research report 377 - health and safety executive · bobcat 130 compact skid steer loader 2.22...

HSEHealth & Safety

Executive

Evaluation of whole-body vibrationexposures in British industry

Prepared by the University of Southamptonfor the Health and Safety Executive 2005

RESEARCH REPORT 377

HSEHealth & Safety

Executive

Evaluation of whole-body vibrationexposures in British industry

M G R TowardT P Gunston

M J GriffinInstitute of Sound and Vibration Research

University of SouthamptonSouthampton

SO17 1BJ

This report describes measurements of whole-body vibration on eight excavators and two compactskid-steer loaders. Of the excavators, four were fitted with impact hammers, two with hydrauliccrushers, one with a backhoe shovel and one with steel shears.

Accelerations were measured on the seat surface and on the floor within the operators’ cabs of themachines in accordance with ISO 2631 (1997). The data have been evaluated in the context of thelevels set out in the European Union Physical Agents (Vibration) Directive (2002/44/EC). The reportprovides predicted daily vibration exposure for each machine. The effects of machine operation andother parameters on the vibration exposures are also considered.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Itscontents, including any opinions and/or conclusions expressed, are those of the authors alone and donot necessarily reflect HSE policy.

HSE BOOKS

ii

© Crown copyright 2005

First published 2005

ISBN 0 7176 6155 5

All rights reserved. No part of this publication may bereproduced, stored in a retrieval system, or transmitted inany form or by any means (electronic, mechanical,photocopying, recording or otherwise) without the priorwritten permission of the copyright owner.

Applications for reproduction should be made in writing to:Licensing Division, Her Majesty's Stationery Office, St Clements House, 2-16 Colegate, Norwich NR3 1BQ or by e-mail to [email protected]

ACKNOWLEDGEMENTS

This report and the work it describes were funded by the Health and Safety Executive. Its

contents, including any opinions and/or conclusions expressed, are those of the authors alone

and do not necessarily reflect HSE policy.

iii

SUMMARY

This report describes measurements of whole-body vibration on eight excavators and two

compact skid-steer loaders. Of the excavators, four were fitted with impact hammers, two with

hydraulic crushers, one with a backhoe shovel and one with steel shears.

Accelerations were measured on the seat surface and on the floor within the operators’ cabs of

the machines in accordance with ISO 2631 (1997). The data have been evaluated in the context

of the levels set out in the European Union Physical Agents (Vibration) Directive (2002/44/EC).

The report provides predicted daily vibration exposure for each machine. The effects of machine

operation and other parameters on the vibration exposures are also considered.

v

CONTENTS

1 INTRODUCTION.............................................................................................................. 1

1.1 Description of test machines ..................................................................................... 1

1.2 Description of test sites .............................................................................................. 1

2 METHODS AND PROCEDURES ................................................................................... 5

2.1 Location and direction of measurements................................................................. 5

2.2 Transducers................................................................................................................ 5

2.3 Data acquisition ......................................................................................................... 5

3 RESULTS............................................................................................................................ 5

3.1 Vibration measures.................................................................................................... 6

3.2 Vibration exposures................................................................................................... 9

3.3 Machine operating patterns .................................................................................... 10

3.3.1 Bobcat 130............................................................................................................. 10

3.3.2 Bobcat 753............................................................................................................. 10

3.3.3 Kubota KX71-2 ................................................................................................... 11

3.3.4 Kubota KX161-3 (impact hammer)....................................................................... 11

3.3.5 Hitachi EX60LC-5 (impact hammer) .................................................................... 12

3.3.6 Hitachi ZX460LCH (impact hammer) .................................................................. 12

3.3.7 Hitachi EX60LC-5 (hydraulic crusher) ................................................................. 12

3.3.8 Hitachi EX455 (hydraulic crusher)........................................................................ 13

3.3.9 Case CX210 (Backhoe shovel).............................................................................. 13

3.3.10 Hitachi ZX460LCH (steel shears)..................................................................... 13

4 DISCUSSION ................................................................................................................... 14

4.1 Machine TYPE......................................................................................................... 14

4.2 Machine tool ............................................................................................................. 14

4.3 Machine operation ................................................................................................... 14

4.4 Seat performance ..................................................................................................... 15

4.5 Comparison with EU 2002/44/EC exposure levels ................................................ 15

5 CONCLUSIONS............................................................................................................... 16

vii

6 REFERENCES ................................................................................................................. 17

ANNEX A: BOBCAT 130 MEASURED 24TH

NOVEMBER 2004....................................... 18

ANNEX B: BOBCAT 753 MEASURED 19TH

NOVEMBER 2004....................................... 24

ANNEX C: KUBOTA KX71-2 MEASURED 12TH

NOVEMBER 2004 ............................ 30

ANNEX D: KUBOTA KX161-3 MEASURED 24TH

NOVEMBER 2004............................. 36

ANNEX E: HITACHI EX60LC-5 MEASURED 19TH

NOVEMBER 2004.......................... 42

ANNEX F: HITACHI ZX460LCH MEASURED 24TH

NOVEMBER 2004 ........................ 48

ANNEX G: HITACHI EX60LC MEASURED 24TH

NOVEMBER 2004 ............................ 54

ANNEX H: HITACHI EX455 MEASURED 9TH

DEC 2004 ................................................. 60

ANNEX I: CASE CX210 MEASURED 9TH

DECEMBER 2004........................................... 67

ANNEX J: HITACHI ZX460LCH MEASURED 22ND

DECEMBER 2004......................... 73

SUMMARY REPORT FORM: PART 5 – RESULTS .......................................................... 76

viii

1 INTRODUCTION

Measurements of vibration were carried out by the Human Factors Research Unit of the

Institute of Sound and Vibration Research on 10 demolition machines during the period

November to December 2004. The vibration exposures of the machine operators were

assessed in the context of the exposure action values and exposure limit values in the

European Union Physical Agents (Vibration) Directive (2002/44/EC). The effects of machine

type, machine tool, machine operation and the performance of the seats fitted in the machines

have also been considered.

1.1 DESCRIPTION OF TEST MACHINES

Whole-body vibration measurements were made on 10 demolition machines: 8 excavators

and 2 skid-steer loaders. The machines are summarised in Table 1 and further details of the

machines are given in the annexes. Where available, manufacturer specifications are available

by clicking on the ‘Model’ in Table 1. The excavators ranged in weight from 2.98 to 47.4

tonnes. Of the excavators, four were fitted with impact hammers, two with hydraulic crushers,

one with a backhoe bucket, and one with steel shears. All of the excavators were fitted with

steel tracks. The skid-steer loaders were fitted with solid rubber tyres and a bucket. The skid-

steers loaders weighed 2.22 tonnes.

1.2 DESCRIPTION OF TEST SITES

Vibration tests were conducted on three demolition sites:

Lloyds Building, London. This was a large multi-story building in central London. The

building was being demolished from the top down on a floor-by-floor basis. The

measurements were being made towards the end of demolition of the building. There were up

to twelve demolition machines operating on site.

Aldermanbury Square, London. This was high-rise office block with a relatively small

footprint in Central London. The upper floors of the tower block were being demolished

during the measurements. There were up to five demolition machines operating on site.

Chatham Street Car Park, Reading. This was a large multi-storey car park in the centre of

Reading. The majority of the building had already been demolished; a small section of the

car-park and concrete floor slab were being demolished during the measurements. There were

three machines operating on site.

Dock Gate 9, Southampton. This was the site of some disused grain silos. The grain silos were

been cut-up and dismantled during the measurements. There were two machines operating on

site during the measurements.

1

Tab

le 1

Tes

t m

ach

ines

Mak

eM

odel

Cla

ssM

ass,

ton

ne

To

ol

con

fig

ura

tio

n

Tes

t d

ate

Lo

cati

on

Ph

oto

gra

ph

Bo

bca

t1

30

Co

mp

act

skid

st

eer

load

er

2.2

2B

uck

et2

4/1

1/2

00

4A

lder

man

bu

ry S

qu

are,

Lo

nd

on

Bo

bca

t7

53

(Ear

lier

ver

sio

n

of

Bo

bca

t 1

30

)

Co

mp

act

skid

st

eer

load

er

2.2

2B

uck

et1

9/1

1/2

00

4L

loy

ds

Bu

ild

ing

, L

on

do

n

Ku

bo

taK

X7

1-2

Min

i st

eel

trac

k

2.9

8Im

pac

t

ham

mer

12

/11

/20

04

Llo

yd

s B

uil

din

g,

Lo

nd

on

2

Ku

bo

taK

X1

61

-3M

idi

stee

l

trac

k

5.1

0Im

pac

t

ham

mer

24

/11

/20

04

Llo

yd

s B

uil

din

g,

Lo

nd

on

Hit

ach

iE

X6

0L

C-5

Mid

i st

eel

trac

k

6.3

9Im

pac

t

ham

mer

19

/11

/20

04

Llo

yd

s B

uil

din

g,

Lo

nd

on

Hit

ach

iZ

X4

60

LC

HC

raw

ler

stee

l tr

ack

47

.4Im

pac

t

ham

mer

24

/11

/20

04

Ch

ath

am S

tree

t C

ar P

ark

, R

ead

ing

Hit

ach

iE

X6

0-L

C5

Mid

i st

eel

trac

k

6.9

2H

yd

rau

lic

cru

sher

24

/11

/20

04

Ald

erm

anb

ury

Sq

uar

e, L

on

do

n

3

Hit

ach

iE

X4

55

Cra

wle

r

stee

l tr

ack

47

.0H

yd

rau

lic

cru

sher

09

/12

/20

04

Ch

ath

am S

tree

t C

ar P

ark

, R

ead

ing

Cas

eC

X2

10

Cra

wle

r

stee

l

traa

ck

20

.9B

ack

ho

e

sho

vel

09

/12

/20

04

Ch

ath

am S

tree

t C

ar P

ark

, R

ead

ing

Hit

ach

iZ

X4

60

LC

HC

raw

ler

stee

l tr

ack

47

.4S

teel

cu

tter

s D

ock

Gat

e 9

, S

ou

tham

pto

n

4

2 METHODS AND PROCEDURES

The tests were conducted to determine the vibration exposure of operators of each of the

machines. Vibration exposures were calculated according to the methods described in the

European Union Physical Agents (Vibration) Directive (2002/44/EC).

