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Executive Health and Safety

Whole-body vibration and ergonomics toolkit Phase 1 Prepared by the Health and Safety Laboratoryfor the Health and Safety Executive 2008

RR612 Research Report


Whole-body vibration and ergonomics toolkit Phase 1 A M Darby BSc(Hons) MSc CPhys MInsP Health and Safety Laboratory Harpur Hill Buxton SK17 9JN

The exact cause of back pain is often unclear but back pain is more common in jobs that involve certain tasks, one of which is driving. Driving exposes the vehicle’s occupants to whole-body vibration and in some cases shocks and jolts, factors which are believed to increase the likelihood of injury or pain in the lower back. The report describes a whole-body vibration and ergonomics toolkit that has been developed for use in assessing driving occupations.

The objectives of this report are:

n to provide a guide on how to approach the control of back pain due to occupational exposure to whole-body vibration and ergonomic risk factors;

n to invite recommendations on how the toolkit detailed in the report can be improved for the vehicles and occupations of interest; and

n to provide a specification for future whole-body vibration data collection activities.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

HSE Books

© Crown copyright 2008

First published 2008

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written 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 1BQor by e-mail to [email protected]

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CONTENTS

1 INTRODUCTION......................................................................................... 11.1 Background ............................................................................................. 11.2 Development of the toolkit ....................................................................... 21.3 Aims of the report .................................................................................... 3

2 TOOLKIT - WHOLE-BODY VIBRATION.................................................... 5

3 TOOLKIT - ANTHROPOMETRIC DESIGN ASSESSMENT....................... 73.1 Taking measurements ............................................................................. 73.2 Calculating percentile ranges ................................................................ 103.3 Suitability of the cab for a specific operator ........................................... 10

4 TOOLKIT - POSTURE ASSESSMENT .................................................... 11

5 TOOLKIT - MANUAL HANDLING ASSESSMENT .................................. 15

6 TOOLKIT - MUSCULOSKELETAL DISORDERS QUESTIONNAIRE ..... 19

7 FUTURE WORK ....................................................................................... 21

8 REFERENCES.......................................................................................... 23

APPENDICES .................................................................................................. 25

APPENDIX A. VIBRATION DATA FOR VEHICLES IN STUDY...................... 27

APPENDIX B. ANTHROPOMETRIC PROFORMAE AND SPREADSHEETS 65

APPENDIX C. POSTURE ANALYSIS ............................................................ 79

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EXECUTIVE SUMMARY

The exact cause of back pain is often unclear but back pain is more common in jobs that involve certain tasks, one of which is driving. Driving exposes the vehicle’s occupants to whole-body vibration and in some cases shocks and jolts, factors which are believed to increase the likelihood of injury or pain in the lower back. The report describes a whole-body vibration and ergonomics toolkit that has been developed for use in assessing driving occupations.


o To provide a guide on how to approach the control of back pain due to occupational exposure to whole-body vibration and ergonomic risk factors.

o To invite recommendations on how the toolkit detailed in the report can be improved for the vehicles and occupations of interest.

o To provide a specification for future whole-body vibration data collection activities.

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1.1

1 INTRODUCTION

BACKGROUND

Musculoskeletal disorders are the most common form of ill health at work. According to HSE’s website (Back pain),

“it is estimated that 4.9 million working days (full-time equivalent) were lost in 2003/2004 due to musculoskeletal disorders mainly affecting the back that were caused or made worse by work.”

The fact that back disorders are the most common form of ill health at work is one reason why HSE has made reducing their prevalence a priority.

The exact cause of back pain is often unclear but back pain is more common in jobs that involve certain tasks, one of which is driving, especially over long distances or over rough ground. Driving exposes the vehicle’s occupants to whole-body vibration, and possibly shocks and jolts, factors that are believed to increase the likelihood of injury or pain in the lower back. However drivers may also be exposed to other factors which may cause lower-back pain such as poor posture while driving and manual handling while loading and unloading goods. The work reported here is the first phase of a project looking at whole-body vibration exposure and other ergonomic risk factors for back pain from driving occupations.

The project is an exploratory study of back pain in drivers. The limited sample size of the study means that it will not be possible to draw strong conclusions about relationships between exposure data and self-reported musculoskeletal disorders. However as future studies use the data collection protocol developed during this project to add to the library of data, it will be possible to analyse the records for evidence of possible combined effects of whole-body vibration and ergonomic stressors as sources of back pain.

The project will:

o collect typical daily exposures for comparison with the exposure action and limit values for whole-body vibration specified in the Control of Vibration at Work Regulations 2005;

o assess the significance of confounding factors for risk of back pain in drivers; and

o consider the relationship of back pain with whole-body vibration quantified by various standard methods.

The project is organised into three phases. The first phase, which is reported here, involves the testing and development of a prototype ‘toolkit’ of data gathering and confounder screening techniques to a number of different vehicles. Phases 2 and 3 involve data gathering using the toolkit and investigation of relationships of back pain with occupational driving, respectively.

The toolkit was developed by specialists in HSL in association with HSE Specialist Inspectors. It seeks to provide a standard data collection procedure for whole-body vibration that provides for establishing the likelihood of manual handling or posture being significant causes of back pain. The toolkit comprises:

o whole-body vibration data acquisition and analysis system;

o a base set of measurements of workstation (driving position) dimensions to assess the adjustability of the workstation to accommodate the operator or range of operators

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employed;

o HSE’s Manual handling Assessment Charts (MAC) to rate severity of manual handling tasks;

o video analysis to assess postures and frequency of adoption; and

o a questionnaire (based on the validated ‘Nordic’ questionnaire) recording self-reported musculoskeletal disorders (MSDs).

1.2 DEVELOPMENT OF THE TOOLKIT

Phase 1 of the project, which is reported here, involved testing, and further developing where necessary, the prototype toolkit by applying it to a number of different driving occupations. The occupations selected were tipper truck driver, delivery van driver, forklift truck driver, council tipper truck driver, and council signage (flat back transit) van driver. The cabs of the vehicles used by these drivers were easy to access, and in most cases it was possible to spend up to three quarters of an hour fitting equipment and measuring the interior of the cab for the anthropometric assessment. Accessibility, both physical and in terms of time, of the cabs was particularly important at this assessment and development stage of the toolkit.

For four of the vehicles two members of staff, neither of whom was an ergonomics specialist, attempted to make all the measurements required by the toolkit. The use of non-specialists was important as the toolkit is intended for use by non-ergonomists. However in one case a third scientist was involved in the visit to reduce the amount of time required to acquire the necessary data.

1.2.1 Whole-body vibration

The whole-body vibration measurement and analysis system was expanded from three to seven channels of data, three on the seat pan, three on the seat base (in the same three orthogonal directions as the seat pan), and one on the seat back (in the fore-aft direction). This allows the SEAT (seat amplitude transmissibility) factor of the seat, for the vertical and two lateral directions, to be determined; thereby allowing the transmissibility of the seat to be assessed for all three directions. The analysis software was also enhanced to determine additional vibration metrics such as the Maximum Transient Vibration Value (ISO 2631-1:1997) for each channel and spine response data (ISO 2631-5:2004). In addition the analysis software now produces resampled time history and cumulative Vibration Dose Value plots for each channel of data.

1.2.2 Anthropometry

The anthropometric proforma in particular underwent substantial development as a result of the site visits. During the initial measurement visit it became clear that there was insufficient time available for the two staff on site to take all the measurements required by the proforma, in conjunction with the other tasks that needed to be completed. This conclusion was based on the premise that in this type of work a loss of production of about half to three quarters an hour at most is tolerated.

