PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Comparison of Acoustic Performance and Subjective Evaluation in
Residential Buildings
Ayça Şentop1; Nurgün Bayazıt21İstanbul Bilgi University, Istanbul Technical University, Turkey
2

Istanbul Technical University, Turkey

ABSTRACTThe "Regulation on Protection of Buildings against Noise” was issued by the Turkish Ministry ofEnvironment and Urbanization in May 2017. The regulation was put into force partially in May 2018
obliging all new buildings to follow acoustical requirements. In May 2019, acoustical project by an
acoustical expert will be obligatory for large scale or multifunctional buildings. The regulation aims tointroduce a scheme for acoustical performance evaluation, ranging from A to F following the EU/COST TU
0901 project outcomes and ISO-CD19488.
This study aims to demonstrate the application of the regulatory requirements with field measurements and asurvey. Airborne and impact sound insulation, indoor noise level, service equipment noise level andreverberation time were measured in 6 residential buildings and acoustic performances were analyzed
according to the classification scheme. A survey was conducted with the residents of the buildings. The
results were compared and the applicability of the regulation was discussed.
Keywords: Acoustic, Performance, Classification, Regulation

1. INTRODUCTION
The new regulation of Turkey "Regulation on Protection of Buildings against Noise” settles thelimit values for sound insulation and sound levels in buildings; provides methods for noise protectionof buildings and introduces acoustic performance evaluation [1,2]. The regulation is prepared inaccordance with EU/COST TU 0901 Harmonization Project and ISO/AWI TS 19488 Acoustics andproposes 6 classes for evaluation of acoustic performance [3,4]. According to the regulation all newbuildings should provide Class C performance while existing buildings should provide Class D
performance in the event of a renewal project. The acoustical class of a building is inferred from theminimum of performance parameters: airborne and impact sound insulation between neighboring units,façade sound insulation, airborne sound insulation inside the dwelling unit, service equipment andindoor background noise levels and reverberation time. The insulation rating descriptors accepted foruse are D nT,w + C (D nT,A), D2m,nT,w + Ctr (D nT,A,tr ), and L' nT,w . If low frequency sounds are in question, an
acoustic consultant may also use D nT,w + C50-3150 (D nT,50 ), D 2m,nT,w + C tr, 50-3150 (D2m,nT,50), and L'nT,w +C I,50-2500 (L'nT,50 ). The service equipment noise level limits are defined in LAeq,nT for continuous noises
and LAFmax,nT for intermittent noises. The interior background noise limits are defined in L Aeq . The
limit values are defined for each acoustic performance class. In order to comply with a classmeasurement results should not show more than 2 dB adverse deviations from the limit. The regulation
defines only one reverberation time limit for acoustic performance classes from A to D. This limit mustbe satisfied for a building to be classified in acoustic performance class A to D.
Although the after-construction measurements are not kept obligatory, an acoustic performancecertificate can be granted upon proving performance with acoustical measurements. In this study,
acoustic performances of 6 buildings were evaluated after measurements in selected dwellings.
Occupants’ opinions were gathered with a survey. Some of the pre-results were discussed in [5,6].

1
2

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ayca.sentop@bilgi.edu.tr
nurgun@itu.edu.tr

2. METHODOLOGY
2.1 Selection of buildings
6 Buildings were selected for the study (Table 1). A preliminary analysis was made regarding toplan layout and surrounding in order to select buildings that were exposed to different noise conditions.
Two of the buildings Yildiz Technical University lodge [YTU] and Istanbul Technical University
Lodge [ITU] were located in university campuses, and consisted of 3+1, 2+1 and 1+1 housing units.
The main noise issue was neighboring noise. One of the buildings Ruyakent [RUY] was located in aquite surrounding and consisted of units that share only one common wall in kitchens; therefore floors
were the main concern for noise evaluation. Another building Finanskent [FIN] had moderateenvironmental noise and a plan layout that contained neighboring bedrooms. Floor and façade
evaluation may be critical for occupants’ comfort. Last 2 buildings Kuleli [KUL] and Erka Konsept[ERK] consisted of 3+1, 2+1 and 1+1 housing units and they were located next to main roads.
Performance related to both exterior and interior building elements were expected to be important.
Table 1 – Selected buildings

