A
(
8
)=
a
we
√
T
e
T
0
Equation 1
where
A(8)
is the daily exposure
a
we
is the energy equivalent mean value of the frequency weighted acceleration
during exposure, which means
- For
Hand-Arm Vibration
the X/Y/Z vector sum of Wh frequency-
weighted RMS values (Equation 2)
a
w
=
√
a
wx
2
+
a
wy
2
+
a
wz
2
Equation 2
- For
Whole-Body Vibration
the highest of the three RMS values
a
wx
, a
wy
and a
wz
with the following frequency and magnitude weightings:
- X and Y with weighting filter Wd and weighting factor 1.4
- Z with weighting filter Wk and weighting factor 1.0
T
e
is the total duration of exposure during one work day
T
0
is the reference duration of 8 hours
Daily exposure may consist of several partial exposures with different vibration
magnitudes. This can be the case if there are longer interruptions in the work
process, if the work equipment or its way of use is changed. A partial exposure sec-
tion should have a roughly constant magnitude and less than 10 % interruptions. Re-
sulting daily exposure is calculated as follows:
Hand-Arm Vibration
:
A
(
8
)=
√
1
T
0
∑
i
=
1
n
a
wi
2
T
ei
Equation 3
where
A(8)
is the daily exposure
a
wi
is the energy equivalent mean value of the Wh frequency weighted accelera-
tion of partial exposure section i
n
is the number of partial exposure sections
T
ei
is the duration of exposure i
T
0
is the reference duration of 8 hours
Whole-Body Vibration
:
Separate daily exposures need to be calculated for X/Y/Z. The highest value is used
for the evaluation, i.e. compared with the limits of Table 1.
A
x
(
8
)=
√
1
T
0
∑
i
=
1
n
a
wxi
2
T
ei
Equation 4
5