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1 1 가전제품의음향파워레벨실태조사 - 냉장고, 진공청소기, 세탁기, 에어컨디셔너, 레인지후드, 선풍기를중심으로 - 교통환경연구소 강대준, 구진회, 이재원, 박형규, 김태석, 권혁제, 김종춘 Survey of the Sound Power Level of Electric Home Appliances - On refrigerator, vacuum cleaner, washing machine, air conditioner, range hood and electric fan - Daejoon Kang, J. Gu, J. W. Lee, H. K. Park, T. S. Kim, H. J. Kwon, J. C. Kim National Institute of Environmental Research 26 국립환경과학원

2 요약문 1. 제목 가전제품의음향파워레벨실태조사 - 냉장고, 진공청소기, 세탁 기, 에어컨디셔너, 레인지후드, 선풍기를중심으로 2. 목적일상생활에서흔히사용하는가전제품중청소기, 레인지후드는고소음을발생시키고, 냉장고, 세탁기, 에어컨디셔너등은저주파의소음을발생시켜일시적청력장애, 대화방해, 거슬림등의현상이나타날수있다. 또한에어컨실외기소음은외부로방사되어주위에영향을미친다. 그러나, 가전제품의사용은필요에의한것이기때문에소음의피해에대해서는간과하기쉽다. 따라서, 가전제품의소음특성을파악하고현황을조사하여저소음제품의생산을유도하는정책이필요하며, 가전제품에대한소음표시제의국내적용가능성을타진코자한다. 3. 연구내용및방법 o 주요가전제품의음향파워레벨측정방법조사 - 음향파워레벨측정방법중직접법과비교법의비교 - 반무향실및잔향실에서의음향파워레벨측정방법및결과비교 o 주요가전제품의음향파워레벨실태조사 - 고주파소음을발생하는가전제품 : 청소기, 레인지후드등의음향 - i -

3 파워레벨현황조사 - 저주파소음을발생하는가전제품 : 냉장고, 세탁기, 에어컨디셔너등의음향파워레벨현황조사 o 가전제품의음향특성조사 - 조사대상가전제품의주파수별소음특성조사 - 소음발생미캐니즘구명 ( 究明 ) o 가전제품에대한소음표시제적용가능성조사 - 외국의소음표시제사례조사 - 국내에가전제품의소음표시제적용가능대상제품선정 4. 연구결과가전제품중냉장고 12대, 세탁기 6대, 진공청소기 16대, 에어컨디셔너 6대, 레인지후드 7대, 선풍기 13대의음향파워레벨및음향특성을분석한결과는다음과같다. o 가전제품의주파수대역별음향특성 - 진공청소기와레인지후드는고주파성분이강하고, 냉장고, 세탁기, 에어컨디셔너는저주파성분이강하다. - 세탁기의음향파워레벨은탈수할때 (63.7 dba) 가세탁할때 (56.7 dba) 보다약 7 db정도크다. - 에어컨디셔너의음향파워레벨은실외기 (61.8 dba) 가실내기 (53.3 dba) 보다약 8.5 db정도크다. - ii -

4 o 가전제품의음향파워레벨측정방법비교 - 진공청소기의경우음향파워레벨의측정불확도 ( 표준편차 ) 가 1.7 db로각측정방법에따른오차가크지않다. - 레인지후드, 냉장고, 세탁기-세탁, 세탁기-탈수, 에어컨디셔너-실내기, 에어컨디셔너-실외기의경우음향파워레벨의측정불확도 ( 표준편차 ) 가각각 2.3, 3., 2.1, 1.2, 3.3, 3.3 db로에어컨디셔너가측정방법에따른오차가가장크다. o 가전제품의음향파워레벨현황 - 진공청소기는 74.6~85.7 dba, 레인지후드는 49.1~69.5 dba, 냉장고는.1~48 dba, 세탁기 ( 세탁 ) 는 53.2~6.6 dba, 세탁기 ( 탈수 ) 는 59.5~7.4 dba, 에어컨디셔너 ( 실내기 ) 는 44.5~62.2 dba, 에어컨디셔너 ( 실외기 ) 는 52.9~67.4 dba의음향파워레벨로진공청소기가가장큰음향파워레벨을발생하고냉장고가가장작은음향파워레벨을발생한다. o 가전제품의소음표시제적용가능성타진 - 음향파워레벨의크기는작으나지속성이크고근거리의실내에서사용자에게영향을주기때문에소음표시제를채택하여저소음제품을구매 생산토록유도할필요가있다. 5. 연구결과의활용에대한건의 o 소비자에게정보를제공하여저소음제품을구매하도록하고생산자 - iii -

5 로하여금저소음제품을생산하도록유도 o 정온한환경조성을위한정책자료로활용 o 실내공간에서의음의질향상을위한기초자료로활용 - iv -

6 Contents Abstract ⅹⅹ Ⅰ. Introduction 1 Ⅱ. Contents and Method 3 1. Investigation Period 3 2. Investigation Subject 3 3. Measurement Method 3 a. Anechoic room method 3 b. Sound intensity method 7 c. Reverberation room method 1 Ⅲ. Results and Discussion Sound power level of refrigerator 16 a. Anechoic room method 16 b. Sound intensity method 16 c. Direct method in the reverberation room 17 d. Comparison method in the reverberation room Sound power level of range hood Sound power level of vacuum cleaner Sound power level of washing machine Sound power level of air-conditioner 54 - v -

7 6. Sound power level of electric fan Characteristics of noise and vibration on electric home appliances78 8. Technology of reducing noise and vibration of the electric home appliances An example of noise labelling from in individual countries Investigation of possibility of applying the noise labelling98 Ⅳ. Conclusion 99 Reference 11 Appendix 17 - vi -

8 목 차 Abstract ⅹⅰ Ⅰ. 서론 1 Ⅱ. 조사내용및방법 3 1. 조사기간 3 2. 조사내용 3 3. 측정방법 3 가. 반무향실법 3 나. 음향세기측정법 7 다. 잔향실법 1 Ⅲ. 연구결과및고찰 냉장고의음향파워레벨 16 가. 반무향실측정법 16 나. 음향세기측정법 16 다. 잔향실직접법 17 라. 잔향실비교법 레인지후드의음향파워레벨 진공청소기의음향파워레벨 세탁기의음향파워레벨 45 - vii -

9 5. 에어컨디셔너의음향파워레벨 선풍기의음향파워레벨 가전제품의소음 진동특성 가전제품의소음 진동저감대책 외국의소음표시제사례 소음표시제적용가능성타진 98 Ⅳ. 결론 99 참고문헌 11 Appendix 17 - viii -

10 Table Caption <Table 3-1> Measurement method of the electric home appliances for noise labelling 97 - ix -

11 Figure Caption (Fig. 2-1) Measurement of the sound power level in the semi anechoic room 4 (Fig. 2-2) Hemispherical measurement surface - key measurement points 5 (Fig. 2-3) Microphone array on the parallelepiped 5 (Fig. 2-4) Measurement of the sound power level by intensity method 8 (Fig. 2-5) Selection of the position of microphone for fixed microphone 12 (Fig. 2-6) Measurement of the sound power level by comparison method in the reverberation room 15 (Fig. 3-1) Sound power level of refrigerator measured by semi anechoic room method 16 (Fig. 3-2) Sound power level of refrigerator measured by inten sity method. 17 (Fig. 3-3) Sound power level of refrigerator measured by direct method in the reverberation room 17 (Fig. 3-4) Sound power level of refrigerator measured by comparison method in the reverberation room 18 (Fig. 3-5) 1/3 Octave band frequency analysis of the noise of refrigerator A 19 (Fig. 3-6) 1/3 Octave band frequency analysis of the noise of - x -

12 refrigerator B 19 (Fig. 3-7) 1/3 Octave band frequency analysis of the noise of refrigerator C 2 (Fig. 3-8) 1/3 Octave band frequency analysis of the noise of refrigerator D 2 (Fig. 3-9) 1/3 Octave band frequency analysis of the noise of refrigerator E 22 (Fig. 3-1) 1/3 Octave band frequency analysis of the noise of refrigerator F 21 (Fig. 3-11) 1/3 Octave band frequency analysis of the noise of refrigerator G 22 (Fig. 3-12) 1/3 Octave band frequency analysis of the noise of refrigerator H1 22 (Fig. 3-13) 1/3 Octave band frequency analysis of the noise of refrigerator H2 23 (Fig. 3-14) 1/3 Octave band frequency analysis of the noise of refrigerator H3 23 (Fig. 3-15) 1/3 Octave band frequency analysis of the noise of refrigerator I 24 (Fig. 3-16) 1/3 Octave band frequency analysis of the noise of refrigerator J 24 (Fig. 3-17) A typical stand of the range hood 25 (Fig. 3-18) Sound power level of range hood measured by anechoic room method 26 - xi -

13 (Fig. 3-19) Sound power level of range hood measured by intensity method 27 (Fig. 3-2) Sound power level of range hood measured by direct method in reverberation room 27 (Fig. 3-21) Sound power level of range hood measured by comparison method in reverberation room 28 (Fig. 3-22) 1/3 Octave band frequency analysis of PWL of range hood A 29 (Fig. 3-23) 1/3 Octave band frequency analysis of PWL of range hood B 29 (Fig. 3-24) 1/3 Octave band frequency analysis of PWL of range hood C 3 (Fig. 3-25) 1/3 Octave band frequency analysis of PWL of range hood D 3 (Fig. 3-26) 1/3 Octave band frequency analysis of PWL of range hood E 31 (Fig. 3-27) 1/3 Octave band frequency analysis of PWL of range hood F 31 (Fig. 3-28) 1/3 Octave band frequency analysis of PWL of range hood G 32 (Fig. 3-29) Structure of the vacuum cleaner 33 (Fig. 3-3) Sound power level of vacuum cleaner measured by anechoic room method 34 (Fig. 3-31) Sound power level of vacuum cleaner measured by - xii -

