42
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
µ
bar)
BAND CENTER FREQUENCIES, Hz
PLA-P1.6KA.UK
PLA-P1.6KA
1
.UK
PLA-P2KA.UK
PLA-P2KA
1
.UK
High
NOTCH
Medium1
Medium2
Low
37
SPL(dB)
35.5
34
32
LINE
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
µ
bar)
BAND CENTER FREQUENCIES, Hz
PLA-P2.5KA.UK
PLA-P2.5KA
1
.UK
High
NOTCH
Medium1
Medium2
Low
39.5
SPL(dB)
38
36.5
35
LINE
6. NOISE CRITERION CURVES
Ambient temperature 27
:
Test conditions are based on JIS Z8731
UNIT
1.5m
MICROPHONE
CEILING
OC240-B--2.qxp 04.9.29 3:31 PM Page 42
