Measurement Report
Kv. Hyttkammaren, Falun
21-2-2012
In-‐situ acoustic-‐vibratory measurements were performed at a lightweight 5-‐storey-‐building “kopparhatten” in Falun (Sweden). The building can be seen in Figures 1 and 2. Two apartments were at our disposal to carry out the
measurements. Both of them were placed on top of each other (2nd and 3rd floor of
the building), allowing measurements between adjacent spaces. By these measurements, it is planned to acquire an insight of the building in terms of sound insulation, impact sound insulation, as well as different aspects regarding its vibratory performance.
Figure 1. Front facing façade.
1.1.-‐ Limiting factors
It should be mentioned that there were some factors, which may affect the results of these measurements. The main issue was that people were living at the building at the time when the measurements were carried out (and moreover, at home in that precise moment doing daily activities). For obvious reasons, that fact made the measurements more complicated when carrying them out, as not as much noise as needed/desired was possible to make. The measurements could have been influenced by those activities and thus the results should be questioned and analysed cautiously.
Moreover, the force transducer of the instrumented hammer available did not work properly thus not being able to display and record its force. Due to this, springiness and mobility measurements were not carried out.
2.- The construction
All construction details of investigated object were not available to us. Therefore details on the dimensions of beams and such are omitted. However, the building is comprised of a wooden frame and façade. The ceiling height is 2.40m and the flooring is parquet throughout the apartment with the exception of the bathroom. A detail of the floor construction and apartment separating walls can be seen in Figure 3.
2.1.-‐ Rooms used for the measurements
The limited amount of time we had to carry out the measurements (9 am -‐16 am) forced us to just be able to measure in a total number of 4 rooms (two rooms in each apartment), which can be described as follows:
-‐ Apartment 3rd floor:
-‐Living room (hereafter denoted LivRoom3):
Volume: 5.05 x 4 x 2.5 m
-‐Room next to the living room (hereafter denoted Room3) Volume: 3.2 x 4 x 2.5 m
-‐ Apartment 2nd floor:
-‐Living room (hereafter denoted LivRoom2 –right below LivRoom3-):
Volume: 5.05 x 4 x 2.5 m
-‐Room next to the living room (hereafter denoted Room2) Volume: 3.2 x 4 x 2.5 m
The layout of the apartments can be seen in Figure 4. The vibratory measurements have been performed in LivRoom2 and LivRoom3 as indicated in the drawing, the walls used for the measurements are indicated in red.
Figure 4. Floor plan. Apartment layout indicated in blue.
LivRoom Room Wall Outer Wa ll In n e r
The equipment used for the measurements is described below:
• MEMS accelerometers (Analog Devices):
ADXL 203
ADXL 202E
• 32-‐channel synchronous data acquisition system
Acquisition software Spectrum SBench 6.1
• ISO B&K tapping machine
• Loudspeaker
• B&K instrumented hammer
• Standarized Japanese Ball
• Amplifiers • Sonometer Norsonic® 140 4.- Measurements
First of all, some preliminary notes should be pointed out regarding the room-‐ acoustic measurements. Along this report, it will be referred to different measurement positions when recording with the sound level meter. Those spots were chosen trying to find a compromise between the location (spread enough) and accessibility (due to existent furniture). They were roughly located as shown in Figure 5.
Figure 5-‐ Measurement positions with the sound level meter in (a) LivRoom2 and LivRoom3; and
(b) Room2 and Room3
4.1.- Airborne sound insulation
The objective of the following is to measure the airborne sound insulation following the current standards (ISO 140-‐7, ISO 717-‐2 and SS 25267), within the frequency range going from 50 Hz to 5000 Hz. Thus, the parameters to be extracted are R’ in third octave bands (50-‐5000 Hz), R’n,w, Cl,50-‐2500 and Cl,50-‐5000.
