indagini socio-acustiche e correlazioni con le prestazioni acustiche

Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, pp. 26-41
INDAGINI SOCIO-ACUSTICHE E CORRELAZIONI
PRESTAZIONI ACUSTICHE DEGLI EDIFICI
ISSN: 2385-2615
www.acustica-aia.it
CON
SOCIO-ACOUSTICS SURVEYS AND CORRELATIONS
BUILDING ACOUSTICS PERFORMANCES
LE
WITH
Chiara Martina Pontarollo
Dipartimento di Ingegneria Industriale - Università degli Studi di Padova
Indirizzo dell’autore di riferimento - Corresponding author’s address:
Via Venezia 1, 35131 - Padova, Italia
e-mail: [email protected]
(Ricevuto il 20/05/2014, accettato il 11/06/2014)
RIASSUNTO
Questo lavoro di ricerca è stato sviluppato nell’ambito del progetto europeo COST TU0901
“Integrazione ed armonizzazione degli aspetti di isolamento acustico nella costruzione di edifici
residenziali sostenibili” che si è sviluppato su quattro anni dal 2009 al 2013. È stata sperimentata un’applicazione nazionale del questionario armonizzato creato dal gruppo di lavoro 2 del
progetto COST TU0901 al fine di ricercare delle correlazioni tra l’isolamento acustico ed il disturbo.
ABSTRACT
This work was developed inside the European Action COST TU0901 “Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions” that has been
running for 4 years 2009-2013. In particular it is a national application of the harmonized questionnaire developed by COST TU0901 working group 2, with the purpose of finding some kind
of correlation between sound insulation and annoyance.
Parole chiave: Questionario; Disturbo; Isolamento acustico.
Keywords: Questionnaire; Annoyance; Sound insulation.
© Associazione Italiana di Acustica, 2014
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
1. Introduction
The Italian application of COST TU0901 questionnaire took place inside a research project
which involved the Department of Industrial Engineering, University of Padova and the Municipal Buildings Agency of Verona (AGEC).
This project involved a whole neighborhood of the city of Verona, named “Borgo Nuovo”,
interested by a global renewal. The most buildings of this district are owned by Verona Municipality and rented to destitute families.
The purpose of the renewal project wasn’t only a thermal and acoustic improvement of existing buildings but also a social renewal of the neighborhood with the construction of new residential buildings and shops. In the stage of the project, called “Contratto di quartiere II”, 8 residential buildings (with a total of 72 flats) were renewed and 3 new building were built (40 flats
and 4 shops).
The Department of Industrial Engineering of Padova University made the first stages of
thermal and acoustic design of refurbished buildings and tested all buildings, new and renovated, at the end of building works.
In years 2011-2012 COST TU0901 questionnaire was distributed in existing buildings (not
interested by the renewal or before the renewal), in renewed buildings and new building, in
these two last cases after at least a year of residence. All renewed and new buildings were completely acoustical tested before tenants occupation; some of existing buildings were not tested
but they are identical to buildings renewed, that were tested before the beginning of works.
In following pages the following topics are analyzed:
- description of COST TU0901 questionnaire;
- description of urban contest in which the questionnaire has been applied;
- description of buildings involved (building structures and acoustic tests mean results);
- description of questionnaire submission method;
- questionnaires elaboration and results.
2. The COST TU0901 questionnaire description
The COST TU0901 Working Group 2 (in the following WG2) had the purpose to
find some methods for the subjective evaluation of sound insulation, in order to deduce
some kind of correlation between sound insulation and annoyance. This objective has
been developed in two ways: preparing a uniform questionnaire on annoyance by
neighbor noise and some guidelines for the design of listening tests.
This work is focused only on description and applications of COST TU0901 socioacoustic questionnaire.
To find some relationships between building structures sound insulation and occupants satisfaction is very important in order to design correctly a building.
However, whereas the measurement of noise insulation parameters is regulated by
international standards, assessing the reaction of occupants to noise in their homes is a
complex task to accomplish. Indeed occupants reactions are often influenced by factors
other than the sound exposure (eg. expectations, satisfaction, sensitivity and attitude to
noise, etc.). Hence, such factors may be expected to influence individual answers given
in a questionnaire.
Some previous work [1], [2], [3] and [4] already deal with this task but using different questions and different kind of approach so results aren’t comparable. COST
TU0901 WG2 tried to develop a uniform questionnaire template, translated in different
languages, in order to make possible, in future, the comparison of national results [5]
and [6].
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 27
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
The questionnaire was written so as to minimize the possibility of unreliable interpretations of terminology or label or scale errors, bearing in mind it should be used in
many countries. Standard ISO/TS 15666 suggestions have been also considered [7].
