乾式二重床の床衝撃音レベル低減量及び現場への適用方法に関する検討

Transcription

1 カテゴリー Ⅱ 日本建築学会環境系論文集第 8 巻第 714 号, ,215 年 8 月 J. Environ. Eng., AIJ, Vol. 8 No. 714, , Aug., 215 乾式二重床の床衝撃音レベル低減量及び現場への適用方法に関する検討 STUDY ON REDUCTION OF FLOOR IMPACT SOUND WITH WOODEN FLOATING FLOOR AND APPLICATION TO ACTUAL BUILDINGS 中森俊介 * **, 吉村純一 Shunsuke NAKAMORI and Junichi YOSHIMURA This study was carried out about influential factors for measurement results of the reduction of floor impact sound pressure level ΔL) with wooden floating floor in laboratory and the application to actual buildings. First, experimental study was conducted to investigate about influence for insulation performance by peripheral treatments and the critical parts of wooden floating floor. Next, the difference of ΔL results measured on two different thickness slabs were viewed. At the last, to predict insulation performance in actual floor from ΔL in laboratory, application methods considering conditions in site (assuming installation area, restriction and ceiling) were investigated. Wooden floating floor, Reduction of floor impact sound pressure level, Peripheral treatment, flexural rigidity, restriction by beams, Installation area 1. 1) ΔL ΔL ΔL JIS A ) -2 3) large specimens 1 m 2 ΔL 1 4) 21) ΔL 1 9) ΔL 2 13) ΔL ΔL 3 21) ΔL ΔL * ** 小林理学研究所 工修 小林理学研究所 博士 ( 工学 ) Kobayasi Institute of Physical Research, M. Eng. Kobayasi Institute of Physical Research, Dr. Eng. 629

2 ΔL AIJES A 9), 1) 6) 5) 8) 4) 11) 12), 13) 7) 16), 17) 14) 18), 19) 15) 2), 21) Fig.1 Typical literatures and keywords of effective factors for floor impact sound with wooden floating floor 2. 1),2),3) 4 m 5 m 15 mm 2 mm m m 5 m 3 m 1 2 ΔL ΔL 2-1 1/4 S1 ΔL 3. 1 Wall_a S8 Wall_b S9 S6 C1 S7 C4 C3 C2 S6~S9: Additional points C1~C4: Vibration measurement points Wall_c Recieving room Specimen Specimen Recieving room Fig.2-2 Vertical section of test room with 15 mm thickness slab 2),1) ΔL ΔL te mm i 15 cm c2 mm mm GW 55 mm Table1 Specifications of wooden floating floor specimens W1 Wall_a (mm) W2 W1~W4: Vibration measurement points Fig.3 35 : : A 15 t i c 7 65 B 15 t e i 7 7 C 2 t e i 7 7 Cw 2 t e i D 2 e 7 65 Dw 2 t e c t: touched surface floor e: elastic contact W3 Wall_b W4 i: identified from surface c: cut off peripheral part F.L. Wall_d Fig.2-1 Plan of test room with 15 mm thickness slab Fig.3 Peripheral treatments by skirting board 63

3 Fig.4 Vertical section of gypsum board lining Air space 4 GW24K Light gauge steel Specimen Gypsum board (decrease radiation sound) 35 4 studs) GW24K Wooden square timber 5 Dw 5 σ 6 7 A B 8 B S1 ΔL 1 db 9 C ΔL 1 S1 1 db 31.5 Hz 63 Hz ΔL Hz 5 Hz 1 db 2 db B 6 7 Ai 31.5 Hz ΔL Specimen Dw Influential by peripheral treatment σ σ Touched Cut off Fig.5 Comparison between with and without peripheral treatment (by lining) db Specimen B Influential part of specimen S1 S1 Touched Identical Fig.8 Influential part of specimen by peripheral treatment (fixed peripheral joist) Specimen A Condition of skirting board Touched Identical Fig.6 Influence by installation method of skirting boards (insulated peripheral joist) Specimen C, Cw Influence with gypsum board lining No lining Lining Fig.9 Influence with gypsum board lining in receiving room (fixed peripheral joist) Specimen B Condition of skirting board Touched Elastic Identical Fig.7 Influence by installation method of skirting boards (fixed peripheral joist) db Specimen C, Cw Influential part of specimen S1 S1 No lining Lining Fig.1 Influential part of specimen with gypsum board lining 631