Please note that the procedure described in the standards was not properly followed due to the occupancy of the building and for instance, only 5 seconds recordings with the loudspeaker were done.
First of all, the reverberation time of LivRoom2 and Room3 was calculated by emitting a noise with the loudspeaker during 15 seconds and recording with the
Norsonic at the five positions previously explained.
The reverberation time will allow us to calculate the effective absorption area,
A[m2], of the receiving room according to (V[m3] volume of the room):
𝑅𝑇 = 0.16 𝑉
𝐴
The equivalent sound pressure levels in the other rooms of interest (Room3 and LivRoom2) were measured when exciting with the loudspeaker, which was placed at the middle of the floor of LivRoom3. Hence, our sending room was LivRoom3 and the receiving rooms all the others.
Thus, R’ [dB] is calculated as:
𝑅! 𝑑𝐵 = 𝐿
!"#$%#&− 𝐿!"#"$%$&'+ 10log
𝑆 𝐴
being Lsending and Lreceiving the sound pressure level in the sending and receiving
room respectively (in decibels), A[m2] the effective absorption area and S[m2] the
surface of the partition to be studied.
The summary of the measurements done is:
Sending Room Receiving Room R'w Cl,50-‐3150 R'w+Cl50-‐3150 Soundclass Apt. Floor Room Apt. Floor Room
3001 3 LivRoom3 2001 2 LivRoom2 56 -‐3 53 C 3001 3 LivRoom3 3001 3 Room3 55 -‐2 53 C
4.1.1.-‐ Sound insulation between LivRoom3 and LivRoom2
The results obtained for the floor partition between LivRoom3 and LivRoom2 are:
NOTE: VolReceiving Room= 50.05 m3
Apartition=20.2 m2 Results R’w=56 dB C50-‐5000=-‐2dB C50-‐3150=-‐3 dB
4.1.1.-‐ Sound insulation between LivRoom3 and Room3
The results obtained for the wall partition between LivRoom3 and Room3 are:
NOTE: VolReceiving Room= 32 m3
Apartition=10 m2 Results R’w=55 dB C50-‐5000=-‐1dB C50-‐3150=-‐2 dB
4.2.- Impact sound insulation
The objective is to measure the structure-‐borne sound insulation following the current standards (ISO 140-‐7, ISO 717-‐2 and SS 25267) within the frequency range 50 Hz -‐ 5000 Hz. In order to calculate the impact sound insulation index the tapping machine was
placed at the middle of the floor in LivRoom3 and recordings with the Norsonic in third
octave bands were performed in LivRoom2 and Room3. The same five different positions were considered when recording. As a result of this analysis, L’ in third octave bands (50-‐5000 Hz), L’nw, and C50-‐3150 should be obtained.
As the volume of all receiving rooms (LivRoom2 and Room3) is larger than 31 m3, the
following correction must be done according to ISO 140-‐7:
𝐿!"## = 𝐿!− 10 log
𝑇
𝑇! [𝑑𝐵]
being Lr the sound pressure level in the receiving room, T the reverberation time for
each frequency and T0=0.5 s.
Hence, L’ [dB] is calculated as follows: 𝐿! 𝑑𝐵 = 𝐿 !"#"$%$&'+ 10log 𝐴 10
being Lreceiving the sound pressure level in the receiving room (in decibels) and A[m2] the
equivalent absorption area, calculated from the reverberation time.