The questionnaire has been designed to obtain averaged responses by the occupants
of buildings for the purpose of correlating those responses to various types of single
number quantity related to airborne sound insulation, impact sound insulation, service
equipment noise and traffic noise. Measurements would be used to determine the physical parameters, or in some cases predicted values from theoretical calculations.
The questionnaire template uses an 11-point (0-10) numerical scale. The scale uses
both verbal descriptions (texts) and graphical emoticons in the extremes in order to remind the occupants of the meaning of the scale and to make respondents see the simple
use of it (Fig. 1).
Fig. 1 -
Istruzioni per la compilazione della scala del questionario - Instructions
for completing the scale of the questionnaire
To keep all questions within one A4 sheet (2 pages) has been proved to be an important property to obtain a high response rate.
The questionnaire first page contains the following sections:
- the research scope explanation;
- some question about personal data (eg. age, gender, years of residence number of persons in the household) (Fig. 2);
- some brief instructions that explain how to fill the questionnaire and the meaning of
the extremes of the scale;
- an introductory example.
Fig. 2 - Parte di richiesta dei dati personali –Personal data collection form.
The second page reports the main part of the questionnaire:
- one question about general noise annoyance, not specifying in detail the type of
sources of noise, trying to be general (Fig. 3);
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 28
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
- questions on noise generated by different noise sources (these answers may be correlated with the sound insulation parameters in the analysis of the results) (Fig. 4);
- one question about expectations (how important is for you sound insulation?) (Fig. 5);
- one question about sensitivity to noise (Fig. 6);
- comments section.
Fig. 3 - Domanda generale - General question
Fig. 4 - Parte di domande relative al disturbo - Annoyance questions segment
Fig. 5 - Domanda relativa alle aspettative - Expectations question
Fig. 6 - Domanda relativa alla sensibilità - Sensitivity question
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 29
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
There is another section of the form, only to be used by the research institute, to be
filled with building data and not included in the questionnaire format.
During the socio-acoustics survey phase is very important try to capture a representative sample of occupants; this allows a correct statistical analyses of responses.
In results examination is possible to test the reliability of responses and examine relationships between subjective responses and objective values of sound insulation.
3. Territorial framework
The buildings under analysis are located in the neighborhood of the city of Verona.
The name of the district is “Borgo Nuovo”. In figures 7 and 8, the distances between the
district area, the main transport infrastructures and the distance from the city center are
shown. The numerical values of distances, expressed in km, are reported in table 1.
There aren’t Pub, Disco or other noisy activities in the surroundings.
Tab 1 -
Distanze tra il quartiere Borgo Nuovo e le principali infrastrutture di trasporto - Distances between Borgo Nuovo district and main transport infrastructures
Main transport infrastructures
Airport
Highway
Railroad
Main road (Corso Milano)
Fig. 7 -
Distance [km]
6.5
4.5
1.0
0.6
Posizione del quartiere Borgo Nuovo rispetto al centro della città di
Verona e posizione delle principali infrastrutture – Neighborhood Borgo Nuovo location in reference to Verona city center and main infrastructures location
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 30
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Fig. 8 -
Immagine satellitare del quartiere Borgo Nuovo e posizione delle principali infrastrutture - Neighborhood Borgo Nuovo satellite image and
position of main infrastructures
4. Buildings description
In table 2 an overview of buildings involved in questionnaires submission is shown.
Some buildings were not added in this experimentation because they were inhabited
from few months or they were still in construction. In the future some more questionnaires could be distributed.
Tab. 2 -
Riepilogo degli edifici coinvolti nella distribuzione dei questionari Overview of buildings involved in questionnaires submission
Building code
Building condition
Ea, Eb
Refurbished
D, C
Refurbished
Ec, Ed
Existing building
F, G
Existing building (*)
C1
New building
(*) only windows have been renewed
Building technology
Brick walls and beam and clay block floors
Concrete walls and floors
Brick walls and beam and clay block floors
Concrete walls and floors
Brick walls and beam and clay block floors
Existing/refurbished building were of two types: with concrete structures (D, C, F,
G) and with bricks structures (Ea, Eb, Ec, Ed).
In existing building not interested by the renewal works, only windows were
changed.
For refurbished buildings, a refurbishing through a “dry” construction site was used,
meaning that the least amount of concrete and mortar possible has to be used. In order
to complete the work in a shorter period of time it has been made wide use of prefabricated products, eg. gypsum plasterboards coupled with soundproofing material.
