Environment, Forestry and Agriculture (Bundesamt für Umwelt, Wald und Landschaft, BUWAL) and carried out in 2003 by the EMPA (Eidgenössischen Materialprüfungs- und Forschungsanstalt) Swiss Materials Science and Technology Research Institute (Walk et. al., 2003), looks at the cost implications of improvements in sound insulation in residential housing in Switzerland.

In their study, Walk et al. (2003) refer to three earlier German studies which estimate the additional costs for massive structures of between 1.5% and 5% of the total expenses, not taking into consideration the loss of living space for an improvement of 2-3 dB in protection against airborne noise (interior noise only) of 7 dB in protection against foot fall noise and of 5 dB in protection against noise from domestic installations. Therefore, the additional cost, not taking into consideration the loss of available living space and without an improvement in protection against exterior noise, may amount to around 0.5-1% per dB of improved sound insulation.

Walk et al. (2003) then go on to examine the cost of additional sound insulation compared with the 1988 edition of the standard SIA 181 for various types of multiple-family dwelling (buildings with 1 to 3 apartments per floor) in different massive structures (brickwork, reinforced concrete, flat-roofed, steep-roofed). The aim of the study was to estimate the cost consequences of a slight tightening of the sound-insulation requirements of SIA 181 with respect to the establishment of the minimum requirements for sound insulation in structural engineering contained in the noise-protection regulations. The available options for implementation which were examined correspond with the three levels of requirements below:

• Level 1: Sound insulation in accordance with the minimum requirements of SIA 181 (1988)

• Level 2: A 2 dB improvement in sound insulation over level 1, in accordance with the minimum requirements of SIA 181 (2006);

• Level 3: A 5 dB improvement in sound insulation over level 1, in accordance with the increased requirements of SIA 181 (1988 and 2006); see Figure 23.

The improvements in sound insulation of 2 dB and 5 dB, respectively, refer to all forms of noise referred to in SIA 181, namely: exterior noise (airborne noise), interior noise (airborne and impact sound), as well as noise from domestic installations.

The study comes to the following conclusions:

The additional expenditure for improved insulation against external noise, representing a shift from level 1 to level 2, averages 1% of the total construction costs, while an improvement in insulation against external noise from level 1 to level 3 would result in extra expenses on an average of 2.5%. Therefore, protection against external noise can be seen to represent, on average, a proportion of 33% of the total additional costs.

As far as internal noise (airborne and impact sound) is concerned, meeting the requirements which correspond to improved level 2 protection would, in comparison to level 1 insulation, likewise involve, on average, additional costs of 1% of the overall expense. However, an improvement in protection against internal noise from the level 1 to level 3 standard brings about an average increase in costs of 5,5%. Consequently, an average proportion of 53% of total additional costs can be attributed to protection against internal noise.

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Figure 23: Comparison of the standard SIA 181 1988 and 2006

Source: Emrich, 2006; translation by IFIP

In comparison with level 1, improving protection against noise from domestic installations to meet level 2 requirements would lead to average additional expenses of 0.5% of the total construction costs, while an additional expenditure of 1-2% can be expected from improving to level 3. On average, then, this means that 20% of total additional expenses can be traced back to protection against noise from domestic installations.

From this we can conclude that, taking the minimum requirements of SIA 181 edition1988 as a starting point, a 2 dB improvement in sound insulation will typically bring about extra expenses of 2.5% of total construction costs. From the same starting point, a 5 dB improvement in sound insulation will, on average, result in 10% more expenditure on overall construction. The ratio of additional costs in the areas of protection against internal noise, external noise and noise from domestic appliances is in each case around 50%:30%:20%.

In the German study Sound insulation costs in residential construction – examples of cost-effective solutions (Kosten des Schallschutzes im Wohnungsbau – Beispiel für kostengünstige Lösungen), Kötz und Blecken (1999), referring to total construction expenditure, calculate the costs of sound insulation of model buildings in massive and light weight constructions for various types of ground plan and building methods. Here, the differences in construction costs resulting from a move from sound insulation level I to levels II and III according to VDI 4100 (see Table 34) are examined.

The study looked at the construction of multiple-family dwellings only, since internal sound insulation is of particular importance there, as the residents have next to no influence on sources of noise in other apartments (the conduct and routine of the residents of other apartments cannot be influenced); this means that avoidable (loud music, etc.) or unavoidable (use of toilets, etc.) noise will arise. Unacceptable disturbance caused by noise from other apartments and the consequent reduction in quality of life must be avoided by means of sound insulation (Kötz, Blecken, 1999). Therefore, only buildings with at least three dwellings were examined.

The following differential costs of sound insulation levels II and III compared with sound insulation level I, expressed as a percentage of overall construction costs and presented in Table 35 were calculated for 42 model buildings on the basis of 4 different floor plan types (buildings with one, two, three and more apartments per floor) and 5 different methods of implementation (single-shell brickwork, single-shell reinforced concrete, double-shell brickwork,

75

double-shell reinforced concrete, and dry lining) using a bottom-up process corresponding to the various floor plan types and implementation methods (Kötz, Blecken, 1999).