Sixty separate measurements were required by the initial anthropometric proforma and associated spreadsheet. The seat, and where appropriate the steering wheel, had to be adjusted during the measurement sequence so that various maximum and minimum distances could be measured. This process was found to be time consuming on site, and could not be completed during the time available. Consequently the anthropometric proforma and associated analysis spreadsheet were revised. On the revised proforma the minimum number of individual measurements required has been reduced to fourteen. The anthropometric proforma and

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spreadsheet are intended to identify marked mismatches between the cab dimensions and the relevant anthropometric dimensions of the selected population. Having recorded the measurements on the proforma the anthropometric spreadsheet is then used to determine the percentage of the chosen population that could be accommodated by the seating. The populations chosen are UK 18 to 65 year old males and UK 18 to 65 year old females. Initial use of the revised proforma has shown it to be useful, however, feedback on its usability in a wider variety of situations would be welcome.

1.2.3 Posture assessment

In the prototype toolkit the postures adopted by the driver while working were videoed and later assessed using a draft of a proforma devised by HSL’s Ergonomics Section, Video Proforma v.1. To assess the usefulness of the video proforma an Ergonomist was asked to assess the video made of the forklift truck driver. The Ergonomist assessed the working postures of the driver firstly using the video proforma, and then with three working posture assessment tools available in the literature. The three assessment tools were RULA (Rapid Upper Limb Assessment tool, which also addresses the trunk and lower limbs) (McAtamney, L. and Corlett, E.N. 1993), REBA (Rapid Entire Body Assessment tool) (Hignett, S. and McAtamney, L. 2000) and OWAS (Ovako Working posture Analysis System) (http://turva1.me.tut.fi/owas/).

The Ergonomist expressed a number of reservations about the video proforma, finding it quite complicated and difficult to use. Her comments on the proforma are reproduced in Appendix C.2. As a consequence it was decided that one of the assessment tools from the literature would be used in the toolkit and RULA was the tool selected. RULA is fairly easy to use, and was developed to investigate the exposure of individual workers to risk factors associated with upper limb disorders. Consequently it was considered the most suitable of the three assessment tools for the assessment of driving occupations.

1.2.4 Manual Handling

The MAC tool was developed by HSE to help the user identify high risk workplace manual handling activities. As the MAC tool underwent considerable development for generic manual handling activities, and is now an accepted tool for the assessment of manual handling activities, it has been included in the toolkit without further assessment.

1.2.5 Musculoskeletal disorders questionnaire

The musculoskeletal disorders questionnaire is based on the validated ‘Nordic’ questionnaire and has already been used extensively by the HSL’s Ergonomics Section. Consequently it has been included in the toolkit without further development. The questionnaire was given to the driver of each of the vehicles in the study, and in each case he was happy to complete it while the instrumentation was fitted to the vehicle cab.

1.3 AIMS OF THE REPORT

The aims of this report are:

o to provide a guide on how to approach the control of back pain due to occupational exposure to whole-body vibration and ergonomic risk factors;

o to invite recommendations on how the toolkit can be improved for the vehicles and occupations of interest;

o to provide a specification for future whole-body vibration data collection activities.

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The next five sections provide a guide to the tools contained in the toolkit at this stage of the project. The appendices to the report give the results obtained for the vehicles included in this phase of the project. (It should be remembered that the toolkit was developed as phase 1 of the project progressed, so that the full toolkit was not used on the earlier vehicles.)

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2 TOOLKIT - WHOLE-BODY VIBRATION

The vibration levels should be measured on the seat pan in the three orthogonal directions shown in Figure 1:

o x-axis fore-aft relative to the seat Z o y-axis across (side-to-side) the seat

Yo z-axis vertical X

Figure 1. Measurement axes

In addition, the vibration levels should also be measured underneath the seat, preferably on the floor pan of the vehicle. The vibration should be measured in the three directions used on the seat.

The vibration levels should also be measured on the seat back (in the x-axis).

Vibration measurements should be made for a representative period of the machine operator’s working day. Normally this will be at least 30 minutes, or at least three cycles for cyclical work such as transporting material from a quarry face to a crusher (Darby, A. 2005).

The vibration exposure duration of the operator for the working day should be recorded.

All measurements must be made in accordance with ISO 2631:1997.

Once collected the vibration data should be analysed to provide the following metrics for each of the seven channels (three on the seat, three below the seat, and one on the seat back) of data:

o acceleration power spectral density;

o r.m.s. (unweighted) level;

o r.m.s. frequency weighted level (ISO 2631-1:1997);

o VDV (ISO 2631-1:1997);

o eVDV (ISO 2631-1:1997);

o crest factor (defined as the frequency weighted peak / frequency weighted r.m.s.) (ISO 2631-1:1997);

o MTVV linear (ISO 2631-1:1997);

o MTVV exponential (ISO 2631-1:1997).

In addition the analyses should determine the:

o A(8) value (8 hour frequency weighted r.m.s. acceleration level for the working day);

o the working times to reach the exposure action and limit values in the CVWR 2005;

o VDV exposure for the working day (VDVexp);

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o the working time to reach a daily VDV exposure of 17 m/s1.75 (HSE’s criterion for risk including significant shock exposure – adopted from ISO 2631-1:1997);

o H1 frequency response spectrum between the seat base and seat pan for each axis and associated coherence;

o Spine response parameters (ISO 2631-5:2004);

o r.m.s. Seat Effective Amplitude Transmissibility Factor for each axis;

o VDV Seat Effective Amplitude Transmissibility Factor for each axis.

Note: SEAT values greater than 1 imply amplification of vibration by the suspension system, values less than 1 imply the suspension system is reducing the vibration transmitted to the driver.

Examples of the data collected and reported from analysis of the vibration recordings can be found in Appendix A.

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3 TOOLKIT - ANTHROPOMETRIC DESIGN ASSESSMENT

3.1 TAKING MEASUREMENTS

The dimensions required by the anthropometric spreadsheet are given below. (The list of measurements is for right hand drive vehicles.) As comparison is to be made with statistical data, measurements to the nearest 5mm are acceptable. Table 1 has been developed for recording the measurements.

Seat:

Dimensions v and h are required (see Figure 2). These values are used to find the accommodated buttock to ankle length assuming both an optimum knee angle for a light pedal force (less than 100N) and an optimum knee angle for a strong pedal force (greater than 100N).

v h

Figure 2. Seat to pedal distances

Seat pan height at front – for comparison with popliteal (back of knee) height

Seat pan depth – for comparison with buttock to popliteal length

Seat pan width – for comparison with hip breadth

Back rest height – for comparison with sitting shoulder height

Back rest width – for comparison with chest breadth at nipple

Head rest height + seat back height – for comparison with sitting height

Steering Wheel:

Top centre of seat back to top of steering wheel – for comparison with forward grip reach

Seat pan to steering wheel – for comparison with thigh depth

Gear Lever:

Top left of seat back to top of gear lever – for comparison with forward grip reach

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Hand Brake:

Top left of seat back to front of hand brake – for comparison with forward grip reach

These measurements are taken at the extremes of the vehicle cab design and represent the maximum or minimum achievable distances. In reality a combination of adjustments would be made to achieve the best compromise for competing adjustment parameters. The following is a guide to setting adjustments to achieve the maximum or minimum of the accommodation range for particular measurements:

v – the seat pan is adjusted such that at the point where it meets the seat back it is set to the maximum or minimum height above the cab floor.

h – the seat pan is set to its maximum or minimum distance back from the pedals or forward bulkhead. For the maximum distance, if the inclination of the seat back restricts this adjustment, the seat back should be set vertical before the seat pan is adjusted. For the minimum distance the seat back should be set to vertical.