2.2 Measurements
One dwelling (housing unit) and its neighbors were measured in each building. Sound insulation ofbuilding elements was measured according to ISO 16283-1-3 [5-7]. The results were given in D nT,A,tr ,D nT,A , L'nT,w . Partitions between neighbors and partitions inside the dwelling were measured separately.
The regulation aims not only the noise passing from neighbours but also noise that occur inside thedwelling. The environmental noise level was measured according to ISO 1996-2 during 24 hours [8].
Lden value was calculated to represent the outside conditions. Service equipment noise levels were
measured according to ISO 16032 [9]. Tap water, flush and ventilation (if existed) sounds were used
for evaluation. For each case, these bathroom sounds were analyzed in a bedroom that belonged to thesame dwelling. The service equipment noise from parent’s bathroom was also measured. Although theregulation doesn’t leave this type of noise out of the scope, it was kept informative in this study.
Finally, reverberation time was measured according to ISO 3382-2 inside the apartment corridors androoms [10]. The results were corrected if the room was unoccupied during the measurement.
2.3 Survey
A questionnaire form was prepared to address different noise issues in buildings by reviewing thesocio-acoustic survey principles referred in ISO 15666 [13] and several other studies [14 -20].20
residents were randomly selected and were interviewed face to face in 10 - 15 minutes of meetings.
Several questions were asked involving overall comfort issues related to build ing and surrounding,demographic issues, time spent in house, noise related problems and reactions. Hearing conditions ofvarious noise sources were investigated and resulted annoyance was rated. Both 5 point likert scaleand numerical scale from 0 to 10 were used. The annoyance was marked as “0” if the noise source wasunheard. This gives a coherent result for some sources that can be assumed to affect each occupant,such as traffic or footstep. However, some other sources depend on life style, such as mus ic and tv.
Evaluation of these annoyances will be further researched. The results were eliminated if the resident
reported a hearing-related problem. In one case 2 responses were eliminated because of inconsistency
in their responses.

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2.4 Acoustic performance evaluation
The measurement results were compared to regulatory limits and an acoustical performance class
was assigned to each measurement result. Deviations up to 2 dB were neglected as stated in theRegulation. The overall acoustic classes were assigned according to minimum of the results.
For classification of an entire building, random sampling would be necessary. However; thebuildings were occupied at the time and permission was limited . Only in RUY and ERK additional
measurements were possible in other dwellings. Since sampling criteria required by the regulation and
ISO/AWI TS 19488 could not been met the measurement and survey results were put into an
importance-performance matrix for comparison. Only the minimum measurement results were used
for each acoustic performance parameter.