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 31
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Within the dwellings it has been planned also the implementation of a ceiling radiant
heating system. The selected option allows to install the system without resorting to the
demolition of floors and screeds. Instead, for the thermal insulation of the buildings the
solution chosen provides the use of a wall cladding system on the external walls. It has
been also done the replacement of all the internal and external doors and windows.
For the new buildings bricks structure with external thermal insulation and radiant
floating floors were chosen.
In consideration of small and medium dimension of buildings, for data analysis they
were grouped in 3 categories: existing, renewed and new buildings. In tables 3, 4 and 5
the mean results of acoustic tests on different buildings are shown.
Tab. 3 -
Valori medi dei parametri acustici per gli edifici ristrutturati - Mean values of acoustic parameters for renewed buildings
RENEWED BUILDINGS
Floors
Walls
Floors
Façade
DnT,W + C(50-5000)
DnT,W + C(50-5000)
L'nT,W + CI (50-2500)
D2m,nT,W + Ctr (50-5000)
Arithmetic
mean [dB]
52.5
55.8
58.0
35.1
Max
[dB]
56.0
58.0
62.0
39.0
Min
[dB]
49.0
52.0
54.0
29.0
∆ [dB]
7.0
6.0
8.0
10.0
Mode
[dB]
52.5
55.8
58.0
35.1
Standard
Dev [dB]
1.88
1.79
2.43
2.40
Tests
number
66
9
45
53
Grouping together the 4 refurbished buildings, the deviation between group measurements do not increase considerably because results are quite homogeneous. Only in
the case of impact level indexes there are bigger differences (indeed building C has
slightly worst impact insulation compared to others). For façade insulation values are
inhomogeneous even inside the same flat as a consequence of the presence of ventilation holes in kitchens. In most cases the addition of spectral index (extended at low frequencies) decrease the spread between group measurements.
Tab. 4 -
Valori medi dei parametri acustici per gli edifici esistenti - Mean values
of acoustic parameters for existing buildings
EXISTING BUILDINGS
Floors
Walls
Floors
Façade
DnT,W + C(50-5000)
DnT,W + C(50-5000)
L'nT,W + Ci (50-2500)
D2m,nT,W + Ctr (50-5000)
Arithmetic
mean [dB]
49.3
50.5
64.0
35.1
Max
[dB]
51.0
53.0
67.0
-
Min
[dB]
48.0
48.0
62.0
-
∆ [dB]
3
5
5
-
Mode
[dB]
48
64
-
Standard
Dev [dB]
1.21
3.54
1.90
-
Tests
number
6
2
6
-
For existing buildings the number of measurements made is very lower but results
are similar for the different types of buildings analyzed (with concrete or brick structures). Any façade measurements were made in existing building so, considering that
windows where recently changed in most of existing building analyzed,
D2m,nT,W + Ctr (50-5000) mean value has been assumed equal to one calculated for renewed
buildings.
At the moment questionnaire was submitted only in one new building, named C1, so
in table 5 only measurements made in this building are reported.
The large deviation between different façade measurements is due on the presence
both of mounting errors in some windows and of ventilation holes in kitchens.
Impact and airborne sound insulation results are more homogenous.
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 32
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
The low value of wall sound insulation is due to a wrong construction choice: rigid
thermal insulation material was used inside double walls, with presence of rigid connections between the two structures.
Tab. 5 -
Valori medi dei parametri acustici per gli edifici nuovi - Mean values of
acoustic parameters for new buildings
NEW BUILDINGS
Floors
Walls
Floors
Façade
DnT,W + C(50-5000)
DnT,W + C(50-5000)
L'nT,W + CI (50-2500)
D2m,nT,W + Ctr (50-5000)
Arithmetic
mean [dB]
52.6
49.0
54.7
30.5
Max
[dB]
57.0
51.0
58.0
36.0
Min
[dB]
51.0
47.0
52.0
21.0
∆ [dB]
6
4
6
15
Mode
[dB]
51
49
55
31
Standard
Dev [dB]
1.71
1.41
1.71
3.21
Tests
number
16
6
15
30
5. Way of submission of questionnaires
Questionnaires have been submitted personally door to door. This distribution way
was chosen in order to have a higher percentage of response from residents.
Building under analysis are social houses, mostly occupied by destitute or old
people. Inhabitants were informed in advanced about the day and hour of questionnaire
visit by posters placed on building entrance.
During questionnaire submission one person from Municipality agency partnered
university technicians in tenants visit. These was for reassure tenants and to increase
their collaboration. In this way all people present at home during the visit collaborate to
the test. Certainly, the procedure of questionnaire submission and return by mail (as
done in northern countries) wouldn’t be equally effective in this particular contest.
