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					                                                                            The 2005 World Sustainable Building Conference,
03-021                                                                      Tokyo, 27-29 September 2005 (SB05Tokyo)



               FREQUENCY CHARACTERISTICS OF INTERIOR NOISES IN HOUSES

                                                                   1
                                          Shih-Pin HUANG Ph.D
                                                                   2
                                         Rong-Ping LAI Professor

1
    Department of Architecture, Kao-Yuan Institute of Technology, No. 1821, Chung-Sun Rd , Luju, Kaohsiung
    county, Taiwan, R.O.C, sphuanh@cc.kyit.edu.tw
2
    Department of Architecture, National Cheng-Kung University, No.1, Ta-Hsueh Rd, Tainan City, Taiwan,
    R.O.C, Lairp@mail.ncku.edu.tw



Keywords: frequency characteristic, interior noise, noise annoyance, interior allowable noise index.




Summary
Sound environment in urban cities becomes worse because high density buildings. Interior noise seriously
         ep ’ e
impact p o ls life in houses. The main aims of this research are to study those source types and frequency
characteristics of interior noise. We first analyze frequency characteristics of interior noise sources by
precious instruments. Those are washing machines, flush toilets, air conditioners, refrigerators, ventilation
fan, drains, exhaust fans, televisions and pumps. The sound pressure level of equipment noise indicates
that exhaust fans at 75.8 dB (A) have the highest levels, pumps have 74.3 dB (A), ventilation fan have 65.5
dB (A) and refrigerators are ranked the lowest one have 43 dB (A). Besides we discuss the influence degree
of noise sources to residents by statistical method. The result shows flush toilets and televisions have the
most annoying degrees, then exhaust fans, washing machines, window air conditioners, pumps are following
in order. We also compare the interior allowable noise index by grouping international index.


1.        Introduction

Following the international trend of sustainable buildings this study discusses several assessment criteria on
sound environments. They are BREEAM (Building Research Establishment Environment Assessment
Method)、LEED (Leadership in Energy and Environment Design)、GBTool(Green Building Tool 2005)、
BEPAC (Building Environmental Performance Assessment Criteria) and CASBEE (Comprehensive
Assessment System for Building Environmental Efficiency).
BREEAM (Building Research Establishment Environment Assessment Method) is developed by Building
Research Establishment(BRE). The contents of EcoHomes list a environmental rating credit about sound
environment that is sound insulation. Its aim is to ensure the provision of sound insulation and reduce the
likelihood of noise complaints.
LEED (Leadership in Energy and Environment Design) is being developed by USGBC (U.S. Green Building
Council). LEED for Homes(LEED-H) is a voluntary initiative to actively promote the transformation of the
mainstream home building industry towards more sustainable practices. The objective, Indoor environmental
 u l , o s’ eo
   iy
q at d e n rc mme da y o i a o t c u ts r o e
             t                    c             i
                       n n tp s b u a o sc o n i .       s
GBTool (Green Building Tool 2002) is developed by Green building Challenge(GBC) . It is a software system
for assessing the environmental and sustainability performance of buildings. Indoor environment quality has
listed and includes six topics. Noise and acoustics, is one of them.
BEPAC (Building Environmental Performance Assessment Criteria) is recommended by University of British
Columbia. It is applied to office buildings. Indoor environment is considered to be a topic. And sound
insulation also assessed in this topic.
CASBEE (Comprehensive Assessment System for Building Environmental Efficiency) is developed in Japan.
The assessment system is applied to evaluate Building Environmental Efficiency (BEE). It mainly compares
environmental quality and performance to environmental loading. Sound environment is one parameter that
it includes background noise, sound insulation and sound absorption.
Besides, Evaluation for Green building in Taiwan includes nine indexes. Indoor environment index is one of
them. This index evaluates sound insulation, natural light, ventilation, decorating material and air quality.




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                                                                                                                                                  The 2005 World Sustainable Building Conference,
                                                                                                                                                  Tokyo, 27-29 September 2005 (SB05Tokyo)



2.                             Measurements
Interior noise in houses is measured by precision instruments. The contents of field measurements include
noise sources and sound pressure levels. Noise sources such as washing machine, water closet, air
conditioner, refrigerator, ventilation fan, exhaust fan, television, water heater and pump.