14 intensity method 35 (Fig. 3-32) Sound power level of vacuum cleaner measured by direct method in reverberation room 35 (Fig. 3-33) Sound power level of vacuum cleaner measured by comparison method in reverberation room 36 (Fig. 3-34) 1/3 Octave band frequency analysis of PWL of vacuum cleaner A 37 (Fig. 3-35) 1/3 Octave band frequency analysis of PWL of vacuum cleaner B 37 (Fig. 3-36) 1/3 Octave band frequency analysis of PWL of vacuum cleaner C 38 (Fig. 3-37) 1/3 Octave band frequency analysis of PWL of vacuum cleaner D 38 (Fig. 3-38) 1/3 Octave band frequency analysis of PWL of vacuum cleaner E 39 (Fig. 3-39) 1/3 Octave band frequency analysis of PWL of vacuum cleaner F 39 (Fig. 3-) 1/3 Octave band frequency analysis of PWL of vacuum cleaner G (Fig. 3-41) 1/3 Octave band frequency analysis of PWL of vacuum cleaner H (Fig. 3-42) 1/3 Octave band frequency analysis of PWL of vacuum cleaner I 41 (Fig. 3-43) 1/3 Octave band frequency analysis of PWL of vacuum - xiii -

15 cleaner J 41 (Fig. 3-44) 1/3 Octave band frequency analysis of PWL of vacuum cleaner K 42 (Fig. 3-45) 1/3 Octave band frequency analysis of PWL of vacuum cleaner L 42 (Fig. 3-46) 1/3 Octave band frequency analysis of PWL of vacuum cleaner M 43 (Fig. 3-47) 1/3 Octave band frequency analysis of PWL of vacuum cleaner N 43 (Fig. 3-48) 1/3 Octave band frequency analysis of PWL of vacuum cleaner O 44 (Fig. 3-49) 1/3 Octave band frequency analysis of PWL of vacuum cleaner P 44 (Fig. 3-5) Sound power level of washing machine measured by direct method in reverberation room(laundry) 46 (Fig. 3-51) Sound power level of washing machine measured by direct method in reverberation room(spin drying) 46 (Fig. 3-52) Sound power level of washing machine measured by comparison method in reverberation room(laundry) 47 (Fig. 3-53) Sound power level of washing machine measured by comparison method in reverberation room(spin drying) 48 (Fig. 3-54) 1/3 Octave band frequency analysis of PWL of washing machine A during laundry 48 (Fig. 3-55) 1/3 Octave band frequency analysis of PWL of - xiv -

16 washing machine B during laundry 49 (Fig. 3-56) 1/3 Octave band frequency analysis of PWL of washing machine C during laundry 49 (Fig. 3-57) 1/3 Octave band frequency analysis of PWL of washing machine D during laundry 5 (Fig. 3-58) 1/3 Octave band frequency analysis of PWL of washing machine E during laundry 5 (Fig. 3-59) 1/3 Octave band frequency analysis of PWL of washing machine F during laundry 51 (Fig. 3-6) 1/3 Octave band frequency analysis of PWL of washing machine A during spin drying 51 (Fig. 3-61) 1/3 Octave band frequency analysis of PWL of washing machine B during spin drying 52 (Fig. 3-62) 1/3 Octave band frequency analysis of PWL of washing machine C during spin drying 52 (Fig. 3-63) 1/3 Octave band frequency analysis of PWL of washing machine D during spin drying 53 (Fig. 3-64) 1/3 Octave band frequency analysis of PWL of washing machine E during spin drying 53 (Fig. 3-65) 1/3 Octave band frequency analysis of PWL of washing machine F during spin drying 54 (Fig. 3-66) Sound power level of indoor unit of air-conditioner measured by anechoic room method 55 (Fig. 3-67) Sound power level of outdoor unit of air-conditioner - xv -

17 measured by anechoic room method 55 (Fig. 3-68) Sound power level of indoor unit of air-conditioner measured by intensity method 56 (Fig. 3-69) Sound power level of outdoor unit of air-conditioner measured by intensity method 57 (Fig. 3-7) Sound power level of indoor unit of air-conditioner measured by direct method in reverberation room 58 (Fig. 3-71) Sound power level of outdoor unit of air-conditioner measured by direct method in reverberation room 58 (Fig. 3-72) Sound power level of indoor unit of air-conditioner measured by comparison method in reverberation room 59 (Fig. 3-73) Sound power level of outdoor unit of air-conditioner measured by comparison method in reverberation room 6 (Fig. 3-74) 1/3 Octave band frequency analysis of indoor unit of air-conditioner A 61 (Fig. 3-75) 1/3 Octave band frequency analysis of indoor unit of air-conditioner B 61 (Fig. 3-76) 1/3 Octave band frequency analysis of indoor unit of air-conditioner C 62 (Fig. 3-77) 1/3 Octave band frequency analysis of indoor unit of air-conditioner D 62 (Fig. 3-78) 1/3 Octave band frequency analysis of indoor unit of - xvi -

18 air-conditioner E 63 (Fig. 3-79) 1/3 Octave band frequency analysis of indoor unit of air-conditioner F 63 (Fig. 3-8) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner A 64 (Fig. 3-81) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner B 64 (Fig. 3-82) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner C 65 (Fig. 3-83) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner D 65 (Fig. 3-84) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner E 66 (Fig. 3-85) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner F 66 (Fig. 3-86) Sound power level of electric fan measured by anechoic room method 67 (Fig. 3-87) Sound power level of electric fan measured by intensity method 68 (Fig. 3-88) Sound power level of electric fan measured by direct method in reverberation room 69 (Fig. 3-89) Sound power level of electric fan measured by comparison method in reverberation room 7 (Fig. 3-9) 1/3 Octave band frequency analysis of PWL of electric - xvii -

19 fan A 71 (Fig. 3-91) 1/3 Octave band frequency analysis of PWL of electric fan B 71 (Fig. 3-92) 1/3 Octave band frequency analysis of PWL of electric fan C 72 (Fig. 3-93) 1/3 Octave band frequency analysis of PWL of electric fan D 72 (Fig. 3-94) 1/3 Octave band frequency analysis of PWL of electric fan E 73 (Fig. 3-95) 1/3 Octave band frequency analysis of PWL of electric fan F 73 (Fig. 3-96) 1/3 Octave band frequency analysis of PWL of electric fan G 74 (Fig. 3-97) 1/3 Octave band frequency analysis of PWL of electric fan H 74 (Fig. 3-98) 1/3 Octave band frequency analysis of PWL of electric fan I 75 (Fig. 3-99) 1/3 Octave band frequency analysis of PWL of electric fan J 75 (Fig. 3-1) 1/3 Octave band frequency analysis of PWL of electric fan K 76 (Fig. 3-11) 1/3 Octave band frequency analysis of PWL of electric fan L 76 (Fig. 3-12) 1/3 Octave band frequency analysis of PWL of - xviii -

20 electric fan M 77 (Fig. 3-13) 1/3 Octave band frequency analysis of PWL of electric fan N 77 (Fig. 3-14) Sources of refrigerator noise 78 (Fig. 3-15) Structure of compressor for refrigerator 79 (Fig. 3-16) Transmission path of refrigerator noise 8 (Fig. 3-17) Sources of range hood noise 81 (Fig. 3-18) Sources of vacuum cleaner noise 83 (Fig. 3-19) Sources of washing machine noise 85 (Fig. 3-11) Sources of indoor-unit noise in the air conditioner system 86 (Fig ) Principle of a cooling system in the air-conditioner 86 (Fig ) T-S chart of the irreversible refrigeration cycle 87 (Fig ) Sources of outdoor-unit noise in the air conditioner system 88 (Fig ) Sound power level of six electric home appliances 98 - xix -

21 ABSTRACT The sound power level of six electric home appliances was investigated in the anechoic room and reverberation room using the four methods for sound power level. As the economy has grown and the main industry in Korea has been changed from secondary industry to tertiary industry, importance of indoor environment has been a matter of common concern, in which one of the main concerns is to improve indoor acoustic conditions. However, even though this is required more than before, there are no measures to protect the human being from the noise of electric home appliances. This is owing to the absence of the data about sound power level of electric home appliances. So, we investigate the sound power level of electric home appliances and analyze the acoustical characteristics of each one. First, we tried to investigate the measuring method of each electric home appliance. After it we test the sound power level of the electric home appliances. From the survey, we can know that the vacuum cleaner is the most noisy electric home appliance, and the refrigerator is the least noisy one. The noise of a range hood is distributed over a wide range frequency. Lastly, we intented to propose the proper method of measuring sound power level on each electric home appliance for applying the product noise labelling. - xx -

22 Ⅰ. 서론 산업기술의발달로생활환경이다양해지고편리해져주거환경의생활양식에많은변화가나타났다. 예전에없던가전제품들의사용증가로생활은편리해졌지만이들가전제품의가동으로인한생활소음이사회문제로나타나게되었다. 정온하고밀폐된공간에서사용되는가전제품의특성상낮은소음도민감하게사용자는느낄수있어쾌적한환경을추구하는소비자에게가전제품의소음도는제품선택시중요항목이되고있다. 종래의우리나라에서는가전제품의소음도측정시 A특성음압도를사용하였는데, 이것은음원으로부터공간으로방사된소리를어느한지점에서측정한값으로음원의성상뿐만아니라측정환경과측정위치에따라값이변화한다. 이에반해음향파워레벨은음원으로부터방사되는모든방향의총음에너지로주위환경에영향을거의받지않는다. 따라서기계의발주및검수를위한시방, 기계의소음저감효과의평가, 소음을예측하기위한기초자료로사용되고있다. 그중냉장고는근래들어대형화경향을보이면서생활필수품으로써정착됨에따라소비자들의요구가점점더다양해지고제품의질적고급화현상이더욱두드러지고있다. 이에소음및진동에대한문제에서도저소음 저진동의제품을요구하게되어가전제품제조회사에서도이에대한대책에많은노력과투자를하고있다. 한편, 가정용레인지후드는주거공간의쾌적성및실내공기질개선대책으로사용빈도가증가하고있으며저소음화에대한요구도늘어가고 - 1 -