2.1 LOCATION AND DIRECTION OF MEASUREMENTS

Vibration was assessed for the driver of each of the machines.

Seat vibration was measured using SIT-pads placed on the seat surface and attached to the

seat backrest. The backrest SIT-pad was attached close to the base of the backrest to

maximise the period the driver remained in contact with the transducer over the measurement

period.

Vibration on the cab floor was measured using three accelerometers mounted on an

aluminium block (40 mm x 40 mm x 25 mm) aligned with each of the three principal

translational axes of the machine. The transducer block was affixed to the machine floor.

2.2 TRANSDUCERS

Vibration on the seat surface, beneath the ischial tuberosities of the operator, was measured

using an HVLab tir-axial SIT-pad containing three Entran EGCSY-240D-10 10g piezo-

resistive accelerometers.

Vibration at the interface between the seat backrest and the operator was measured using a

single-axis HVLab SIT-pad containing an EGCSY-240D-10 10g, piezo-resistive

accelerometer.

Vibration on the cab floor was measured using Entran EGCS-DO-101/V10/L4M 10g piezo-

resistive accelerometers.

In this report, the fore-and-aft (surge) direction is referred to as the x-axis, the side-to-side

(sway) direction is referred to as the y-axis, and the vertical (heave) direction is referred to as

the z-axis.

2.3 DATA ACQUISITION

A PC-based system was used to acquire the transducer signals. The 9-channel system

comprised a laptop PC with a Measurement Computing DAS16/16 PCMCIA data acquisition

board in conjunction with a signal-conditioning box providing offset and gain control and a

low-pass filter box. The low-pass filtering was set to 100 Hz to prevent aliasing of the signals.

Data were sampled at 400 samples per second. Signals from the accelerometers were digitised

and stored using the HVLab toolbox (version 1.1) running under MATLAB (version 7.0). The

acquisition system was set to sample the seven input channels simultaneously during the

measurement period. The acquisition process and subsequent analysis of the data were carried

out using MATLAB (version 7.0) and functions in the HVLab (version 1.1) and MATLAB

signal processing (version 6.2) toolboxes.

3 RESULTS

Vibration exposures were calculated for each of the machines; a summary of the data is given

in Table 2 (Section 3.2). Comprehensive data sets for each machine can be found in the

Annexes. An explanation of the vibration measures in the tables is given in Section 3.1. The

operating patterns of each of the machines and illustrative video clips are given in Section 3.3.

5

3.1 VIBRATION MEASURES

An explanation of the vibration measures used in the tables is given below.

Duration, T, is the time that the machine was operating with the driver in it. Periods where

the driver got out during the measurement period were removed from the analysis.

Extrapolated 8-hour r.m.s, A(8)e, was calculated assuming the driver was exposed

continuously for 8-hours to the same level of vibration as in the measurement period. This

value is equivalent to the dominant axis of frequency-weighted r.m.s vibration (according to

ISO 2631, 1997) on the seat surface. The backrest data were not included in this analysis but

the A(8)e values can be found in the Annexes.

Time to EAV using r.m.s, Ta(r.m.s), is the time taken to reach the exposure action value (0.5

ms-2) assuming the driver is continuously exposed to vibration at the same level as during the

measurement period.

( )20 )8(÷×=)..( ea AEAVTsmrT

where: T is the duration of exposure and T0 is the reference duration of 8 hours (28,800

seconds)

Time to ELV using r.m.s, Tl(r.m.s), the time taken to reach the exposure limit value (1.15

ms-2) assuming the driver is continuously exposed to vibration at the same level as during the

measurement period.

( )20 )8(÷×=)..( el AELVTsmrT

Extrapolated 8-hour VDV, is the vibration dose value the drivers would receive assuming

they are exposed continuously for 8-hours to the same level of vibration as during the

measurement period. The extrapolated 8-hour VDV, VDVe, is calculated as:

4 40×= ie VDV

T

TVDV

where: T is the duration of exposure and VDVi is the dominant axis VDV measured on the

seat surface (excluding the backrest).

Time to reach EAV using VDV, is the predicted time taken to reach the EAV of 9.1 ms-1.75,

estimated from the VDV over the measurement period, assuming continuous exposure.

( )40 )8(÷×=)( ea AEAVTVDVT

Time to reach ELV using VDV, is the predicted time taken to reach the ELV of 21.0 ms-1.75,

estimated from the VDV over the exposure period, assuming continuous exposure.

( )40 )8(÷×=)( el AELVTVDVT

ax, ay, ax, (Annexes) are the unweighted r.m.s acceleration measured on the floor and on the

seat over the measurement duration, periods where the driver was out of the seat were

excluded from the time histories.

awx, awy, awx, (Annexes) are the weighted (ISO 2631, 1997) r.m.s accelerations measured on

the floor and on the seat over the measurement duration. Seat surface weightings were used

for measurements on the floor so that SEAT values could be calculated. Multiplying factors,

k, were applied to the weighted accelerations where:

x-axis: Wd, k = 1.4

y-axis: Wd, k = 1.4

z-axis: Wk, K = 1.0

6

SEATawx, SEATawy, SEATawz. (Annexes) SEAT values (seat effective amplitude

transmissibility) are non-dimensional measures of the ability of a seat to isolate the body from

vibration in each of the orthogonal directions. The values here have been calculated as the

weighted r.m.s acceleration measured on the seat divided by the weighted r.m.s acceleration

measured on the floor.

VDVx, VDVy, VDVz (Annexes) are the vibration dose values measured on the floor and on the

seat in each of the orthogonal directions. The vibration dose value is a cumulative measure of

the vibration received by a person during the measurement period:

4/1

0

4 )(Tt

t

w dttaVDV

SEATVDVx, SEATVDVy, SEATVDVz. (Annexes) SEAT values (seat effective amplitude

transmissibility) are non-dimensional measures of the ability of a seat to isolate the body from

vibration in each of the orthogonal directions. The values here have been calculated as the

VDV measured on the seat divided by the VDV measured on the floor.

Power spectral density. (Annexes) The unweighted acceleration power spectral density

(PSD) was calculated separately for each of the seven acceleration time histories (seat base x,

y and z, seat surface x, y and z and backrest x) recorded for each machine. The frequency-

weighted acceleration power spectral density was also calculated for the seat surface and

backrest accelerometers including the effect of the appropriate multiplying factor for each

axis and location.

The power spectral densities were calculated using Welch’s modified periodogram method.

Each time history was divided up into Hamming-windowed 4096-point Fourier transforms

with 50% overlap. The power spectral densities were calculated from the modified

periodogram of each overlapping section:

2

1

2

1

n

q

q

n

q

qj

qq

j

w

eaw

eS

where the modified periodogram of each overlapping section S(ej ) was given by the length of

the Fourier transform, n, the Hamming window, w, and the section of the digitised time

history, a. The resulting periodograms were averaged and then divided by the sampling rate of

the digitised time history to give the power spectral density. Each power spectral density had

a frequency resolution of 0.10 Hz. The number of degrees of freedom of each power spectral

density is shown in the appropriate figure caption.

Transfer function and coherence. (Annexes) The transfer function between the acceleration

time histories recorded at the seat base and those recorded at the seat surface were calculated

separately for each orthogonal axis (x, y, and z). The transfer functions were calculated using

the cross spectral density (CSD) method where the linear transfer function, H(ej ), was

calculated from the cross spectral density between the seat base acceleration and the seat

surface acceleration Pbc, and the power spectral density of the seat base acceleration Pbb:

j

bb

j

bcj

eP

ePeH

Welch’s method was used to calculate both the power spectral densities and cross spectral

densities, with each time history divided up into Hamming-windowed 4096-point Fourier

transforms with 50% overlap. The power spectral density, Pbb, was calculated as described in

the preceding section. The cross spectral density, Pbc, was calculated from:

7

n

q

q

n

q

qj

qq

n

q

qj

qq

j

w

ebwecw

eS

1

2

*

11

where the modified periodogram of each overlapping section S(ej ) was given by the length of

the Fourier transform, n, the Hamming window, w, and the section of the digitised time

histories at the seat base, b, and at the seat cushion, c. The resulting periodograms were

averaged and then divided by the sampling rate of the digitised time history to give the cross

spectral density. The resolution of the transfer functions was 0.10 Hz.