The interviewer read questions to tenants registering their responses and helping
them in case of doubts.
In table 6 the percentage of apartments visited is shown. In building Ed only one
questionnaire were submitted because only one flat was occupied in that moment (others occupants were already moved in order to start renewal works).
Tab. 6 -
Percentuale di appartamenti visitati per ogni edificio - Percentage of apartments visited for each building
Building ID
Building group
Eb
Ea
D
C
C1
Ec
Ed
G
F
Renewed
Renewed
Renewed
Renewed
New
Existing
Existing
Existing
Existing
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 33
Questionnaires
N°
5
3
3
4
9
4
1
8
10
Apartments
N°
6
6
6
6
16
6
6
12
30
Percentage of apartments visited
83%
50%
50%
67%
56%
67%
17%
67%
33%
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
6. Residents characterization
On following pie charts (Fig. 9) the compositions of apartments residents (asked in
the first part of questionnaire) is reported.
Because all building analyzed were social houses most of tenants are retired women
over 65 year old or also housewives (working period Not Applicable, N/A).
In all cases, the apartment was for rent from Verona Municipality.
For these reasons respondents characteristics aren’t well distributed. Probably with
the future submission of questionnaire on new buildings already involved in the survey,
respondents characteristics will be more varied. Indeed one of the purpose of district renovation was to avoid the social segregation, introducing in new and renewed houses
young families and mixing Italian and immigrants peoples.
Building condition
32%
49%
Years of residence
RENEWED
NEW
EXISTING
19%
0-1
2-5
>5
36%
51%
13%
Nr. of persons per household
Gender of respondent
4%
11%
1
2
3
4-6
>6
22%
27%
36%
20%
M
F
80%
Working period
Age of respondent
9%
16%
18-25
40%
22%
2%
day
night
26-39
13%
mixed
40-65
29%
>65
69%
N/A
Fig. 9 - Diagrammi con i dati dei residenti - Diagrams with residents data
7. Results
Questionnaires data have been elaborated following Simmons report calculation [4]
[5] in order to have comparable results. So, more explanations about statistical parameters choice can be found in Simmon’s report [4].
In tables 7, 8 and 9 are reported, for each group of buildings and for all questionnaire questions, the following data:
- average rating (A50), for each question;
- standard deviation (s) of scores given for each question;
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 34
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
- 95% confidence interval of the average rating: A50_CI 95 = 2s/√N (N is the answers
number for each question);
- average rating increased by one standard deviation: A16 = A50 + s;
- percentage of people assigning a disturb score ≥3, ≥5, ≥8 (where higher scores correspond to higher disturb).
Questionnaire subjective score ranges have the following meaning:
- score ≥3 indicates that people are “Quite disturbed, Disturbed and Very disturbed”;
- score ≥5 indicates people “Disturbed and Very disturbed”;
- score ≥8 indicates people “Very disturbed only”.
The score has a different meaning for last two questions, asking the importance of
“Noise in general eg. from neighbours, technical installations” (question 15) and the tolerance/sensitivity to “Noise in general eg. from neighbours, technical installations”
(question 16).
Question 6 asking about “rattling or tinkling noise from your own furniture when the
neighbours move on the floor above you” resulted not significant for heavy building
structure considered, for this reason in tables 7, 8 and 9 the corresponding column in
marked with a grey filling.
The number of respondent is not always the same for all questions because in some
cases people didn’t give any answer.
In tables 7, 8 and 9 rows corresponding to the count of rates of “Quite disturbed,
Disturbed and Very disturbed” people (score ≥ 3) are marked in yellow if respondent
percentage ≥20% and in red if ≥ 40%.
For “Disturbed and Very disturbed” people the acceptable and limit percentage are ≥
10% and ≥ 20%.
For “Very disturbed only” this limits are fixed respectively in 5% and 10%.