Table 34: Sound insulation requirements in accordance with the sound insulation levels laid out in VDI 4100

Sound insulation

VDI 4100 Sound

insulation level I

VDI 4100 Sound

insulation level II

VDI 4100 Sound

insulation level III

Building component Quality of sound insulation basic normal enhanced

separating walls between apartments

Protection against airborne sound: required weighted sound reduction index R'w in dB

53 56 59

Protection against airborne sound: required R'w in dB 54 57 60

floors between apartments Protection against impact sound: required L'n,w in dB 53a 46b 392

Stairwell walls Protection against airborne sound: required R'w in dB 52 56 59

Flights of stairs and –podeste landings

Protection against impact sound: required L'n,w in dB 58 53 46

Apartment doors Protection against airborne sound: required Rw in dB 27

Calculation using values for separating walls between apartments

a Elastic floor coverings may not be included in verification of the requirements b Elastic floor coverings may be included in verification of the requirements

Source: Baasch et al., 1999

Table 35: Differences in sound-insulation costs for sound insulation level II and III compared with sound insulation level I in accordance with VDI 4100, with reference to total construction costs in %

Without consideration of changes in size of living space:

massive

construction level I → II

massive construction level II → III

massive construction level I → III

light weight construction level I → II

light weight construction level II → III

light weight construction level I → III

Walls incl. doors 1.1 % 0.3 % 1.4 % 0.7 % 0.3 % 1.0 % Ceilings incl. stairs 0.1 % 2.3 % 2.4 % 0.1 % 2.5 % 2.6 %

Installations 0.5 % 0.9 % 1.4 % 0.4 % 0.1 % 0.5 %

Total 1.7 % 3.5 % 5.2 % 1.2 % 2.9 % 4.1 %

With consideration of changes in size of living space:

massive

construction level I → II

massive construction level II → III

massive construction level I → III

light weight construction level I → II

light weight construction level II → III

light weight construction level I → III

Walls incl. doors 4.2 % 1.8 % 6.0 % 1.2 % 2.5 % 3.7 %

floors incl. stairs 0.1 % 2.3 % 2.4 % 0.2 % 2.4 % 2.6 %

Installations 0.5 % 0.9 % 1.4 % 0.4 % 0.1 % 0.5 %

Total 4.8 % 5.0 % 9.8 % 1.8 % 5.0 % 6.8 %

Source: Kötz, Blecken, 1999

In the following section, the question is whether the expenses associated with various measures which result in different levels of sound insulation in newly-constructed residential buildings correlate significantly with the overall construction costs.

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5.2 Total net costs and sound insulation in massive residential constructions in Upper Austria and Styria For most of the buildings described in Table 29 and Table 30 in which sound insulation was determined by measurements for rooms above and next to one another, figures for the total net construction costs, the number of constructed accommodation units and living space were provided by the housing subsidies department of the Federal State Government. From this, the total net costs per square metre can be calculated. The total net construction costs of buildings completed at different times within the period from 1989 to 1999 were converted to values for the year 2000 using the building costs index (Table 36), meaning that the costs per square metre represent those of the year 2000. This represents the basis for an objective comparison.

Table 36: Building costs index 2000 Year BCI 2000

1989 69.3

1990 73.1

1991 76.3

1992 80.1

1993 83.8

1994 86.8

1995 89.8

1996 91.2

1997 93.7

1998 95.8

1999 97.7

2000 100.0 2001 102.1 2002 103.7 2003 106.4 2004 111.8 2005 114.3

Source: Statistik Austria

Table 37 shows the sound insulation for rooms above and next to one another, the number of residences in individual buildings, the living space available in each building, the total net construction costs and the cost per square metre. The total net construction costs are made up of the expenses for construction only, the costs of domestic installations, incidental and installation expenses, as well as all fees including financing costs, albeit without taking into consideration VAT. From Table 37 a contrast turns out between buildings with a low cost per square metre and a high degree of sound insulation on the one hand, and buildings with a high cost per square metre and lower levels of sound insulation on the other hand. Table 38 presents the maximum differences in the individual ranges of costs per square metre.

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Table 37: Sound insulation for rooms above and next to one another and costs per square metre

Construction project

Rooms above one

another

Rooms next to one

another Residences

Total net construction costs at year 2000 prices

Total living space

Costs per square metre

DnT,w [dB] measured

DnT,w [dB] measured EUR m2

EUR/m2

Aussee 55.0 n. v 14 915,940 509 1,798

Bruck/Mur-Re 54.0 58.0 19 1,602,658 1,382 1,160

Bruck/Mur-Ti 56.3 n. v 21 2,077,384 2,269 916

Frojach 62.0 60.5 8 837,162 562 1,491

Gleisdorf n. v 59.5 12 1,313,683 909 1,445

Graz-Bf 55.2 n. v 147 12,384,618 10,147 1,221

Graz-Ber 68.0 66.0 43 4,877,320 3,138 1,554

Graz-Gh 59.0 63.0 313 7,481,014 7,899 947

Graz-Go 56.5 58.0 109 9,002,189 7,462 1,206

Graz-Gri n. v 59.0 36 4,928,958 2,778 1,774

Graz-Wie 57.0 62.0 162 19,631,788 12,577 1,561

Graz-Zel n. v 60.5 32 3,300,498 2,381 1,386

Leonding 56.0 56.0 44 3,532,598 3,077 1,148

Linz-Schu 60.5 64.0 40 3576869 3,427 1,044

Linz-Komm n. v 57.0 16 1437428 1248 1152

Linz-Par 58.0 58.5 58 3,297,454 2,794 1,180

Oberzeiring 61.0 58.0 12 1,225,227 906 1,353

Öblarn 61.5 n. v 8 775,850 561 1,384

St. Georgen 58.0 n. v 6 795,793 687 1,158

Unterpremstätten 57.5 n. v 8 943,228 639 1,476

Wels 58.0 57.0 46 3,551,871 3,000 1,184

Zeltweg 58.0 n. v 16 1,537,594 1,197 1,285

Source: IFIP, 2006 (based on the data from Table 29 and Table 30, and cost figures supplied by the subsidising Federal State Government Authority)

Table 38: Maximum difference in sound insulation versus the range of cost per square metre

Rooms above one another

Rooms next to one another

Range of net cost per square metre

DnT,w [dB] maximum difference

DnT,w [dB] maximum difference

900-1100 4,2 1,0

1100-1300 4,0 2,5

1300-1600 4,5 2,5

1600-1800 13,0 7,0

Source: IFIP, 2006 (based on data from Table 37)

The data from Table 37 are represented diagrammatically in Figure 24 The correlation coefficient for sound insulation in rooms above one another and the net cost per square metre is 0.228, while that for rooms next to one another and the net cost per square metre is 0.154. If both data series are summarised, the correlation coefficient is 0.201.