The coherence, Cbc, was calculated from the power spectral density at the seat base, Pbb, and

that at the seat cushion surface, Pcc, and the cross spectral density between the seat base and

the cushion surface, Pbc, according to:

( ))()(

)(=

2

jcc

jbb

jbcj

bcePeP

ePeC

Frequency-weighted time history and running root-mean-square average. (Annexes) The

frequency-weighted acceleration recorded at the seat surface, including the relevant multi-

plying factor, was calculated and is shown graphically. The running root-mean-square (r.m.s)

average of the frequency-weighted acceleration recorded at the seat surface was also

calculated:

2

2

21

nm

nmq

qm cn

r

where the root-mean-square acceleration, r, in the vicinity of data point, m, was calculated

from the frequency-weighted seat cushion acceleration, c, over a sample of n data points

equally distributed before and after point m. The calculation was performed using n=4000 and

evaluating r for values of m at intervals of n/2. This resulted in each value of r being

calculated from a 10-second sample of data and each 10-second sample overlapping the

previous sample by 50%.

The sample length of 10 seconds was arbitrarily selected to calculate the running RMS to aid

the identification of tasks for the particular machines investigated where unusually high

vibration was observed as compared with the remainder of the observed operating period. A

10-second moving average with a 50% overlap was estimated to be of the right order of

magnitude to differentiate between different parts of a working cycle (e.g. loading, travelling,

unloading, hammering, trimming) for the particular machines studied while still having the

capability to capture a complete part of the cycle (e.g. filling the bucket of a small loader by

pushing the machine into a rubble pile and then lifting the shovel).

The choice of 10 seconds for the averaging period was arbitrary and intended to aid in the

identification of machine tasks. It was not intended to have any quantitative relevance to the

assessment of the vibration exposure of the machine operator.

8

3.2

V

IBR

AT

ION

EX

PO

SU

RE

S

Ta

ble

2 V

ibra

tio

n e

xp

osu

res

Mac

hin

e

mak

e

Mac

hin

e

mo

del

To

ol

Du

rati

on

Ex

trap

ola

ted

8-

ho

ur

VD

V

(hh

:mm

:ss)

(ms-1

.75)

Tim

e to

EA

V u

sin

g

VD

V

(hh

:mm

:ss)

Tim

e to

EL

V u

sin

g

VD

V

(hh

:mm

:ss)

Ex

trap

ola

ted

8-h

ou

r r.

m.s

(ms-2

)

Tim

e to

EA

V u

sin

g

r.m

.s

(hh

:mm

:ss)

Tim

e to

EL

V u

sin

g

r.m

.s

(hh

:mm

:ss)

Bobca

t130

Bu

cket

00

:36

:05

21.8

20

0:1

4:3

10

6:5

1:0

00

.88

02

:35

:54

13

:44

:41

Bobca

t753

Bu

cket

00

:34

:30

22.1

70

0:1

3:3

70

6:2

6:0

01

.01

01

:58

:11

10

:25

:09

Ku

bo

taK

X71

-2a

Imp

act

ham

mer

0

1:0

5:2

61

8.0

90

0:3

0:4

51

4:3

2:0

00

.76

03

:29

:01

18

:25

:40

Ku

bo

taK

X16

1-3

Imp

act

ham

mer

0

1:4

6:4

31

7.1

60

0:3

7:5

51

7:5

5:2

80

.73

03

:45

:11

19

:51

:12

Hit

ach

iE

X6

0L

C-5

Imp

act

ham

mer

0

1:5

1:4

91

5.3

90

0:5

8:4

42

7:4

5:3

20

.66

04

:32

:08

23

:59

:37

Hit

ach

iZ

X4

60

LC

HIm

pac

t h

amm

er

02

:02

:09

17.3

50

0:3

6:1

71

7:0

9:0

50

.80

03

:07

:25

16

:31

:24

Hit

ach

iE

X6

0L

C-5

Hy

dra

uli

c cr

ush

er0

1:4

4:3

71

3.9

00

1:2

8:1

01

7:4

0:2

60

.58

05

:52

:08

<2

4

Hit

ach

iE

X455

Hy

dra

uli

c cr

ush

er0

1:2

1:5

31

2.7

60

2:0

4:0

25

8:3

7:3

40

.46

09

:32

:34

<2

4

Cas

eC

X210

Bac

kh

oe

sho

vel

0

2:0

7:1

61

0.8

40

3:5

8:0

51

12

:32

:19

0.4

60

9:2

6:3

2<

24

Hit

ach

iZ

X4

60

LC

HS

teel

cu

tter

s 0

1:2

9:1

54

.94

91

:50

:12

26

04

:31

:12

0.2

0<

24

<2

4

9

3.3 MACHINE OPERATING PATTERNS

3.3.1 Bobcat 130

The machine was employed clearing loose rubble from an area of concrete floor and loading

this into skips.

The first part of the motion up to, and immediately after, a 145-second refuelling break

involved clearing of the ground and pushing rubble into a pile. The machine then waited for a

skip to be craned onto the working area, loaded it and then re-piled the rubble that had

become somewhat scattered while the skip was being loaded. The machine operator then

waited for a second skip (the second pause at around t=1700 seconds) then loaded the

remaining rubble.

Following completion of the work, it was possible to request that the machine was driven at

an approximately constant speed both with the shovel up, and with the shovel down causing

the front wheels to lift. These constant speed tests may be seen in video clips

Bobcat130_24Nov04_shovelup.mpg and Bobcat130_24Nov04_shoveldown.mpg. Both of

these tests took place after the ‘clearing and loading rubble’ activity and the data from these

tests were not included in the analysis of this activity or in the graphs shown in Annex A.

Video of the ‘clearing and loading’ and the constant speed tests may be found in the file

Bobcat130_24Nov04.mpg on the annex DVD.

The events marked E1, E2 and E3 in Figure 3 and Figure 4 in Annex A correspond to the

following events:

E1: Driving over rubble (Bobcat130_24Nov04_E1.mpg).

E2: Running the machine into a rubble pile to load the shovel and then lifting and

lowering the front of the machine whilst pushing the machine into the rubble in order

to better load the shovel (Bobcat130_24Nov04_E2.mpg).

E3: The machine travelling over obstacles on the ground

(Bobcat130_24Nov04_E3.mpg).

3.3.2 Bobcat 753

The machine was observed to be moving loose rubble across the site. This involved short (<1

minute) cycles consisting of running the machine into the rubble to load the shovel, lifting the

shovel, reversing, turning and transporting the rubble, then unloading, reversing, turning and

moving back to the original rubble pile. The loading events as the machine was driven into

the rubble piles can clearly be seen from the x-axis acceleration data.

Video of the observed working time may be found in the file Bobcat753_19Nov04.mpg on

the annex DVD.

The single-cycle results shown in the table in Annex B were extracted from within the first

three minutes of the complete ‘moving rubble’ acquisition. These cycles can be found in the

video clip Bobcat753_2_19Nov04_cycles. The machine reversed over loose rubble during the

first cycle. This resulted in the frequency-weighted r.m.s. vertical vibration at the seat surface

being the dominant axis for this cycle, despite some useful vertical vibration isolation by the

seat. This may be compared with the following four cycles where the fore-and-aft axis gave

the highest weighted seat surface r.m.s. acceleration, in a large part due to the impact as the

machine is driven into the rubble pile to load the shovel.

The events marked E1 to E3 in Figure 7 and Figure 8 in Annex B correspond to:

E1: Loading the shovel and then reversing over loose rubble

(Bobcat753_19Nov04_E1.mpg).

10

E2: Loading the shovel (Bobcat753_19Nov04_E2.mpg).

E2: Loading the shovel (Bobcat753_19Nov04_E3.mpg).

3.3.3 Kubota KX71-2

The machine was measured for one hour and five minutes breaking a concrete floor and

trimming and clearing rubble from the steel support structure that became exposed.

Video of the working period may be found in the file KX71-2alpha_12Nov04.mpg on the

annex DVD.

The events marked E1, E2 and E3 in Figure 11 and Figure 12 in Annex C correspond to video

clips:

KX71-2alpha_12Nov04_E1.mpg



These events were all situations where the front of the tracks lifted off the ground as the

weight of the machine was used to apply more force to the hammer. The machine dropped as

the hammer broke through causing the high accelerations visible in the running r.m.s.

3.3.4 Kubota KX161-3 (impact hammer)

The machine was breaking a concrete floor and trimming and clearing rubble from the steel

support structure that became exposed. The machine activity might be divided into four

activities:

travelling between working locations

hammering down onto concrete floor sections using the powered impact hammer

approximately vertically.

trimming concrete still adhering to the steel building supports using the powered

impact hammer at a variety of angles.

clearing loosened concrete and steel from the working area using the tip or the body

of the unpowered impact hammer.