Seat pan height at front – the seat pan should be set to its lowest height above the cab floor.

Top centre of seat back to top of steering wheel – the seat pan should be set as far forward as possible and the seat back inclined back to the vertical position. If the steering wheel or dashboard is adjustable, it should be set such that the top of the steering wheel is at its furthest back position i.e. closest to the seat.

Seat pan to steering wheel – the seat pan should be set to its maximum height above the cab floor and if the steering wheel is adjustable, it should be set to its lowest position above the seat pan.

Top left of seat back to top of gear lever – the seat back should be set to its most forward position as described in Top centre of seat back to top of steering wheel. The gear lever should be placed in its furthest forwards or left position relative to the driver.

Top left of seat back to front of hand brake – the seat back should be set to its most forward position as described in Top centre of seat back to top of steering wheel.

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Table 1.

Vehicle Cab Anthropometric Assessment Proforma v.1

Date …………………………. Location ………………………………………….

Vehicle Type ……………………………………………………………………

Driver …………………………………

Dimension (mm) Min Max Fixed User

v

h v h

Seat pan height at front

Seat pan depth (front to back)

Seat pan width

Back rest height

Back rest width

Head rest height

Top centre of seat back to top of steering wheel Seat pan to steering wheel (vertical) Top left of seat back to top of gear lever Top left of seat back to front of hand brake

Officer (1) …………………………….. Signed …………………………….

Officer (2) …………………………….. Signed …………………………….

Note: Shaded areas of table will not normally need to be filled in, however for some cabs this data may be useful.

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3.2 CALCULATING PERCENTILE RANGES

In order to assess the accommodation of the vehicle cab, the percentage of the user population the adjustments will fit is calculated. In general the adult worker population is the chosen population range i.e. 18 to 65 year old adult males and females. The maximum and minimum adjustment measurements will give the upper and lower percentiles. These are calculated as follows:

Calculate the z score –

z = (measurement - body dimension mean value) / Body dimension standard deviation

The z score will give a signed value where 0 is 50th percentile (average), negative numbers are smaller than average and positive numbers are larger than average.

Look up the equivalent percentile in a pz table (pz tables are usually published with tables of body data e.g. Adultdata, DTI).

An example calculation is given below:

Top centre of seat back to top of steering wheel max = 790 mm, min = 690 mm Forward grip reach adult male mean = 738 mm, SD = 41 mm

Max z = (790 – 738) / 41 = 1.27 p = 90th

Min z = (690 – 738) / 41 = -1.17 p = 12th

The accommodated population range is therefore 12th to 90th percentile adult male.

To simplify this process an anthropometric spreadsheet has been produced which calculates z scores and percentiles for British adult males and females. The spreadsheet uses the percentile rank function to estimate p values from a list of z scores. Examples of completed anthropometric spreadsheets can be found in Appendix B.2.

3.3 SUITABILITY OF THE CAB FOR A SPECIFIC OPERATOR

If the suitability of the cab for a specific operator is an issue then the subject in question should set any adjustments to how they would normally use them. Once set, no further adjustment is made until a full set of measurements is taken. Measurements should be recorded in the ‘user’ column in Table 1. Anthropometric measurements of the subject will also be required.

It is useful to ascertain whether adjustments can be made to accommodate the single subject. Having made the measurements described above, the limits of adjustment can be measured as described in Section 3.1.

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4 TOOLKIT - POSTURE ASSESSMENT

The driver’s postures and actions while working should be videoed for later analysis. After the site visit the video should be analysed to identify postures that are associated with increased risk of musculoskeletal disorders using the Rapid Upper Limb Assessment (RULA) tool (McAtamney, L. and Corlett, E.N. 1993). This tool gives an action level with an indication of urgency.

RULA uses the concept of numbers to represent postures. The body segments considered by RULA are divided into two groups, A and B. Group A includes the upper arm, lower arm, and wrist, while Group B includes the neck, trunk and legs. The range of movement for each body segment is divided into sections. The segments are numbered so that the number one is given to the range of movement where the risk factor is minimal and higher numbers are given to ranges of movement involving the more extreme postures.

The score for each body segment is entered in the appropriate box in the RULA score sheet (Figure 3) and then posture score A and posture score B are found using Tables A and B (McAtamney, L. and Corlett, E.N. 1993) respectively. Muscle use scores and force scores are added to posture scores A and B to find scores C and D respectively. Table C (McAtamney, L. and Corlett, E.N. 1993) is then used to find the grand score from scores C and D. The grand score gives the action level, where:

• Action level 1 is given by a grand score of 1 or 2, and indicates that the posture is acceptable if it is not maintained or repeated for long periods;

• Action level 2 is given by a grand score of 3 or 4, and indicates that further investigation is needed and changes may be required;

• Action level 3 is given by a grand score of 5 or 6, and indicates that investigation and changes are required soon;

• Action level 4 is given by a grand score of 7, and indicates that investigation and changes are required immediately.

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Task: A

B Neck Using Table B Posture score B

Trunk Muscle Force Score D

+ + =

Legs

Figure 3. RULA scoring sheet.

An example of a completed RULA sheet is shown in Figure 4. This assessment was of the posture adopted by a forklift truck driver while reversing (Figure 5), and it produced an action level of 2.

Upper arm

Lower arm

Wrist

Wrist twist

Using Table A Posture score A

+ Muscle Force Score C

+ =

Using Table C Grand score

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Task: Fork lift truck driver (reversing) A

2

1

1

0

B Using Table B

4 Posture score B

0 0 52 5 + + =

0

Figure 4. RULA scoring sheet for reversing posture (forklift truck driver)

Using Table A Posture score A

2 + 0 + 0 2=

Using Table C

Figure 5. Reversing posture

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5 TOOLKIT - MANUAL HANDLING ASSESSMENT

Manual handling tasks carried out by the operator should be identified and rated using HSE’s Manual Handling Assessment Chart (MAC) tool (www.hse.gov.uk/msd). The MAC incorporates a numerical and a colour coding score system to highlight high risk manual handling tasks. The colour coding score (green – low level of risk, amber – medium level of risk, red – high level of risk, purple – very high level of risk ) is used by the whole-body vibration and ergonomics toolkit. The numerical score is not used by the toolkit.

There are three types of assessment that can be carried out with the MAC tool, lifting operations, carrying operations, and team handling operations. Taking the first of these, lifting operations, as an example, each of the following factors is considered in turn: load weight / frequency; hand distance from the lower back; vertical lift region; trunk twisting and sideways bending; postural constraints; grip on load; floor surface;other environmental factors. Using the Lifting Operation Assessment Guide in the MAC tool (Figure 5) a colour band (green, amber, red or purple) is given to each factor.

Figure 5(a). Lifting Operation Assessment Guide (I) (HSE MAC tool)

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Figure 5(b). Lifting Operation Assessment Guide (II) (HSE MAC tool)

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Figure 5(c). Lifting Operation Guide (III) (HSE MAC tool)

The colour code is then entered into the MAC score sheet.(Figure 6).

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Figure 6. MAC Score Sheet (HSE MAC tool).

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6 TOOLKIT - MUSCULOSKELETAL DISORDERS QUESTIONNAIRE

The musculoskeletal disorders questionnaire (Figure 7) is based on the validated ‘Nordic’ questionnaire. The questionnaire should be used to record self-reported musculoskeletal disorders.