4 S1 t iδl 8 ΔL 1 Hz 25 Hz ΔL 9 1 Hz S1 ΔL Hz 2 Hz ΔL ΔL 25 Hz RC ΔL S1ΔL 4. 2 ΔL 15 mm 2 mm ΔL FF1 FF15 1 m 2 FC1FC C1 C4 a d a b 2 4 W1 W mm db 1 kg/s Table2 Specifications of specimens kg/m mm mm FF1 FF t, e, i 6.5 mm FC1 13 mm FC2 Difference of ΔL (db) Wooden floating floors averaged (n=15) 5 Mass per unit area: Lower 2 kg/m 2 F F 2 to 5 kg/m Octave band center frequency(hz) Octave band center frequency(hz) Octave band center frequency(hz) Fig.11 Relative value of ΔL with wooden floating floors measured on 15 mm and 2 mm slab thickness F Over 5 kg/m 2 F 5 632

5 FF1 FF15 15 mm ΔL 2 mm ΔL 15 mm ΔL ΔL ΔL mm 35 Hz 38 Hz 2 mm 41 Hz 44 Hz 23) ΔL 5 9 ΔL 5 9 FF12 FF Hz 2 Hz 63 Hz 5 Hz ΔL mm ΔL 2 mm ΔL -.5 db.2 db 5 Table3 Level difference of reduction of impact sound between 15 mm and 2 mm slab FF12 FF13 FF14 5 (.3) (1.8) (2.6) (.2) 9 (-.1) (1.6) (2.6) 5 (1.9) (-.6) (.5) (-.5) 9 (2.2) (.1) (1.) 5 (1.6) (1.3) (1.8) (.) 9 (1.1) (1.5) (2.1) Unit: db FC1 FC2 FF1 FF5 FF12 FF14 a 2 S =1 log1(a 2 S)63 Hz 5 Hz 15 mm 2 mm 4 25 mm 24) 1 LRS LRW 1 LRT ΔLRT ΔLRT 15 mm ΔLRT 2 mm ΔLRT 5 63 Hz ΔL.1 db 125 Hz 4 ΔL L Rj 1 log 1 PC j L kj (1) PCjSW % 12 Lkj db 4 LRjdB Slab Wall σ σ Fig.12 Ratio of radiation energy from slab and walls Table4 Sound radiation coefficient level from surface plate 63 Hz 125 Hz 25 Hz 5 Hz 15 mm mm mm -1 Unit: db Table5 Level difference of reduction of radiation sound from slab and walls in receiving room 63 Hz 125 Hz 25 Hz 5 Hz (n=2) (n=8) Unit: db 633

6 ΔL db 13 FF12 FF14 FC1 FC2 15 mm 2 mm 1 db 4 db Increment of impedance(db) Solid marker and solid line...15 mm thick Void marker and broken line...2 mm thick FF14 FC2 FC1 FF12 FF Fig.13 Increment of impedance by floor coverings on slabs 24) B a 2 (2) b 2 (3) B a E 1 h E 2 h (2) 3 h B b E x h 2 1 h h E x h 1 h 2 2 h 2 2 (3) Ba, BbNm 2 E1, E2N/m 2 h1, h2 mm x=(h1+h2)/2 m db 6 b ρ1 23 kg/m 3 E N/m 2 2 kg/m 3 32 mm25 kg/m 3 44 mm N/m 2 h2 h1 x Fig.14 Structure model combined with wooden board and slab Table6 Addition of flexural rigidity (impedance of infinite plate) with wooden board m2, ρ2, E2 m1, ρ1, E1 mm db db a 15 mm..1 2 mm..1 b 15 mm mm ΔL ) 2 mmδl σ 63 Hz 125 Hz 125 Hz 5 Hz mm 44 mm19 kg/m 2 32 kg/m 2 68 mm 168 mm GW 3 t, e, i 63 Hz ΔL 125 Hz ΔL 634

7 125 Hz ΔL 25 Hz ΔL S1 63 Hz 125 Hz ΔL 125 Hz ΔL 8 S1 ΔL 125 Hz ΔL 26 Relative value of impact s. p. l. (db) S4 S2 +σ σ S3 Bare slab Relative value of ΔL (db) σ σ Octave band center frequency (db) Floating floor (n=26) Fig.15 Relative values at each excitation point (impact sound in the left, ΔL in the right, using tire) S3 S mm 1 m 2 m 1 m 3 m 1 m 7 m W625 H14 H65 7 L 22) 63 Hz MDF ) ΔL 8 23) Fig Section of floor-ceiling structure in actual building Table7 Situation and measurement results of actual rooms L 1 63 Hz, db ( 16-1 ) (/) m 2 2 4A-BR MDF / A-LD MDF / / B-BR MDF / / B-LD MDF / A-BR / / A-LD / / B-BR MDF / B-LD MDF / / t 2 635