The machine was dropped onto the working area from a cantilever crane and was stationary

while hammering, trimming, and clearing. The machine operator would switch between

hammering, trimming and clearing and repositioning the machine, spending up to 40 seconds

travelling and between a few seconds and four minutes on each of the other activities

according to the requirements of the task.

Video of the working period may be found in the file KX161-3_12Nov04.mpg on the annex

DVD.

The events marked E1 to E3 in Figure 15 and Figure 16 in Annex D correspond to:

E1 and E2: Using the unpowered hammer to break loosened concrete from a steel

beam (KX161-3_12Nov04_E1.mpg, KX161-3_12Nov04_E2.mpg)

E3: Manoeuvring over rubble. The driver was observed to clear this loose rubble from

the working area immediately as shown towards the end of the clip (KX161-

3_12Nov04_E3.mpg).

11

3.3.5 Hitachi EX60LC-5 (impact hammer)

The machine was employed trimming concrete from vertical steel beams with an impact

hammer. The machine was at ground level with the working terrain consisting of uneven

brick and concrete rubble.

Video of the observed working activity may be found in the file EX60LC_Hammer_19Nov04

Tapes 1 and 2.mpg on the annex DVD.

The events marked E1 to E3 in Figure 19 and Figure 20 in Annex E correspond to:

E1, the two closely spaced peaks in x-axis graph in Figure 19: The first peak

corresponded to using the unpowered impact hammer to pull loose rubble towards

the machine. The second peak corresponded to the machine moving over rubble to a

new location. This latter event was only partially captured on video.

(EX60LC_Hammer_19Nov04_E1.mpg).

E2 and E3: Movement of the machine over rubble

(EX60LC_Hammer_19Nov04_E2.mpg, EX60LC_Hammer_19Nov04_E3.mpg).

3.3.6 Hitachi ZX460LCH (impact hammer)

The machine was mainly employed breaking up a ground-level concrete floor.

Video of the observed working activities may be found in the files

ZX460_8Dec2004Tape1.mpg and ZX460_8Dec2004Tape2.mpg on the annex DVD.

The events marked E1 and E2 in Figure 23 and Figure 24 in Annex F correspond to:

E1: The hammer slipping off the working surface while using the hammer vertically.

The front of the machine had been lifted off the ground and dropped as the hammer

tip slipped free (ZX460_8Dec04_E1.mpg).

E2: The hammer slipping off the working surface while using the hammer

horizontally against a vertical structure. The front of the machine had been lifted off

the ground and dropped as the hammer tip slipped free (ZX460_8Dec04_E2.mpg).

3.3.7 Hitachi EX60LC-5 (hydraulic crusher)

The machine was measured for a period of 1 hour and 44 minutes. During the measurement

period the machine was mainly involved in demolishing a wall consisting of a concrete frame

with large windows. The concrete structure was crushed in selected places and pulled to the

ground. The windows and supporting structure were lifted clear and the fallen concrete

structure was partially broken up. The machine also cleared loose concrete and other items

into skips.

The complete operating period was videoed and may be reviewed in the video files

EX60LC_Muncher_24Nov04 Tape 1.mpg and EX60LC_Muncher_24Nov04 Tape 2.mpg on

the annex DVD.

The events marked E1, E2 and E3 on Figure 27and Figure 28 in Annex G the results section

correspond to the following events:

E1: Transit over rubble (EX60LC_Muncher_24Nov04_E1.mpg)

E2: Transit over flat ground with some obstacles

(EX60LC_Muncher_24Nov04_E2.mpg).

E3: Using the unpowered muncher attachment to hammer against an object on the

ground (Bobcat130_24Nov04_E3.mpg).

12

3.3.8 Hitachi EX455 (hydraulic crusher)

The machine was employed for approximately 1 hour and 10 minutes crushing steel-

reinforced concrete beams to separate the steel reinforcement and reduce the concrete to loose

rubble. The machine then spent approximately 8 minutes ‘munching’ concrete from upper

storey floor section of a partially demolished building. The data was analysed up to the point

when the machine completed this part of the work and then came to a stop.

Video of the observed working activities may be found in the file EX455_9Dec04_Tapes 1

and 2.mpg on the annex DVD.

The events marked E1 to E3 in Figure 31 and Figure 32 in Annex H correspond to:

E1: Moving into position (EX455_9Dec04_E1.mpg).

E2: Crushing building debris lying on the ground. The front machine appears to be

lifted off the ground as the muncher is pushed down into the pile of debris and then

drops as the muncher closes (EX455_9Dec04_E2.mpg).

E3: Jolt caused by using the weight of the machine to pull at a part of the building

structure. The back of the machine lifts and then drops as the muncher breaks free of

the building (EX455_9Dec04_E3.mpg).

3.3.9 Case CX210 (Backhoe shovel)

The machine was employed loading rubble into trucks. For most of the observed working

time the machine was positioned on top of approximately flat-topped rubble piles. There were

some pauses in the region of two minutes during the data acquisition with the machine

stationary waiting for the next truck to arrive. These were considered part of the typical

working cycle and were included in the analysis. The driver remained seated in the machine.

A longer break of just over 8 minutes where the driver left the machine was excluded from

the analysis.

Video of the complete work activity may be found in the file ‘CX210_9Dec04_Tapes1 and

2.mpg’ on the annex DVD.

The events marked E1, E2 and E3 in Figure 35 and Figure 36 in Annex I correspond to:

E1: The machine moving back and forth on top of the rubble

(CX210_9Dec04_E1.mpg).

E2: The machine travelling to a new working position on the site

(CX210_9Dec04_E2.mpg).

E3: Appears to be associated with a jolt caused by loading the shovel. However, the

excavator is obscured from view by the truck into which rubble is being loaded. A

transient movement of the upper part of the cab can clearly be seen but the exact

cause cannot be positively identified (CX210_9Dec04_E3.mpg).

3.3.10 Hitachi ZX460LCH (steel shears)

The machine was employed dismantling a steel structure with rotary shears. Video of the

observed working activities may be found in the file ZX460_22Dec04 Tapes 1 and 2.mpg on

the annex DVD.

The events marked E1 and E2 in the Figure 39 and Figure 40 in Annex J correspond to:

E1 and E2: The machine manipulating the arm and transiting to a new location on the

work site (ZX460_22Dec04_E1.mpg), (ZX460_22Dec04_E2.mpg).

13

4 DISCUSSION

The effect of machine type, tool, seat and machine operation upon the vibration exposure

experienced by operators are discussed below. The exposures are also compared with the

exposure action values and exposure limit values in EU 2002/44/EC.

4.1 MACHINE TYPE

Vibration exposures recorded on the compact skid-steers were higher than those recorded on

the other machines.

Vibration exposures recorded on the tracked crawlers using the same type of tool generally

decreased with increasing mass of the machine. The mass of the machine would act to reduce

the accelerations transmitted by a force and it is reasonable to expect that for the same force

less vibration would be transmitted to the drivers of the larger machines.

4.2 MACHINE TOOL

All vibration exposures recorded on excavators fitted with impact hammers were higher than

those recorded on machines with hydraulic crushers or steel cutters. This indicates that the

vibration caused by the tool attachment influenced the exposure of the driver. Some of the

tasks carried out by machines fitted with impact hammers could also have been carried out by

machines fitted with hydraulic crushers. Where it is possible to carry out a task using a

hydraulic crusher rather than an impact hammers it may reduce the vibration exposure of the

driver.

4.3 MACHINE OPERATION

Inspection of the time histories indicates that shock events recorded on the skid-steers had a

large effect on the vibration exposure of the driver. The main causes of these shock events

were driving over obstacles (loose rubble) on the ground and impacts with piles of rubble

prior to picking them up. The compact skid-steers had solid rubber tyres and therefore

provided little attenuation of the vibration transmitted to the driver. Generally, drivers would

try to clear the floor area of obstacles using the bucket before transiting over it. The degree to

which the floor is cleared of obstacles would therefore affect the vibration exposure of the

driver. When picking up rubble from piles, the skid-steer operators would drive into the

rubble with the bucket down in order to scoop up some of the rubble. The speed at which the

bucket impacted the rubble affects the severity of the shock experienced by the driver. It is

likely that reducing the speed at impact with piles of rubble would also reduce the vibration

exposure of the driver. The vibration exposure of skid-steers operators would be influenced

by the way in which the machines are operated and that in certain conditions (e.g. aggressive

driving, uneven terrain) drivers may be subjected to higher exposures than those measured.

Inspection of the video recordings of the excavators fitted with impact hammers show that

some of the peaks in the time histories were caused by the weight of the machines being lifted

off the ground to apply more force to the hammer and then dropping as the hammer broke

through. There were also peaks in the time histories associated with using the unpowered

hammer to clear rubble or break concrete off a steel beam. The severity of these peaks would

be influenced by the manner in which the machine is operated and therefore it might be

possible to reduce the exposure of the driver by changing their operating methods. There were

also peaks in the time histories associated with the machine transiting over rubble.