Figure 7(a). HSL Musculoskeletal Disorders Questionnaire (I)

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Figure 7(b). HSL Musculoskeletal Disorders Questionnaire (II)

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7 FUTURE WORK

Phase 1 of the project, which involved testing the prototype toolkit and developing it further where necessary, has successfully been completed. The toolkit has been effectively applied to the occupations of tipper truck driver, delivery van driver, forklift truck driver, council tipper truck driver and council signage (flat back transit) van driver. Initial use of the toolkit has shown it to be useful, however, feedback on its usability in a wider variety of situations would be welcome, and recommendations on how the all parts of the toolkit can be improved for the vehicles and occupations of interest are invited.

The next phase of the project involves the collection of whole-body vibration and ergonomic data from a wider variety of vehicles. Phase 2 is planned for 12 machines, but can be extended to cover whatever range of machinery and tasks HSE may require subject to time and cost extensions. The use of the toolkit will allow ergonomic data to be recorded as well as the usual whole-body vibration data. This is important, as non-vibration risk factors for back pain are often present in driving occupations.

The following issues will be addressed in the report on phase 2:

• how vibration exposures are likely to compare with the exposure action values and exposure limit values in the regulations and hence the applicability of generic assessments within particular industries;

• the importance of manual handling and posture as risk factors for back pain in the operators of the machinery assessed;

• the prevalence and nature of musculoskeletal disorders reported by volunteers from the workforce.

Phase 3 of the project will be an investigation of relationships of back pain with occupational driving. The effect of using different whole-body vibration metrics for vibration assessments, comparing the back injuries reported on the questionnaire with the vibration exposure, will be assessed. Phase 3 will provide information in support of holistic guidance on the management of back pain in drivers.

Progression through the project phases is sequential and dependent upon successful completion of the previous phase as ascertained from the draft report on that phase. Phases 2 and 3 are: also dependent upon the successful completion of the whole-body vibration database, which is part of a separate piece of work currently being undertaken by HSL for HSE.

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8 REFERENCES

1. European Parliament and the Council of the European Union (2002) Official Journal of the European Communities Directive 2002/44/EC on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (vibration). OJ L177, 6.7.2002, p13.

2. Control of Vibration at Work Regulations 2005, ISBN 0110727673, Statutory Instrument 2005 No. 1093

3. Darby, A. Assessment of whole-body vibration exposure and other ergonomic factors associated with back pain. Proceedings of the Institute of Acoustics: Let’s get Physical. HSL, Buxton 13th July 2005

4. Hignett, S. and McAtamney, L. Rapid Entire Body Assessment (REBA) Applied Ergonomics 2000, 31, 201-205

5. ISO 10326-1:1992 Mechanical vibration - Laboratory method for evaluating vehicle seat vibration -- Part 1: Basic requirements

6. ISO 2631-1:1997 Mechanical vibration and shock -- Evaluation of human exposure to whole-body vibration -- Part 1: General requirements

7. ISO 2631-5:2004 Mechanical vibration and shock -- Evaluation of human exposure to whole-body vibration -- Part 5: Method for evaluation of vibration containing multiple shocks

8. McAtamney, L. and Corlett, E. N. Rula – a survey method for the investigation of work-related upper limb disorders. Applied Ergonomics 1993, 24(2), 91-99

9. http://www.hse.gov.uk/msd and http://www.hse.gov.uk/pubns/indg143.pdf (manual handling)

10. http://turva1.me.tut.fi/owas/ (OWAS)

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APPENDICES

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APPENDIX A. VIBRATION DATA FOR VEHICLES IN STUDY

Appendix A.1 Site visit 1

Equipment

Item Type

Transducer B&K 4322

Transducer B&K 4322

Calibrator B&K 4294

Charge amplifier B&K 2635






Data recorder TEAC RD135T

Analysis system Pulse

Analysis system MatLab

Serial number or

1249795 (w/o nitrile pad)

2010827

1688502

1493483

2448013

1473734

1709839

1493485

2448014

723517

2325758

Program vdv2_4

Section ID

445

674

Figure A.1 Tipper truck

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Site/meas. no. 1/1 Vehicle: Renault 370 dci (tipper truck) Measurement date: 02/02/2005 Seat: ISRI, no model number Tape/ID no: 1/8 self adjusting air suspension

Analysis length : 5215 seconds Task: Depot to construction site to golf course Freq. increment: 0.125 Hz (transporting soil)

Seat Seat base Seat back x y z x y z x

RMS (m/s²) (Unweighted) 0.43 0.44 0.68 0.44 0.73 0.68 -

RMS (m/s²) (ISO 2631-1:1997) 0.20 0.22 0.44 0.17 0.38 0.43 -

VDV (m/s1.75) (ISO 2631-1:1997)

5.40 3.84 6.23 3.54 6.42 10.12 -

eVDV (m/s1.75) (ISO 2631-1:1997)

2.40 2.58 5.26 2.06 4.58 5.12 -

Crest factor (ISO 2631-1:1997) 38 18 12 18 13 28 -

MTVV linear (m/s²) (ISO 2631:1997) 4.24 2.77 2.18 1.52 3.68 5.10 -

MTVV exp. (m/s²) (ISO 2631:1997) 3.50 2.25 1.90 1.45 3.12 4.33 -

SEAT factor (RMS) 1.2 0.6 1.0

SEAT factor (VDV) 1.5 0.6 0.6

Exposure duration: 09:00:00

A(8) value for comparison with the exposure action (0.5 m/s² A(8)) and limit (1.15 m/s² A(8)) values in the Control of Vibration at Work Regulations 2005

A(8) (m/s²) 0.47 (z direction) Time to action value 10:14:47

Time to limit value > 24 hrs

VDV for comparison with HSE's criterion for significance of shock

VDVexp (m/s1.75) 11.9 (x direction) Time to 17 m/s1.75 > 24 hrs

Spine response data for comparison with the criterion set out in ISO 2631-5:2004, R < 0.8 low probability of an adverse health effect, R > 1.2 high probability of an adverse health effect

Dx Dy Dz Sed (m/s 2) (m/s 2) (m/s 2) (MPa) 13.2 7.6 8.2 0.4

R Age (yrs)

20 30 40 50 60 65 0.2 0.3 0.4 0.5 0.6 0.6

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Site/meas. no. 1/1Measurement date: 02/02/2005Tape/ID no: 1/8

Vehicle: Renault 370 dci (tipper truck)Seat: ISRI, no model number

Freq. increment: 0.125 Hz

0.001

0.01

0.1

1

0.1 1 10 100Frequency (Hz)

Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce

x frequencyresponsex coherence

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce

y frequencyresponsey coherence

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce

z frequencyresponsez coherence

30

Site/meas. no. 1/1 Vehicle: Renault 370 dci (tipper truck)

x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s1.75)

x seat

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520

y seat

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520

z seat

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520

x base

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520

y base

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520

z base

-20-10

01020

0 10 20 30 40 50 60 70 80

05101520


Analysis length : 5215 seconds Task: Golf course to Paddington to golf course Freq. increment: 0.125 Hz (transporting soil)



RMS (m/s²) (ISO 2631-1:1997) 0.21 0.29 0.56 0.19 0.48 0.42 -

VDV (m/s1.75) (ISO 2631-1:1997)

3.45 4.75 8.83 2.97 7.21 6.72 -

eVDV (m/s1.75) (ISO 2631-1:1997)

