CESVA VC431, User Manual, Page: 7 / 72

VC431
Instruction manual
5
The evaluation of the level of exposure to vibrations is based on measuring the daily
exposure to vibration value, normalised for a reference period of 8 hours, A(8) expressed
as the greater of the daily exposure to vibration values on the three axes. The daily
exposure to vibration value, normalised for a reference period of 8 hours, A
i
(8), on each
axis is obtained from the RMS values of the acceleration with frequency weighting,
determined according to the three orthogonal axes (1,4a
dx
, 1,4a
dy
, a
kz
), in accordance with
the ISO 2631-1 Standard.
The VC431 makes it possible to measure vibration in the place where the contact
between the human body and the source of vibration (feet, seat or backrest) takes place,
always observing the corresponding system of coordinates.
To perform these measurements it is necessary to have the triaxial accelerometer
AC033 .
The VC431 measures the following functions simultaneously:
The VC431 makes it possible to make measurements during a time shorter than the
exposure time and evaluate the projected daily exposure to vibration value A(8)
p
, for a
programmable projection time (forecast exposure time), as the greater value of the
projected daily exposure to vibration values for each axis A
x
(8)
p
, A
y
(8)
p
, A
z
(8)
p
.

The WHOLE BODY IN BUILDINGS application is designed to measure the vibrations
transmitted to the whole body inside buildings (houses, residential, hospital, educational
or cultural) according to the ISO 2631-2 Standard.
The evaluation of the level of vibration transmitted to the whole body inside buildings is
based on measuring the MTVV parameter (Maximum Transient Vibration Value)
expressed as the greatest of the MTVV values on the three axes (MTVV
x
, MTVV
y
, MTVV
z
)
using the frequency weighting W
m
as indicated by the ISO 2631-2 Standard. The total
combined RMS acceleration value is also measured, consisting of combining the RMS
values of weighted acceleration with the frequency weighting Wm on the three coordinate
axes (a
mx
, a
my
and a
mz
) as displayed below (k
x
=1, k
y
=1 and k
z
=1):
2 2 2
mx mx mx mv
a a a a
  
a
dx
RMS value of acceleration on the x axis with W
d
weighting
a
dy
RMS value of acceleration on the y axis with W
d
weighting
a
kz
RMS value of acceleration on the z axis with W
k
weighting
A
x
(8)
Daily exposure to vibration on the x axis
A
y
(8) Daily exposure to vibration on the y axis
A
z
(8) Daily exposure to vibration on the z axis
A(8)
Daily exposure to vibration
A
x
(8)
p
Projected daily exposure to vibration on the x axis
A
y
(8)
p
Projected daily exposure to vibration on the y axis
A
z
(8)
p
Projected daily exposure to vibration on the z axis
A(8)
p
Projected daily exposure to vibration