Some of the highest peaks in the vibration time histories recorded on the excavators fitted

with hydraulic-crushers, steel shears and backhoe shovels were associated with the machine

transiting around the site. It is likely that the amount of movement a machine would be

required to perform over the day, and the unevenness of the terrain, would influence the

vibration exposure of the operator. There were also peaks in the vibration time-histories

14

caused by the weight of the machine being used to pull at part of the building structure: in

these cases part of the machine would lift and then drop, as the tool breaks free of the building

causing a jolt.

4.4 SEAT PERFORMANCE

All the seats fitted in the machines were either mechanically suspended or air suspended. The

SEAT values (calculated using VDVs) show that all the seats attenuated the vibration

transmitted to the operator in the vertical direction while increasing slightly the vibration

transmitted in the horizontal directions. Where possible, the preload adjustment setting was

checked for each of the seats; in all cases the seat was set appropriately for the operator.

Vertical SEAT values (VDV) on the excavators fitted with impact hammers ranged from 0.6

to 0.75. It is likely that the seats attenuated some of the high frequency vibration transmitted

through the machine from the hammers.

SEAT values (VDV), in the vertical direction, on the skid-steer loaders ranged from 0.77 to

0.83. The suspension stroke of the seats fitted in these machines was shorter than those fitted

in the other machines, increasing the likelihood of the suspension ‘bottoming out’.

The vertical SEAT values (VDV) on the excavators fitted with hydraulic crushers, buckets

and steel cutters ranged from 0.5 to 0.75, this indicates that the seat significantly reduced the

vibration reaching the operator.

4.5 COMPARISON WITH EU 2002/44/EC EXPOSURE LEVELS

Daily vibration exposures measurements on the compact skid-steer loaders indicate that the

exposure action value (EAV) could be exceeded, over a typical working day, when assessed

using either the VDV or r.m.s method. The measurements indicate that it is unlikely that the

exposure limit value (ELV) assessed using r.m.s. values would be exceeded over a working

day. However, the ELV assessed using the VDV method would have been exceeded after 6

hours 51 minutes on the Bobcat 130 and after 6 hours 26 minutes on the Bobcat 130. During

discussions with the skid-steer operators it was stated that the machines would not normally

be operated for more than 4 hours over a typical working day.

Measurements on all the excavators fitted with impact hammers indicate that the EAV (r.m.s

or VDV) could be exceeded during a working day. The ELV (r.m.s or VDV) was not

predicted to be exceeded on any of the machines fitted with impact hammers.

Neither of the excavators fitted with hydraulic crushers was predicted to exceed the ELV

(r.m.s or VDV) during a working day. However, the action value calculated using the VDV

method may be exceeded on both machines. Assuming the operators were exposed

continuously at the measured levels, the r.m.s exposure action value would have been

exceeded after 5 hours 52 minutes on the Hitachi EX60LC-5 and after 9 hours 32 minutes on

the Hitachi EX455.

Vibration measurements on the Case CX210 fitted with a backhoe shovel indicated that the

EAV could be exceeded over a working day if calculated using the VDV method but would

be unlikely to exceed the r.m.s exposure action value. These measurements suggest that the

machine could be operated for more than 24 hours without exceeding the ELV (r.m.s or

VDV).

The vibration exposure of the operator of the Hitachi ZX460LCH fitted with the steel cutters

was very low. From these measurements it would be unlikely that either the EAV or the ELV

would be exceeded over a working day.

15

5 CONCLUSIONS

From the measurements it is predicted that operators of the skid-steer loaders and the

excavators fitted with impact hammers could be exposed to vibration greater than the Physical

Agents exposure action value (VDV or r.m.s.) during the course of a working day. The

vibration exposure on one of the excavators fitted with a hydraulic crusher was predicted to

above the r.m.s. exposure action value while the exposure on the other machine fitted with a

crusher was predicted to be below the r.m.s exposure action value. The vibration recorded on

the excavators fitted with the backhoe shovel and the steel cutters was below the exposure

action values.

None of the machines would have exceeded the r.m.s exposure limit value over an 8-hour

period. However, the VDV exposure limit value was predicted to be exceeded on both the

skid-steer loaders during the course of a working day. The exposure limit values (VDV or

r.m.s) would not have been exceeded for any of the excavators.

The magnitude of the vibration on each of the machines will vary with a large number of

factors (driving style, terrain, seat, etc.) and in some instances, might be more severe than

those measured.

16

6 REFERENCES

Council of the European Union (2002). Physical Agents (Vibration) Directive 2002/44/EC:

on the minimum health and safety requirements regarding the exposure of workers to the risks

arising from physical agents (vibration) (16th individual Directive within the meaning of

Article 16(1) of Directive 89/391/EEC). 94/449 (COD). Council of European Union,

Brussels.

International Organization for Standardization (1997). Mechanical vibration and shock –

Evaluation of human exposure to whole-body vibration – Part 1: General requirements. ISO

2631-1-1997/E. International Organization for Standardization, Geneva.

17

Annex A: Bobcat 130 measured 24th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Bobcat 130

Family: Loader

Kind: Compact skid steer loader

Serial number: 524711256

Power, kW: 34.3

Machine mass, kg: 2223

Year of manufacture: 2004

Working hours: 250

Motion system: Solid rubber wheels

Track/tyre width: 18cm x 38cm

Driver’s seat make and model: Bobcat

Seat stroke: 50mm stroke

Adjustment: Weight adjustment setting was approximately correct for driver

Driver mass, kg: 102

Driver height, m: 185

Driver age: 52

Driver experience: high

Vehicle load / tool configuration: Loader bucket

18

Summary report form: Part 2- Test environment

Description of the test environment:

Demolition site. Originally a multi-storey office block. The work site was a flat concrete floor

approximately 70m x 70m. There was some loose rubble on the surface of the floor.

19

Summary report form: Part 3– Vehicle usage

Description of the operating patterns in which this vehicle is used:

The vehicle was used to clear rubble into piles and load rubble into skips.

Times for which the vehicle is used in each operating pattern by day and week, with

seasonal variations:

The vehicle was active for approximately 2 hours of the 10-hour shift. The vehicle was used

for 30-60 minute at a time. During the shift a single driver operated the vehicle.

From questioning the operator it was evident that the operating patterns for this vehicle are

variable and depend on the nature of the site. On larger sites, with more breakers operating,

the vehicle could be operated for up to 6 hours during a shift. However, typically the vehicle

would be operated for 2-4 hours during a shift.

The operator observed no weekly or seasonal operating patters.

Comments on specific factors likely to affect the vibration exposure and methods by

which the vibration exposure may be reduced:

The speed at which operators impact with piles of rubble, in order to scoop it up, would affect

the vibration exposure.

The smoothness of the terrain would affect the vibration exposure of the driver. Ensuring

drivers cleared the site of loose rubble, as far as possible, before driving over the site could

reduce the vibration exposure. Also it should be ensured that tyres appropriate for the work

site are used.

20

Summary report form: Part 5 – Results

Vehicle manufacturer Bobcat

Vehicle model 130

Tool Shovel

Test date 24th Nov 2004

Task Clearing and

loading rubble

(updated

20/12/2004)

Three ~20-

second runs,

constant speed,

shovel up

Three ~20-

second runs,

constant speed,

shovel down

Duration (hh:mm:ss) '0:36:05 00:01:01 00:01:00

Extrapolated 8-hour r.m.s. (ms-2) 0.88 0.75 0.74

Time to EAV using the r.m.s. (hh:mm:ss) '2:35:54 03:31:50 03:38:01

Time to ELV using the r.m.s. (hh:mm:ss) '13:44:41 18:40:37 19:13:17

Eight hour eVDV (ms-1.75) 16.00 13.73 13.53

Extrapolated 8-hour VDV (ms-1.75) 21.82 14.79 12.83

Time to EAV using the VDV (hh:mm:ss) '0:14:31 01:08:43 02:01:24

Time to ELV using the VDV (hh:mm:ss) '6:51:52 08:28:38 09:22:59

Cab floor ax (ms-2) 1.03 0.56 0.80

Cab floor ay (ms-2) 1.10 0.69 0.88

Cab floor az (ms-2) 1.16 1.36 1.47

Cab floor awx (ms-2) 0.83 0.45 0.45

Cab floor awy (ms-2) 0.60 0.44 0.49

Cab floor awz (ms-2) 0.84 0.85 0.92

Seat surface awx (ms-2) 0.88 0.48 0.54

Seat surface awy (ms-2) 0.69 0.54 0.57

Seat surface awz (ms-2) 0.68 0.75 0.74

Backrest awx (ms-2) 0.86 0.61 0.60

SEATawx 1.06 1.05 1.19

SEATawy 1.14 1.25 1.17

SEATawz 0.81 0.88 0.81

Cab floor VDVx (ms-1.75) 9.90 2.53 2.06

Cab floor VDVy (ms-1.75) 7.29 1.70 2.24

Cab floor VDVz (ms-1.75) 13.76 3.86 3.67

Seat surface VDVx (ms-1.75) 11.05 2.35 2.37

Seat surface VDVy (ms-1.75) 8.33 2.18 2.47

Seat surface VDVz (ms-1.75) 11.43 3.17 2.74

Backrest VDVx (ms-1.75) 12.80 2.45 2.44

SEATVDVx 1.12 0.93 1.15

SEATVDVy 1.14 1.28 1.10

SEATVDVz 0.83 0.82 0.75

21

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2

Figure 1 Unweighted (—) and frequency-weighted (---) power spectral densities calculated with 712 degrees of freedom and a frequency resolution of 0.10 Hz.