2.55 3.45 6.66 2.32 5.68 5.05 -

Crest factor (ISO 2631-1:1997) 20 14 28 10 11 14 -


MTVV exp. (m/s²) (ISO 2631:1997) 1.53 2.20 3.30 1.04 2.69 1.84 -








VDVexp (m/s1.75) 13.9 (z direction) Time to 17 m/s1.75 19:51:35


Dx Dy Dz Sed (m/s 2) (m/s 2) (m/s 2) (MPa)

7.3 8.9 22.6 1.0

R Age (yrs)

20 30 40 50 60 65 0.5 0.8 0.9 1.1 1.4 1.5

31

32




0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


33



x seat

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10

y seat

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10

z seat

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10

x base

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10

y base

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10

z base

-10-505

10

0 10 20 30 40 50 60 70 80

0

5

10


Analysis length : 900 seconds Task: Golf course to Paddington Freq. increment: 0.125 Hz (empty)



RMS (m/s²) (ISO 2631-1:1997) 0.25 0.25 0.63 0.22 0.52 0.49 -

VDV (m/s1.75) (ISO 2631-1:1997)

2.34 2.52 5.08 2.02 4.58 5.43 -

eVDV (m/s1.75) (ISO 2631-1:1997)

1.88 1.93 4.86 1.70 3.98 3.78 -

Crest factor (ISO 2631-1:1997) 10 11 6 8 7 20 -


MTVV exp. (m/s²) (ISO 2631:1997) 1.06 1.31 1.84 0.85 1.79 2.10 -








VDVexp (m/s1.75) 12.4 (z direction) Time to 17 m/s1.75 > 24 hrs



5.0 6.1 6.2 0.4

R Age (yrs)

20 30 40 50 60 65 0.2 0.3 0.4 0.5 0.6 0.7

34

35




0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


36



x seat

-5

0

5

0 2 4 6 8 10 12 14

0

5

10

y seat

-5

0

5

0 2 4 6 8 10 12 14

0

5

10

z seat

-5

0

5

0 2 4 6 8 10 12 14

0

5

10

x base

-5

0

5

0 2 4 6 8 10 12 14

0

5

10

y base

-5

0

5

0 2 4 6 8 10 12 14

0

5

10

z base

-5

0

5

0 2 4 6 8 10 12 14

0

5

10


Equipment

Item Type Serial number or Section ID

Transducer B&K 4322 1249795 (w/o nitrile pad) 445

Transducer B&K 4322 2010827 674

Calibrator B&K 4294 2361765

Charge amplifier B&K 2635 17009921






Data recorder TEAC RD135T 730217

Analysis system Pulse 2325758

Analysis system MatLab Program vdv2_4

Figure A.2 Transit van

37

Site/meas. no. 2/1 Vehicle: VW Diesel Transit LT35 TDi Measurement date: 21/04/2005 Seat: Conventional, no identification Tape/ID no: 1/9

Analysis length : 2406 seconds Task: Driving from HSL, Buxton to Freq. increment: 0.125 Hz edge of Newcastle-under-Lyme



RMS (m/s²) (ISO 2631-1:1997) 0.18 0.25 0.43 0.16 0.22 0.43 -

VDV (m/s1.75) (ISO 2631-1:1997)

2.73 3.04 5.62 2.69 2.56 5.31 -

eVDV (m/s1.75) (ISO 2631-1:1997)

1.72 2.44 4.22 1.59 2.15 4.19 -

Crest factor (ISO 2631-1:1997) 15 11 17 16 10 14 -


MTVV exp. (m/s²) (ISO 2631:1997) 1.21 1.41 2.50 1.23 1.14 1.77 -











6.6 6.2 9.4 0.4

R Age (yrs)

20 30 40 50 60 65 0.2 0.3 0.4 0.5 0.6 0.7

38

39


Vehicle: VW Diesel Transit LT35 TDiSeat: Conventional, no identification


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


40

Site/meas. no. 2/1 Vehicle: VW Diesel Transit LT35 TDi


x seat

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10

y seat

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10

z seat

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10

x base

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10

y base

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10

z base

-5

0

5

0 5 10 15 20 25 30 35 40

0

5

10


Equipment

Item Type

Transducer B&K 4322

Transducer B&K 4322

Calibrator B&K 4294










Figure A.3 Fork lift truck

Serial number or Section ID

1249795 (w/o nitrile pad) 445

2010827 674

1688502

17009921

1658804

1340163

1493483

1493485

1473733

730217

2325758

Program vdv2_4

Figure A.4 Fork lift truck (cab)

41

Site/meas. no. 3/1 Vehicle: Yale 032 counterbalance lift truck Measurement date: 02/11/2005 Seat: Conventional, no identification Tape/ID no: 1/6

Analysis length : 208 seconds Task: Driving round yard Freq. increment: 0.125 Hz


RMS (m/s²) (Unweighted) 0.76 0.93 0.73 - - - -

RMS (m/s²) (ISO 2631-1:1997) 0.20 0.35 0.70 - - - -

VDV (m/s1.75) (ISO 2631-1:1997)

1.16 1.92 4.89 - - - -

eVDV (m/s1.75) (ISO 2631-1:1997)

1.09 1.88 3.72 - - - -

Crest factor (ISO 2631-1:1997) 5 6 9 - - - -

MTVV linear (m/s²) (ISO 2631:1997) 0.62 1.10 2.95 - - - -

MTVV exp. (m/s²) (ISO 2631:1997) 0.52 0.99 2.55 - - - -

SEAT factor (RMS) - - -

SEAT factor (VDV) - - -




Time to limit value 21:39:48





2.5 5.2 5.3 0.4

R Age (yrs)

20 30 40 50 60 65 0.2 0.3 0.4 0.5 0.6 0.6

42

43


Vehicle: Yale 032 counterbalance lift truckSeat: Conventional, no identification


x seat

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seat

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seat

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

44

Site/meas. no. 3/1 Vehicle: Yale 032 counterbalance lift truck


x seat

-5

0

5

0 0.5 1 1.5 2 2.5 3

0

5

10

y seat

-5

0

5

0 0.5 1 1.5 2 2.5 3

0

5

10

z seat

-5

0

5

0 0.5 1 1.5 2 2.5 3

0

5

10

Site/meas. no. 3/2 Vehicle: Yale 032 counterbalance lift truck Measurement date: 02/11/2005 Seat: Conventional, no identification Tape/ID no: 1/7

Analysis length : 290 seconds Task: Simulated loading and unloading Freq. increment: 0.125 Hz


RMS (m/s²) (Unweighted) 0.68 0.64 0.35 - - - -

RMS (m/s²) (ISO 2631-1:1997) 0.28 0.22 0.29 - - - -

VDV (m/s1.75) (ISO 2631-1:1997)

2.20 1.46 2.62 - - - -

eVDV (m/s1.75) (ISO 2631-1:1997)

1.60 1.26 1.68 - - - -

Crest factor (ISO 2631-1:1997) 7 7 9 - - - -

MTVV linear (m/s²) (ISO 2631:1997) 1.47 0.75 1.44 - - - -

MTVV exp. (m/s²) (ISO 2631:1997) 1.34 0.66 1.21 - - - -

SEAT factor (RMS) - - -

SEAT factor (VDV) - - -



A(8) (m/s²) 0.27 (x direction) Time to action value 13:13:46



VDVexp (m/s1.75) 8.2 (x direction) Time to 17 m/s1.75 > 24 hrs



4.9 3.6 3.0 0.3

R Age (yrs)

20 30 40 50 60 65 0.1 0.2 0.2 0.3 0.3 0.4

45

Site/meas. no. 3/2 Measurement date: 02/11/2005 Tape/ID no: 1/7

Vehicle: Yale 032 counterbalance lift truck Seat: Conventional, no identification


1

1 10 100 )

.