23 있다. 현재레인지후드의제작기술은성능보다는주방기구의일부로서레인지후드의외관및주방가구와의조화를중점으로개발하고있는실정이다. 그밖에진공청소기, 세탁기, 에어컨디셔너, 선풍기등의가전제품또한생활소음을발생시키는대표적인가전제품이다. 따라서이연구에서는일반가정에서많이사용되는가전제품중냉장고 (12 종 ), 레인지후드 (6종 ), 진공청소기 (16 종 ), 세탁기 (6종 ), 에어컨디셔너 (6종 ), 선풍기 (13 종 ) 을대상으로반무향실및잔향실에서음압도를측정하여음향파워레벨을산출하고반무향실과잔향실에서이용된측정방법별음향파워레벨값을비교하였다. 이번시험을통해가전제품사용시노출되는소음도및주파수별소음특성을파악하여가전제품소음저감대책에활용하고가전제품소음표시제를대비한기초자료로활용할수있을것으로기대한다

24 Ⅱ. 조사내용및방법 1. 조사기간 26 년 1 월 ~12 월 (12 개월간 ) 2. 조사내용가정에서사용되는냉장고 (1 대 ) 를대상으로음압법에의한소음원의음향파워레벨측정방법중잔향실에서의정밀측정방법 (KS A ISO 3741), 반무향실및무향실에서의정밀측정방법 (KS A ISO 3745) 그리고음향세기에의한소음원의음향파워레벨측정방법 (KS A ISO 9614) 에따라반무향실과잔향실에서음압도를측정하여음향파워레벨을산출하였다. 3. 측정방법가. 반무향실법반무향실법은어떤음향파워를방사하는음원에서의측정구면또는반구면상에서평균한평균제곱음압이음향파워에비례한다는전제에바탕을둔측정법으로반사의영향이전혀없는반자유음장 (semi-free field) 의조건이성립하는반무향실에서측정한다. 반무향실측정법은 측정시주변환경의영향을거의받지않는환경을제공한다는장점이 있다

25 (1) 측정기기및측정방법측정은먼저위의반구면상의 1개지점에서반무향실내의배경소음을측정한후측정대상기기를작동시켜마이크로폰 (B&K Type 2671) 과 B&K PULSE System(Type 7536) 으로음압도를측정하였고비교법에서의기준음원은 Reference Sound Source(B&K Type 424) 을사용하여음향파워레벨을산출하였다. (Fig. 2-1) Measurement of the sound power level in the semi-anechoic room. (2) 측정환경반구면측정법에서사용하는구면은음원의음향중심에중심을두도록하였다. 측정구면의반지름은최대음원치수의 2배이상또는반사면으로부터음원의음향중심까지의거리의 3배이상중에서큰쪽을선택하였으며이연구에서는 2 m로선정하였다. 반구면에마이크로폰을 1개설치하였고, 설치위치는 (Fig. 2-2) 와같다. (Fig. 2-3) 은측정면 - 4 -

26 이평행육면체인경우이며, 한쪽벽면에붙여바닥에놓는기기의마이 크로폰설치위치를나타낸다. (Fig. 2-2) Hemispherical measurement surface - Key measurement points 한편, 에어컨디셔너의경우설치상의제약으로인해음향파워레벨측정면을평행육면체 (KS C IEC 674-1) 로하였다. 아래의 (Fig. 2-3) 은에어컨디셔너의측정면을나타낸다. 일반적으로기기의앞면은 x축방향을가리키며, 측정거리 d의선호되는값은 1 m이다. 여기에서 2a = + d, 2b = + d, c = + d 이다. (Fig. 2-3) Microphone array on the parallelepiped - 5 -

27 (3) 음향파워레벨의산출 마이크로폰위치가시험구의같은부분면적에대응하고있을때에는 표면음압도 를얻기위하여아래의식 (1) 을사용한다. =1 log (1) 여기에서 : 시험구상의표면음압도 (db) : i 번째의마이크로폰위치에대한배경소음을보정한음압도 (db), 기준값 (2 Pa) N : 마이크로폰위치의수 한편, 음향파워레벨은다음의식 (2) 로산출한다. = + + C (2) 여기에서 : 측정대상의음향파워레벨 (db) = 4 : ( 반지름 r 의 ) 시험구의면적 = 1 m ( 기준면적 ) C : 온도및대기압의영향에대한보정항 (db) C = -25 여기에서 : 섭씨온도 : 기압 (hpa) : hpa ( 표준대기압 ) - 6 -

28 나. 음향세기측정법음향세기는어떤점의순간입자속도방향에수직인단위단면적을통화하는단위시간당의음향에너지흐름의순간값 (W/m ) 을나타낸다. 따라서측정단면적을지나는수직인음향세기성분의총합은부분음향파워레벨이되며, 전체측정면에대한부분음향파워레벨의총합은측정대상으로하는소음원의전체음향파워레벨이된다. 즉, 음원으로부터방사되는음향파워는음원을둘러싼폐곡면에서의음향세기벡터와면요소벡터의스칼라적을폐곡면전체에걸쳐서적분한것과같다. 음향세기에의한소음원의음향파워레벨측정방법은시험환경의배경소음에의한영향이작고, 실제로음원이설치되어있는장소에서도측정할수있다는장점이있다. (1) 측정기기및측정방법먼저음향세기의측정은 B&K 社의음향세기측정기 (Sound Intensity Probe Kit - Type 3599) 를이용하였고, 음향파워레벨의산정은 B&K 社의 PULSE System(Type 7536) 을이용하였다. 아래의 (Fig. 2-4) 는음향세기측정기를이용하여음향세기를측정하는그림이다. 음향세기측정에의한음향파워레벨은 KS A ISO ( 스캐닝에의한측정 ) 에의한방법으로수행하였다

29 (Fig. 2-4) Measurement of the sound power level by intensity method (2) 소음원의설치소음원은반무향실의중앙에설치하였다. 소음원의바닥에는소음원의진동을절연할수있는진동절연체 ( 카펫트 ) 를깔았다. 측정시소음원은최대의출력상태로고정하였다. (3) 음향세기스캐닝음향세기측정기의스캐닝은수동으로행하였다. 음향세기의스캐닝은설정한경로를따라서, 측정면에대한프로브축이항상수직이되도록하고, 프로브의이동속도 (.1~.5 m/s) 가일정하도록주의하여스캐닝하였다. 측정면은 5개의면요소로분할하였으며 1개의면요소상에서의 1-8 -

30 회스캐닝시간은 2 초이상으로하였다. 각측정면에서음원과면요소 의평균거리가 2 mm 이상되도록설정하였다. (4) 음향파워레벨의산출 1 각면요소의부분음향파워계산각면요소에서아래의식 (1) 에의해각주파수대역의부분음향파워를계산한다. (3) : i번째면요소의부분음향파워 : i번째면요소의면적 = : i 번째면요소에서측정된수 직음향세기성분의면상평균치 : i번째면요소에대한 2회의스캐닝에의 해측정된 의값 면요소 i에대한수직음향세기레벨 가 XX db로나타내어질경우, 값은 으로계산한다. 또한면요소 i에대한 수직음향세기레벨 가 (-)XX db로나타내어질경우, 의값은 으로계산한다. 여기서 는기준음향세기 (= W/m ) 이다

31 2 전체음향파워레벨의계산 각주파수대역마다음원의음향파워레벨 를식 (4) 에따라계산 한다. = db (4) 여기에서 N : 면요소의총수 : 식 (4) 로계산한 i 번째면요소의부분음향파워 : 기준음향파워 (= W/m ) 다. 잔향실법 잔향실법은공간및시간으로평균한평균제곱음압 ( ) 이그음향파 워에비례하고, 그외에는잔향실의음향특성과기하학적형상및공기의물리정수에만의존한다는사실에근거하고있다. 따라서잔향실에서측정된음향파워레벨은잔향실의고유모드와실내에서의음원위치에따라그크기가크게영향을받는특성이있다. 잔향실법에서의음향파워레벨측정은잔향실의잔향시간을이용하여산출하는직접법과기준음압을이용해산출하는비교법이있다. 이번시험에서는직접법과비교법으로가전제품의음향파워레벨을측정하였다. (1) 마이크로폰의위치선정 직접법으로측정시음원과마이크로폰 (B&K Type 2671) 위치사이 의거리는대상으로하는각주파수대역에서식 (5) 에의한값이상으로 - 1 -

32 한다. (5) 여기에서 : 음원과마이크로폰간거리의최소값 (m) :.8 : 잔향실의용적 (m 3 ) : 잔향시간 (s) 비교법으로측정시소음원과마이크로폰간의최소거리는아래식 (6) 으로 산출한다. (6) 여기서 d min : 음원과마이크로폰과의거리의최소값 (m) C 2 :.4 L wr : 기준음원의이미알고있는음향파워레벨 (db) L pr : 기준음원을작동할때의잔향실안의평균음압도 (db) 위의식으로없어진값을가지고잔향실의모든표면에서 1 m, 음원으로 부터 d min 보다더떨어진지점 6 곳에마이크로폰을설치하였다

33 (Fig. 2-5) Selection of the position of microphone for fixed microphone (2) 잔향시간을이용하여산출하는방법 ( 직접법 ) 측정대상음원의음향파워레벨은실내의평균음압도 (B&K PULSE System, Type 7536 사용 ) 과음원설치시에구한잔향실의등가흡음 면적을이용하여식 (7) 에따라서산출한다. (7) 여기에서 : 측정대상음원의음향파워레벨 (db)