Tab. 7 -
Risultati del questionario per gli edifici ristrutturati - Questionnaires results for renewed buildings
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 35
1
General
2.92
3.43
13
1.90
6.35
38%
31%
15%
9
Wat
0.85
1.57
13
0.87
2.42
15%
8%
0%
RENEWED BUILDINGS
2
3
4
5
Walls Floors Bass Footfall
2.38
4.23
0.18
4.25
2.93
3.70
0.60
4.27
13
13
11
12
1.63
2.05
0.36
2.46
5.32
7.93
0.78
8.52
46%
62%
0%
50%
15%
46%
0%
50%
8%
31%
0%
33%
RENEWED BUILDINGS
10
11
12
Heater Equipm Premise
0.08
0.58
0.70
0.29
1.08
1.34
12
12
10
0.17
0.63
0.85
0.37
1.67
2.04
0%
8%
10%
0%
0%
0%
0%
0%
0%
13
Traffic
1.23
2.80
13
1.56
4.03
15%
15%
8%
6
Rattle
7
Stair- well
5.08
3.35
13
1.86
8.43
69%
69%
31%
14
Own family
2.77
2.83
13
1.57
5.60
46%
23%
15%
15
Import
7.69
2.53
13
1.40
10.20
100%
92%
54%
8
Stairs
4.23
3.49
13
1.94
7.72
54%
46%
31%
16
Sensit
1.92
2.47
13
1.37
4.39
23%
8%
8%
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Tab. 8 -
Risultati del questionario per gli edifici nuovi - Questionnaires results for
new buildings
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
1
General
2.11
2.8
9
1.87
4.91
33%
33%
0%
9
Wat
3.25
3.49
8
2.47
6.74
38%
25%
25%
NEW BUILDINGS
2
3
4
Walls Floors Bass
2.11
1.00
0.14
3.48
2.35
0.38
9
9
7
2.32
1.56
0.29
5.59
3.35
0.52
33%
11%
0%
22%
11%
0%
22%
0%
0%
10
Heater
2.86
3.67
7
2.78
6.53
43%
43%
14%
NEW BUILDINGS
11
12
Equipm Premise
0.22
1.00
0.67
1.66
9
9
0.44
1.11
0.89
2.66
0%
11%
0%
11%
0%
0%
5
Footfall
1.25
2.43
8
1.72
3.68
13%
13%
0%
13
Traffic
0.89
1.69
9
1.13
2.58
11%
11%
0%
6
Rattle
7
Stair- well
2.11
2.85
9
1.90
4.96
33%
11%
11%
14
Own family
2.20
2.77
5
2.48
4.97
20%
20%
0%
15
Import
6.00
3.94
9
2.62
9.94
67%
67%
44%
8
Stairs
2.33
3.5
9
2.33
5.83
33%
22%
11%
16
Sensit
1.44
2.19
9
1.46
3.63
22%
11%
0%
Tabella 9 - Risultati del questionario per gli edifici esistenti - Questionnaires results
for existing buildings
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
Question
Parameter
A50 average
S
N
A50 CI95 (2s/√N)
A16 Average + StdDev
Fract ≥3 Some disturb
Fract ≥5 Disturbed
Fract ≥8 Very disturbed
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 36
1
General
4.00
3.13
23
1.31
7.13
57%
48%
13%
9
Wat
4.41
3.83
22
1.63
8.23
59%
45%
32%
EXISTING BUILDINGS
2
3
4
5
Walls Floors Bass Footfall
2.45
3.41
0.82
3.76
3.32
3.70
2.40
3.52
20
22
11
21
1.48
1.58
1.45
1.54
5.77
7.11
3.22
7.28
35%
45%
9%
52%
30%
45%
9%
43%
15%
23%
9%
19%
EXISTING BUILDINGS
10
11
12
13
Heater Equipm Premise Traffic
2.27
1.82
3.75
3.27
3.35
3.12
3.74
3.79
15
11
12
22
1.73
1.88
2.16
1.62
5.61
4.94
7.49
7.07
27%
27%
58%
41%
27%
9%
42%
32%
13%
9%
33%
23%
6
Rattle
7
Stair- well
5.39
3.71
23
1.55
9.11
70%
57%
39%
14
Own family
3.90
3.54
20
1.58
7.44
60%
45%
15%
15
Import
7.05
3.34
22
1.43
10.40
86%
82%
55%
8
Stairs
4.86
3.73
22
1.59
8.6
68%
55%
27%
16
Sensit
3.91
3.3
23
1.38
7.21
52%
39%
17%
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Results are given as percentage of people assigning a disturb rate higher or equal of
a certain level (≥3, ≥5, ≥8) versus the mean value (A50) of the corresponding acoustic
parameter.
In following figures rhombus symbol represents renovated houses; the square
represents new houses and the triangle existing ones. Unfortunately having only three
points the regression line between results is in the most of cases not so representative
(very low R2) and only some observations can be made.