Consequently, no correlation can be established between the sound insulation employed and the net cost per square metre. However, on account of the small number of samples, this statement cannot be generalised. On the other hand, for this particular sample it can be stated

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that other features certainly do have a far greater influence on construction cost than the quality of the installed sound insulation.

Figure 24: Net cost per square metre and sound insulation for rooms above and next to one another

Source: IFIP, 2006 (based on the data from Table 37)

Furthermore, Kötz und Blecken (1999) determined that no interdependency can be identified between sound insulation costs and the ground plan plan type (buildings with one, two, three or more dwellings per floor). In addition, no pattern can be recognised either in the relationship between sound insulation costs and the various layouts of the apartments within the building. Similarly, they were unable to find a constant relationship between sound insulation costs and the number of wall areas requiring sound insulation. Consequently, they concluded that the suggestion be discarded that costs for sound insulation should be observed as a function of the type of ground plan. The following Figure 25 shows the interrelationship between net costs per square metre and the number of residences on the basis of the data from Table 37. No correlation can be established here either. The correlation coefficient generated is -0.301.

Figure 25: Net building costs per square metre and the number of residences constructed

Source: IFIP, 2006 (based on the data from Table 37)

900 1.000 1.100 1.200 1.300 1.400 1.500 1.600 1.700 1.800 1.900

53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 D nT,w [dB]

� Rooms above one another Upper Austria � Rooms above one another Styria � Rooms next to one another Upper Austria � Rooms next to one another Styria

EU

R p

er m

2

900

1.000

1.100

1.200

1.300

1.400

1.500

1.600

1.700

1.800

1.900

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 Number of residences constructed

�� Upper Austria � � Styria

EU

R p

er m

2

79

To sum up, this study shows that for the chosen sample of massive constructions, features other than sound insulation have a far more important impact on the total expenses for the construction of the building. However, it can also be concluded from this that the installation of improved sound insulation has only a minimal cost-driving effect with regard to the overall expenses for construction.

These findings are confirmed in a study by Ferk (currently awaiting completion). There, the net construction costs per square metre for 22 massive constructions erected in Styria between 2001 and 2005 were examined. 13 of these fulfil the minimum requirements of ÖNORM, while in the other 9, sound insulation levels above ÖNORM were achieved, although these are not specified in detail. The net construction costs per square metre at year 2000 prices, calculated using the buildings costs index, can be found in Table 39 and Figure 26.

Table 39: Net construction costs per square metre for massive constructions in Styria with sound insulation levels in line with ÖNORM or higher levels of sound insulation than laid down in ÖNORM

Minimum sound insulation levels in line with ÖNORM Higher sound insulation levels than

laid down in ÖNORM Property no. Year EUR/m2

(2000) Property

no. Year EUR/m2

(2000) 1 2005 1,272 1 2005 1,184

2 2005 1,187 2 2005 1,248

3 2005 1,176 3 2005 1,016

4 2005 1,085 4 2005 1,168

5 2004 1,185 5 2002 1,291

6 2004 1,229 6 2004 1,077

7 2003 1,202 7 2002 1,092

8 2003 1,276 8 2003 1,179

9 2003 1,426 9 2002 1,295

10 2002 1,387

11 2002 1,070

12 2002 1,455

13 2001 1.320

Source: Ferk (Study on sound insulation in residential construction, currently awaiting completion; data: Federal State of Styria – housing subsidies)

If the mean value for the net construction costs per square metre in massive buildings with higher levels of sound insulation (EUR 1172/m2) is compared with the figure for properties which only meet the minimum requirements (EUR 1252/m2), it can be seen that the net construction costs per square metre for properties with greater sound insulation are on average EUR 79/m2 lower.

The data from Table 39 are shown in Figure 26 and show similar relationships to those presented in Figure 24.

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Figure 26: Net construction costs per square metre and sound insulation levels of massive constructions in Styria

Source: IFIP, 2006 (based on the data from Table 39)

5.3 Total net construction costs and sound insulation in lightweight wooden residential buildings in Styria Ferk’s study (currently awaiting completion) likewise examines 19 lightweight wooden properties erected in Styria between 1995 and 2005. 12 of these fulfil the minimum requirements of ÖNORM with regard to sound insulation, while 7 have a higher degree of sound insulation than laid down by that standard. The net construction costs per square metre of these properties, calculated at year 2000 prices using the building costs index, are shown in Table 40 and in Figure 27.

As with the massive constructions, some of these lightweight wooden constructions fulfil only the minimum requirements of ÖNORM and yet have construction costs per square metre which are at least as high as those of the properties which enjoy a higher level of sound insulation than set out in ÖNORM.

If the mean net construction costs per square metre for lightweight wooden properties with greater levels of sound insulation (EUR 1318/m2) are compared with those for buildings which simply meet the minimum requirements EUR 1244/m2), it can be seen that the net construction costs per square metre are on average EUR 74/m2 higher for objects with better levels of sound insulation.

On the basis of the limited size of the sample and because of the fact that the higher levels of sound insulation over and above ÖNORM are not defined in greater detail, a generally valid trend with regard to the influence of the implemented sound insulation on construction costs cannot be extrapolated. However, it may be speculated that particularly in lightweight wooden constructions, the influence of improved soundproofing on building costs is more significant than in massive constructions.