3. Results
3.1 Measurement results
The measurement results are given in Figure 1. The regulatory limit values differ according to thefunction of the room. For a clear comparison of cases, bedroom results were plotted on chart and limit
values for Acoustical Performance Class-C were shown. If more than one sample was measured for a
performance, the adverse result was plotted on chart. In some cases this did not correspond to a
bedroom result, so the second measurement was also marked on the chart. Further research is required
on which of these performances was more influential for occupants’ judgement. Only the corridor
reverberation times were put on the chart since occupied rooms already met the regulation limits.
3.2 Acoustic performance evaluation
Dwelling in Yildiz Technical University lodge (YTU):
x YTU provided Class C airborne sound insulation performance between neighbours. The
partitions between the bedrooms of the same dwelling were Class C, however partition between
living room and bathroom was Class D with 2 dB deviation from the Class D requirements. The
impact sound insulation was classified as Class C although there was 2 dB deviation from thelimit value. Building’s façade met Class D. However the main noise issue was the children’s
playground and there was no road nearby in this case. When C adaptation term was appliedinstead of C tr in correspondence with ISO 717, the performance met Class C. This issue should
be further studied with spectral analysis.
x The indoor background noise level was found as Class B. The service equipment noise level
was found Class B in the bedroom, and Class D in the living room. Also, the sound fromparent’s bathroom was measured in parents’ bathroom and found as Class C.
x All rooms met reverberation time criteria except for the apartment stairwell.
x The overall sound insulation class was Class D due to lower performance of the wall between
the living room and the bathroom. The overall acoustic performance assessment was Class E
because of long reverberation time in apartment stairwell.
Dwelling in Ruyakent Housing Estate (RUY):
x Airborne sound insulation of partitions between neighbours was evaluated based on themeasurement between two (secondary) living rooms of upstairs and downstairs, since theregulation and ISO/AWI TS 19488 states that unoccupied rooms shall not be selected asreceivers [1,4]. The preliminary results were 58 dB corresponding to Class B. However, due tounfavorable measurement conditions and contradictory results of annoyance reported byoccupants, the measurement was repeated and results decreased to 52 dB, corresponding toClass C. Wall between two adjacent kitchens was Class B and wall that separates the common
corridor from the dwelling was found Class D but these results were kept informative.
According to the regulation the limit values are 14 dB lower for walls with doors and this wasapplied to the latter case. The partitions inside the dwelling were evaluated as Class E based on
the minimum of the results. The impact sound insulation was Class C. The façade airborne
sound insulation was Class B.
x The indoor background noise level was measured in a bedroom and an unoccupied living room.
The measurement result in unoccupied room was standardized to a reverberation time of 0,5 sn.
Both resulted as Class A. The service equipment noise level exceeded Class F requirements.
x The reverberation time of apartment’s common corridor exceeded the limits.

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(a)

(b)
(c)
Figure 1 – Measurement results a) sound insulation, b) sound level, c) reverberation timex

The overall sound insulation class was Class E due to partitions inside the dwelling. The overall
acoustic performance of the dwelling was below Class F due to the service equipment noise.
Dwelling in Istanbul Technical University lodge (ITU):
x Airborne sound insulation of partitions (walls and floors) between neighbours was found asClass D with the performance of the weakest wall, i.e. the wall that separated the living room ofa dwelling from the kitchen of the neighbor. Airborne sound insulation of partitions inside thedwelling and impact sound insulation was Class D. Façade was found as Class C.
x The indoor background noise level was found as Class A. Bedroom of an empty apartment wasalso measured and standardized. The service equipment noise was not evaluated because; thebathroom and bedrooms were separated in plan layout. Sound level from parents’ bathroom
was measured in parents’ bathroom and found as Class F.
x The corridor hall reverberation time exceeded the limit value of 1,2 s.
x Overall sound insulation class was Class D. Overall acoustic performance of the dwelling wasClass E due to reverberation time. Service equipment noise level was not evaluated.
Dwelling in Finanskent Housing Estate (FIN):
x Airborne and impact sound insulation of partitions (walls and floors) between neighbors wasfound as Class C as well as the partitions inside the dwelling. Façade was also measured as