1

1 10 100 )

.

1

1 10 100 )

/ .

x seat

0.001

0.01

0.1

0.1 Frequency (Hz

Acc

. PS

D (m

/s²)²

/Hz

0.001

0.01

0.1

0.1 Frequency (Hz

Acc

. PS

D (m

/s²)²

/Hz

0.001

0.01

0.1

0.1 Frequency (Hz

Acc

. PS

D (m

s²)²/

Hz

y seat

z seat

46

47

Site/meas. no. 3/2 Vehicle: Yale 032 counterbalance lift truck


x seat

-5

0

5

0 0.5 1 1.5 2 2.5 3 3.5 4

0

5

10

y seat

-5

0

5

0 0.5 1 1.5 2 2.5 3 3.5 4

0

5

10

z seat

-5

0

5

0 0.5 1 1.5 2 2.5 3 3.5 4

0

5

10


Equipment

Item Type

Transducer B&K 4322

Transducer B&K 4322

Transducer B&K 4322

Calibrator B&K 4294











Force gauge Mecmesin Advanced Force Gauge



2010827 674

1793182 (borrowed from L. Beirne)

1688502

17009921

1658804

1340163

1493483

1493485

1473733

1709839

730217

2325758

Program vdv2_4

KN03032606

Figure A.5 Road repair depot tipper truck (1) Figure A.6 Road repair depot tipper truck (2)

48

Site/meas. no. 4/1 Vehicle: Leyland DAF 55 tipper truck (Y746 HKY) Measurement date: 22/11/2005 Seat: Conventional, no identification Tape/ID no: 1/1

Analysis length : 1500 seconds Task: Driving from depot at Chapel-en-le-Frith Freq. increment: 0.125 Hz to Goyt valley


RMS (m/s²) (Unweighted) 0.55 0.69 0.83 1.09 0.72 0.78 0.65

RMS (m/s²) (ISO 2631-1:1997) 0.19 0.30 0.64 0.22 0.25 0.60 0.53

VDV (m/s1.75) (ISO 2631-1:1997)

2.03 3.17 8.95 2.33 2.68 6.21 5.30

eVDV (m/s1.75) (ISO 2631-1:1997)

1.69 2.60 5.59 1.95 2.22 5.24 4.59

Crest factor (ISO 2631-1:1997) 9 9 25 8 9 10 11

MTVV linear (m/s²) (ISO 2631:1997) 0.76 1.42 4.53 1.07 1.35 2.21 1.75

MTVV exp. (m/s²) (ISO 2631:1997) 0.69 1.21 4.25 0.89 1.16 1.97 1.55








m/s1.75VDVexp ( ) 17.4 (z direction) Time to 17 m/s1.75 05:25:05


Dx Dy Dz Sed (m/s2) (m/s2) (m/s2) (MPa)

4.5 7.4 43.6 2.2

R Age (yrs)

20 30 40 50 60 65 1 1.7 2 2.5 3 3.4

49

50


Vehicle: Leyland DAF 55 tipper truck (Y746 HKY)Seat: Conventional, no identification


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

. x seat back

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


51

Site/meas. no. 4/1 Vehicle: Leyland DAF 55 tipper truck (Y746 HKY)


x seat

-5

0

5

0 5 10 15 20 25

0

5

10

y seat

-5

0

5

0 5 10 15 20 25

0

5

10

z seat

-5

0

5

0 5 10 15 20 25

0

5

10

x base

-5

0

5

0 5 10 15 20 25

0

5

10

y base

-5

0

5

0 5 10 15 20 25

0

5

10

z base

-5

0

5

0 5 10 15 20 25

0

5

10

x back

-5

0

5

0 5 10 15 20 25

0

5

10


Analysis length : 1500 seconds Task: Driving from Goyt valley to tipping area Freq. increment: 0.125 Hz



RMS (m/s²) (ISO 2631-1:1997) 0.18 0.31 0.61 0.18 0.26 0.60 0.49

VDV (m/s1.75) (ISO 2631-1:1997)

2.27 3.06 6.35 2.37 2.61 6.36 5.40

eVDV (m/s1.75) (ISO 2631-1:1997)

1.56 2.68 5.31 1.59 2.25 5.24 4.29

Crest factor (ISO 2631-1:1997) 18 7 9 15 9 11 9


MTVV exp. (m/s²) (ISO 2631:1997) 1.30 1.10 1.91 1.49 0.90 1.91 2.14











6.5 7.0 6.7 0.4

R Age (yrs)

20 30 40 50 60 65 0.2 0.3 0.4 0.5 0.6 0.6

52

53




0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

. x seat back

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


54



x seat

-5

0

5

0 5 10 15 20 25

0

5

10

y seat

-5

0

5

0 5 10 15 20 25

0

5

10

z seat

-5

0

5

0 5 10 15 20 25

0

5

10

x base

-5

0

5

0 5 10 15 20 25

0

5

10

y base

-5

0

5

0 5 10 15 20 25

0

5

10

z base

-5

0

5

0 5 10 15 20 25

0

5

10

x back

-5

0

5

0 5 10 15 20 25

0

5

10


Analysis length : 1800 seconds Task: Dumping load and driving from tipping area Freq. increment: 0.125 Hz to Goyt valley



RMS (m/s²) (ISO 2631-1:1997) 0.22 0.35 0.64 0.23 0.29 0.61 0.52

VDV (m/s1.75) (ISO 2631-1:1997)

2.44 3.81 8.55 2.45 3.24 6.64 5.82

eVDV (m/s1.75) (ISO 2631-1:1997)

2.01 3.19 5.83 2.08 2.67 5.56 4.73

Crest factor (ISO 2631-1:1997) 10 8 29 8 9 9 13


MTVV exp. (m/s²) (ISO 2631:1997) 0.82 1.28 3.61 0.81 1.10 2.13 1.96











5.3 8.2 22.6 1.1

R Age (yrs)

20 30 40 50 60 65 0.5 0.8 1 1.2 1.5 1.7

55

56




0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

. x seat back

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


57



x seat

-10-505

10

0 5 10 15 20 25 30

0

5

10

y seat

-10-505

10

0 5 10 15 20 25 30

0

5

10

z seat

-10-505

10

0 5 10 15 20 25 30

0

5

10

x base

-10-505

10

0 5 10 15 20 25 30

0

5

10

y base

-10-505

10

0 5 10 15 20 25 30

0

5

10

z base

-10-505

10

0 5 10 15 20 25 30

0

5

10

x back

-10-505

10

0 5 10 15 20 25 30

0

5

10


Equipment

Item Type

Transducer B&K 4322

Transducer B&K 4322

Transducer B&K 4322

Calibrator B&K 4294













2010827 674

1793182 (borrowed from L. Beirne)

1688502

17009921

1658804

1340163

1493483

1493485

1473733

1709839

723517

2325758

Program vdv2_4

Figure A.7 Flat back transit van (1) Figure A.8 Flat back transit van (2)

58

Site/meas. no. 5/1 Vehicle: Ford transit LF 53 (Y599 PHL) Measurement date: 30/11/2005 Seat: Conventional, no identification Tape/ID no: 1/8

Analysis length : 1190 seconds Task: Driving from depot at Chapel-en-le-Frith to check Freq. increment: 0.125 Hz road works at Bamford