Four main parameters were analyzed:
- walls airborne insulation (parameter DnT,W + C(50-5000)), related to question n° 2
(Neighbours; daily living, eg. people talking, audio, TV through the walls);
- floors airborne insulation (parameter DnT,W + C(50-5000)), related to question n° 3
(Neighbours; daily living, eg. people talking, audio, TV through the floors/ceilings);
- floors impact sound insulation (parameter L’nTw + CI (50-2500)), related to question n° 5
(Neighbours; footstep noise, i.e. you hear when they walk on the floor);
- façade sound insulation (D2m,nT,W + Ctr (50-5000)), related to question n° 13 (Traffic (cars,
buses, trucks, trains or aircraft); heard indoors with windows closed).
Data analysis is very important to group responses according to subjective score
rages (≥3, ≥5, ≥8) ant to use the mean value of acoustic parameters for each building.
Indeed in some preliminary elaborations [9] the score given by each respondent were
considered and related to parameters values for each flat: in this way a lot of points were
obtained in diagrams but there was no trend line in data.
Figures 10, 11 and 12 show graphs for subjective score higher or equal to 3, 5 and 8.
Question 2 - Airborne sound insulation
Neighbours: noise through walls (vertical partitions)
55
50
45
Renovated
New
Existing
60
DnT,w + C(50-5000) floors [dB]
DnT,w + C(50-5000) walls [dB]
60
40
Question 3 - Airborne sound insulation
Neighbours: noise through floors/ceilings
(horizontal partitions)
55
50
y = -0,0174x + 52,168
(R² = 0,0582)
45
Renovated
0
20
40
60
80
% habitants giving subjective score >=3 [%]
100
0
(a)
Existing
Question 5 - Impact sound insulation
Neighbours: footstep noise
(horizontal partitions)
65
60
y = 0,1621x + 52,764
(R² = 0,6374)
55
Renovated
New
Existing
50
0
20
40
60
80
% habitants giving subjective score >=3 [%]
(c)
20
40
60
80
% habitants giving subjective score >=3 [%]
100
(b)
45
100
D2m,nT,w + Ctr(50-5000) facade [dB]
70
L'nT,w + CI(50-2500) [dB]
New
40
Question 13 - Facade sound
insulation - Traffic heard with
windows closed
40
y = -0,0626x + 33,404
35
(R² = 0,145)
30
Renovated
New
Existing
25
0
20
40
60
80
% habitants giving subjective score >=3 [%]
100
(d)
Fig. 10 - Percentuale di residenti che ha dato un punteggio soggettivo maggiore
di 3 per i quattro parametri analizzati - Percentage of inhabitants giving
a subjective score higher than 3 for the four parameters analyzed
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 37
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
For airborne and façade sound insulation the expected trend should be the one with
lower percentage of disturbed people at the increase of building acoustic parameter value; the opposite should be for impact levels.
In all graphs, except the one of Figure 10a (sound insulation of wall for subjective
score ≥3), the trend line has a correct slope, although the correlation coefficient R2 is in
the most of cases very low. Only for wall sound insulation, for subjective score ≥5 and
≥8 (Figure 11a and 12a), the correlation coefficient R2 results more significant with a
value, respectively of 0.57 and 0.87.
It is interesting to observe that trend lines for noise from walls (question 2) and
noise from floors (question 3) have, in all cases, higher slope in the case of noise from
walls, indicating a stronger sensibility to low variation on wall sound insulation whereas
differences in floors sound insulation do not lead to evident change in people judgment.
Slope of trend lines for impact sound insulation are also quite high (slope sign is opposite cause higher impact sound pressure levels lead to higher disturb).
For façade sound insulation trend lines slope is very low, as in the case of floors
sound insulation.
60
Question 2 - Airborne sound insulation
Neighbours: noise through walls
(vertical partitions)
DnT,w + C(50-5000) floors [dB]
DnT,w + C(50-5000) walls [dB]
60
55
y = -0,4078x + 60,755
50
(R² = 0,5707)
45
Renovated
New
Existing
Question 3 - Airborne sound insulation
Neighbours: noise through floors/ceilings
(horizontal partitions)
55
y = -0,0481x + 53,127
50
(R² = 0,2677)
45
Renovated
Existing
40
40
0
20
40
60
80
% habitants giving subjective score >=5 [%]
100
0
(a)
Question 5 - Impact sound insulation
Neighbours: footstep noise
(horizontal partitions)
65
y = 0,1464x + 53,824
60
(R² = 0,4148)
55
Renovated
New
Existing
50
0
20
40
60
80
% habitants giving subjective score >=5 [%]
(c)
20
40
60
80
% habitants giving subjective score >=5 [%]
100
(b)
45
100
D2m,nT,w + Ctr(50-5000) facade [dB]
70
L'nT,w + CI(50-2500) [dB]
New
Question 13 - Facade sound
insulation - Traffic heard with
windows closed
40
y = -0,0778x + 33,51
35
(R² = 0,1031)
30
Renovated
New
Existing
25
0
20
40
60
80
% habitants giving subjective score >=5 [%]
100
(d)
Fig. 11 - Percentuale di residenti che ha dato un punteggio soggettivo maggiore
di 5 per i quattro parametri analizzati - Percentage of inhabitants giving
a subjective score higher than 5 for the four parameters analyzed
Another observation that can be derived from Figures 10, 11 and 12 graphs is about
theoretical parameters values that lead to a 0% of people disturbed by noise (with score
≥3, ≥5, ≥8): these values correspond to intercepts of trend lines equation on y-axis.
