VIacoustics ACCULAB RSS-101 - Calibration and Periodic Checks

2021 RSS Manual all models.doc. Page 7 // 02/12/21
CALIBRATION
Periodic acoustic checks of the RSS as described in ISO 6926/ANSI S12.5 section 5.6.3 at least
every 6 months or any time the unit appears to have incurred damage. Units that are regularly
transported to field locations may need to have the periodic check performed more frequently. A
periodic check both before and after transporting the RSS assures that the RSS continues to operate
at its calibrated sound power.
The periodic check should be conducted using at least four (4) fixed measurement positions relative
to the RSS in the same test environment. If the standard deviation of the average of the sound
pressure levels at the measurement positions of the periodic check measurements over time exceeds
the values shown below, the RSS should be re-calibrated per ISO 6926/ANSI S12.5
1/3 OB Center
Frequency (Hz)
Maximum Standard Deviation
of Repeatability (dB)
50 Hz - 80 Hz
2.3
100 Hz – 160 Hz
1.1
200 Hz – 20 kHz
(or max frequency of
use)
0.6
Recalibration according to ISO 6926 is advised when fan wheel or surge band damage has been
repaired, when fan wheel RPM deviates constantly more that 1 % from the RPM reported at the
calibration voltage or when more than ten (10) years have elapsed since the last calibration.
Calibration should be performed in a laboratory that is accredited per ISO 17025 and conducting the
calibration in accordance with ISO 6926/ANSI S12.5, Free Field over a Reflecting Plane.