The summary of the measurements done is:
Sending Room Receiving Room L'n,w Cl,50-‐2500 L'n,w+Cl50-‐2500 Soundclass Apt. Floor Room Apt. Floor Room
3001 3 LivRoom3 2001 2 LivRoom2 54 5 59 D 3001 3 LivRoom3 3001 3 Room3 60 0 60 D
Plots with the results are presented next:
4.2.1.-‐ Impact sound insulation between LivRoom3 and LivRoom2
The results obtained for the floor partition between LivRoom3 and LivRoom2 regarding impact sound insulation are:
NOTE: VolReceiving Room= 31 (50.05) m3
Results L’nw=54 dB C50-‐2500=5 dB
4.2.2.-‐ Impact sound insulation between LivRoom3 and Room3
The results obtained for the wall partition between LivRoom3 and Room3 regarding impact sound insulation are:
NOTE: VolReceiving Room= 31 (32) m3
Results L’nw=60 dB C50-‐2500=0 dB
4.3.- Sound from the Japanese ball
The sound produced and transmitted when dropping the Japanese ball from 1 meter height on the middle of the floor of LivRoom3 (sending room) was measured in all receiving rooms (Room3, LivRoom2 and Room2) in the frequency range 20 Hz-‐500 Hz (time constant: fast 125 ms). In the following table, the values of the maximum sound pressure levels are presented for the sending room (LivRoom3) and the receiving rooms.
Table 1. Total Lmax [dB] in all rooms.
Floors Room Lmax (centre) [dB] Lmax (centre) [dBA] Lmax (corner) [dB] Lmax (corner) [dBA]
3 LivRoom 3 102,7 64 98,6 60.3 3 Room3 90,5 50.4 91,1 51.1 2 LivRoom2 93,8 53.8 93,8 54.3 2 Room2 88,4 47.3 89,7 51.6
4.4.- Vibrations from the Japanese ball (only possible for LivRoom3)
The vibrations produced by the Japanese ball in the frequency range from 1 Hz to 500 Hz are to be measured. It was dropped from 1 meter high and it bounced until it came to a complete rest. Meanwhile, the response of the floor was measured as
shown in Figure 6. The parameters of interest are the maximum acceleration (amax)
and also the lowest eigenfrequency as well as plot “acceleration versus time”.
Figure 6 – Layout of accelerometers and excitation point
Table 2. Maximum RMS acceleration created by the Japanese ball Room Amax acc5 m/s2 rms Amax acc6 m/s2 rms
LivRoom3 3,53 3,03 0.5m Acc6 Acc5 Excitation Response 0.5m
f (Hz) 10 16 20 25 31,5 40 50 63 80 Acc 5 0,173 0,170 0,159 0,194 0,157 0,089 0,084 0,126 0,176 Acc 6 0,208 0,061 0,129 0,325 0,197 0,061 0,127 0,100 0,164 f (Hz) 100 125 160 200 250 315 400 500 Acc 5 0,089 0,174 0,387 0,156 0,090 0,062 0,047 0,042 Acc 6 0,209 0,185 0,154 0,084 0,068 0,091 0,092 0,035
In Figures 7, 8 and 9 a detail of the impulse from the ball is presented. The first eigenfrequency can be clearly identified at about 14Hz.
Figure 7 – Impulse from the Japanese Ball measured by Acc5
Figure 9 -‐ Impulse in the frequency domain from the Japanese Ball measured by Acc6
4.5.- Flanking transmission (between LivRoom3 and LivRoom2)
The objective is to measure how the vibrations travel through a junction in the frequency range 1 Hz-‐500 Hz (when exciting with the Japanese ball) and 10-‐ 3150 Hz (when having the tapping machine as excitation source)
The excitation was on the middle of LivRoom3 when dropping the Japanese ball from 1 m height and the tapping machine measuring with the accelerometer setup shown in Figures 10-‐11. Note that the accelerometers placed on the walls (acc10-‐ 14 and acc25-‐29) are in a vertical line and not in the horizontal. The walls used for the measurements are indicated in Figure 4.
Figure 11 – Accelerometers distribution, left upper (sending) room, right lower (receiving) room.
The same measurement was performed three times (for the tapping machine) and five times (for the Japanese ball) in order to have a good repeatability.
The Flanking transmissions in both narrow band and third octave band for all measurement cases in Figures 12-‐19. In tables 4 and 5 the mean acceleration for the different measurement groups are shown, in third octave band and in
maximum acceleration (Amax).