2.1                            Samples
The samples are selected in urban city that include eleven houses, five apartments and one traditional
house.


2.2                            Method
The precision instruments are sound pressure levels meter, RION NL-11 and sound analyzer, RION NA-27.
Frequency domain is from 63Hz to 8000Hz. Sound pressure levels (SPL) are recorded by 1/1 octave band
centre frequency. The overall value is also captured. Sound pressure levels of those noises are measured
at one meter in front of residential equipments.


2.3                            Frequency characteristics of interior noises
The results of interior noises are shown in figure 1 to figure 7. those noise sources are window air
conditioners、separate air conditioner、Pumps、ventilation fans、washing machines、water closets and
exhaust fans. SPL of window air conditioners in Figure 1 show from 50 dB(A) to 63dB(A), and frequency
characteristics display striking noise locate at middle frequency domain. In figure 2, SPL of separate air
                                                                                           its ey o y
conditioner is about 69 dB(A). In figure 3, SPL of pumps has the most value about 87 dB(A), ’av r n i  s
source. In figure 4, SPL of ventilation fans are from 56dB(A) t0 70dB(A). In figure 5, SPL of washing
machines are from 54 dB(A) to 63dB(A). In figure 6, SPL of water closets are from 64 dB(A) to 73dB(A). In
figure 7, SPL of exhaust fans are from 64dB(A) to 85dB(A), it also creates loud noise.


                                                                                                                               80
                                                                                                                               70
                                                                                                                               60
                                                                                                      Sound pressure levels
      Sound pressure levels




                                         70                                                                                    50
                                         60                                                                                    40
                                                                                                             dB(A)




                                         50                                                                                    30
             dB(A)




                                         40                                                                                    20
                                         30
                                                                                                                               10
                                         20
                                         10                                                                                    0
                                          0                                                                                         63     125   250   500     1k    2k     4k     8k    Lin
                                                                                                                                                       Frequency, Hz
                                                63   125   250 500     1k   2k   4k   8k   Lin
                                                                 Frequency, Hz                                                                    indoor fan         outdoor chiller

 Figure 1 SPL of window air conditioners .                                                            Figure 2 SPL of separate air conditioner .


                                         100
     S o u n d p re s s u re le v e ls




                                                                                                                               80
                                                                                                       Sound pressure levels




                                          90                                                                                   70
                                          80                                                                                   60
                                          70                                                                                   50
                d B (A )




                                                                                                              dB(A)




                                          60                                                                                   40
                                          50                                                                                   30
                                          40                                                                                   20
                                          30                                                                                   10
                                          20                                                                                    0
                                               63    125   250   500   1k   2k   4k   8k    Lin                                      63     125 250 500        1k      2k    4k    8k    Lin
                                                                 Frequency, Hz                                                                           Frequency, Hz

 Figure 3 SPL of Pumps .                                                                              Figure 4                            SPL of ventilation fans.




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                                                                                                                                  The 2005 World Sustainable Building Conference,
                                                                                                                                  Tokyo, 27-29 September 2005 (SB05Tokyo)




                                                                                                           80
 Sound pressure levels

                          70




                                                                                   Sound pressure levels
                                                                                                           70
                          60
                          50                                                                               60
        dB(A)



                          40                                                                               50




                                                                                          dB(A)
                          30                                                                               40
                          20                                                                               30
                          10                                                                               20
                           0                                                                               10
                               63       125 250 500   1k    2k   4k   8k   Lin                              0
                                                                                                                63    125   250      500    1k     2k     4k     8k     Lin
                                                 Frequency, Hz                                                                       Frequency, Hz

 Figure 5                           SPL of washing machines .                      Figure 6                          SPL of water closets .


                              90
      Sound pressure levels




                              80
                              70
             dB(A)




                              60
                              50
                              40
                              30
                              20
                                   63   125 250 500    1k   2k   4k   8k   Lin
                                                 Frequency, Hz

 Figure 7                           SPL of exhaust fans.