1.000

1.050

1.100

1.150

1.200

1.250

1.300

1.350

1.400

1.450

1.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Property number

Minimum sound insulation Increased sound insulation

EU

R p

er m

2

81

Table 40: Net construction costs per square metre of lightweight wooden constructions in Styria which meet the minimum requirements for sound insulation in accordance with ÖNORM or exceed the sound insulation requirements laid down in ÖNORM

Minimum sound insulation levels in line with ÖNORM Higher sound insulation levels than

laid down in ÖNORM Property no. Year EUR/m2

(2000) Property

no. Year EUR/m2

(2000) 1 2004 1,333 1 2005 1,102

2 2003 1,158 2 2005 1,172

3 2002 1,171 3 2003 1,359

4 2001 1,124 4 2002 1,423

5 2001 1,177 5 2002 1,383

6 2001 1,149 6 2000 1,431

7 2001 1,217 7 1995 1,357

8 2001 1,263

9 2000 1,426

10 2000 1,319

11 2001 1,413

12 2001 1,177

Source: Ferk (Study on sound insulation in residential construction, currently awaiting completion; data: Federal State of Styria – housing subsidies)

Figure 27: Net construction costs per square metre and sound insulation levels of lightweight wooden constructions in Styria

Source: IFIP, 2006 (based on the data from Table 40.

1.000

1.050

1.100

1.150

1.200

1.250

1.300

1.350

1.400

1.450

1.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Property number

EU

R p

er m

2

Minimum sound insulation Increased sound insulation

Net construction costs per square metre and sound insulation levels of lightweight wooden constructions

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6 Current thinking on the measurement of the effects of disturbance caused by noise and its reduction

In contrast to burdens on the environmental media of air, water or soil caused by pollutants, noise has no polluting effects on any particular resources in the classical sense. Noise has a direct impact on people, whereas emissions of airborne pollutants, for instance, require the environmental medium of “air” in order to develop their damaging effects. Although this has the advantage that we need not be concerned with the effects of storage and delay, noise reduction is made more difficult in so far as the various sources of emissions, unlike with air, do not accumulate to represent an environmental risk to the entire population; instead, they rather have a clearly defined time- and place-related impact on specific regional groups or individuals (BUWAL, 2002).

Noise has a range of effects, whereby the occurrence and intensity of these basically increases with rising sound levels.

In general, 3 categories of effects can be identified: 1. Effects on health (physical and psychological) 2. Social effects 3. Economic effects in connection with, or as a consequence of, both of the aforementioned.

With the exception of very high sound levels, which can lead directly to hearing damage, the relationship between cause and effect is hard to prove, since the damaging effects vary greatly from person to person and are principally dependent on non-acoustic aspects. In this respect the relationship between cause (noise) and effect (reaction) is basically influenced by moderating factors such as the individual attitude to the noise, the source of the noise, biological rhythms, sociological factors, and so on (BUWAL, 2002).

Thus it can be shown that at comparable sound levels, air-traffic noise is felt to be more of a disturbance than road-traffic noise, which is in turn more disturbing than rail-traffic noise. Sound levels starting from 50-55 dB (A) were chosen as the threshold for noise disturbance, with levels above 65 dB(A) assumed to represent a serious disturbance. As a guideline, the WHO designates <50 dB(A) during the day and 40-45 dB(A) at night as mean noise levels, whereby only a small number of people feel this to be a moderate level of annoyance (BSV, 2004)

Figure 28: Trend over time of air-traffic noise level (LDN in dB(A)) associated with a constant proportion of seriously affected individuals of 25%

Source: Guski et al., 2004 ; translation by IFIP

Furthermore, Guski et al. (2004) have shown that the published levels of reaction to disturbance, for instance for air-traffic noise, display an increasing trend over time (see Figure

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28): if only those noise levels from published studies which correspond in each case to 25% seriously disturbed / annoyed people were observed, the result would be a decline of around 8 dB between 1965 and 1995. In other words, the same proportion of people seriously annoyed by air-traffic noise is reached after 30 years with a time-average sound pressure level24 of approximately 8 dB below that of 1965.

6.1 Effects of noise on health The World Health Organisation (WHO) defines health as “a state of complete physical, mental and social well-being”, which is not only meant as the absence of illnesses. This notion is further refined by the fact that the highest possible achievable form of such a state of health is a fundamental right of every individual. On the basis of this definition, effects on health should not simply be understood as the bodily impairment of health (physical effects of noise), but also as the disturbed subjective well-being (psychological effects of noise) which in the long term can similarly have adverse physical effects.

The physical reactions brought about by noise can be categorised as aural (pertaining to the ear) and extra-aural effects. Aural impairments usually appear in the form of damage to hearing as a consequence of high sound levels. In particular at sound levels which without doubt have no aural impact whatsoever, as far as the prevention of noise is concerned, attention must be paid to extra-aural effects which are manifested in individuals as psychological, social and physical impairments. In this respect, bodily changes often occur which are not consciously perceived. According to the WHO definition, all of these types of damage have an impact on health. Therefore, the popular belief that noise does not disturb, or that noise is something which one can simply become accustomed to, does not rule out the possibility of damage to health in the long term (BUWAL, 2002).