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Class C. The airborne sound insulation of floor and façade elements were measured in livingroom as distinct from other cases where they were measured at least in one of the bedrooms.
Both regulatory limits and sizes differ for bedrooms; therefore results were supported withadditional measurements for clear comparison of cases. The results were Class C.
x The indoor background noise level was found as Class B. The service equipment noise wasmeasured as Class C. Sound level from parent’s bathroom was Class E, but it was not involvedin overall evaluation.
x The reverberation time of apartment corridor was 0,8 providing the limit value of 1,2s.
x Both sound insulation class and the overall acoustic performance were found as Class C.
Dwelling in Kuleli Apartment (KUL):
x Airborne sound insulation of partitions between neighbors was evaluated as Class D. The
partition between two bedrooms of the same dwelling was measured as Class E. Anotherpartition with a sliding door separates bedroom from living room and was found as Class F. The
impact sound insulation was Class E. The façade sound insulation was rated below Class F. The
environmental noise levels were high in this area and required sound insulation was higher.
x The indoor background noise level was Class C. The service equipment nois e was Class F. A
strong tonal component was noted around 500 Hz, caused by ventilation system of bathroom.
x The reverberation time was sufficient in the apartment hall.
x Sound insulation and the overall acoustic performance were below F because of the façade.
Dwelling in Erka Apartment (ERK):x Airborne sound insulation of partitions between neighbors was evaluated as Class F. The
partitions inside the dwelling were found as Class E. The impact sound insulation was Class Cwith 2 dB deviation from the required value. The façade sound insulation was Class E.
x The indoor background noise level was measured in an unoccupied bedroom and after
standardization it was found as Class A. The service equipment noise level was found as Class
E. Sound level from parent’s bathroom was below F, but it was kept informative.
x The apartment corridor reverberation time exceeded the reverberation limits.
x Both sound insulation class and the overall acoustic performance were Class F.
3.3 Survey results
The respondents’ ratio who rated their annoyance more than 3 in scale of 0 to 10 are plotted on achart in Figure 1. There were 20-25 participants from each building. At total 136 occupants
participated in the survey and 131 responses were found valid.
x YTU results showed that mechanical noises (radiators 55%, pump 50%, elevator 32%, waterfrom neighbor 45% and water from own dwelling 35%), occupant’s own noise coming fromnext room inside the dwelling (35%) and speech sounds coming from apartment hall (35%)
were the noise issues in the building. Amongst outdoor noise sources children sound comingfrom outside was rated as annoying by 53%. The pump noise was especially efficient at lower
floors. All occupants living at ground and 1st floor were annoyed with the average of 9 / 10.
x RUY results showed that occupants of this building complained more about speech soundcoming from upstairs/downstairs (61%), footstep (52%) and neighbor’s water sound (50%).
Upstairs child running was rated by 42% and speech from apartment hall was rated by 45%.
x ITU results showed that the most important noise issue was speech sounds from next-door(58%). Both footstep sound from upstairs and occupant’s own noise coming from next room
was rated by 47%. Upstairs-child run was rated by 40%, speech from apartment hall by 42%
and speech from up/downstairs by 37%. Amongst outdoor noise sources, construction sound
was rated by 42%. Considering that dwellings at the farthest edges of the building were moreadvantageous regarding the plan layout, next-door speech annoyance was re-analyzed
excluding these dwellings and the annoyance rating rose up to %75.
x FIN results showed that main noise issue related to the building was the speech sounds comingfrom apartment hall (55%). Upstairs child run (40%) and speech sound fromupstairs/downstairs (32%) created also noise issues. Additionally, the annoyance related toelevator sound rose to 33% when only the dwellings adjacent to the elevator were in question.
x KUL results showed that occupant’s own noise coming from next room was rated by 39% andmusic coming from upstairs or downstairs was rated by 32%. The most common noise problem
in this case was the outside noises (traffic 67% and construction 50%). The building consisted

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x

of two blocks, Block A faced a highway and Block B faced dense urban settlement. The
building had T-shape plan layout and Block A provided a barrier for Block B. Consequently,
traffic related annoyance rose up to 85% in Block A while it was 45% in Block B. In Block B,
annoyances related to outside speech and outside music were 31% and 45% respectively. The
outside construction noise was important in both Blocks (38% in Block A and 64% in Block B).
ERK results showed that 56% of occupants rated speech sounds from next -door, 55% rated
speech sounds from apartment hall and 50% rated footstep from upstairs. Footstep fromapartment hall (41%), upstairs child run (35%) speech sound from upstairs/downstairs ( 36%),
music from next-door (%31) were other issues. Water sound from both neighbor and own
dwelling annoyed 36%. Amongst outdoor noise sources, traffic was rated by 45%, speechcoming from outside was rated by 32% and construction was rated by 32%. Considering thatbuildings higher than 21,5 m are classified as high-rise buildings in Zoning Regulation for
Planned Areas [21] , the responses from 8 th and upper levels were grouped and the annoyance
related to outside noise sources were analyzed in two steps. The variance was important foroutside-speech results. Reported annoyance was 50% in lower levels while none of theresidents in upper levels was annoyed by this source.