RMS (m/s²) (ISO 2631-1:1997) 0.17 0.19 0.37 0.15 0.16 0.38 0.31

VDV (m/s1.75) (ISO 2631-1:1997)

1.72 1.77 3.60 1.53 1.41 3.63 2.76

eVDV (m/s1.75) (ISO 2631-1:1997)

1.42 1.59 3.08 1.24 1.32 3.09 2.52

Crest factor (ISO 2631-1:1997) 8 8 9 8 7 9 7


MTVV exp. (m/s²) (ISO 2631:1997) 0.71 0.74 1.33 0.64 0.55 1.14 0.98











4.2 4.3 4.6 0.3

R Age (yrs)

20 30 40 50 60 65 0.1 0.2 0.3 0.3 0.4 0.4

59

60


Vehicle: Ford transit LF 53 (Y599 PHL)Seat: Conventional, no identification


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

. x seat back

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


61

Site/meas. no. 5/1 Vehicle: Ford transit LF 53 (Y599 PHL)


x seat

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

y seat

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

z seat

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

x base

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

y base

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

z base

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

x back

-20-10

01020

0 2 4 6 8 10 12 14 16 18

0

5

10

Site/meas. no. 5/2 Vehicle: Ford transit LF 53 (Y599 PHL) Measurement date: 30/11/2005 Seat: Conventional, no identification Tape/ID no: 1/9

Analysis length : 1500 seconds Task: Driving from road works at Bamford to depot Freq. increment: 0.125 Hz at Chapel-en-le-Frith



RMS (m/s²) (ISO 2631-1:1997) 0.14 0.16 0.32 0.14 0.13 0.32 0.27

VDV (m/s1.75) (ISO 2631-1:1997)

1.43 1.62 3.10 1.61 1.27 3.17 2.50

eVDV (m/s1.75) (ISO 2631-1:1997)

1.18 1.39 2.77 1.23 1.11 2.80 2.32

Crest factor (ISO 2631-1:1997) 10 9 8 8 8 7 7


MTVV exp. (m/s²) (ISO 2631:1997) 0.60 0.73 0.93 0.84 0.49 0.92 0.73











3.2 4.6 3.7 0.3

R Age (yrs)

20 30 40 50 60 65 0.1 0.2 0.2 0.3 0.4 0.4

62

63


Vehicle: Ford transit LF 53 (Y599 PHL)Seat: Conventional, no identification


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

. x seat back

0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

x seatx seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

y seaty seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


0.001

0.01

0.1

1


Acc

. PS

D (m

/s²)²

/Hz

.

z seatz seat base

0.1

1

10


Mag

nitu

de .

0

0.5

1

Coh

eren

ce


64

Site/meas. no. 5/2 Vehicle: Ford transit LF 53 (Y599 PHL)


x seat

-5

0

5

0 5 10 15 20 25

0

5

10

y seat

-5

0

5

0 5 10 15 20 25

0

5

10

z seat

-5

0

5

0 5 10 15 20 25

0

5

10

x base

-5

0

5

0 5 10 15 20 25

0

5

10

y base

-5

0

5

0 5 10 15 20 25

0

5

10

z base

-5

0

5

0 5 10 15 20 25

0

5

10

x back

-5

0

5

0 5 10 15 20 25

0

5

10

APPENDIX B. ANTHROPOMETRIC PROFORMAE AND SPREADSHEETS

Appendix B.1 Initial Anthropometric proforma and spreadsheet

Date…………………………. Location………………………………………….

Vehicle Type………………………………………………………………………

Driver

Dimension Fixed (mm) Max (mm) Min (mm) User (mm) Pedals

H-point vertical height Projection of H-point to Heel-point (horizontal)

Steering Wheel Top of seat back to top of steering wheel Bottom of steering wheel to seat back (horizontal) Seat pan to steering wheel Diameter of steering wheel

Gear Lever Top left of seat back to top of gear lever

Hand Brake Top left of seat back to front of hand brake

Seat Seat pan height at front Seat pan depth

Seat pan width

Back rest height

Back rest width

Head rest height

Seat pan (back) to cab roof

65

Anthropometric Cab Design Assessment for Driving Occupations Version 1.2 Body dimensions taken from Peebles & Norris, 1998, Adultdata, DTI All dimensions in millim

HSL Project Number: Site: Date of measurements: Vehicle :

British Adult Male British Adult Female

Pedals Low force High force Pedals Min Max Min Max Measure pedal force accurately using a force dynamometer

Angle (degrees) 135 95 150 150 Alternatively simply place a 10kg weight on H point height 450 450 the pedals and note whether it moves them down H point to heel 650 990 Buttock to heel 791 1087

Accommodated leg length 836 1455 798 1106

Z Score -4.99 5.32 -5.61 -0.49 Z Score Z Score Corrected -2.34 2.34 -2.34 -0.49 Z Score Corrected

Percentile 0 100 0 31 Percentile

Required force < 100N (10kg) Required force < 100N Males between 0 and 100 percentile Females between can sit with the recommended knee angle (95 to 135 degrees) can sit with the recomm Required force > 100N (10kg) Required force > 100N Males between 0 and 31 percentile Females between can sit with the recommended knee angle (150 degrees) can sit with the recomm

Steering Gap A Gap B Gap A = Horizontal, wheel set as close to driver as possible and seat as far forwards as possible Steering

Top wheel - backrest 500 800 Gap B = Horizontal, wheel set as close to driver as possible and seat as for back as possible Top wheel Z Score -5.80 1.51 **although the reach zone ranges may be satisfied, the position of the pedals will Z Score

Z Score Corrected -2.34 1.51 primarilly determine the seat position and therefore the required wheel position / potential grip distances Z Score Corrected Percentile 0 93 Dimension used is Forward Grip Reach Percentile

The smallest male who can reach the far edge of the steering wheel is 0.00 percentile With the seat as far back as possible, a male of 93.00 percentile can reach the back of the steering wheel

380 500

Bottom wheel - backrest

Bottom wheel - backrest

Step 1. Set seat up so that small (5th %ile) male is in comfortable pedal zone (ideally approximately 110 degrees)(use spreadsheet cells to calculate position) then measure Gap A

Step 2. Set seat up so that large (95th %ile male) is in comfortable pedal zone - measure Gap B

Gap A Gap B Gap A = Horizontal, wheel set max dist from driver and seat for 5th %ile male Gap B = Horizontal, wheel set as close to driver as possible and seat set for 95th %ile driver Bot wheel

Z Score 0.70 6.70 **If wheel is not adjustable, do seat adjustments and take measurements Z Score Z Score Corrected 0.70 2.34 Dimension used is Back of elbow to grip Z Score Corrected

Percentile 75 100 Percentile

Small (5th %ile) drivers have adequate space available between the seat back and the near edge of the wheel when seating is adjusted If Gap B = <400mm adjust wheel to check that 400mm can be made available. If it can, clearance is adequate for most drivers if 400mm cannot be made available, some larger drivers may find there is not sufficient space between the wheel and the seat If Gap B = >400mm there is adequate clearance for larger drivers (but check they can reach the far edge of the wheel)

Gap A Gap B Gap A = vertical distance with seat in lowest pos and wheel fully raised Wheel to pan 500 200 Gap B = vertical distance when seat fully up and wheel fully raised Wheel to pan

Z Score 17.53 1.74 **must remember though that between these positions the potential gap may be much greater Z Score Z Score Corrected 2.34 1.74 Dimension used is thigh depth Z Score Corrected