Research into the effects of noise has identified, in addition to direct damage to hearing, cardiovascular disease, high blood pressure, headaches, hormonal changes, psychosomatic illnesses, sleep disorders, reduction in physical and mental performance, stress reactions, aggression, constant feelings of displeasure and reduction in general well-being as possible consequences for health. However, these effects cannot be attributed specifically to noise, rather they are much more the result of manifold factors. Research in this field, though, focuses mainly on noise from land and air traffic. In the German study Environment – Health – Traffic, Content and Forms of Communication the Interrelationship of Effects of the Environment, Health and Traffic (BSV, 2004), the health implications of traffic noise are summarised as follows:

Constant exposure to over 70 dB(A) during the day and over 60 dB(A) at night is classified as a danger to health. The limit of detection for an increased risk of heart attack thereby lies at a time-average sound pressure level of 65 dB(A) in the daytime and 55 dB(A) at night. Epidemiological studies have shown, for instance, that the risk of heart attack for those living close to very frequently-used streets with a time-average sound pressure level of 65-70 dB(A) and above is around 20% higher than for residents of quieter streets with noise disturbance levels below 55 dB(A). Therefore, approximately 2% of heart attacks in Germany can be attributed to road traffic noise. The associated risk of mortality would thus be roughly equivalent to that for passive smoking and higher than incidences of cancer resulting from air pollution caused by traffic. People living in residential areas which are seriously affected by road traffic noise seek medical help for high blood pressure more often than residents of less affected streets. The connection between treatment for high blood pressure and night-time noise disturbance is particularly strong – the risk at an average sound level of 55 dB(A) is almost twice as high as that at a time-average sound pressure level of below 50 dB(A). Non-specific stress reactions of the cardiovascular system (e.g. short-term changes in blood pressure and heart rate, release of stress hormones) occur involuntarily at prevailing sound levels of

24 The time-average sound pressure level commonly used in Germany corresponds to the Austrian equivalent continuous sound level.

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more than 60 dB(A). In the long term, an increase in such reactions can lead to chronic damage to the cardiovascular system. The long-term damage to health brought about by sleep disorders has, to a large extent, not been researched as yet, although it does form part of the wider field of research into the effects of noise. It does, however, seem clear that people react more sensitively to noise at night than during the day. In the literature, threshold values for sleep disorders of 30-35 dB(A) internally and 35-45 dB(A) externally, as well as peak levels of up to 40 dB(A) internally and 45-55 dB(A) externally are mentioned. Learning and concentration disorders in enclosed rooms can be identified at noise levels as low as 40 dB(A). Consequences of noise-related decreases in performance can include daytime fatigue and slower reaction times.

6.2 Social effects of noise The social impacts of noise include breakdowns in communication and changes in attitude to social behaviour among those affected, the latter being characterised by increasing aggression, reduced readiness to assist others and changes in the evaluation of other people. In addition, however, segregation connected with noise in residential areas is primarily of interest. Evidence may actually exist that, in urban areas in particular, the proportion of people living on or below the poverty line in the vicinity of noisy industrial or traffic zones is especially high, although empirical research on and documentation of this relationship is still thin on the ground.

6.3 Economic effects of noise – the external costs of noise From an economist’s point of view, noise and disturbance caused by noise represent negative externalities, i. e. external costs. An externality can be defined as the mutual impacts of economic agents which are not covered by the market and thus not evaluated. Externalities are mainly the consequence of the nature of environmental goods such as air and quietness, which are seen as public goods and characterised by non-rivalry25 and non-exclusivity26 of consumption. Consequently, therefore, such goods do not usually have a market price. Extensive use of these goods by economic agents thus increases their benefit, but possible negative consequences in the form of external costs of such use arise for certain or all other individuals.

Traffic noise represents the most important source of noise in the European Union, and is therefore also the best recorded and documented. Total externalities from traffic noise (road, rail and air) in the EU 15 Member States is put at EUR 51.7 billion per year and is distributed among the various sources of noise as shown in Figure 29. Externalities from neighbourhood noise are scarcely recorded.

Table 41 shows the proportion of GDP accounted for by externalities from road traffic noise in selected European countries.

As with the health-related and social impacts, the economic cost of noise is often underestimated. In addition to the direct costs resulting from damage to health and the costs of noise prevention measures designed to offer protection against such health-related effects, a range of other cost components exists, as illustrated in Figure 30.

25 A commodity possesses the characteristic of non-rivalry (of consumption) when consumption of the commodity does not exclude simultaneous consumption of that particular commodity by others.

26 A commodity possesses the characteristic of exclusivity when potential users can be excluded from consuming the commodity.

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Figure 29: External costs because of noise in the EU 15 Member States, in EUR million per year

Source: Reh, 2004, translation by IFIP

Table 41: Externalities from road traffic noise as % of GDP in selected European countries Country Year % of GDP

Finland 1989 0.30

France 1994 0.10

Germany 1992 1.40

Norway 1987 0.30

Sweden 1992 0.40

Switzerland 1988 0.26

Source: Lambert et al., 1998

For many areas, the models required to precisely quantify the economic impacts of noise are not available. The costs of noise cannot be estimated as a consequence of the lack of market prices, meaning that they are borne by the general public as externalities, in the economic sense, in accordance with the “social cost” principle27.

The cost components of reduced quality of living, breakdowns or falls in production as a result of increased sick leave or reduced concentration, as well as the costs of medical treatment of physical effects brought about by noise are particularly difficult to quantify and thus almost impossible to express in monetary terms, owing to a lack of knowledge of the causal relationships involved.

27 In contrast to the polluter pays principle, whereby the party responsible for the externality must also bear the resulting external costs, the social cost principle dictates that public authorities, as opposed to the responsible party, shall bear the costs using public funds. The social cost principle is applied then when the party responsible for an externality cannot be identified, or when the number of responsible parties is very large, meaning that the share of costs borne by each party cannot be determined (e.g. traffic noise).

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Health costs arising from the treatment of existing illnesses caused by noise are also part of the economic effects of noise, as are costs incurred by increases in the number of accidents resulting from lapses in concentration brought about by noise disturbance.

Figure 30: Overview of the key cost components of economic effects caused by noise

Source: BUWAL, 2002; translation by IFIP

Economic costs also include noise protection expenses, i.e. expenses arising from efforts to protect the population from noise.