34 : 실내평균음압도 (db) : 잔향실의등가흡음면적 (m 2 ) : 1 m 2 ( 기준흡음면적 ) : 잔향실의전체표면적 (m 2 ) : 잔향실의용적 (m 3 ) : 측정주파수대역의중심주파수 (Hz) : 소리의속력 (m/s) = 2.5 : 기온 ( ) : 기압 (hpa) : hpa ( 표준대기압 ) 잔향실의등가흡음면적 A 는각주파수대역마다, 세이빈의잔향식 ( 식 8) 에의해산출된다. (8) 여기에서 : 잔향실의등가흡음면적 (m 2 ) : 각주파수대역에서의잔향시간 (s) : 잔향실의용적 (m 3 ) (3) 기준음원의음향파워레벨과비교하여산출하는방법 ( 비교법 ) 1 기준음원의설치 기준음원 (Reference Sound Source, B&K 424) 의설치는잔향실

35 의모든벽면과측정대상음원으로부터 1.5 m 떨어진바닥위에한다. 2 기준음원에의한실내평균음압도의산출기준음원의작동에의한실내평균음압도를산출한다. 기준음원에의한음압도는대상주파수범위의모든대역에서배경소음보다도 15 db 이상크므로, 배경소음에대한보정은필요로하지않는다. 3 측정대상음원의음향파워레벨산출측정대상음원의음향파워레벨은기준음원과측정대상음원에의한실내평균음압도로부터식 (9) 로산출한다. (9) 여기에서 : 측정대상음원의 1/3 옥타브대역음향파워레벨 : 특성임피던스 ρ c = 4, Ns/m 3 인환경조건하에서교정한기준음원의 1/3 옥타브대역음향파워레벨 : 실내평균 1/3 옥타브대역음압도 : 기준음원에의한실내평균 1/3 옥타브대역음압레벨

36 (Fig. 2-6) Measurement of the sound power level by comparison method in the reverberation room

37 Ⅲ. 연구결과및고찰 1. 냉장고의음향파워레벨냉장고소음은압축기가작동되는동안에측정한다. 냉장고소음측정시간은반무향실측정법에서는 3 초, 음향세기측정법에서는 18 초, 잔향실측정법에서는 3 초로하였다. 가. 반무향실측정법반무향실측정법에의한냉장고의음향파워레벨은아래의 (Fig. 3-1) 과같다. 평균음향파워레벨은약 45 dba 이며, 1, Hz미만의저주파성분이주를이루고있다 Refrigerator (Anechoic Room) ,6 3,15 6,3 O.A. A (Electric Power : 55 W, Volume: 16 L) B (Electric Power : 1,46 W, Volume: 5 L) C (Electric Power : 53 W, Volume: 18 L) D (Electric Power : 1,54 W, Volume: 36 L) E (Electric Power : 1,677 W, Volume: 5 L) F (Electric Power : 1,282 W, Volume: 57 L) G (Electric Power : 1,493 W, Volume: 4 L) H1 (Electric Power : 1,583 W, Volume: 425 L) H2 (Electric Power : 1,583 W, Volume: 425 L) H3 (Electric Power : 1,583 W, Volume: 425 L) I (Electric Power : 1,83 W, Volume: 679 L) J (Electric Power : 1,277 W, Volume: 5 L) (Fig. 3-1) Sound power level of refrigerator measured by semi-anechoic room method. 나. 음향세기측정법음향세기측정법에의한냉장고의음향파워레벨은아래의 (Fig. 3-2) 와같다. (Fig. 3-2) 에서알수있는바와같이평균음향파워레벨은약 41 dba 이며, 1, Hz 미만의저주파성분이주를이루고있다

38 Refrigerator (Intensity) ,6 3,15 6,3 O.A. A (Electric Power : 1,83 W, Side By Side Type, Volume: 679 L) B (Electric Power : 1,277 W, Top Mount Type, Volume: 5 L) (Fig. 3-2) Sound power level of refrigerator measured by intensity method. 다. 잔향실직접법잔향실직접법에의한냉장고의음향파워레벨은아래의 (Fig. 3-3) 과같다. 평균음향파워레벨은약 44 dba이며, 마찬가지로 1, Hz미만의저주파성분이주를이루고있다 Refrigerator (Reverberation Room[Direct]) ,6 3,15 6,3 O.A. A (Electric Power : 55 W, Volume: 16 L) B (Electric Power : 1,46 W, Volume: 5 L) C (Electric Power : 53 W, Volume: 18 L) D (Electric Power : 1,54 W, Volume: 36 L) E (Electric Power : 1,677 W, Volume: 5 L) F (Electric Power : 1,282 W, Volume: 57 L) G (Electric Power : 1,493 W, Volume: 4 L) H1 (Electric Power : 1,583 W, Volume: 425 L) H2 (Electric Power : 1,583 W, Volume: 425 L) H3 (Electric Power : 1,583 W, Volume: 425 L) I (Electric Power : 1,83 W, Volume: 679 L) J (Electric Power : 1,277 W, Volume: 5 L) (Fig. 3-3) Sound power level of refrigerator measured by direct method in the reverberation room

39 라. 잔향실비교법잔향실비교법에의한냉장고의음향파워레벨은아래의 (Fig. 3-4) 와같다. (Fig. 3-4) 에서알수있는바와같이평균음향파워레벨은약 45 dba 이며, 1, Hz미만의저주파성분이주를이루고있음을알수있다 Refrigerator (Reverberation Room[comparison]) ,6 3,15 6,3 O.A. A (Electric Power : 55 W, Volume: 16 L) B (Electric Power : 1,46 W, Volume: 5 L) C (Electric Power : 53 W, Volume: 18 L) D (Electric Power : 1,54 W, Volume: 36 L) E (Electric Power : 1,677 W, Volume: 5 L) F (Electric Power : 1,282 W, Volume: 57 L) G (Electric Power : 1,493 W, Volume: 4 L) H1 (Electric Power : 1,583 W, Volume: 425 L) H2 (Electric Power : 1,583 W, Volume: 425 L) H3 (Electric Power : 1,583 W, Volume: 425 L) I (Electric Power : 1,83 W, Volume: 679 L) J (Electric Power : 1,277 W, Volume: 5 L) (Fig. 3-4) Sound power level of refrigerator measured by comparison method in the reverberation room 냉장고음향파워레벨은저주파대역에서송풍기소음이주류를이루고있고, 고주파대역에서는압축기소음이주류를이루고있다. 각평가방법에따른음향파워레벨의측정불확도 ( 표준편차 ) 는평균 3. db이며, 평균음향파워레벨값은 5.8 dba로.1~6.8 dba에걸쳐서분포하고있다. 아래의 (Fig. 3-5~16) 은개개의냉장고에대한음향파워레벨측정결과를보여주고있다

40 6 Refrigerator A (Electric Power: 55 W, Volume : 16 L ) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-5) 1/3 Octave band frequency analysis of the noise of refrigerator A 6 Refrigerator B (Electric Power: 1,46 W, Volume : 5 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-6) 1/3 Octave band frequency analysis of the noise of refrigerator B

41 6 Refrigerator C (Electric Power: 53 W, Volume : 18 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-7) 1/3 Octave band frequency analysis of the noise of refrigerator C 6 Refrigerator D (Electric Power: 1,54 W, Volume : 679 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-8) 1/3 Octave band frequency analysis of the noise of refrigerator D - 2 -

42 6 Refrigerator E (Electric Power: 1,677 W, Volume : 5 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-9) 1/3 Octave band frequency analysis of the noise of refrigerator E 6 Refrigerator F (Electric Power: 1,282 W, Volume : 57 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-1) 1/3 Octave band frequency analysis of the noise of refrigerator F

43 6 Refrigerator G (Electric Power: 1,493 W, Volume : 4 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-11) 1/3 Octave band frequency analysis of the noise of refrigerator G 6 Refrigerator H-1 (Electric Power: 1,583 W, Volume : 425 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-12) 1/3 Octave band frequency analysis of the noise of refrigerator H1-22 -

44 6 Refrigerator H-2 (Electric Power: 1,583 W, Volume : 425 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-13) 1/3 Octave band frequency analysis of the noise of refrigerator H2 6 Refrigerator H-3 (Electric Power: 1,583 W, Volume : 425 L) ,6 3,15 6,3 O.A. Anechoic Room Reverberation Room(comparison) Reverberation Room(direct) (Fig. 3-14) 1/3 Octave band frequency analysis of the noise of refrigerator H3-23 -

45 Refrigerator I (Electric Power: 1,83 W, Volume : 679 L, Side by Side Type ) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-15) 1/3 Octave band frequency analysis of the noise of refrigerator I Refrigerator J (Electric Power: 1,277 W, Volume: 5 L, Top Mount Type ) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-16) 1/3 Octave band frequency analysis of the noise of refrigerator J

46 2. 레인지후드의음향파워레벨 레인지후드의음향파워레벨측정은가정용및이와유사한전기기기의소음측정방법-제2 13부 : 레인지후드의개별요구사항 (KS C IEC ) 을준용한다. 레인지후드의설치는규정에따라표준스텐드위에설치하고, 작동부하는최대로한다. 아래의 (Fig. 3-17) 은표준스텐드를보여준다. 표준스텐드는나무로제작이되고, 시험시진동의절연을위해바닥에고무판을깐다. 한편, 레인지후드의소음측정시간은반무향실법이 3초, 음향세기측정법이 18 초, 잔향실법은 3초로하였다. (Fig 3-17) A typical stand of the range hood

47 가. 반무향실측정법반무향실측정법에의한레인지후드의음향파워레벨은아래의 (Fig. 3-18) 과같다. 반무향실측정법에서평균음향파워레벨은약 64.9 dba 이며, 1, Hz 대역의중간주파수성분이주를이루고있다 Range Hood (Anechoic Room) ,6 3,15 6,3 O.A. A (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) B (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) C (Electric Power : 136 W, Wind Flow : 61 m3 /h, Power : 75 W) D (Electric Power : 6 W, Wind Flow : m3 /h, Power : 5 W) E (Electric Power : 122 W, Wind Flow : m3 /h, Power : 81 W) F (Electric Power : 65 W, Wind Flow : 36 m3 /h, Power : 65 W) G (Electric Power : 7 W, Wind Flow : 18 m3 /h, Power : 7 W) (Fig. 3-18) Sound power level of range hood measured by anechoic room method 나. 음향세기측정법음향세기측정법에의한레인지후드의음향파워레벨은아래의 (Fig. 3-19) 와같다. 음향세기측정법에서평균음향파워레벨은약 74.7 dba 이며, 1, Hz 대역의중간주파수성분이주를이루고있다

