NIOSH VIBRATION
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been clearly documented. Those levels
within the HGCZ indicate caution with
respect to potential health risks. The
exposure limit value (ELV) is the level
above which health risks are likely. Ta-
bles 1 and 2 display the EAVs and ELVs
in terms of aw and VDV.
Results
Figures 2 and 3 are the graphical dis-
plays of a
w
and VDV in the vertical di-
rection and the percent difference be-
tween the Siemens/LMS and the iPod
measured at the seat and normalized for
an 8-hour exposure duration. The figures
indicate good agreement between the
two systems for the selected equipment.
Absolute differences in percent for a
w
(8) measures comparing the Siemens/
LMS and iPod measurement systems
ranged from 0.1 to 8.5. Twelve of the 13
instances showed percent differences of
4.2% or less.
Absolute differences in percent for
VDV (8) measures comparing the Sie-
mens/LMS and iPod measurement sys-
tems ranged from 0.3% to 18.8%. Elev-
Figure 2—A
w
measured in the vertical direction at the seat and normalized to an 8-hr shift for equipment ID Nos.
shown above.
Figure 3—VDV measured in the vertical direction at the seat and normalized to an 8-hr shift for equipment ID
Nos. shown above.