In Austria from 1993 to 2000, public expenditure on the reduction of disturbance from noise caused by road and rail traffic alone amounted to EUR 305 million28. Of this, EUR 114 million was spent on road traffic: EUR 70 million (61%) on noise-reduction measures on the roads themselves (quiet asphalt, noise barriers, etc.) and EUR 44 million (39%) on property-related measures (soundproofed windows, etc.). In the same period, EUR 191 million was spent on rail-related measures (railway infrastructure as well as buildings). Statistics for expenditure by private households and public authorities on measures aimed at the reduction of neighbourhood noise are barely recorded.

In Germany, the costs incurred by road traffic alone (installation of soundproofed windows in affected apartments, as well as state-of-the-art vehicle- and highway-related measures) are estimated at EUR 7.5 billion per year (BSV, 2004).

Also included in the economic costs of noise are reduced rental income and lower property prices in areas seriously affected by noise. In Germany, calculations have shown that, from a starting level of around 30 dB(A), each 1 dB(A) increase in noise levels results in a fall of 0.5-1.7% in the value of a property (BSV, 2004).

According to work by Bateman et al. (2000), which summarises the results of hedonic price models from various studies in Europe, North America and Japan, the reduction in the value of properties resulting from road traffic noise ranges from 0.21 to 1.7% per dB(A) increase in Norway, Sweden, Switzerland and Finland.

In a study carried out on behalf of the European Commission, Navrud (2002) summarises the results of several analyses of willingness to pay with regard to road noise. The findings showed

28 These figures are the result of the author’s own calculations based on the 6th and 7th State of the Environment reports (UBA, 2001; UBA, 2004)

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that the willingness to pay for a reduction in disturbance caused by road traffic noise amounts to between EUR 2 and 99 per household per year (see Table 42).

Table 42: Results from Stated Preference29 studies of road traffic noise; as experienced inside the dwelling.

Study (Valuation Method)

Site (Scenario description) / Year of study

WTP /dB/hh/year (Original estimate in national currency

in year of study)

WTP /dB/hh/y in EUR (in2001

price level) Pommerehne 1988 (CV)

Basel, Switzerland (50 % reduction in experienced noise level) / 1988

112 CHF (= 75 CHF/month for 8dB) 99

Soguel 1994a’ (CV)

Neuchatel, Switzerland (50 % reduction in experienced noise level) / 1993

84 – 100 CHF (= 56-67 CHF/month for 8 dB) 60 - 71

Sælensminde & Hammer 1994, Sælensminde 1999 (CV and CE)

Oslo and Akershus counties, Norway (50 % reduction in experienced noise level) / 1993

281 – 562 NOK (=2250-4500 NOK/year for 8 dB) 47 – 97

Wibe 1995 (CV)

Sweden – national study (Elimination of noise annoyance) / 1995

240 SEK (= 200 SEK/month for 10 dB) 28

Vainio 1995, 2001 (CV)

Helsinki, Finland (Elimination of noise annoyance) / 1993 33 - 48 FIM 6 - 9

Thune–Larsen 1995 (CV and CE)

Oslo and Ullensaker, Norway (50 % reduction in experienced noise level) / 1994

117 NOK (= 78 NOK/month for 8 dB) 19

Navrud 1997 (CV)

Norway – national study (Elimination of noise annoyance) / 1996

11 NOK (= 115 NOK/year for10 dB) 2

Navrud 2000b (CV)

Oslo, Norway (only hh exposed to > 55 dB) (Elimination of noise annoyance) / 1999

152 – 220 NOK(= 1520 – 2200 NOK / year for 10 db) 23 - 32

Arsenio et al 2000 (CE)

Lisbon, Portugal (Avoiding a doubling of the noise level) /1999

9,480 PTE (= 7900 PTE / month for10 – 15 dB) 50

Barreiro et al 2000 (CV)

Pamplona, Spain (Elimination of noise annoyance) / 1999

476 ESP (= 4765 ESP / year for10 db) 2 - 3

Lambert et al 2001 (CV)

Rhones - Alpes Region, France (Elimination of noise annoyance) / 2000

7 euros (= 73 euros /year for 10 dB) 7

CV - Contingent Valuation30 CE - Choice Experiments31 WTP – Willingness to pay per decibel (db) per household (hh) per year (y) The EUR values have been calculated using exchange rates as of January 2002 and adjusting to 2001–value using GDP deflators (used by the European Commission) for the respective countries where the studies were conducted.

Source: Navrud, 2002

29 Stated-preferences methods record the probable behavioural reactions of those surveyed by presenting a range of decision-making situations with different general parameters where various forms of behaviour can be chosen. Therefore, with stated-preferences methods, information on expected forms of behaviour can be collected and the subject’s willingness to utilise and pay in hypothetical but realistic situations (e.g. implementation of measures) can be ascertained.

30 The contingent valuation (CV) method has become prevalent in the direct economic valuation of public environmental goods. This approach was used for the first time by Robert K. Davis in the USA in 1963. However, there still exists no single approach for the implementation of the method. Therefore, it is categorised as a methodical approach which must be modified for individual use. CV is based on the determination of preferences expressed by users which are uncovered by means of surveys. The surveys refer to hypothetical situations presented to the participants. The evaluation is carried out under specific, precisely expressed conditions referring to the situations and to changes in the environment.

31 So-called choice experiments (CE) are a further development of the conventional contingent valuation method, whereby those questioned must select one alternative from two or more options. Within the framework of the CE, the relationships between a) observable selection behaviour and b) the characteristics of the alternatives examined and the individual characteristics of the inquirer are investigated. Thus, when the influence of various features on selection decisions becomes of interest, choice experiments have an advantage over contingent valuation.