48 Range Hood (Intensity) ,6 3,15 6,3 O.A. A (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) B (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) C (Electric Power : 136 W, Wind Flow : 61 m3 /h, Power : 75 W) D (Electric Power : 6 W, Wind Flow : m3 /h, Power : 5 W) E (Electric Power : 122 W, Wind Flow : m3 /h, Power : 81 W) F (Electric Power : 65 W, Wind Flow : 36 m3 /h, Power : 65 W) G (Electric Power : 7 W, Wind Flow : 18 m3 /h, Power : 7 W) (Fig. 3-19) Sound power level of range hood measured by intensity method 다. 잔향실직접법잔향실직접법에의한레인지후드의음향파워레벨은아래의 (Fig. 3-2) 과같다. 잔향실직접법에서평균음향파워레벨은약 62.6 dba 이며, 1, Hz 대역의중간주파수성분이주를이루고있다 Range Hood (Reverberation Room[Direct]) ,6 3,15 6,3 O.A. A (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) B (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) C (Electric Power : 136 W, Wind Flow : 61 m3 /h, Power : 75 W) D (Electric Power : 6 W, Wind Flow : m3 /h, Power : 5 W) E (Electric Power : 122 W, Wind Flow : m3 /h, Power : 81 W) F (Electric Power : 65 W, Wind Flow : 36 m3 /h, Power : 65 W) G (Electric Power : 7 W, Wind Flow : 18 m3 /h, Power : 7 W) (Fig. 3-2) Sound power level of range hood measured by direct method in reverberation room

49 라. 잔향실비교법잔향실비교법에의한레인지후드의음향파워레벨은아래의 (Fig. 3-21) 과같다. 잔향실비교법에서평균음향파워레벨은약 73.4 dba 이며, 1, Hz 대역의중간주파수성분이주를이루고있다 Range Hood (Reverberation Room[comparison]) ,6 3,15 6,3 O.A. A (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) B (Electric Power : 9 W, Wind Flow : 66 m3 /h, Power : 1 W) C (Electric Power : 136 W, Wind Flow : 61 m3 /h, Power : 75 W) D (Electric Power : 6 W, Wind Flow : m3 /h, Power : 5 W) E (Electric Power : 122 W, Wind Flow : m3 /h, Power : 81 W) F (Electric Power : 65 W, Wind Flow : 36 m3 /h, Power : 65 W) G (Electric Power : 7 W, Wind Flow : 18 m3 /h, Power : 7 W) (Fig Sound power level of range hood measured by comparison method in reverberation room 레인지후드의각평가방법에대한음향파워레벨의측정불확도 ( 표준편차 ) 는평균 2.3 db이다. 음향파워레벨값은작게는냉장고수준 (~5 dba) 인 49.1 dba 에서크게는진공청소기수준 (7~9 dba) 인 69.5 dba 에걸쳐서가장넓게분포하고이는레인지후드각제품에따른음향파워레벨의편차가큼을알수있다. 아래의 (Fig. 3-22~28) 은개개의레인지후드에대한음향파워레벨측정결과를나타낸다

50 8 Range Hood A (Electric Power: 9 W, Wind Flow : 66 m3 /h, Motor Power : 1 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-22) 1/3 Octave band frequency analysis of PWL of range hood A Range Hood B (Electric Power: 9 W, Wind Flow : 66 m3 /h, Motor Power : 1 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-23) 1/3 Octave band frequency analysis of PWL of range hood B

51 Range Hood C (Electric Power: 136 W, Wind Flow : 61 m3 /h, Motor Power : 75 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-24) 1/3 Octave band frequency analysis of PWL of range hood C Range Hood D (Electric Power: 6 W, Wind Flow : m3 /h, Motor Power : 5 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-25) 1/3 Octave band frequency analysis of PWL of range hood D - 3 -

52 Range Hood E (Electric Power: 112 W, Wind Flow : m3 /h, Motor Power : 81 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-26) 1/3 Octave band frequency analysis of PWL of range hood E Range Hood F (Electric Power: 65 W, Wind Flow : 36 m3 /h, Motor Power : 65 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-27) 1/3 Octave band frequency analysis of PWL of range hood F

53 Range Hood G (Electric Power: 7 W, Wind Flow : 18 m3 /h, Motor Power : 7 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-28) 1/3 Octave band frequency analysis of PWL of range hood G

54 3. 진공청소기의음향파워레벨 진공청소기의음향파워레벨측정은가정용및이와유사한전기기기의소음측정방법-제2 1부 : 전기진공청소기의개별요구사항 (KS C IEC ) 을준용한다. 아래의 (Fig 3-29) 는진공청소기의음향파워레벨측정을위한측정환경을나타낸다. 진공청소기의노즐과기기본체와의이격거리는 2 cm로하였고, 바닥은규격 (KS C IEC ) 에따라카페트를깔았으며작동부하는최대로하였다. 기준시험카페트는종류가 Wilton 이고, 무게가 2.9 kg/m 이며, 양털재료 는처음짠 1 % 의양털로써양털의밀도는.1~.145 g/cm 이 다. 이연구에사용된카페트의크기는 1 1 m 이다. 한편, 진공청소기 의소음측정시간은반무향실법이 3 초, 음향세기측정법이 18 초, 잔 향실법은 3 초로하였다. (Fig 3-29) Structure of the vacuum cleaner

55 가. 반무향실측정법반무향실측정법에의한진공청소기의음향파워레벨은아래의 (Fig. 3-3) 과같다. 반무향실측정법에서평균음향파워레벨은약 82.1 dba 이다. 진공청소기의팬모터는약 3, rpm 이상의고속으로회전하며이때발생되는고주파영역의공력소음이주소음원으로써작용한다. 따라서진공청소기의음향파워레벨은 1,Hz 대역이상의성분이주를이루고있다. 1 Vacuum Cleaner (Anechoic Room) ,6 3,15 6,3 O.A. A (Electric Power : 1, W) B (Electric Power : 1, W) C (Electric Power : 1,5 W) D (Electric Power : 1,2 ~ 1, W) E F G (Electric Power : 1,2 W) H (Electric Power : 1,3 W) I (Electric Power : 1,1 W) J (Electric Power : 1,1 W) K (Electric Power : 1,5 W) L (Electric Power : 1,2 W) M (Electric Power : 1, W) N (Electric Power : 1,112 W) (Fig. 3-3) Sound power level of vacuum cleaner measured by anechoic room method 나. 음향세기측정법음향세기측정법에의한진공청소기의음향파워레벨은아래의 (Fig. 3-31) 과같다. 평균음향파워레벨은 8.2 dba 이며, 1, Hz 대역이상의고주파성분이주를이루고있다

56 Vacuum Cleaner (Intrnsity) ,6 3,15 6,3 O.A. K (Electric Power : 1,5 W) L (Electric Power : 1,2 W) M (Electric Power : 1, W) N (Electric Power : 1,112 W) O (Electric Power : 1,177 W) P (Electric Power : 1,5 W) (Fig. 3-31) Sound power level of vacuum cleaner measured by intensity method 다. 잔향실직접법 잔향실직접법에의한진공청소기의음향파워레벨은아래의 (Fig. 3-32) 와같다. 잔향실직접법에서평균음향파워레벨은약 8.7 dba 이 며, 1, Hz 대역이상의고주파성분이주를이루고있다 Vacuum Cleaner (Reverberation Room[Direct]) ,6 3,15 6,3 O.A. K (Electric Power : 1,5 W) L (Electric Power : 1,2 W) M (Electric Power : 1, W) N (Electric Power : 1,112 W) O (Electric Power : 1,177 W) P (Electric Power : 1,5 W) (Fig. 3-32) Sound power level of vacuum cleaner measured by direct method in reverberation room

57 라. 잔향실비교법잔향실비교법에의한진공청소기의음향파워레벨은아래의 (Fig. 3-33) 과같다. 잔향실비교법에서평균음향파워레벨은약 82. dba 이며, 1, Hz 대역이상의고주파성분이주를이루고있다 Vacuum Cleaner (Reverberation Room[comparison]) ,6 3,15 6,3 O.A. K (Electric Power : 1,5 W) L (Electric Power : 1,2 W) M (Electric Power : 1, W) N (Electric Power : 1,112 W) O (Electric Power : 1,177 W) P (Electric Power : 1,5 W) (Fig. 3-33) Sound power level of vacuum cleaner measured by comparison method in reverberation room 각평가방법에대한음향파워레벨의측정불확도 ( 표준편차 ) 는평균 1.7 db이고, 69.4~86.5 dba에걸쳐서분포하고있다. 진공청소기의음향파워레벨은평균 81.3 dba 로 6종 ( 냉장고, 레인지후드, 진공청소기, 세탁기, 에어컨디셔너, 선풍기 ) 의가전제품중에서가장크다. 아래의 (Fig. 3-34~39) 는개개의진공청소기에대한음향파워레벨측정결과를나타낸다

58 Vacuum Cleaner A (Electric Power: 1, W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-34) 1/3 Octave band frequency analysis of PWL of vacuum cleaner A Vacuum Cleaner B (Electric Power: 1, W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-35) 1/3 Octave band frequency analysis of PWL of vacuum cleaner B

59 Vacuum Cleaner C (Electric Power: 1,5 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-36) 1/3 Octave band frequency analysis of PWL of vacuum cleaner C Vacuum Cleaner D (Electric Power: 1,2~1, W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-37) 1/3 Octave band frequency analysis of PWL of vacuum cleaner D

60 Vacuum Cleaner E ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-38) 1/3 Octave band frequency analysis of PWL of vacuum cleaner E Vacuum Cleaner F ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-39) 1/3 Octave band frequency analysis of PWL of vacuum cleaner F