0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce

0 10 20 30 40Frequency (Hz)

0 10 20 30 40 50

Figure 2 Seat transfer functions calculated using the CSD method with 712 degreesof freedom and a frequency resolution of 0.10 Hz.

22

−15−10−5

05

1015

x ac

cele

ratio

n(m

s−2)

145 s break here

−15−10−5

05

1015

y ac

cele

ratio

n(m

s−2)

0 500 1000 1500 2000 2500

−15−10−5

05

1015

Operating time (s)

z ac

cele

ratio

n(m

s−2)

Figure 3 Frequency-weighted acceleration at the seat surface. Periods of greaterthan 60 seconds where the vehicle was not operating were excluded. These periodsare indicated by vertical dotted lines.

00.5

11.5

22.5

3

a wx (

ms−2

)

145 s break here

(E2)

00.5

11.5

22.5

a wy (

ms−2

)

0 500 1000 1500 2000 25000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

(E1)(E3)

Figure 4 Running (50% overlap) 10-second r.m.s. weighted acceleration on the seatsurface. Periods where the driver was not in the vehicle were excluded from the analysis. These periods are indicated by vertical dotted lines.

23

Annex B: Bobcat 753 measured 19th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Bobcat 753 (an earlier version of the Bobcat 130)

Family: Loader

Kind: Compact skid steer loader


Power, kW: 32.5



Working hours: 1500

Motion system: Solid rubber wheels

Track/tyre width: 18cm x 38cm

Driver’s seat make and model: Bobcat

Seat stroke: 50mm stroke


Driver mass, kg: 79

Driver height, m: 1.70

Driver age: 39


Vehicle load / tool configuration: Loader bucket

24




approximately 50m x 80m. There was some loose rubble on the surface of the floor.

25



The vehicle was used to pick up rubble from a pile and deposit it in another pile on the other

side of the work site.



The vehicle was active for approximately 4 hours of the 10-hour shift. The vehicle was used

for 30-60 minute at a time. During the shift a single driver operated the vehicle.

From questioning the operator it was evident that the operating patterns for this vehicle are

variable and depend on the nature of the site. On larger sites, with more breakers operating,

the vehicle could be operated for up to 6 hours during a shift. However, typically the vehicle

would be operated for 2-4 hours during a shift.

The operator observed no weekly or seasonal operating patters.



The speed at which operators impact with piles of rubble, in order to scoop it up, would affect

the vibration exposure.

The smoothness of the terrain would affect the vibration exposure of the driver. Ensuring

drivers cleared the site of loose rubble, as far as possible, before driving over the site could

reduce the vibration exposure. Also it should be ensured that tyres appropriate for the work

site are used.

26

Summary report form: Part 5 – ResultsVehicle manufacturer Bobcat

Vehicle model 753

Tool Shovel


Task Moving rubble Moving rubble, single cycles

Duration (hh:mm:ss) 00:34:30 0:00:37 0:00:31 0:00:26 0:00:23 0:00:27

Extrapolated 8-hour r.m.s. (ms-2) 1.01 1.13 1.13 1.11 1.09 1.12

Time to EAV using the r.m.s. (hh:mm:ss) 01:58:11 1:33:20 1:33:46 1:37:05 1:40:37 1:35:08

Time to ELV using the r.m.s. (hh:mm:ss) 10:25:09 8:13:47 8:16:02 8:33:32 8:52:14 8:23:18

Eight hour eVDV (ms-1.75) 18.38 20.68 20.63 20.28 19.92 20.48

Extrapolated 8-hour VDV (ms-1.75) 22.17 34.14 22.25 22.30 26.05 24.05

Time to EAV using the VDV (hh:mm:ss) 00:13:37 0:02:25 0:13:26 0:13:18 0:07:09 0:09:51

Time to ELV using the VDV (hh:mm:ss) 06:26:22 1:08:42 6:21:07 6:17:20 3:22:41 4:39:08

Cab floor ax (ms-2) 1.33 1.38 1.46 1.38 1.40 1.37

Cab floor ay (ms-2) 1.10 1.24 1.21 1.15 1.13 0.99

Cab floor az (ms-2) 1.11 1.66 1.10 1.09 1.21 1.11

Cab floor awx (ms-2) 0.93 0.82 1.02 1.04 1.03 1.05

Cab floor awy (ms-2) 0.55 0.69 0.55 0.57 0.58 0.51

Cab floor awz (ms-2) 0.83 1.48 0.84 0.83 0.93 0.87

Seat surface awx (ms-2) 1.01 0.92 1.13 1.11 1.09 1.12

Seat surface awy (ms-2) 0.61 0.80 0.57 0.58 0.66 0.55

Seat surface awz (ms-2) 0.78 1.13 0.83 0.83 0.91 0.83

Backrest awx (ms-2) 0.87 1.11 0.96 0.81 0.91 0.87

SEATawx 1.09 1.13 1.11 1.07 1.06 1.07

SEATawy 1.11 1.15 1.03 1.02 1.15 1.07

SEATawz 0.95 0.77 0.99 1.00 0.97 0.96

Cab floor VDVx (ms-1.75) 10.43 3.34 3.55 3.56 4.08 3.84

Cab floor VDVy (ms-1.75) 6.46 3.31 2.11 1.89 1.81 1.66

Cab floor VDVz (ms-1.75) 12.91 10.03 3.09 3.26 3.86 3.14

Seat surface VDVx (ms-1.75) 11.48 3.68 4.03 3.87 4.38 4.21

Seat surface VDVy (ms-1.75) 7.35 3.74 2.13 1.93 2.05 1.76

Seat surface VDVz (ms-1.75) 9.91 6.46 2.98 2.85 2.93 2.82

Backrest VDVx (ms-1.75) 11.51 7.72 3.95 2.94 3.74 3.77

SEATVDVx 1.10 1.10 1.13 1.09 1.07 1.10

SEATVDVy 1.14 1.13 1.01 1.02 1.13 1.06

SEATVDVz 0.77 0.64 0.96 0.88 0.76 0.90

27

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50

Figure 6 Seat transfer functions calculated using the CSD method with 812 degreesof freedom and a frequency resolution of 0.10 Hz.

28

−15−10−5

05

1015

x ac

cele

ratio

n(m

s−2)

−15−10−5

05

1015

y ac

cele

ratio

n(m

s−2)

0 500 1000 1500 2000 2500

−15−10−5

05

1015

Operating time (s)

z ac

cele

ratio

n(m

s−2)

Figure 7 Frequency-weighted acceleration at the seat surface.

00.5

11.5

22.5

3

a wx (

ms−2

) (E2) (E3)

00.5

11.5

22.5

a wy (

ms−2

)

0 500 1000 1500 2000 25000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

(E1)

Figure 8 Running (50% overlap) 10-second r.m.s. weighted acceleration on the seatsurface.

29

Annex C: Kubota KX71-2 measured 12th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Kubota KX71-2

Family: Excavator

Kind: Compact crawler excavator

Serial number: unknown

Power, kW: 22.1



Working hours: 2000

Motion system: Steel tracks

Track/tyre width: 0.3 m

Driver’s seat make and model: Unknown (Grammer?)

Seat stroke: 80




Driver age: 54


Vehicle tool: Impact hammer

Tool make: Krupp

Tool model: HM140V


Tool mass: 240 kg

Serial number: 0855

30



Site was originally a multi-storey office block. The vehicle was operating on a flat concrete floor slab. The

floor slab was approximately 200 mm thick.

31



The machine was used for three main activities:

1. Breaking concrete, using the hydraulic hammer to systematically break off sections of

flooring.

2. ‘Trimming’ concrete from steel structures using the hydraulic hammer to ‘chisel’

away any concrete adhering to the steel girders.

3. Clearing the working area, using the body of the hammer, without power, to bend

exposed reinforcing bars out of the way and clear loose concrete that had not fallen

away from the working area.

The operator was observed to switch fairly rapidly between these three tasks, usually

spending less than a minute on each activity.



Operators commentated that the operating patterns for this type of machine were highly

variable depending on the nature of the site. This site was unusual in that hammering

operations were only permitted for two-hour periods due to the noise generated in the city

location of the site. Generally operators would be operating constantly during each 2-hour

period. There were three such periods during a shift and therefore the maximum exposure, on

this site, would be 6 hours.

Operators stated that on other sites without a two-hour restriction then continuous operation

might take place for substantially longer than two hours.

The operators observed no weekly or seasonal patterns. The prime factor affecting the vehicle

operating patterns was the immediate requirements of the site.



At times the operator used the weight of the machine, to help break through the slab, by

pushing down on the tool so that the front of the machine lifted of the ground. When the tool

broke through the floor slab the front of the machine impacted the ground causing a peak in

the time histories. Reducing the number of such events could reduce the vibration exposure of

the driver.