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A study in Switzerland, (Lorenz, 2000) shows that 54% of the Swiss population would be willing to pay higher rents for a quieter residential area. 48% would be willing to pay between SFR 200 and 500, while 18% were in favour of an additional expenditure of SFR 500-2000. In this respect, those living in single-family dwellings tended to show greater willingness to pay more for a quieter residential area than those living in multiple-family properties. Additionally, individuals who have spent the majority of their lives in the country are prepared to spend more in return for quieter living conditions than those who have lived mainly in towns.

6.4 Economic effect of neighbourhood noise There is hardly any other area which, in terms of living, is so subjectively evaluated as sound insulation. What one person regards as quiet may be perceived by another as loud. Although comfort is closely related to sound insulation, this is often neglected, resulting in reductions in property value, legal altercations, financial losses and, quite commonly, damage to health for the residents (Kötz, Blecken, 1999).

A study carried out in Great Britain, covering England and Wales, was based on a sample of 3,136 complaints, whereby the citizens’ complaints with regard to noise disturbance from neighbours were statistically evaluated (Grimwood, Ling, 1999), and produced the annoyance profiles shown in Table 43. The authors point out that the obtained profile corresponds closely with that produced by other investigations.

Table 43: Ranking of sources of noise leading to complaints about neighbours

Type of noise 1988 Study

Noise complaints (%)

Current Study Primary source for noise complaints (%)

(n =3136)

Current Study Secondary source for noise complaints (%)

(n = 227) Music 34c 42 11

Domestic noise 9d 18 n/a

Dogs barking 33 7 17

Parties n/a 6 18

House/Car alarms n/a 3 2

Shouting & banging n/a 3 n/a

TV or radio n/a 2 9

DIY 5 2 6

Sound insulation n/a 1 n/a

Other animals 1 1 2

Car repairs 3 1 1

Banging doors n/a 1 7

Children playing n/a 1 5

Domestic appliances 1 1 1

Voices 9 n/a 1

Othera 6 n/a 9

Misclassifiedb n/a 13 n/a a ‘Other noises’ in the 1988 data includes: fireworks; intimate and personal sounds; bad language; drums; beach buggy racing. b ’Misclassified’ complaints are those that were incorrectly recorded as neighbour noise c ‘Music’ includes TV or radio in the 1988 data. d ‘Domestic activities’ in the 1988 data.

Source: Grimwood, Ling, 1999

Additionally, the time-based profile of noise pollution caused by neighbours was studied. The smallest increase in disturbance by neighbourhood noise is recorded in the period from 5:00 to 12:00 midday. After this, annoyance levels increase once again and reach a peak in the period from 22:00 to 02:00; the level of disturbance during this period is also the highest throughout the entire day.

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Figure 31: Disturbance profile for noise from neighbours’ activity over a day according to Grimwood und Ling.

Source: Grimwood, Ling, 1999

Thus it can be seen that the greatest disturbance occurs at night. Annoyance caused by music occurs primarily in the period from 18:00 to 03:00, while disturbance from other neighbourly activities takes place mainly in the morning between 07:00 and 10:00, and from 15:00 to 17:00 in the afternoon. Figure 31 presents this trend in the disturbance profile in graphic form.

Particularly with regard to evaluation of the benefit derived from measures aimed at reducing neighbourhood noise, hardly any research is currently underway. This may be due to the fact that the majority of rules related to sound insulation are laid down in the building regulations, and noise-related problems and conflicts between neighbours are handled in the civil courts. Consequently, the problem of neighbourhood noise, for example, is not covered by the European Union environmental noise directive; on the contrary, it is clearly excluded therein.

It has been proven that noise does have impacts on health, although as previously mentioned in chapter 6.1, research has mainly focused on land and air traffic. However, the importance of neighbourhood noise in this regard was referred to for the first time in a WHO study (Niemann, Maschke, 2004). The investigation found that annoyance is a primary consequence of noise, whereby this disturbance is perceived as a feeling of discomfort, leading to indisposition, anxiety, irritability and agitation, as well as a sense of helplessness and restricted personal freedom. Furthermore, the analysis established a cause-and-effect relationship between persistent annoyance and illness.

Traffic noise (road, rail and air traffic) is a major source of disturbance, but neighbourhood noise represents a second important cause. Neighbourhood noise in this context refers to noise from the neighbouring apartment, from the stairwell, from children playing and other noise which has its origins within the property.

According to this WHO study, annoyance caused by neighbourhood noise has until now been underestimated. The study argues that persistent annoyance from neighbourhood noise increases the risk of adults being affected by diabetes, stomach ulcers, heart attacks and strokes. For children, increased chances of developing bronchitis, breathing difficulties, migraine and skin problems can also be identified, while elderly people (aged 60 and over) face a greater risk of falling victim to arthritis, stomach ulcers, depression and strokes as a result of neighbourhood noise.

The study confirms that increased annoyance by noise is reflected in a higher risk of illness and comes to the conclusion that neighbourhood noise is no different to traffic noise in terms of its

90

negative impacts on health. Table 44 below shows the ODDS ratios32 for various illnesses as a function of different sources of disturbance, as calculated in the study.

Table 44: Significantly ODDS Ratio (OR) for diseases calculated in the WHO-LARES study

Significantly OR for diseases Adults Elderly Children

general traffic noise strongly annoyed

Hypertension Cardiovascular symptoms Stroke Asthma Bronchitis Respiratory symptoms Arthritic symptoms Depression SALSA

1,588 1,545

---- ----

1,861 1,969 1,754 2,229 1,879

---- ----

2,718 ---- ---- ----

2,066 ---- ----

---- (5,455)

n. c. ----

2,624 2,563

---- n. c. ----

general neighbourhood noise strongly annoyed

Hypertension Cardiovascular symptoms Stroke Asthma Bronchitis Respiratory symptoms Arthritic symptoms Depression SALSA

1,706 1,601

---- ----

1,907 1,572 2,346 1,780 2,276

---- ----

2,415 ---- ---- ----

1,885 1,989

----

n. c. ----

n. c. ----

3,453 3,562

---- n. c.