These values are summarized in Table 10.
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 38
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
For airborne sound insulation, DnT,W + C(50-5000) (0% disturbed) stays in the range
58.8-60.8 dB for walls and in the range 52.1-53.1 dB for floors so in case of vertical
structures not only a bigger sensibility in insulation variations is observed but also the
needing of higher sound protection.
For impact noise L′nW + CI (50-2500) (0% disturbed) is in the range 52.7-56.8 dB.
External noise (traffic/premises) do not seem to be very relevant and related percentage of annoyed people are quite low (with slightly higher percentage for existing buildings). D2m,nT,W + Ctr (50-5000) (0% disturbed) is around 33 dB but this data seem to be very
week, also considering that the area is enough quite.
60
Question 2 - Airborne sound insulation
Neighbours: noise through walls
(vertical partitions)
DnT,w + C(50-5000) floors [dB]
DnT,w + C(50-5000) walls [dB]
60
55
y = -0,4572x + 58,495
50
R² = 0,8728
45
Renovated
New
Existing
Question 3 - Airborne sound insulation
Neighbours: noise through floors/ceilings
(horizontal partitions)
55
y = -0,0352x + 52,109
50
(R² = 0,0911)
45
Renovated
0
20
40
60
80
% habitants giving subjective score >=8 [%]
0
100
Existing
20
40
60
80
% habitants giving subjective score >=8 [%]
(a)
70
Question 5 - Impact sound insulation
Neighbours: footstep noise
(horizontal partitions)
65
y = 0,1177x + 56,841
60
(R² = 0,1752)
55
Renovated
New
Existing
50
0
100
(b)
45
D2m,nT,w + Ctr(50-5000) facade [dB]
L'nT,w + CI(50-2500) [dB]
New
40
40
20
40
60
80
% habitants giving subjective score >=8 [%]
100
Question 13 - Facade sound
insulation - Traffic heard with
windows closed
40
y = -0,042x + 32,423
35
(R² = 0,0336)
30
Renovated
New
Existing
25
0
20
40
60
80
% habitants giving subjective score >=8 [%]
(c)
100
(d)
Fig. 12 - Percentuale di residenti che ha dato un punteggio soggettivo maggiore
di 8 per i quattro parametri analizzati - Percentage of inhabitants giving
a subjective score higher than 8 for the four parameters analyzed
Tab. 10 -
Valori dei parametri teoricamente corrispondenti ad una percentuale di
persone disturbate (per punteggi ≥3, ≥5, ≥8) uguale a zero - Parameters
values theoretically giving a percentage of disturbed people (score ≥3,
≥5, ≥8) equal to zero
Airborne noise (walls)
DnT,W + C(50-5000) [dB]
Airborne noise (floors)
DnT,W + C(50-5000) [dB]
Impact noise (floors)
L′nT,W + CI (50-2500) [dB]
Façade sound insulation
D2m,nT,W + Ctr (50-5000) [dB]
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 39
Score ≥3
Score ≥5
Score ≥8
-
60.8
58.8
52.2
53.1
52.1
52.7
53.8
56.8
33.4
33.5
32.4
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Finally in Figure 13, pie charts represent the score range assigned by respondents in
questions 1 (Disturb by noise in general), 15 (Importance of sound insulation) and 16
(Tolerance/sensitivity to noise). From these graphs it is possible to see that more than
half of respondent is globally not disturbed by noise (53%); the most of interviewed
consider the sound insulation very important (73%); and 62% of people consider themself tolerant relative to neighbors noise.