32

Summary report form: Part 5 – ResultsVehicle manufacturer Kubota

Vehicle model KX71-2alpha

Tool Impact

hammer


Task Breaking and

trimming

Duration (hh:mm:ss) 01:05:26

Extrapolated 8-hour r.m.s. (ms-2) 0.76

Time to EAV using the r.m.s. (hh:mm:ss) 03:29:01

Time to ELV using the r.m.s. (hh:mm:ss) 18:25:40

Eight hour eVDV (ms-1.75) 13.82

Extrapolated 8-hour VDV (ms-1.75) 18.09

Time to EAV using the VDV (hh:mm:ss) 00:30:45

Time to ELV using the VDV (hh:mm:ss) 14:32:19

Cab floor ax (ms-2) 1.08

Cab floor ay (ms-2) 1.24

Cab floor az (ms-2) 1.45

Cab floor awx (ms-2) 0.52

Cab floor awy (ms-2) 0.37

Cab floor awz (ms-2) 0.67

Seat surface awx (ms-2) 0.76

Seat surface awy (ms-2) 0.48

Seat surface awz (ms-2) 0.49

Backrest awx (ms-2) 0.94

SEATawx 1.46

SEATawy 1.28

SEATawz 0.73

Cab floor VDVx (ms-1.75) 7.55

Cab floor VDVy (ms-1.75) 5.63

Cab floor VDVz (ms-1.75) 11.37

Seat surface VDVx (ms-1.75) 10.99

Seat surface VDVy (ms-1.75) 7.01

Seat surface VDVz (ms-1.75) 6.86

Backrest VDVx (ms-1.75) 15.72

SEATVDVx 1.45

SEATVDVy 1.24

SEATVDVz 0.60

33

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50

Figure 10 Seat transfer functions calculated using the CSD method with 1536degrees of freedom and a frequency resolution of 0.10 Hz.

34

−10−5

05

10x

acce

lera

tion

(ms−2

)

88 s break here 123 s break here

−10−5

05

10

y ac

cele

ratio

n(m

s−2)

0 500 1000 1500 2000 2500 3000 3500 4000

−10−5

05

10

Operating time (s)

z ac

cele

ratio

n(m

s−2)

Figure 11 Frequency-weighted acceleration at the seat surface. Periods of greater than 60 seconds where the vehicle was not operating were excluded. These periodsare indicated by vertical dotted lines.

00.5

11.5

22.5

3

a wx (

ms−2

)


(E1) (E2) (E3)

00.5

11.5

22.5

a wy (

ms−2

)

0 500 1000 1500 2000 2500 3000 3500 40000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

Figure 12 Running (50% overlap) 10-second r.m.s. weighted acceleration on the seat surface. Periods of greater than 60 seconds where the vehicle was not operatingwere excluded from the analysis. These periods are indicated by vertical dotted lines.

35

Annex D: Kubota KX161-3 measured 24th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Kubota KX161-3

Family: Excavator

Kind: Compact crawler excavator

Serial number: S/N WKFRGX00

Power, kW: 29.4



Working hours: 300



Driver’s seat make and model: Grammer ZOBERT MSGTOFZ M V5 –OT,

Seat stroke: 80




Driver age: 37



Tool make: Sandhurst (Krupps)

Tool model: SMCXT300


Tool mass: 220 kg


36



Site was originally a multi-storey office block. The vehicle was operating on a flat concrete floor slab.

The floor slab was approximately 200 mm thick.

37



The machine was used for three main activities:

1. Breaking concrete, using the hydraulic hammer to systematically break off

sections of flooring.

2. ‘Trimming’ concrete from steel structures using the hydraulic hammer to ‘chisel’

away any concrete adhering to the steel girders.

3. Clearing the working area, using the body of the hammer, without power, to bend

exposed reinforcing bars out of the way and clear loose concrete that had not

fallen away from the working area.

The operator was observed to switch fairly rapidly between these three tasks, usually

spending less than a minute on each activity.















The vehicle operator was observed to clear areas to be traversed or broken up using the body

of the hammer to push rubble aside. The unpowered hammer also was used to break loosened

concrete from a steel beam by impacting the hammer against the beam. These events were

associated with peaks in the recorded vibration time histories. Reducing the occurrence of

these operations could reduce the vibration exposure of the operator.

38

Summary report form: Part 5 – ResultsVehicle manufacturer Kubota

Vehicle model KX161-3

Tool Impact

hammerTest date 12-Nov-04

Task Breaking,

trimming and

clearing

rubble.Duration (hh:mm:ss) 01:46:43














Seat surface awx (ms-2) 0.73Seat surface awy (ms-2) 0.39



SEATawx 1.25

SEATawy 1.18

SEATawz 0.76








SEATVDVx 1.26

SEATVDVy 1.17

SEATVDVz 0.60

39

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2

Figure 13 Unweighted (—) and frequency-weighted (---) power spectral densitiescalculated with 2504 degrees of freedom and a frequency resolution of 0.10 Hz.

0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


40

−10−5

05

10x

acce

lera

tion

(ms−2

)

276 s break here

−10−5

05

10

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000 7000

−10−5

05

10

Operating time (s)

z ac

cele

ratio

n(m

s−2)


00.5

11.5

22.5

3

a wx (

ms−2

)

276 s break here

(E1)(E2)

(E3)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 5000 6000 70000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)


41

Annex E: Hitachi EX60LC-5 measured 19th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Hitachi EX60LC-5

Family: Excavator

Kind: Crawler excavator

Serial number: 101PO54909

Power, kW: 41.0



Working hours: 3000



Driver’s seat make and model: Kab 411

Seat stroke: 100


Driver mass, kg: 84


Driver age: 40



Tool make: Montiavert

Tool model: 140SMS


Tool mass: 420 kg


42



The work site was a concrete slab approximately 200mm thick. The slab was covered in loose rubble.

43



The vehicle was mainly used to ‘trim’ concrete from upright steel beams. Betweeneach beam the vehicle was repositioned. At times the unpowered tool was used to clear rubble from the path of the machine.















The vehicle operator was observed to clear areas to be traversed or broken up using the body

of the hammer to push rubble aside. These events were associated with peaks in the recorded

vibration time histories. Reducing the occurrence of these operations could reduce the

vibration exposure of the operator.

Peaks in the vibration time histories occurred when the machine tracked over rubble. By

clearing a site of rubble before performing breaking operations the vibration exposure of the

operator could be reduced.

44


Vehicle manufacturer Hitachi

Vehicle model EX60LC

Tool Impact hammer

Test date 19-Nov-04

Task Trimming



















SEATawx 1.05

SEATawy 1.22

SEATawz 0.74








SEATVDVx 1.08

SEATVDVy 1.17

SEATVDVz 0.68

45

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


46

−10−5

05

10

x ac

cele

ratio

n(m

s−2)

98 s break here

−10−5

05

10

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000 7000

−10−5

05

10

Operating time (s)

z ac

cele

ratio

n(m

s−2)


00.5

11.5

22.5

3

a wx (

ms−2

)

98 s break here

(E1) (E2) (E3)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 5000 6000 70000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)


47

Annex F: Hitachi ZX460LCH measured 24th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Hitachi ZX460LCH

Family: Excavator


Serial number: ICIRO54864

Power, kW: 235



Working hours: 220


Track/tyre width, m: 0.6

Driver’s seat make and model: Unknown

Seat stroke: 125


Driver mass, kg: 89


Driver age: 38



Tool make: MSB

Tool model: 800


Tool mass: unknown

Serial number: ORF 006

48



The site was originally a multi-story car park. The work site consisted of a mixture of rubble, earth and flat

concrete. The floor slab was approximately 300 mm thick.

49



The machine was used to break up the floor slab of a multi-storey car park. Themachine broke up a section of the slab before tracking to a new location. At the end of the measurements the machine tracked across the site across a smooth concretesurface.




variable depending on the nature of the site. Typically the machine would be used for up to 8

hours during a shift.





At times the operator used the weight of the machine, to help break through the slab, by

pushing down on the tool so that the front of the machine lifted of the ground. When the tool

broke through the floor slab the front of the machine impacted the ground causing a peak in

the time histories. Reducing the number of such events could reduce the vibration exposure of

the driver.

50

Summary report form: Part 5 – ResultsVehicle manufacturer Hitachi

Vehicle model ZX460LCH

Tool impact hammer

Test date 08-Dec-04

Task Breaking concrete

floor



















SEATawx 1.20

SEATawy 1.19

SEATawz 0.92








SEATVDVx 1.21

SEATVDVy 1.14

SEATVDVz 0.75

51

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


52

−15−10−5

05

1015

x ac

cele

ratio

n(m

s−2)

−15−10−5

05

1015

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000 7000 8000

−15−10−5

05

1015

Operating time (s)

z ac

cele

ratio

n(m

s−2)

(E1) (E2)

Figure 23 Frequency-weighted acceleration at the seat surface. Periods of greater than 60 seconds where the vehicle was not operating were excluded.