3,322

Sleep disturbed by noise

Hypertension Cardiovascular symptoms Stroke Asthma Bronchitis Respiratory symptoms Arthritic symptoms Depression SALSA

1,485 1,449

---- ----

1,455 1,632 1,598 1,466 2,260

---- ---- ----

2,019 ---- ----

1,617 ----

1,413

---- ----

n. c. ----

3,674 1,943

(7,308) ----

3,413 ( ) = very large confidence intervals n. c. = not calculable, SALSA considers the "trend to depression"

Source: Niemann, Maschke, 2004

Several studies have shown that an often significant willingness also exists to pay in order to reduce neighbourhood noise. Klemp (2005) states that in Sweden, 60% of all residents of houses with several floors – in other words, almost all – would be willing to accept an increase in rent of 10% to be able to live in an apartment with sufficient sound insulation.

In an investigation of high-rises in Lithuania, Slovakia and formerly East Germany (Bonnefoy 2003) designed to find evidence of the economic significance of sound insulation, residents who had complained about noise annoyance were asked how much they would be prepared to pay for an apartment which was not affected by noise disturbance. Those residents who had not complained about noise were asked how much compensation they would expect if they were annoyed by noise. The results are summarised in Table 45 below.

32 The ODDS ratio evaluates the risk of contracting a particular illness when a particular annoying factor (e.g. traffic noise or neighbourhood noise, etc.) occurs. It is a relative measure of the risk and describes how more likely a person exposed to the annoyance is to develop a particular illness, compared to an unaffected individual. The ODDS ratio of a result is the probability of the event taking place, divided by the probability of its not occurring.

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Table 45: Monetary Evaluation of Noise Disturbance City

Monetary unit Schwedt-Oder

DM Bratislava

Slovak Crown Vilnius Litas

Monetary compensation 0 <100 >100 0SK <500SK >500SK 0Lit <50Lit >50Lit

Willingness to pay per month for getting a similar flat but more quiet

22% (10-38)

56% (26-88)

22% (9-43)

69% (54-81)

20% (10-33)

11% (4-24)

43% (32-55)

42% (25-61)

15% (6-30)

Expected monthly compensation if the flat became exposed to noise

10% (3-24)

69% (32-97)

21% (8-44)

72% (55-85)

10% (3-24)

18% (8-34)

75% (42-99)

16% (3-30)

9% (0-20)

Data in parentheses represent the standard deviation values 100DM are ca. 51€, 500SK are ca. 11,90€, and 50Lit are ca. 14,60€ (exchange rates June 2001)

Source: Bonnefoy, 2003

In Austria in 1974, during the study referred to in chapter 2.4 it was discovered by means of questionnaires that at that time people would have been willing to pay 2-3% more for better soundproofing in their apartments, in particular to reduce disturbance from neighbourhood noise.

6.5 Proposals for further research The field of neighbourhood noise has been much less well researched than the areas of air, road and rail traffic noise, as well as industrial noise. However, rising rates of population indicate that the problem of neighbourhood noise will grow in importance in future.

Therefore, research into measures designed to reduce neighbourhood noise from an economic perspective is urgently needed; such investigations have already been carried out countless times before on the subject of environmental noise. Cost-benefit analyses of neighbourhood noise do not appear in the literature, although this may be due to the fact that it is far more difficult to determine the benefit of a reduction in annoyance from neighbourhood noise than that from road or air traffic noise.

Moreover, as a consequence of a lack of data, many methods to evaluate the benefit from a reduction in disturbance from neighbourhood noise cannot be applied. Therefore, there is a significant need for more research in this field.

92

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Standards

Austria: ÖNORM B 8115-2. Schallschutz und Raumakustik im Hochbau – Anforderungen an den Schallschutz 2002 12 01

Belgium: NBN S01-400-1: Acoustique – Valeurs limites des niveaux de bruit en vue d´éviter l´ ínconfort dans les batiments.

Croatia: JUS U.J6.201 1989: Akustika u zgradarstvu – Tecnicki uslovi za projektovanje i gradenje zgrada (technical requirements for designing and constructing of buildings).

Denmark: DS 490: Lydklassifikation af boliger (Sound classification of buildings) 2001 04 19

Finland: SFS 5907 Acoustic Classification of Spaces in Buildings 2004 09 06

Germany: DIN 4109:Schallschutz im Hochbau, Anforderungen und Nachweise und VDI 4100: Schallschutz von Wohnungen, Kriterien für Planung und Beurteilung September 1994

Netherlands: NEN 1070: Geluidwering in gebouwen – Specificatie en beoordeling van de waliteit (Noise control in building – Specification and rating of quality) März 1999 NPR 5070 Geluidwering in woongebouwen – Voorbeelden van wanden en vloeren in steenachtige draagconstructies (Noise control in dwellings – Examples of stony partition walls and floors) Februar 2005

Norway: NS 8175: Lydforhold i bygninger – Lydklassifisering av bygninger (Sound conditions in buildings - Sound classes for various types of buildings.1997, 2005

Spain: NBE-CTE (II): Codigo Tecnico de la edificacion

Sweden: SS 25267:2004: Byggakustik – Ljudklassnig av utrymmen I byggnader – Bostäder (Acoustics – Sound classification of spaces in buildings – Dwellings 2004 02 20

Switzerland: SN 5290 181 Schallschutz im Hochbau gültig ab 1. Juni 2006. Vernehmlassungsentwurf 2003 10 21