61 Vacuum Cleaner G (Electric Power: 1,2 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-) 1/3 Octave band frequency analysis of PWL of vacuum cleaner G Vacuum Cleaner H (Electric Power: 1,3 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-41) 1/3 Octave band frequency analysis of PWL of vacuum cleaner H - -

62 Vacuum Cleaner I (Electric Power: 1,1 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-42) 1/3 Octave band frequency analysis of PWL of vacuum cleaner I Vacuum Cleaner J (Electric Power: 1,1 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-43) 1/3 Octave band frequency analysis of PWL of vacuum cleaner J

63 Vacuum Cleaner K (Electric Power: 1,5 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-44) 1/3 Octave band frequency analysis of PWL of vacuum cleaner K 1 Vacuum Cleaner L (Electric Power: 1,2 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-45) 1/3 Octave band frequency analysis of PWL of vacuum cleaner L

64 Vacuum Cleaner M (Electric Power: 1, W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-46) 1/3 Octave band frequency analysis of PWL of vacuum cleaner M 1 Vacuum Cleaner N (Electric Power: 1,112 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-47) 1/3 Octave band frequency analysis of PWL of vacuum cleaner N

65 Vacuum Cleaner O (Electric Power: 1,177 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-48) 1/3 Octave band frequency analysis of PWL of vacuum cleaner O 1 Vacuum Cleaner P (Electric Power: 1,5 W) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-49) 1/3 Octave band frequency analysis of PWL of vacuum cleaner P

66 4. 세탁기의음향파워레벨 일반적으로세탁기는세탁및탈수시에상하진동이크게발생하여주변구조물을가진한다. 이번시험에서세탁기의상하진동은무향실의바닥을가진하여주변측정기기 ( 마이크로폰및다채널소음분석기 ) 의정상적인작동을방해하였다. 따라서세탁기의음향파워레벨의측정은잔향실에서직접법과비교법에의해서행해졌다. 세탁기의소음측정방법은 가정용및이와유사한전기기기의소음측정방법 : 전기세탁기및탈수기의개별요구사항 (KS C IEC ) 을준용한다. 세탁기의세탁및탈수시의소음은비정상신호 (Nonstationary signal) 이므로소음변동주기의 5배이상을측정시간으로하고, 5 초동안측정하였다. 한편, 세탁및탈수시에사용한시험포는 KS C IEC 의규격을충족시키는단위면적당중량이 17±1 g/m, 날실이 3±2 tex, 씨실이 3±2 tex, 천의크기가 6 8 mm이다. 시험포의개수변화에대한소음변화는 1 db 이내로작으므로세탁기용량에따른시험포의개수는 2개로통일하여사용하였다. 가. 잔향실직접법잔향실직접법에의한세탁기의음향파워레벨은아래의 (Fig. 3-5~ 51) 과같다. 잔향실직접법에서세탁시음향파워레벨은약 58.1 dba 이며, 탈수시음향파워레벨은 65.8 dba 로탈수시음향파워레벨이 7.7 db 높다

67 7 Washing Machine (Reverberation Room[Direct]-Laundry) ,6 3,15 6,3 O.A. A (Electric Power : W, Drum Type, Capacity : 1 kg) C (Electric Power : 55 W, Agitator Type, Capacity : 1 kg) E (Electric Power : 43 W, Drum Type, Capacity : 9 kg) B (Electric Power : 489 W, Drum Type, Capacity : 8 kg) D (Electric Power : 699 W, Drum Type, Capacity : 11 kg) F (Electric Power : 45 W, Agitator Type, Capacity : 12 kg) (Fig. 3-5) Sound power level of washing machine measured by direct method in reverberation room(laundry) Washing Machine (Reverberation Room[Direct]-Spin Drying) ,6 3,15 6,3 O.A. A (Electric Power : W, Drum Type, Capacity : 1 kg) C (Electric Power : 55 W, Agitator Type, Capacity : 1 kg) E (Electric Power : 43 W, Drum Type, Capacity : 9 kg) B (Electric Power : 489 W, Drum Type, Capacity : 8 kg) D (Electric Power : 699 W, Drum Type, Capacity : 11 kg) F (Electric Power : 45 W, Agitator Type, Capacity : 12 kg) (Fig. 3-51) Sound power level of washing machine measured by direct method in reverberation room(spin drying)

68 나. 잔향실비교법 잔향실비교법에의한세탁기의음향파워레벨은아래의 (Fig. 3-52~ 53) 과같다. 잔향실비교법에서세탁시음향파워레벨은약 56.2 dba 이며, 탈수시음향파워레벨은 63.7 로탈수시음향파워레벨이 7.5 db 높다. 각평가방법에대한음향파워레벨의측정불확도 ( 표준편차 ) 는평균 3. db 이고, 세탁시 53.2~6.6 dba, 탈수시 59.5~7.4 dba 의음향파워레벨을발생한다. (Fig. 3-54~59) 와 (Fig. 3-6~65) 는각각세탁시와탈수시의세탁기의음향파워레벨을측정한결과이다. 7 Washing Machine (Reverberation Room[comparison]-Laundry) ,6 3,15 6,3 O.A. A (Electric Power : W, Drum Type, Capacity : 1 kg) B (Electric Power : 489 W, Drum Type, Capacity : 8 kg) C (Electric Power : 55 W, Agitator Type, Capacity : 1 kg) D (Electric Power : 699 W, Drum Type, Capacity : 11 kg) E (Electric Power : 43 W, Drum Type, Capacity : 9 kg) F (Electric Power : 45 W, Agitator Type, Capacity : 12 kg) (Fig. 3-52) Sound power level of washing machine measured by comparison method in reverberation room(laundry)

69 8 7 Washing Machine (Reverberation Room[comparison]-Spin drying) ,6 3,15 6,3 O.A. A (Electric Power : W, Drum Type, Capacity : 1 kg) B (Electric Power : 489 W, Drum Type, Capacity : 8 kg) C (Electric Power : 55 W, Agitator Type, Capacity : 1 kg) D (Electric Power : 699 W, Drum Type, Capacity : 11 kg) E (Electric Power : 43 W, Drum Type, Capacity : 9 kg) F (Electric Power : 45 W, Agitator Type, Capacity : 12 kg) (Fig. 3-53) Sound power level of washing machine measured by comparison method in reverberation room(spin drying) (1) 세탁시각세탁기의음향파워레벨 Washing Machine A (Electric Power: W, Drum Type[Capacity : 1 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-54) 1/3 Octave band frequency analysis of PWL of washing machine A

70 Washing Machine B (Electric Power: 489 W, Drum Type[Capacity : 8 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-55) 1/3 Octave band frequency analysis of PWL of washing machine B Washing Machine C (Electric Power: 55 W, Agitator Type[Capacity : 1 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-56) 1/3 Octave band frequency analysis of PWL of washing machine C

71 Washing Machine D (Electric Power: 699 W, Drum Type[Capacity : 11 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-57) 1/3 Octave band frequency analysis of PWL of washing machine D Washing Machine E (Electric Power: 43 W, Drum Type[Capacity : 9 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-58) 1/3 Octave band frequency analysis of PWL of washing machine E - 5 -

72 Washing Machine F (Electric Power: 45 W, Agitator Type[Capacity : 12 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-59) 1/3 Octave band frequency analysis of PWL of washing machine F (2) 탈수시각세탁기의음향파워레벨 Washing Machine A (Electric Power: W, Drum Type 형 [Capacity : 1 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-6) 1/3 Octave band frequency analysis of PWL of washing machine A

73 Washing Machine B (Electric Power: 489 W, Drum Type[Capacity : 8 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-61) 1/3 Octave band frequency analysis of PWL of washing machine B Washing Machine C (Electric Power: 55 W, Agitator Type[Capacity : 1 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-62) 1/3 Octave band frequency analysis of PWL of washing machine C

74 Washing Machine D (Electric Power: 699 W, Drum Type[Capacity : 11 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-63) 1/3 Octave band frequency analysis of PWL of washing machine D Washing Machine E (Electric Power: 43 W, Drum Type[Capacity : 9 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-64) 1/3 Octave band frequency analysis of PWL of washing machine E

75 Washing Machine F (Electric Power: 45 W, Agitator Type[Capacity : 12 kg]) ,6 3,15 6,3 O.A. Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-65) 1/3 Octave band frequency analysis of PWL of washing machine F 5. 에어컨디셔너의음향파워레벨일반적으로에어컨디셔너는실외기와실내기사이의동관길이에따라설치위치에대한제한이따르고, 일반인이설치하기가용이하지않아에어컨디셔너설치전문가에게설치를의뢰해야하는어려움이있다. 따라서반무향실법측정에서에어컨디셔너의음향파워레벨측정면은반구면을사용하지않고전기기기의소음측정방법 (KS C IEC 674-1) 에의한측정위치에설치하였다. 에어컨디셔너의소음측정시간은반무향실법이 3초, 음향세기측정법은 18 초, 잔향실법은 3초로하였다. 한편, 잔향실법측정에서에어컨디셔너설치위치는잔향실입구쪽에설치하고마이크로폰위치는기존의측정지점으로했다. 가. 반무향실측정법 반무향실측정법에의한에어컨디셔너의음향파워레벨은아래의 (Fig

76 3-66~67) 과같다. 반무향실측정법에서실내기의평균음향파워레벨은 약 58.6 dba 이며, 실외기의평균음향파워레벨은 68.7 dba 로실외기의 음향파워레벨이실내기보다 1.1 db 크다 Air Conditioner (Anechoic Room-Indoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-66) Sound power level of indoor unit of air-conditioner measured by anechoic room method Air Conditioner (Anechoic Room-Outdoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-67) Sound power level of outdoor unit of air-conditioner measured by anechoic room method

