
SEBU8213-04 27
Safety Section
Sound Information and Vibration Information
Table 1
“ISO Reference Table A - Equivalent vibration levels of whole body vibration emission for earthmoving equipment.”
Vibration Levels Scenario Factors
Machine
Type
Typical Operating
Activity
X axis Y axis Z axis X axis Y axis Z axis
dozing 0,74 0,58 0,70 0,31 0,25 0,31
ripping 1,25 1,19 1,02 0,40 0,41 0,28
T rack-T ype
Tractors
transfer 0,87 0,80 0,97 0,43 0,40 0,34
Note: Refer to “ISO/TR 25398 Mechanical Vibration -
Guideline for the assessment of exposure to whole
body vibration of ride on operated earthmoving
machines” for more information about vibration.
This publication uses data that is measured
by international institutes, organizations and
manufacturers. This document provides information
about the whole body exposure of operators of
earthmoving equipment. Refer to Operation and
Maintenance Manual Supplement , SEBU8257 for
more information about machine vibration levels.
The Caterpillar suspension seat meets the criteria of
“ISO 7096”. This represents vertical vibration level
under severe operating conditions. This seat is tested
with the input “spectral class EM6”. The seat has a
transmissibility factor of “SEAT<0.7”.
The whole body vibration level of the machine varies.
There is a range of values. The low value is 0.5
meter per second squared. The machine meets the
short term level for the design of the seat in “ISO
7096”. The value is 1.61 meter per second squared
for this machine.
Guidelines for Reducing Vibration Levels on
Earthmoving Equipment
Properly adjust machines. Properly maintain
machines. Operate machines smoothly. Maintain the
conditions of the terrain. The following guidelines can
help reduce the whole body vibration level:
1. Use the right type and size of machine, equipment,
and attachments.
2. Maintain machines according to the manufacturer's
recommendations.
a. Tire pressures
b. Brake and steering systems
c. Controls, hydraulic system and linkages
3. Keep the terrain in good condition.
a. Remove any large rocks or obstacles.
b. Fill any ditches and holes.
c. Provide machines and schedule time in order
to maintain the conditions of the terrain.
4. Use a seat that meets “ISO 7096”. Keep the seat
maintained and adjusted.
a. Adjust the seat and suspension for the weight
and the size of the operator.
b. Inspect and maintain the seat suspension and
adjustment mechanisms.
5. Perform the following operations smoothly.
a. Steer
b. Brake
c. Accelerate.
d. Shift the gears.
6. Move the attachments smoothly.
7. Adjust the machine speed and the route in order
to minimize the vibration level.
a. Drive around obstacles and rough terrain.
b. Slow down when it is necessary to go over
rough t errain.
8. Minimize vibrations for a long work cycle or a long
travel distance.
a. Use machines that are equipped with
suspension systems.
b. U se the ride control system on Track-Type
Tractors.
c. If no ride control system is available, reduce
speed in order to prevent bounce.
d. Haul the machines between workplaces.
9. Less operator comfort may be caused by other risk
factors. The following guidelines can be effective
in order to provide better operator comfort: