Design
D - 27
Table 1 Sound-proofing calculation sheet (filled in example)
Frequency Hz 63 125 250 500 1000 2000 4000 8000
From the operating sound characteristics diagram in the outdoor unit manual
1)Operating sound of outdoor unit dB
69 66 62 59 56 49.5 45 41.5
From distance attenuation
2) Distance attenuation dB
From Figure 1, attenuation of unit operating sound –22
Figure 2 Refraction attenuation quantity,
sound path difference d=A+B-d δ:0.5
3) Refraction attenuation dB
-3.5 -5 -6.5 -9 -12 -15 -18 -21
Figure 6 additional sound due to reflections (wall) 4) Increase for reflections (wall
surface)
dB
By calculation or the simplified method, the combined two sounds MAX value is +3
Figure 7 additional sound due to reflection (ground surface) 5) Increase for reflections(ground
surface)
dB
By calculation or the simplified method, the combined two sounds MAX value is +3
6) Sub-total dB 49.5 45 39.5 34 28 18.5 11 4.5
Conversion factors for A characteristic 7) Overall A characteristic correction
factor
dB
-26 -16 -9 -3 0 +1 +1 -1
8)A characteristic dB(A) 23.5 29 30.5 31 28 19.5 12 3.5
Frequency Hz 63 125 250 500 1000 2000 4000 8000
From the operating sound characteristics diagram in the outdoor unit manual
1) outdoor unit operation sound dB
Distance attenuation
2) distance attenuation dB
Distance attenuation value:
Refraction attenuation sound path difference d=A+B d δ:
3) Refraction attenuation
dB
Additional sound due to reflections (wall) 4) Additional sound due to reflection
(wall surface)
dB
By calculation or the simplified method, the combined two sounds MAX value is +3
Figure 7 additional sound due to reflections (ground surface) 5) Additional sound due to reflection
(ground surface)
dB
By calculation or the simplified method, the combined two sounds MAX value is +3
6) Sub-total dB
Conversion factors for A characteristic 7) Overall A characteristic conversion
factor
dB
-26 -16 -9 -
-
3 0 +1 +1 -1
8) A characteristic dB(A)
When the calculation in the above table is complete, the overall A characteristic is calculated at the reception point.
(calculate in order of largest sound level). When the overall A characteristic is calculated, combine this with the
background noise level to obtain the total sound level at the reception point.
When the calculation in Table 1 is completed, the overall A characteristic is calculated.
(8)Sound-proofing calculation sheet (example)
6. Sound-proofing measures