77 나. 음향세기측정법 음향세기측정법에의한에어컨디셔너의음향파워레벨은아래의 (Fig. 3-68~69) 와같다. 음향세기측정법에서실내기의평균음향파워레벨은약 53.1 dba 이며, 실외기의평균음향파워레벨은 65.9 dba 로실외기의음향파워레벨이실내기보다 12.8 db 크다. 6 Air Conditioner (Intensity-Indoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-68) Sound power level of indoor unit of air-conditioner measured by intensity method

78 Air Conditioner (Intensity-Outdoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-69) Sound power level of outdoor unit of air-conditioner measured by intensity method 다. 잔향실직접법 잔향실직접법에의한에어컨디셔너의음향파워레벨은아래의 (Fig. 3-7~71) 과같다. 잔향실직접법에서실내기의평균음향파워레벨은약 56.8 dba 이고, 실외기의평균음향파워레벨은 68.9 dba 로실외기의음향파워레벨이실내기보다 11.9 db 크다

79 Air Conditioner (Reverberation Room[Direct]-Indoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-7) Sound power level of indoor unit of air-conditioner measured by direct method in reverberation room Air Conditioner (Reverberation Room[Direct]-Outdoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-71) Sound power level of outdoor unit of air-conditioner measured by direct method in reverberation room

80 라. 잔향실비교법 잔향실비교법에의한에어컨디셔너의음향파워레벨은아래의 (Fig. 3-72~73) 과같다. 잔향실직접법에서실내기의평균음향파워레벨은약 57.5 dba 이며, 실외기의평균음향파워레벨은 69.8 dba 로실외기의음향파워레벨이실내기보다 12.3 db 크다 Air Conditioner (Reverberation Room[comparison]-Indoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-72) Sound power level of indoor unit of air-conditioner measured by comparison method in reverberation room

81 Air Conditioner (Reverberation Room[comparison]-Outdoor Unit) ,6 3,15 6,3 O.A. A (Electric Power : 1,77 W, Stand Type) B (Electric Power : 1,75 W, Wall-Hanging Type) C (Electric Power : 6 W, Wall-Hanging Type) D (Electric Power : 6 W, Wall-Hanging Type) E (Electric Power : 1,8 W, Stand Type) F (Electric Power : 2,6 W, Stand Type) (Fig. 3-73) Sound power level of outdoor unit of air-conditioner measured by comparison method in reverberation room 각평가방법에대한음향파워레벨의측정불확도 ( 표준편차 ) 는평균 3.3 db이고, 실내기가 44.5~62.2 dba, 실외기가 52.9~67.4 dba 음향파워레벨을발생하고있다. 아래의 (Fig. 3-74~79) 와 (Fig. 3-8~85) 는각각실내기와실외기개개의음향파워레벨측정결과를나타낸다

82 Air Conditioner A (Electric Power: 1,77 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-74) 1/3 Octave band frequency analysis of indoor unit of air-conditioner A Air Conditioner B (Electric Power: 1,75 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-75) 1/3 Octave band frequency analysis of indoor unit of air-conditioner B

83 Air Conditioner C (Electric Power: 6 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-76) 1/3 Octave band frequency analysis of indoor unit of air-conditioner C Air Conditioner D (Electric Power: 6 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-77) 1/3 Octave band frequency analysis of indoor unit of air-conditioner D

84 Air Conditioner E (Electric Power: 1,8 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-78) 1/3 Octave band frequency analysis of indoor unit of air-conditioner E Air Conditioner F (Electric Power: 2,6 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-79) 1/3 Octave band frequency analysis of indoor unit of air-conditioner F

85 Air Conditioner A (Electric Power: 1,77 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-8) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner A Air Conditioner B (Electric Power: 1,75 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-81) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner B

86 Air Conditioner C (Electric Power: 6 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-82) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner C Air Conditioner D (Electric Power: 6 W, Wall-Hanging Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-83) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner D

87 Air Conditioner E (Electric Power: 1,8 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-84) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner E Air Conditioner E (Electric Power: 2,6 W, Stand Type) ,6 3,15 6,3 O.A. Anechoic Room Intensity Reverberation Room(direct) Reverberation Room(comparison) (Fig. 3-85) 1/3 Octave band frequency analysis of outdoor unit of air-conditioner F

88 6. 선풍기의음향파워레벨선풍기소음측정시간은반무향실법이 3초, 음향세기측정법이 18 초, 잔향실법은 3초로하였다. 특히음향세기는바람세기에영향을받기때문에음향세기측정기가선풍기바람을정면으로바라보지않게하여측정하였다. 가. 반무향실측정법반무향실측정법에의한선풍기의음향파워레벨은아래의 (Fig. 3-86) 과같다. 반무향실측정법에서평균음향파워레벨은약 59.9 dba 이며, 15 Hz 대역의저주파성분이두드러진특징이있다 Electric Fan (Anechoic Room) ,6 3,15 6,3 O.A. A (Electric Power : 64 W, Fan Size : 35 mm) B (Electric Power : 62 W, Fan Size : 35 mm) C (Electric Power : 62 W) D (Electric Power : 62 W) E (Electric Power : 62 W, Fan Size : 35 mm) F (Electric Power : 55 W, Fan Size : 3 mm) G (Electric Power : 56 W, Fan Size : mm) H (Electric Power : 45 W) I (Electric Power : 55 W, Fan Size : mm) J (Electric Power : 58 W, Fan Size : 35 mm) K (Electric Power : 6 W, Fan Size : 3 mm) L (Electric Power : 185 W, Fan Size : 6 mm) M (Electric Power : 35 W, Fan Size : 35 mm) N (Electric Power : 45 W, Fan Size : mm) (Fig. 3-86) Sound power level of electric fan measured by anechoic room method 나. 음향세기측정법

89 음향세기측정법에의한선풍기의음향파워레벨은아래의 (Fig. 3-87) 과같다. 음향세기측정법에서평균음향파워레벨은약 59.7 dba 이며, 15 Hz 대역의저주파성분이두드러진특징이있다 Electric Fan (Intensity) ,6 3,15 6,3 O.A. L (Electric Power : 185 W, Fan Size : 6 mm) N (Electric Power : 45 W, Fan Size : mm) M (Electric Power : 35 W, Fan Size : 35 mm) (Fig. 3-87) Sound power level of electric fan measured by intensity method 다. 잔향실직접법 잔향실직접법에의한선풍기의음향파워레벨은아래의 (Fig. 3-88) 과같다. 잔향실직접법에서평균음향파워레벨은약 59.8 dba 이며, 15 Hz 대역의저주파성분이크게튀는특징이있다

90 Electric Fan (Reverberation Room[Direct]) ,6 3,15 6,3 O.A. L (Electric Power : 185 W, Fan Size : 6 mm) N (Electric Power : 45 W, Fan Size : mm) M (Electric Power : 35 W, Fan Size : 35 mm) (Fig. 3-88) Sound power level of electric fan measured by direct method in reverberation room 라. 잔향실비교법 잔향실비교법에의한선풍기의음향파워레벨은아래의 (Fig. 3-89) 와같다. 잔향실비교법에서평균음향파워레벨은약 61.6 dba 이며, 15 Hz 대역의저주파성분이크게튀는특징이있다

91 Electric Fan (Reverberation Room[comparison]) ,6 3,15 6,3 O.A. L (Electric Power : 185 W, Fan Size : 6 mm) N (Electric Power : 45 W, Fan Size : mm) M (Electric Power : 35 W, Fan Size : 35 mm) (Fig. 3-89) Sound power level of electric fan measured by comparison method in reverberation room 각평가방법에대한음향파워레벨은 53.3~66.1 dba 이고, 측정불확도 ( 표준편차 ) 는평균 2.7 db 이다. 아래의 (Fig. 3-9~12) 는개개의선 풍기에대한음향파워레벨측정결과를나타낸다

92 Electric Fan A (Electric Power: 64 W, Fan Size: 35 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-9) 1/3 Octave band frequency analysis of PWL of electric fan A 7 Electric Fan B (Electric Power: 62 W, Fan Size: 35 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-91) 1/3 Octave band frequency analysis of PWL of electric fan B

93 6 Electric Fan C (Electric Power: 62 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-92) 1/3 Octave band frequency analysis of PWL of electric fan C 7 Electric Fan D (Electric Power: 62 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-93) 1/3 Octave band frequency analysis of PWL of electric fan D

94 7 Electric Fan E (Electric Power: 62 W, Fan Size: 35 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-94) 1/3 Octave band frequency analysis of PWL of electric fan E 6 Electric Fan F (Electric Power: 55 W, Fan Size: 3 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-95) 1/3 Octave band frequency analysis of PWL of electric fan F

95 7 Electric Fan G (Electric Power: 56 W, Fan Size: mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-96) 1/3 Octave band frequency analysis of PWL of electric fan G Electric Fan H (Electric Power: 45 W) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-97) 1/3 Octave band frequency analysis of PWL of electric fan H

96 Electric Fan I (Electric Power: 55 W, Fan Size: mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-98) 1/3 Octave band frequency analysis of PWL of electric fan I 6 Electric Fan J (Electric Power: 58 W, Fan Size: 35 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-99) 1/3 Octave band frequency analysis of PWL of electric fan J

97 6 Electric Fan K (Electric Power: 6 W, Fan Size: 3 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-1) 1/3 Octave band frequency analysis of PWL of electric fan K 7 Electric Fan L (Electric Power: 185 W, Fan Size: 6 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-11) 1/3 Octave band frequency analysis of PWL of electric fan L

98 6 Electric Fan M (Electric Power: 35 W, Fan Size: 35 mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-12) 1/3 Octave band frequency analysis of PWL of electric fan M 6 Electric Fan N (Electric Power: 45 W, Fan Size: mm) ,6 3,15 6,3 O.A. Anechoic Room (Fig. 3-13) 1/3 Octave band frequency analysis of PWL of electric fan N