Question 1 - Noise in general
Question 15 - Importance of
sound insulation
0%
0%
Not disturbed 0-2
24%
Not important 0-2
14%
Quite disturbed 3-5
53%
22%
Quite important 3-5
14%
Disturbed 6-10
Very important 6-10
Don't know N
73%
Don't know N
Question 16 - Tolerance/
sensitivity respect to noise
0%
Tolerant 0-2
20%
Quite tolerant 3-5
18%
Sensitive 6-10
62%
Don't know N
Fig. 13 - Diagrammi a torta con le risposte alle domande 1, 15 e 16 - Pie charts
with responses to questions 1, 15 and 16
Conclusioni
Per una corretta correlazione tra le risposte dei questionari e parametri di acustica
edilizia risultano fondamentali due aspetti: raccogliere un campione di edifici e di intervistati sufficientemente rappresentativo ed eseguire un’analisi statistica dei dati.
Nel caso in esame le palazzine considerate erano tutte di taglia piccola per cui, per
avere un numero sufficiente di questionari è stato necessario raggruppare insieme edifici
con analoghe caratteristiche. Comunque i gruppi considerati sono stati solo tre (edifici
ristrutturati, esistenti e nuovi) corrispondenti a tre soli punti nei diagrammi risposta soggettiva – parametro; per tale motivo le correlazioni trovate risultano molto deboli. Per
future applicazioni del questionario risulterebbe conveniente la scelta di edifici di grandi
dimensioni con almeno 20-30 unità immobiliari. Il vantaggio di adottare un questionario
armonizzato ed una comune analisi dei dati consente di raggruppare diverse ricerche al
fine di aggiungere nuovi punti nel punti nei diagrammi risposta soggettiva – parametro.
Risulta interessante la maggior sensibilità ai rumori aerei trasmessi attraverso le pareti rispetto a quelli trasmessi attraverso i solai, con valori attesi di DnT,W + C(50-5000)
(corrispondenti allo 0% di persone disturbate) più elevati per le pareti (58.8-60.8 dB)
che per i solai (52-53 dB). Tale risultato andrà però confermato aggiungendo ai diagrammi dati derivanti da studi futuri.
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 40
Chiara Martina Pontarollo
Indagini socio-acustiche e correlazioni con le prestazioni acustiche degli edifici
Socio-acoustics surveys and correlations with building acoustics performances
Summary
Two points are very important for a correct correlation analysis between questionnaire subjective responses and building acoustic parameters: to have a large building
and respondents sample and to make statistical analysis of data.
All buildings considered in this application were quite small, so, in order to have
enough questionnaires, similar buildings were grouped together. Three groups were
considered (renewed, existing and new buildings), corresponding to three points in subjective response – parameter diagrams. For this reason correlations found era very weak.
Buildings with at least 20-30 units should be used for questionnaire future applications. Using an harmonized questionnaire with a commune data analysis makes possible
to put together results from different research adding new points in subjective response parameter diagrams.
The greater sensibility to airborne noise through wall than ones through floor and
the higher values for expected DnT,W + C(50-5000) (0% disturbed) for walls (58.8-60.8 dB)
than for floors (52-53 dB) are interesting remarks. However they should be proved adding new data in subjective response - parameter diagrams.
Bibliografia
[1] Hagberg K., Evaluation of sound insulation in the field, Wespack IX, Sweden,
2006
[2] Park H.K. & Bradley J. S., Evaluating standard airborne sound insulation measures in terms of annoyance, loudness, and audibility ratings, J. Acoust. Soc. Am.
126, 208 (2009)
[3] Holm Pedersen T., Measurements and Judgments of sound in relation to Human
Sound Perception, DELTA, Denmark, 2001
[4] Simmons C., Hagberg K., Backman E., Acoustical Performance of Apartment
Buildings – Resident’s Survey and Field Measurements Project report 2 from the
AkuLite-project, SP Report 58, 2011
[5] Simmons C., Gallego F.J.A., A proposal for a harmonized questionnaire and an
overview of its development, Proc. 2010 EAA Symposium on Harmonization of
European Sound Insulation Descriptors and Classification Standards, Ljubljana,
15-18 September 2010
[6] Rasmussen B. & Machimbarrena M. (editors), COST Action TU0901 – Building
acoustics throughout Europe. Volume 1: Towards a common framework in building acoustics throughout Europe, e-ISBN: 978-84-697-0158-4, 2014
[7] ISO/TS 15666:2003, Acoustics -- Assessment of noise annoyance by means of social and socio-acoustic surveys
[8] Simmons C., Hagberg K., Backman E., Acoustical performance of apartment
buildings - Resident’s survey and field measurements, SBUF 12403 Report, 2011
[9] Di Bella A., Pontarollo C.M., Vigo M., Comparison between European acoustic
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surveys, Proceedings Euronoise 2012, Prague, 10-13 June 2012
Rivista Italiana di Acustica
Vol. 38 (2014), N. 1, p. 41

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