7
NOISE CRITERIA CURVES
5
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
TERESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
A
VE BAND SOUND PRESSURE LEVEL, 0dB = 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
Test conditions.
Cooling :DB35
:
WB24
:
Heating :DB 7
:
WB 6
:
COOL
NOTCH
HEAT
46
SPL(dB
(A)
)
47
LINE
MXZ-24UV -
E1
OB287--1.qxp 10/9/01 3:29 PM Page 7