99 7. 가전제품의소음 진동특성 가. 냉장고의소음 진동특성냉장고는압축기에서흡입된냉매가스의체적을압축시키고응축기 ( 콘덴서 ) 에서액화된냉매를냉동고뒷면에위치한증발기에서기화시키면서빼앗기는 ( 주변보다낮아지는 ) 열을이용하여냉장고내부의온도를낮추는냉동사이클을갖추고있다. 냉장고의주요소음원으로는압축기소음, 응축기및증발기의송풍소음, 구조물의진동에의한진동소음등이며, 이중에서도압축기소음이전체냉장고소음의 6 % 를차지할정도로가장크며, 고주파성분이두드러져소비자들에게짜증을유발시키는주소음원으로파악되고있다. 아래의 (Fig. 3-14) 는냉장고의소음발생구조를나타내고있다. (Fig. 3-14) Sources of refrigerator noise

100 특히, 환경친화적인대체냉매 (R134a) 는기존의프레온가스 (CFC) 에비해서압축비상승및고효율화가필수적이기때문에, 압축기소음은더욱상승할수밖에없는실정이다. 가정용냉장고에서는대부분왕복동식압축기를사용하며, (Fig. 3-15) 는냉장고용압축기의개략도를나타낸다. (Fig. 3-15) Structure of compressor for refrigerator 압축기는전동기의회전운동으로구동되는슬라이더-크랭크 (slider-crank) 기구에의하여흡입및토출밸브의작동에따라냉매가압축되어토출되는반복사이클을갖는다. 가전제품의사용목적에따라서냉장고용압축기는별도의정비없이 1년이상의가동이보증되어야한다. 일반적으로왕복동식압축기는약 3,6 rpm 의고속운전이이루어지게되며, 냉매의흡입, 압축및토출과정에서다양한형태의진동및소음이발생하게된다. 특히, 압축기의토출과정은약 1 기압에해당하는고압

101 상태의맥동 (pulsation) 이발생하기때문에토출배관이심하게진동할수있다. 이때, 토출배관이심하게굴곡되어있을때에는과도한진동이나타날수있기때문에, 토출배관의급격한방향전환이없도록설계되어야한다. 압축기자체의진동은압축기내부에서발생하는진동 ( 유도전동기의전기적진동, 기계적인불평형질량등 ) 과압축기외부에서발생하는진동 ( 냉매파이프, 압축기표면진동등 ) 이혼합되어서구조물기인소음 (structure borne noise) 을유발시키게된다. 한편, 냉장고의소음중에서공기기인소음 (air borne noise) 으로는송풍기소음, 압축기소음등이있으며, 이중에서송풍기소음은회전수와날개수의곱으로계산되는높은주파수의특성을가지며, 압축기소음은압축기모터의간극 (air gap) 에서발생되는고주파소음으로 1,~ 수 khz 의영역에존재한다. (Fig. 3-16) 은냉장고에서발생하는소음의전달경로를보여준다. (Fig. 3-16) Transmission path of refrigerator noise - 8 -

102 나. 레인지후드의소음 진동특성 레인지후드의소음은크게팬의회전에의한공력소음과렌인지후드판넬의진동에의한구조물진동소음으로볼수있다. 가정용레인지후드에주로사용되는팬은시로코팬 (sirocco fan) 으로서, 시로코팬의형상은소음발생에밀접한영향을준다. 팬의공력소음을줄이기위하여팬형상의변형, 팬의공력소음발생에관한수치적해석등에관련된연구가활발히수행중이며, 제진재를사용하여레인지후드판넬의진동에의해발생하는소음을저감하는연구도각연구기관에서수행중이다. 아래의 (Fig. 3-17) 은레인지후드의소음발생구조를나타내고있다. (Fig. 3-17) Sources of range hood noise

103 다. 진공청소기의소음 진동특성 (1) 진공청소기의구조및소음원진공청소기는노즐, 확장튜브, 호스, 청소기본체로이루어져있으며각부분은소음원으로써작동하여전체청소기소음을발생시키는구조로형성되어있다. (2) 작동정류자전동기 (commutator motor) 로회전날개를 1만회이상회전시켜내부를진공상태로만들고먼지나찌꺼기를흡입구를통해빨아들인먼지 찌꺼기등은필터에서걸러주고공기는배기구로빠져나간다. 전원코드를자동으로감아주는기능이있고, 또한전원코드를빼거나감을때톱니바퀴가작동하여필터에붙어있는먼지를자동적으로털어주는장치도부착되어있다. 흡입구도사용장소에따라사용하기편리하게설계되어있다. (3) 소음 진동특성진공청소기소음은크게팬모터에의한공력소음, 배기소음 ( 고주파대역 ), 흡입노즐에서발생하는공력소음, 모터의진동에기인하는청소기본체의진동소음 (5 Hz 대역 ) 으로나뉘며, 이들소음중주소음원은팬모터에의한공력소음과흡입노즐에서발생하는공력소음이다. 팬모터에의한공력소음은 3, rpm 이넘는속력으로회전하는임펠러와성능향상을위해서작은간격을두고설치한디퓨저의공기역학적인상

104 호작용에의해서발생하는유동소음이다. 흡입노즐에서발생하는공력소음은흡입노즐과바닥면사이의급격한압력변화가강한부압을발생시켜노즐전방과측면에서흡입된공기가노즐의흡입구로들어갈때발생하며매우강한와류에의해생기는유동소음이다. 배기소음은흡입된먼지가먼지필터에걸러지고난후밖으로배출되는공기에의해발생하며강한공기의배출에의해서발생하는유동소음이다. 아래의 (Fig. 3-18) 은진공청소기의소음발생구조를나타내고있다. (Fig. 3-18) Sources of vacuum cleaner noise 라. 세탁기의소음 진동특성 (1) 세탁기의구조및작동일반적으로세탁기는펄세이터형 (Pulsator Type), 에지테이터형 (Agitator Type), 드럼형 (Drum Type) 으로나뉜다. 펄세이터형은세탁조밑에있는회전날개에의해세탁하는방식으로현재국내시장에서가

105 장많이사용하는세탁기이며, 구조가간단하고고장이적으며소음이적은장점을갖는다. 하지만회전날개에의해세탁하기때문에세탁물이잘상하는단점을갖고있다. 한편, 에지테이터형은세탁조한가운데에봉이있어, 세탁시세탁봉이회전및왕복운동을한다. 미국에서가장많이사용하는방식으로옷감의손상이적고한번에많은양의세탁이가능하며, 소음이다소큰특징을갖는다. 드럼형은세탁조가횡으로설치되어회전하며, 세탁물이위에서밑으로떨어지는낙차를이용한세탁방식이다. 유럽에서많이사용하며세탁물의손상이가장작은특징이있다. 하지만탈수시세탁조내의편심중량이발생하기쉬어진동이심하고소음이큰단점을갖고있다. (2) 소음 진동특성세탁기소음은크게세탁소음과탈수소음으로나눌수있으며, 세탁소음은다시모터전동소음, 모터지지대방사소음, 기어소음, 물소음으로나뉘며, 탈수소음은세탁조회전소음, 터브울림소음으로나뉜다. 일반적으로탈수소음 (64 dba) 은세탁소음 (57 dba) 보다약 7 db가량크게발생하고, 탈수시세탁물의편심중량에의해발생하는소음이세탁기소음의가장큰문제점이다. 모터전동소음은모터구동시에발생하며, 모터의진동은모터지지대에전달되어세탁기바닥으로소음을방사하는특성을갖는다. 기어소음은세탁기생산공정결함으로발생한불량기어에의해발생하거나오랜사용으로기어에결함이생기면발생한다. 기어소음은고주파대역에서발생하는특성을가지며단일주파수형태로발생한다. 물소음은세탁시물의유동에의해발생하며세탁물의종류와

106 양에따라다양하게변하는특성을갖는다. 탈수시발생하는세탁조회전소음은세탁조의회전속도에비례하여발생한다. 탈수시발생하는터브울림소음은세탁물의중량편심에의해발생하며특히드럼형세탁기에서크게발생하는특징을갖는다. (Fig. 3-19) 는세탁기의소음발생구조를나타내고있다. (Fig. 3-19) Sources of washing machine noise 마. 에어컨디셔너의소음 진동특성 (1) 실내기의소음 진동특성실내기소음은크게송풍소음과냉방소음으로나뉘며, 약풍모드에서는냉방소음이크게발생하고강풍모드에서는송풍소음이크게발

107 생하는특징을가지고있다. 아래의 (Fig. 3-11), (Fig ) 은각 각에어컨디셔너의소음발생구조와냉동사이클을나타낸다. (Fig. 3-11) Sources of indoor-unit noise in the air-conditioner system (Fig ) Principle of a cooling system in the air-conditioner

108 에어컨의냉동사이클에서실내기로들어온고온고압의냉매는팽창밸브를통과하면서저온저압의상태로변한다. 에어컨의증발기를통과하면서액상에서기상으로상 ( 相 ) 변화를일으키며이때냉매의비체적이증가하게되고체적유량이증가하게되어실내기의증발기를지나는냉매의속도는팽창밸브입구냉매에비해크게증가한다. 이러한냉방사이클의특성에따라실내기증발기입구에서부터냉매소음이발생하며증발기입구의냉매상태에따라냉매소음크기는커지거나작아진다. 아래의 (Fig ) 는에어컨디셔너각위치에따른냉동사이클의 T-S선도를나타낸다. (Fig ) T-S chart of the irreversible refrigeration cycle (2) 실외기의소음 진동특성실외기소음은크게압축기소음, 송풍소음, 구조물의진동소음으로나뉜다. (Fig ) 은실외기의소음발생구조를나타내고있다. 전체실외기소음중각실외기소음이차지하는비율은 PAC(Packaged Air

109 Conditioner) 형인경우고풍량으로인해송풍소음이전체실외기소음의 8~9 % 를차지하고압축기소음과구조물의진동소음이 1~2 % 를차지하고있다. RAC(Room Air Conditioner) 형은송풍소음이 ~5 % 를차지하고압축기소음과구조물의진동에의한소음이 5~6 % 를차지하고있다. (Fig ) Sources of outdoor-unit noise in the air-conditioner system