Sanyo ECO G SGP-EW120M2G2W, Technical Data Manual

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System Design
6. Sound-proofing measures
D-30
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 Fig. 1, attenuation of unit operating sound = -22
Fig. 2, Refraction attenuation, sound path difference
δ
= A + B – d = 0.5
3) Refraction attenuation dB
－
3.5
－
5
－
6.5
－
9
－
12
－
15
－
18
－
21
Fig. 6, Additional sound due to reflections (wall)
4) Additional sound from
reflections (wall surface)
dB
By calculation or the simplified method, the maximum value of the two
combined sounds is +3
Fig. 7, Addition sound due to reflection (ground surface)
5) Additional sound from
reflections (ground surface)
dB
By calculation or the simplified method, the maximum value of the two
combined sounds is +3
6) Subtotals dB 49.5 45 39.5 34 28 18.5 11 4.5
Conversion factors for A weighting
7) Overall A-weighting correction
factors
dB
－
26
－
16
－
9
－
3 0 +1 +1
－
1
8) A weighting dB(A) 23.5 29 30.5 31 28 19.5 12 3.5
When the calculations of Table 1 are completed, the overall A weighting can be calculated.
31 30.5 29 28 23.5
Difference = 0.5
(31 + 2.7)
33.7
Difference = 4.7
(33.7 + 1.2)
34.9
Difference = 6.9 35.95 30.0
(34.9+0.8)
35.7 Difference = 5.95
Difference = 12.2 (35.95+0.95)
35.7 + 0.25 = 35.95 dB =36.9
(8) Sound-proofing calculation sheet (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
Distance attenuation
2) Distance attenuation dB
Distance attenuation value =
Refraction attenuation, sound path difference
δ
= A + B – d,
δ
=
3) Refraction attenuation dB
Additional sound due to reflections (wall)
4) Additional sound from
reflections (wall surface)
dB
By calculation or the simplified method, the maximum value of the two
combined sounds is +3
Fig. 7, Addition sound due to reflection (ground surface)
5) Additional sound from
reflections (ground surface)
dB
By calculation or the simplified method, the maximum value of the two
combined sounds is +3
6) Subtotals dB
Conversion factors for A weighting
7) Overall A-weighting correction
factors
dB
－
26
－
16
－
9
－
3 0 +1 +1
－
1
8) A weighting dB(A)
By completing the calculations in the above table, the overall A weighting at the reception point is obtained
(calculate in order from the highest sound level).
Once the overall A weighting has been calculated, combine with the ambient noise level to obtain to total sound
level at the reception point.
The overall A weighting at the reception point is
calculated to be 35.95 dB(A).
If the ambient noise (when the unit is not
operating) is 30.0 dB(A), the combining these
levels gives 36.9 dB(A).