21
SOUND PRESSURE LEVELS
5
5-1. Sound pressure level
Measurement location
2m
2m
Aux. duct
1.5m
test unit
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
63
125
250
500
1k
2k
4k
8k
NC-60
NC-50
Approximate minimum
audible limit on
continuous noise
NC-40
Octave band center frequencies (Hz)
NC-20
NC-30
High
Middle
Low
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
63
125
250
500
1k
2k
4k
8k
NC-60
NC-50
Approximate minimum
audible limit on
continuous noise
NC-40
Octave band center frequencies (Hz)
NC-20
NC-30
High
Middle
Low
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
63
125
250
500
1k
2k
4k
8k
NC-60
NC-50
Approximate minimum
audible limit on
continuous noise
NC-40
Octave band center frequencies (Hz)
NC-20
NC-30
High
Middle
Low
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
63
125
250
500
1k
2k
4k
8k
NC-60
NC-50
Approximate minimum
audible limit on
continuous noise
NC-40
Octave band center frequencies (Hz)
NC-20
NC-30
High
Middle
Low
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
63
125
250
500
1k
2k
4k
8k
NC-60
NC-50
Approximate minimum
audible limit on
continuous noise
NC-40
Octave band center frequencies (Hz)
NC-20
NC-30
High
Middle
Low
(External static pressure 35Pa)
(External static pressure 100Pa)
(External static pressure 50Pa)
(External static pressure 70Pa)
(External static pressure 150Pa)
Ceiling concealed
5-2. NC curves
PEAD-M35JA(L)
HWE16130.qxd 17.4.3 13:15 Page 21