Acc1 Acc14 Acc13 Acc12 Acc11 Acc10 Acc9 Acc8 Acc7 Acc6
Acc5 Acc4 Acc3 Acc2
FLOOR
Acc21 Acc20
Acc19 Acc18 Acc17 Acc16 Acc15
Acc25 Acc23 Acc24 Acc26 Acc27 Acc29 Acc28 CEILING WALL WALL Acc1 Acc12 Acc11 Acc10 Acc9 Acc8 Acc7 Acc6
Acc5 Acc4 Acc3 Acc2
FLOOR
Acc21 Acc20
Acc19 Acc18 Acc17 Acc16 Acc15
Acc25 Acc23 Acc24 Acc26 Acc27 Acc29 Acc28 CEILING WALL WALL
Figure 13 -‐ Mean of vibrations over flank using tapping machine (measured along an internal wall)
one third octave band.
Figure 14 -‐ Mean of vibrations over flank using Japanese Ball (measured along an internal wall) narrow band.
Figure 15 -‐ Mean of vibrations over flank using Japanese Ball (measured along an internal wall) one third band
Figure 17 -‐ Mean of vibrations over flank using Tapping Machine (measured along an outer wall) one third band
Figure 18 -‐ Mean of vibrations over flank using Japanese Ball (measured along an outer wall) narrow band.
Figure 19 -‐ Mean of vibrations over flank using Japanese Ball (measured along an outer wall) one
third band.
Table 4. Frequency content of accelerations for the mean of the different accelerometers (mm/s^2 rms. excitation: Japanese ball) in Third Octave bands.
Frequency (Hz) (mm/sWall Up 2) Floor Inner (mm/s2) Floor Outer (mm/s2) Wall Down (mm/s2) Ceiling Inner (mm/s2) Ceiling Outer (mm/s2) 10 3,68 42,75 56,26 11,09 21,87 11,94 16 6,40 47,79 71,42 7,68 20,87 21,96 20 13,45 46,03 47,29 11,96 35,28 44,85 25 29,28 77,74 80,95 17,12 26,50 36,99 32 13,80 48,62 50,73 6,57 16,44 13,63 40 11,68 41,68 31,03 3,31 8,05 12,39 50 5,28 33,83 12,46 4,70 7,79 5,49 63 8,03 49,96 51,56 4,40 9,28 10,80 80 5,10 44,93 32,35 4,01 13,10 9,09 100 9,23 49,18 45,65 7,21 14,10 20,82 125 13,33 36,44 49,18 5,59 11,10 15,31 160 12,80 26,12 85,45 3,47 9,75 14,69 200 5,08 13,85 48,87 3,07 3,21 3,38 250 2,64 13,49 24,21 2,09 1,97 2,05 315 2,92 6,75 9,45 1,91 1,97 1,77 400 2,40 3,47 4,81 2,03 1,70 1,76 500 2,11 2,52 3,58 2,01 1,71 1,61 630 1,92 2,32 2,54 1,76 1,69 1,69 800 1,82 2,25 3,49 1,85 1,76 1,66 1000 1,78 1,94 3,22 1,78 1,55 1,51 1250 1,68 1,81 2,72 1,68 1,53 1,40 1600 1,62 1,73 1,88 1,49 1,33 1,37
4.6.- Surface Vibration of the Floor (LivRoom3)
The objective is to measure and analyse how the vibrations travel through the floor and how they are dampened from the source. The frequency ranges of interest are 1-‐500 Hz when exciting with the Japanese ball and 20-‐3150 Hz when exciting with the hammer machine.
The excitation was at the middle of LivRoom3 when dropping the Japanese ball from 1 m height and the tapping machine. The accelerometers’ setup is shown in Figure 20. In Figures 21-‐24 the resulting surface vibrations in the two directions are shown bot in narrow band and in third octave band. The acceleration from the Japanese ball is shown in third octave bands in table 6 and in table 7 the maximum acceleration is shown.
