12
SOUND PRESSURE LEVELS
5
5-1. Sound pressure level
Measurement location
2m
1m
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 0.14 [in.WG] (35Pa) External static pressure 0.40 [in.WG] (100Pa)
External static pressure 0.20 [in.WG] (50Pa)
External static pressure 0.28 [in.WG] (70Pa)
External static pressure 0.60 [in.WG] (150Pa)
Ceiling concealed
5-2. NC curves
PEAD-A24AA