2.4                      The average of sound pressure levels (SPL)
Sound pressure levels of interior noises are shown in table 1. Noise dynamic range and the average are
tabulated. Outdoor noise of exhaust fans gets the highest noise about 75.8 dB(A) . Pumps get the second
one about 74.3 dB(A). Refrigerator is the quietest source about 43 dB(A).


                                          Table 1 Sound pressure levels (SPL) of various noise sources. Unit: dB(A)
                                                  Noise sources       samples     Noise dynamic      The average
                                                                                        range
                                          Water closets                  19          64.3-77.7         71.1
                                          washing machines               14          53.5-68.8         60.7
                                          window air conditioners         8          50.8-67.5         58.1
                                          pumps                           6          67.8-87.2         74.3
                                          underwater pumps                2          55.6-59.8         57.7
                                          ventilation fans—indoor        14          56.1-74.9         65.5
                                            noise
                                          ventilation fans—outdoor        2          60.3-65.2         62.8
                                            noise
                                          refrigerators                   2          40.6-45.4         43
                                          separate air conditioner—       1               -            69.3
                                            outdoor chiller
                                          separate air conditioner—       2          55.0-61.1         58.1
                                            indoor fan
                                          Car noise from basement         5          60.3-74.2         69
                                            entrance
                                          exhaust fans—indoor noise       7          65.5-80.6         72.5
                                          exhaust fans—outdoor            3          64.4-84.8         75.8
                                            noise




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                                                                                                                                                                                The 2005 World Sustainable Building Conference,
                                                                                                                                                                                Tokyo, 27-29 September 2005 (SB05Tokyo)



3.              Survey of questionnaire
In order to realize the aspect of sound environment on residential quality this study surveys noise annoyance
of interior noise and neighborhood noise by questionnaires.


3.1             Samples of questionnaire
The samples of survey have sixty four that include thirty seven samples from houses, fifteen samples from
apartments, five samples from apartment in combined building and seven samples from the others.


3.2             Noise annoyance
The results in figure 8 show Annoying degrees of various noises. Water heater noise has 63% of no
annoyance, water closets noise has 83% from a little annoying to extremely annoying, electric motor door
noise has 65% from a little annoying to extremely annoying, computer noise has 67%, washing machine
noise has 68%, window air conditioner noise has 66%, separate air conditioner noise has 42%, pump noise
has 60%. To compare the whole annoyances we get the order of annoying degrees that water heater noise
is the least annoying source. Ventilation fans get the most percentage of seriously annoying factor. Pumps
get the most percentage of extremely annoying factor.



              100%
                90%
                80%
                70%
                60%
                50%
                40%
                30%
                20%
                10%
                  0%                                                                              w ashing       w ashing      w ashing                   ventilation ventilation  w indow air   w indow air  separate air
                                                          electric motor
                          w ater heater   flush toilets                    computer     printer   machine--     machine--    machin--bee-   television            d
                                                                                                                                                         fn —i o r fn —o to r conditioners-- conditioners-- c n i n r
                                                                                                                                                         a s n o a s ud o                                         to
                                                                                                                                                                                                               o di e—         pumps   refrigerators
                                                               door
                                                                                                  w ashing    w ater release  bee sound                     noise       noise     outdoor noise indoor noise outdoor chiller

     not annoying             63%            17%              35%            33%         23%        32%           32%            36%          17%           31%           45%           42%           34%           58%        40%         44%
     a little annoying        31%            63%              33%            54%         45%        35%           40%            48%          42%           32%           28%           32%           41%           19%        22%         28%
     fair annoying             6%            17%              24%            11%         27%        29%           24%            15%          41%           24%           19%           14%           15%           23%        31%         25%
     seriously annoying        0%             2%               7%            2%          5%          5%            3%            2%            0%           13%            9%           12%           10%           0%          4%         4%
     extremely annoying        0%             2%               0%            0%          0%          0%            2%            0%            0%            0%            0%           0%            0%            0%          4%         0%




                                                                                      Figure 8        Annoying degrees of various noises.


3.3             Neighborhood noise
According to the result of survey we get table 2. It shows electric motor door noise is the highest annoyance
from neighborhood noises about 24%, Air conditioner is the second one has 20%.