Figure 20 – Layout 0.5m Acc6 Acc5 Excitation Response Acc1 Acc3 Acc4 Acc2 0.32m 0.5m 0.5m 0.375m 0.5m Acc7 Acc8 Acc9 Acc10
Figure 22 -‐ Floor vibrations from tapping machine narrow band
Figure 23 -‐ Floor vibrations from tapping machine one third octave band
Figure 24 -‐ Floor vibrations from tapping machine one third octave band.
Table 6. Frequency content in accelerations for the different accelerometers (mm/s^2 rms. excitation: Japanese ball) in Third Octave bands.
Pos Freq
Acc1 Acc2 Acc3 Acc4 Acc5 Acc6 Acc7 Acc8 Acc9 Acc10 10,00 13,53 51,65 92,66 138,94 172,71 207,90 165,54 144,90 124,65 66,14 16,00 45,15 119,91 165,23 175,61 170,12 61,37 70,93 81,48 65,16 36,97 20,00 77,51 194,70 253,86 234,11 159,43 129,02 187,84 189,98 160,56 81,85 25,00 109,77 221,27 240,61 157,84 193,94 325,14 368,92 355,11 316,07 141,92 31,50 52,90 99,59 104,68 97,18 156,93 196,73 234,06 231,89 217,17 102,14 40,00 33,76 76,08 77,02 42,69 89,21 60,99 139,39 184,27 202,96 102,78 50,00 13,58 29,38 30,76 40,10 83,84 126,66 97,67 101,74 141,72 76,92 63,00 31,01 79,97 89,01 149,33 126,42 100,36 280,58 97,73 146,40 44,87 80,00 42,49 125,83 123,01 234,68 176,07 164,35 284,05 64,05 198,68 107,70 100,00 33,75 128,87 102,55 140,32 88,91 208,74 165,74 48,56 71,85 108,87 125,00 60,98 184,53 147,35 135,93 174,28 184,67 123,46 71,82 52,04 91,00 160,00 143,44 205,54 197,05 251,43 386,54 153,57 72,68 49,16 58,45 65,45 200,00 61,86 42,62 54,62 90,86 155,58 84,23 24,12 10,58 12,63 7,31 250,00 35,64 26,15 53,57 61,35 89,60 67,86 28,54 12,28 7,42 4,70 315,00 15,06 14,59 31,58 53,11 62,35 91,41 20,33 12,27 9,77 4,69 400,00 7,92 10,05 17,23 38,24 46,89 91,67 21,79 14,66 11,28 6,40 500,00 4,52 7,06 8,01 13,97 41,81 35,10 27,29 18,90 6,81 3,32
Table 7. Maximal accelerations from Japanese Ball Amax (m/s^2 rms) positions as in Figure 12. Point Amax (m/s2) Point Amax (m/s2)
Acc1 1,09 Acc6 3,03
Acc2 1,87 Acc7 2,29
Acc3 1,94 Acc8 1,38
4.7.- Wall Response (only one of LivRoom3 –furniture on others-‐)
The objective was to calculate the lowest eigenfrequency of the structure when hitting the wall with an instrumental hammer with a rubber tip
Figure 25 – Measurement disposition on the wall
Note: This measurement could only be done for the inner wall in LivRoom 3 as indicated in Figure 4 as the others were covered with furniture all the way. And note also that, as previously mentioned the force transducer of the instrumented hammer available didn’t work.
0.83m Acc14 Excitation Response 1.33m 0.83m 1.33m Hammer
Figure 27 -‐ Vibrations on inner –apartment separating-‐ wall in third-‐octave bands.
4.8.- Springinness
Not performed, as the instrumented hammer did not work.
4.9.- Mobility
Not performed, as the instrumented hammer did not work.
Drawings of Hyttkammaren.