00.5

11.5

22.5

3

a wx (

ms−2

)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 5000 6000 7000 80000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

Figure 24 Running (50% overlap) 10-second r.m.s. weighted acceleration on the seat surface.

53

Annex G: Hitachi EX60LC measured 24th

November 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Hitachi EX60LC-5

Family: Excavator


Serial number: ICIRO54864

Power, kW: 41.0



Working hours: 3000




Seat stroke: 100


Driver mass, kg: 82


Driver age: 53


Vehicle tool: Hydraulic crusher

Tool make: NPK

Tool model: 7XA


Tool mass: 700 kg


54




approximately 70m x 70m. There was some loose rubble on the surface of the floor. Steel reinforced

concrete pillars were located around the circumference of the work site. There was glazing between the

pillars.

55



During the measurement period the machine was mainly involved in demolishing a wall consisting of a concrete frame with large windows. The concrete structure was crushed in selected places and pulled to the ground. The windows and supportingstructure were lifted clear and the fallen concrete structure was partially broken up.The machine also cleared loose concrete and other items into skips.










Peaks were recorded in the vibration time-histories associated with the machine travelling

over loose rubble on the floor. Insuring that the floor around the machine is clear of rubble

could reduce the vibration exposure of the driver.

The operator was observed to use the unpowered tool to ‘hammer’ down upon a beam to

remove loose concrete from it. This event was associated with a peak in the time history.

56


Vehicle manufacturer Hitachi

Vehicle model EX60-LC

Tool Muncher

Test date 24-Nov-04

Task Loading skips and

pulling down walls



















SEATawx 1.06

SEATawy 1.19

SEATawz 0.76








SEATVDVx 1.09

SEATVDVy 1.21

SEATVDVz 0.59

57

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


58

−10−5

05

10x

acce

lera

tion

(ms−2

)


−10−5

05

10

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000 7000

−10−5

05

10

Operating time (s)

z ac

cele

ratio

n(m

s−2)


00.5

11.5

22.5

3

a wx (

ms−2

)


(E1)

(E3)

00.5

11.5

22.5

a wy (

ms−2

)

(E1)

0 1000 2000 3000 4000 5000 6000 70000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

(E2)


59

Annex H: Hitachi EX455 measured 9th

Dec 2004

Summary report form: Part 1– vehicle characteristics

Vehicle make and model: Hitachi EX455

Family: Excavator


Serial number: 0224

Power, kW: 225



Working hours: 4591




Seat stroke: 125


Driver mass, kg: 86


Driver age: 52


Vehicle tool: Hydraulic crusher

Tool make: Allied

Tool model: Unknown

Year of manufacture: Unknown

Tool mass: Unknown

Serial number: Unknown

60



The site was originally a multi-story car park. The work site consisted of a mixture of rubble, earth and flat

concrete. A small section of the structure of the multi-storey car park remained.

62



The machine was employed crushing steel-reinforced concrete beams to separatethe steel reinforcement and reduce the concrete to loose rubble. The machine thenspent approximately 8 minutes ‘munching’ concrete from upper storey floor section ofa partially demolished building.










Peaks were recorded in the vibration time histories associated with the back of the machine

impacting the ground. This occurred when tool was used to pull at a section of the building

such that the back of the machine lifted off the ground; when the structure gave way the back

of the machine impacted with the ground.

Peaks in the vibration time histories occurred when the machine tracked over rubble. By

clearing a site of rubble before performing breaking operations the vibration exposure of the

operator could be reduced.

63

Summary report form: Part 5 – ResultsVehicle manufacturer Hitachi

Vehicle model EX455

Tool Muncher

Test date 09-Dec-04

Task Building

demolition



















SEATawx 1.12

SEATawy 1.13

SEATawz 0.89








SEATVDVx 1.15

SEATVDVy 1.13

SEATVDVz 0.75

64

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


65

−15−10−5

05

1015

x ac

cele

ratio

n(m

s−2)

−15−10−5

05

1015

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000

−15−10−5

05

1015

Operating time (s)

z ac

cele

ratio

n(m

s−2)

Figure 31 Frequency-weighted acceleration at the seat surface.

00.5

11.5

22.5

3

a wx (

ms−2

)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 50000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)

(E1)

(E2) (E3)

Figure 32 Running (50% overlap) 10-second r.m.s. weighted acceleration on the seat surface.

66

Annex I: Case CX210 measured 9th

December 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Case CX210

Family: Excavator


Serial number: DCH21B0695

Power, kW: 105



Working hours: 3699




Seat stroke: 125


Driver mass, kg: 83


Driver age: 28


Vehicle tool: Backhoe shovel

Tool make: Geith

Tool model: 5 foot bucket

Year of manufacture: unknown

Tool mass: unknown

Serial number: unknown

67



Earth and rubble, mostly operating on top of piles of rubble.

68



The machine was employed loading rubble into trucks. For most of the observed working

time the machine was positioned on top of approximately flat-topped rubble piles. There were

some pauses in the region of two minutes when the machine stationary waiting for the next

truck to arrive.










Recorded vibration exposures were quite low on this vehicle. The highest levels of vibration

occurred when the vehicle was tracking around the site. Reducing the amount of tracking the

vehicle performs during a working day could reduce the vibration exposure of operators.

69

Summary report form: Part 5 – ResultsVehicle manufacturer CASE

Vehicle model CX210

Tool Shovel

Test date 09-Dec-04

Task Loading rubble



















SEATawx 1.09

SEATawy 1.10

SEATawz 0.68








SEATVDVx 1.13

SEATVDVy 1.11

SEATVDVz 0.50

70

10−3

10−2

10−1

100

x−axisS

eat b

ase

PS

D((

ms−2

)2 Hz−1

)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


71

−5

0

5x

acce

lera

tion

(ms−2

)

493 s break here

−5

0

5

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000 7000 8000

−5

0

5

Operating time (s)

z ac

cele

ratio

n(m

s−2)

Figure 35 Frequency-weighted acceleration at the seat surface. Periods where the driver exited the vehicle are excluded. These periods are indicated by vertical dottedlines.

00.5

11.5

22.5

3

a wx (

ms−2

)

493 s break here

(E1)(E2) (E3)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 5000 6000 7000 80000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)


72

Annex J: Hitachi ZX460LCH measured 22nd

December 2004

Summary report form: Part 1– vehicle characteristicsVehicle make and model: Hitachi ZX460LCH

Family: Excavator

Kind: Crawler excavator fitted with an 8 meter boom for extended reach.


Power, kW: 235



Working hours: unknown




Seat stroke: 125


Driver mass, kg: 90


Driver age: 57


Vehicle tool: Rotary steel shears

Tool make: MMR

Tool model: unknown

Year of manufacture: unknown

Tool mass: unknown

Serial number: 3096

73



Flat, hard roadway. This appeared to be damaged in places by the passage of the vehicle.

74



The machine was employed dismantling an aluminium grain silo using steel shears.The machine was stationary for most of the measurement period. However, the operator repositioned the machine a number of times during the measurementperiod.










Vibration levels recorded on this machine were relatively low. Periods when the vehicle was

tracking to different location on the sire were responsible for the greatest levels of measured

vibration.

75

Summary report form: Part 5 – Results Vehicle manufacturer Hitachi

Vehicle model ZX460LCH

extended reach

Tool Rotary steel shears

Test date 22-Dec-04

Task Cutting metal

structures



















SEATawx 1.16

SEATawy 1.16

SEATawz 0.86








SEATVDVx 1.19

SEATVDVy 1.11

SEATVDVz 0.85

76

10−3

10−2

10−1

100

x−axis

Sea

t bas

e P

SD

((m

s−2)2 H

z−1)

y−axis z−axis

10−3

10−2

10−1

Sea

t sur

face

PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

10−3

10−2

10−1

Bac

kres

t PS

D((

ms−2

)2 Hz−1

)

10−1

100

101

Frequency (Hz)10

−110

010

110

2


0

1

2

3x−axis

Tra

nsm

issi

bilit

y

y−axis z−axis

−pi/2

0

pi/2

Pha

se (

radi

ans)

0 10 20 30 400

0.5

1

Coh

eren

ce


0 10 20 30 40 50


77

−2.5

0

2.5x

acce

lera

tion

(ms−2

)


−2.5

0

2.5

y ac

cele

ratio

n(m

s−2)

0 1000 2000 3000 4000 5000 6000

−2.5

0

2.5

Operating time (s)

z ac

cele

ratio

n(m

s−2)


00.5

11.5

22.5

3

a wx (

ms−2

)


(E1) (E2)

00.5

11.5

22.5

a wy (

ms−2

)

0 1000 2000 3000 4000 5000 60000

0.51

1.52

2.5

a wz (

ms−2

)

Operating time (s)


78

Printed and published by the Health and Safety ExecutiveC30 1/98

Printed and published by the Health and Safety ExecutiveC1.10 10/05

RR 377

£25.00 9 78071 7 661 5 5 8

ISBN 0-7176-6155-5

Eva

lua

tion

of w

ho

le-b

od

y vibra

tion

exp

osu

res in

British

ind

ustry

HS

EB

OO

KS

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