8 Table9 Combination of measurement conditions in laboratory Condition 1 Condition 2 Condition 3 Condition m 2 1 m 2 1 m m 2 2 m 2 1 m 2 4 Table8 5 2 Fig Section of floor-ceiling structure in laboratory Table8 Maximum level difference of floor impact sound at excitation points at 63 Hz (db) 2 mm , σ (db) ΔL 9 ΔL ΔL ΔL L ΔL L 17 L ΔL =ΔL3 db A 173 db S/N 63 Hz 2 Hz 31.5 Hz 1 Hz Condition 1 Condition 2 2 m 2 Condition 1 2 m 2 ΔL Condition 3 ΔL 5 Condition 4 ΔL ΔL L A L A L-number calculated from ΔL in laboratory Condition 1 Condition 3 Condition 2 69% Tapping machine 54% 77% 77% 77% 73% 77% Condition 4 91% 64% L-number rated from measurements in actual rooms A-weighted impact s. p. l. calculated from ΔL in laboratory (db) % Tapping machine Condition 1 Condition 3 69% 85% 1% 64% Condition 2 85% Condition 4 91% 77% 82% A-weighted impact s. p. l. measured in actual rooms (db) Fig. 17 Comparison with measurements in actual room and calculated from ΔL in the lab. (L-num. in the left, dba in the right) 636

9 ΔL L Condition 1 3 db A Condition 1 Condition 3 Condition 4 ΔL m 2 ΔL ΔL A 6. ΔL 1 ΔL ΔL ΔL 2 ΔL ΔL ΔL m 2 5 ΔL 1) ) JIS A ) JIS A ) D-1 pp ) pp ) CD-ROM pp ) 3 CD-ROM pp ) No. 546 pp ) D-1 pp ) D-1 pp ) 2 D-1 pp ) CD-ROM pp ) pp ) CD-ROM pp ) D-1 pp ) No. 6 pp ) Vol. 77 No. 681 pp ) 8 CD-ROM pp ) A CD-ROM pp ) 1 28 pp ) CD-ROM pp ) ) Nakamori Shunsuke, Yoshimura Junichi Influential factors on floor impact sound insulation measurements of floating floors, Inter-Noise 27, Congress program and abstracts, in7-13, ) ) CD-ROM pp

10 STUDY ON REDUCTION OF FLOOR IMPACT SOUND WITH WOODEN FLOATING FLOOR AND APPLICATION TO ACTUAL BUILDINGS Shunsuke NAKAMORI * and Junichi YOSHIMURA ** * Kobayasi Institute of Physical Research, M. Eng. ** Kobayasi Institute of Physical Research, Dr. Eng. Owing to the spread of impact force around excitation point on floor coverings belongs to the category 2 such as wooden floating floor supported by legs with elastic rubber, the floor impact sound is influenced by peripheral treatment and installation area. In addition, the reduction performance with floor coverings is changed by various situations on-site, e.g. kinds of building structure and the arrangement conditions (vibration mode of slab and the restriction by beams). Moreover, ceiling board is finished with air space (it calls suspended ceiling) in many case, in order to arranged air-ducts and electric wires there. Therefore, the guideline on measurement method for the reduction of floor impact sound in laboratory (ΔL) is specified that measurement is carried out using reinforced concrete boxed-wall chamber, specimen is assembled 1 m 2 with peripheral treatment, and the installation are is arranged in the condition on the slab supported by two walls crossed at right angles. The main purpose of ΔL in laboratory is to compare with insulation performance of products measured in provided condition, however it is desirable to correspond to performance in various actual buildings. Therefore in this report, the following things were studied. First, influence by peripheral treatment such as peripheral joist and skirting board was investigated in various experimental conditions. In order to search critical parts of specimen for peripheral treatment, the radiation sound from walls in receiving room made to be reduced with lining boards constructed on concrete walls with air space. Next, the difference in ΔL between 15 mm and 2 mm thickness slab was investigated to aim the following factors; vibration mode of slab, influence in radiation sound from walls and addition of flexural rigidity with floor coverings to bare slab. Last, the application methods were explored to use knowledge from laboratory study on ΔL. The ΔL for prediction were considered installation area, restriction of slab by beams and condition of suspended ceiling, according to measurement conditions in each actual room. And estimations from the ΔL were compared with measurements of actual rooms in a building using the values of L-number and A-weighted floor impact sound pressure level. As a result, the following knowledge is obtained. Deterioration of ΔL performance by peripheral treatment in the center of slab is more remarkable than on the edge of slab. In considering addition of flexural rigidity to bare slab by wooden floating floor, the thicker slab is, the lower the additional value of flexural rigidity becomes. So we suppose that ΔL on 2 mm slab is lower than 15 mm slab. Correspondence between estimations and measurements in 13 rooms various condition at an actual building, was not so bad without considering installation area and restriction of slab by beams. However, without considering condition of suspended ceilings, each evaluation value became worse correspondence. So it is necessary to predict with accuracy insulation performance with suspended ceilings. (214 年 12 月 1 日原稿受理,215 年 4 月 24 日採用決定 ) 638