B11Noise Level Test - Heraeus HS 9 Service Manual

B Field tests
B11 Noise level test
Purpose of the test:
This test is performed to measure the noise levels
produced by an operating cabinet as an aid in mini-
mizing cabinet operator fatigue.
Apparatus:
Sound level meter with a range of at least 50-100 db
and an "A" weighting scale.
Calibrator for the sound analyzer.
Calibration of the apparatus:
The sound level meter must be calibrated in accor-
dance with the manufacturer's instructions.
Test area:
Place the microphone outside the cabinet at a dis-
tance of 30 cm (12 in) to the work opening and at a
height of 45 cm (18 in) above the work surface at the
centre of the work opening.
Test conditions:
Normal conditions at the place of location.
Perform the test measurement:
1. With the cabinet not operating, perform the meas-
urement and record the value.
2. Turn on the cabinet and the cabinet lighting, de-
termine the noise level and record the value.
Determine the noise level value:
Noise level value = operating value - background
value
Acceptance according to NSF, 49, Annex F:
The ambient noise level must not exceed 57 dbA.
With the cabinet operating, the noise level must not
exceed 67 dbA.
Figure B13
Fig. B13, Measuring point for noise level test
12 in
18 in
Troubleshooting:
Excessive noise level:
Check the entire cabinet for loose screw connec-
tions or components.
In case of vastly excessive values, check the
blower for imbalance.
NOTE - Unit commissioning:
Prior to the commissioning of the unit:
Perform test run!
Check safety devices for proper opera-
tion!
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Service Instructions HERAsafe HS/12/18
Valid: 05.2001 / 50060091 / A