Figure 2 – Survey results corresponding to the percentage of annoyance 3 or more.
3.4 Importance – performance analysis of the results
Importance-performance matrix is an analysis method usually used in marketing in order to provide
efficient source management. In the matrix, y-axis shows the achieved performance and x-axis shows
the relative importance given by the customer to that performance. Based on this approach soundinsulation-annoyance matrix is prepared. Sound insulation is given in y-axis and annoyance is given in
x-axis. According to the Regulation, Class C acoustical performance is mandatory for new buildings[1]. Deviation of the result from the Class C sound insulation limit value is plot on y -axis. Accordingto [17] fraction of respondents responding 3 or higher should be under 20%. Following this assumption
the axis intersection is driven from 20%. As a result, 4 cells are occurred in the graphic.
The results are expected to fall in 1st (favorable situation) and 3rd (primary improvement required)cells. 4th cell represents low annoyance in spite of the weak performance. The re ason of a data in thiscell can be that the noise source is inactive or active for only a small period or that it has lower level
than expected. 2nd cell represents observations where there’s high annoyance although the regulation
requirements are met. The reasons should be analyzed. It may be due to characteristics of the noise ofinterest or a wrong assumption in the study. More samples should be measured, and subjects should beinterviewed. A possible misinterpretation is that building element in question may be different than the
one effecting subjects’ evaluation. If annoyance due to a specific noise source falls in this cell in all
studies, regulation requirements should be reviewed.
Survey and measurement results were plot on the matrix. The horizontal (represented as ‘H’) andvertical (represented as ‘V’) sound transmissions between neighbors and corresponding annoyancewere shown in Figure 3. The outdoor noise sources (represented as ‘OUT’) and annoyance were shownin Figure 4. Only the speech, footfall and traffic sounds were analyzed because they tend be moreconsistent throughout the building.

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Figure 3 – Survey results corresponding to the percentage of annoyance 3 or more for indoor noises.

Figure 4 – Survey results corresponding to the percentage of annoyance 3 or more for outdoor noises.
In occupied buildings, sampling criteria suggested by the regulation is not always feasible due torestrictions brought by occupants. The importance-performance analysis can be a way of verifying theacoustic performance evaluation of the building. In figure 5 and 6, the ‘X’ marks represents theprimary results that were used in the graphic, later replaced with additional measurements or group
analysis as explained earlier.
Annoyance related to vertical speech transmission was high in RUY, however sound in sulation
measurement results were relatively high, contradictory to the annoyance. When the room conditions
were changed, and measurements were repeated, results were more satisfactory. The vertical speechtransmission and façade insulation were measured in a living room in FIN and they did not correlate to
the annoyance levels. The results were replaced by bedroom results in competence with all the othercases. In YTU, there wasn’t any main road nearby and the main noise source was the playgrounds.
D nT,A was used in primary results but later replaced by D nT,A,tr for clear comparison and to be further

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discussed. The survey results were analyzed according to plan layouts of the building and residents
were grouped according to their exposition level. In ERK, upper levels were not exposed to speechsounds from outside; therefore the percentage was replaced with the percentage of floors up to 7. KUL
consisted of two Blocks, Block A was exposed to traffic noise and Block B to the outside -speech noise
and the percentages are re-calculated separately for each Block.

4. CONCLUSIONS
Acoustical performances of 6 buildings were evaluated based on the acoustical measurements.
Façade sound insulation, airborne and impact sound insulation between neighbors, airborne soundinsulation inside the dwelling, background noise levels, service equipment noise levels andreverberation time results were compared to the regulatory limits and an acoustical performance class
was assigned for each performance. A survey study was conducted with the residents of the buildings.
The results were compared in importance-performance matrix and relevancy of annoyance to theresults that were selected as basis for acoustic performance evaluation was discussed.

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