４５
(2) Put freezer onto 5-10mm elastic cushion.
(3) Freezer must be empty and running at least 30 minutes before
measuring. If normal stop happens, please make the measurement 3
minutes after freezer starting again.
(4) 4 measuring positions are required, they are 1m away from freezer at
front, back, front left, front right respectively. The height is 1/2 of freezer;
the instrument is accurate sound level meter (A weighted).
12.6.12 What
’
s the different between national noise
standard 52dB(A) and ministry of light industry standard
42dB?
Answer: The noise of 52dB(A) in national standard is the sound power level.
Under the measuring conditions stipulated in national standard, measure
the freezer noise at four points, take the average of indicated reading at
greater noise situation, calculate the arithmetic average value of the four
points. This value is the average sound pressure level of noise, the
calculation formula is:
L
w
=(L
PA
-2)+10LgS
where: L
W
—
sound power level, dB
L
PA
-average sound pressure level of measuring surface, dB
S
—
the envelope area of measuring surface, m
2
MAINTENANCE SERVICE AND TROUBLE SHOOTING
Maintenance Service and Trouble Shooting
The standard 42dB of the ministry of light industry is the noise pressure
level measured 1m away from freezer door. This value plus 10 is the
PDF created with pdfFactory trial version
www.pdffactory.com