                                                          Table 2 The percentages of annoyance from neighborhood noises.
                                                            Number        Noise sources      Percentages of annoyance
                                                                1      Air conditioner                  20 %
                                                                2      Washing machine                   9%
                                                                3      Water closets                    12 %
                                                                4      Television                       17 %
                                                                5      Electric motor door              24 %
                                                                6      Pump                              9%
                                                                7      Others                           11 %




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                                                                             The 2005 World Sustainable Building Conference,
                                                                             Tokyo, 27-29 September 2005 (SB05Tokyo)




4.     Interior allowable noise index

This study collects international standards about interior allowable noise index as table 3, such as from
Australia standard, Architectural Society of Japan, ASHRAE, EPA of U.S.A., Finland, Hungary, Sweden, U.K.
and R.O.C. Most standards recommend interior allowable noise index within 30 dB(A) to 40dB(A).

                                      Table 3 Interior allowable noise index.
                                            Interior allowable noise index
                  Australia standard        35dB(A)
                  Architectural Society of Superior class: 30dB(A),NC20,NR25
                  Japan                     First class: 35dB(A),NC25,NR30
                                            Second class: 40dB(A),NC30,NR35
                  ASHRAE                    HVAC: RC25-35
                  EPA of U.S.A.             45dB(A),NC40,NR45
                  Finland                   Daytime: 35dB(A),nighttime: 30dB(A)
                  Hungary                   Daytime: 40dB(A),nighttime: 35dB(A)
                  Sweden                    Close window: 30dB(A),open window:
                                            55dB(A)
                  U.K.                      Urban living room: 50dB(A)
                                            Urban bedroom: 35dB(A)
                                            Suburban living room: 45dB(A)
                                            Suburban bedroom: 40dB(A)
                  R.O.C.(Draft)             40dB(A)




5.       Strategy

Interior sound environment in buildings is a very important factor of residential qualities. Besides sustainable
building in the world also consider it to promote the environment now. So we recommend the strategy of
improving interior sound environment could consider the following items,
a. Reduce or control noise of machine and equipment product.
b. Consider the site of noisy sources to avoid impacting sound environment.
c.   Evaluate noise path and handle with various ways such as sound barrier, silencer, enclosure, etc.
d. Improve the sound insulation of wall or partition.
e. Control vibration from machines and equipments.
f.   Control neighborhood noise by increasing the distance.


6.       Conclusions
a. Sound environment is discussed about sustainable buildings by several international assessment criteria.
b. According to field measurements interior noise in order from high SPL to low SPL, they are water closets,
   indoor noise of ventilation fans, washing machines, window air conditioners, indoor fan of separate air
   conditioner and refrigerators. Outdoor noise in order from high SPL to low SPL, they are exhaust fans,
   pumps, outdoor chiller of separate air conditioner, Car noise from basement entrance, outdoor noise of
   ventilation fans. Outdoor noise becomes neighborhood noise.
c. Most sound pressure levels of interior noises are larger than Interior allowable noise index. Those are
   window air conditioners、separate air conditioner、Pumps、ventilation fans、washing machines、water
   closets.
d. The result of survey display annoyance degrees of equipments from extreme annoyance to no annoyance
   they are water closets and television, indoor noise of ventilation fans, washing machines, indoor noise of




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                                                                              The 2005 World Sustainable Building Conference,
                                                                              Tokyo, 27-29 September 2005 (SB05Tokyo)



   window air conditioners, pumps, outdoor noise of ventilation fans, outdoor chiller of separate air
   conditioner and water heater.
e. This study collects international standards about interior allowable noise index.


References

Building Research Establishment, 2005, Building Research Establishment Environment Assessment Method.

U.S. Green Building Council, 2004, Leadership in Energy and Environment Design.

Green Building Challenge, 2005, Green Building Tool.

University of British Columbia, Canada, Building Environmental Performance Assessment Criteria.

Architecture and Building Research Institute, Ministry of the Interior Affairs, 2005, Evaluation manual for
green buildings in Taiwan.


Acknowledgement
Thanks to National Science Council of R.O.C. sponsor this research.




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