With the seat in its lowest height setting, all drivers will have sufficient thigh clearance available With the seat at highest setting some larger drivers (Gap B %ile and above) may not have sufficient thigh clearance ** If the seat at highest setting potentially restricts the thigh clearance for larger drivers, consider whether the seat would actually be used in that position. Adjust the seat into a 95th %ile comfortable pedal zone position and measure the gap again. If it is greater than 198mm, the clearance is likely to be adequate during normal use for larger drivers

66

Gear Lever Min Max Measure distance between near shoulder point and the mid point of the gear lever grip Gear Lever

Seat to lever 700 800 Min shoulder point = 586mm above seat pan (& seat adjusted to 5%ile comfort pedal zone) Seat to lever Z Score -0.93 1.51 Max shoulder point = 683mm above seat pan (& seat adjusted to 95%ile comfort pedal zone) Z Score

Z Score Corrected -0.93 1.51 Dimension used is forward grip reach Z Score Corrected Percentile 17 93 Percentile

Some smaller drivers may have difficulty reaching the gear lever from a neutral posture Taller drivers should be able to reach the gear lever without difficulty

Hand Brake Min Max Measure distance between shoulder point and the mid point of the hand brake grip Hand Brake

Seat to lever 700 800 Min shoulder point = 586mm above seat pan (& seat adjusted to 5%ile comfort pedal zone) Seat to lever Z Score -0.93 1.51 Max shoulder point = 683mm above seat pan (& seat adjusted to 95%ile comfort pedal zone) Z Score

Z Score Corrected -0.93 1.51 Dimension used is forward grip reach Z Score Corrected Percentile 17 93 Percentile

Some smaller drivers may have difficulty reaching the hand brake from a neutral posture Taller drivers will be able to reach the gear lever without difficulty

Seat Min Max Measure height of seat pan edge above the surface that the heels rest on during driving Seat

Pan height 370 440 Pan height Z Score -2.93 -0.33 Z Score

Z Score Corrected -2.34 -0.33 Z Score Corrected Percentile 0 36 Percentile

Small drivers (5th %ile and smaller) should be able to adjust the seat to a comfortable height Some taller drivers (95%ile and above) will have difficulty adjusting the seat so that their legs can bend at approximately 95 degrees

Min Max Min and Max if appropriate (e.g. if back height can be adjusted) Pan depth 500 600 Pan depth

Z Score -0.49 2.37 Z Score Z Score Corrected -0.49 2.34 Z Score Corrected

Percentile 31 100 Percentile Pan width 390 399 Pan width

Z Score -0.10 0.19 Z Score Z Score Corrected -0.10 0.19 Z Score Corrected

Percentile 46 57 If any of these max. distances are calculated as < 95%ile, Percentile Back height 610 610 some larger drivers may not find the seat comfortable Back height

Z Score -0.83 -0.83 Z Score Z Score Corrected -0.83 -0.83 Z Score Corrected

Percentile 20 20 Percentile Back width 300 500 Back width

Z Score -1.25 5.89 high backrest not always useful, especially if drivers are turning around frequently Z Score Z Score Corrected -1.25 2.34 Z Score Corrected

Percentile 10 100 Percentile Head rest Head rest Sitting height 610 610 Sitting height

Z Score -8.61 -8.61 Z Score Z Score Corrected -2.34 -2.34 Z Score Corrected


It may be useful to build a simple 5th and 95th %ile leg (2 jointed lengths of wood) - taking into account shoe depth to make setting up the seat in approximate 5th and 95th %ile pedal comfort zones quiker and more straightforward A model like this could also incorporate joint angles (95, 135 and 150 degrees)

67

400 0

0 0 0

450 0 0

610 0 0

410 0 0

0810 0 0

Appendix B.2 Anthropometric spreadsheets for vehicles in study

WBV Anthropometric Design Assessments v4

Body dimensions taken from PeopleSize 2000 Professional Version 2.05

Project number: JR45083 Site: 1

Date of measurements: 21/04/2005 Vehicle: Renault tipper truck

British Adult Male British Adult Female Min. or Min. or Max Min Max Max Min Max Fixed Fixed

Pedals

Knee angle 135 ° 95 ° 160 ° 140 ° 135 ° 95 ° 160 ° 140 °

H-point vertical height 340 Projection of H-point to heel point (horizontal) 810 Accommodated hip to ankle distance 926

340 340 340 340 340 340 340 810 810 810 810 810 810 810 1166 867 910 926 1166 867 910

For light pedal force ( < 100N )male drivers above 88 percentile

and female drivers above 99 percentile may not have sufficient leg room to adopt a comfortable knee angle

For strong pedal force ( > 100N )male drivers above 1 percentile

and female drivers above 1 percentile may not have sufficient leg room to adopt a knee angle in the optimum range

400

Seat

Seat pan height at front (Dimension used: popliteal height)

Male drivers above 1 percentile and female drivers above 31 percentile should be able to place their feet on the floor while seated

Seat pan depth (front to back) (Dimension used: buttock to popliteal)

Male drivers below 1 percentile and female drivers below 1 percentile may find the seat pan too deep (front to back)

Seat pan width 450 (Dimension used: hip breadth)

Male drivers above and female drivers above

98 87

percentile percentile may find the seat pan too narrow

Back rest height (Dimension used: sitting shoulder height)

610

Male drivers above and female drivers above

19 85

percentile percentile will have a greater shoulder sitting height than the seat back

Back rest width (Dimension used: chest breath at nipple)

410

Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow

Head rest height 200 Sitting height 810

68

880 0 0

0 210 0

400

0 0 0

l 880 ( )

Steering

Top of seat back to top of steering wheeDimension used: forward grip reach

At the limits of adjustment males below 99 percentile, and females below 99 percentile may have difficulty reaching the far edge of the steering wheel

Seat pan to steering wheel (vertical) 210 (Dimension used: thigh depth)

With the seat at lowest height setting male drivers above 98 percentile may not have sufficient thigh clearance and female drivers above 98 percentile may not have sufficient thigh clearance

400 ( )

Gear Lever

Top left of seat back to top of gear lever Dimension used: forward grip reach

Male drivers below 1 percentile and female drivers below 1 percentile may have difficulty reaching the gear lever from a neutral posture

( )

Hand Brake

Top left of seat back to front of hand brake Dimension used: forward grip reach

Male drivers below 1 percentile and female drivers below 1 percentile may have difficulty reaching the hand brake from a neutral posture

69

470 0

0 0 0

470 0 0

570 0 0

500 0 0

0720 0 0

1




Date of measurements: 21/04/2005 Vehicle: Transit

British Adult Male British Adult Female

User Max Min Max User Max Min Max

Pedals

Knee angle 135 ° 95 ° 160 ° 140 ° 135 ° 95 ° 160 ° 140 °

H-point vertical height 520 520 520 520 520 520 520 520 Projection of H-point to heel point (horizontal) 790 790 790 790 790 790 790 790 Accommodated hip to ankle distance 999 1258 935 981 999 1258 935 981

For light pedal force ( < 100N ) male drivers above 99 percentile and female drivers above 99 percentile may not have sufficient leg room to adopt a comfortable knee angle

For strong pedal force ( > 100N ) male drivers above 2 percentile and female drivers above 19 percentile may not have sufficient leg room to adopt a knee angle in the optimum range

Seat

470 Seat pan height at front (Dimension used: popliteal height)


Seat pan depth (front to back) (Dimension used: buttock to popliteal)



Male drivers above 99 percentile and female drivers above 94 percentile may find the seat pan too narrow

Back rest height 570 (Dimension used: sitting shoulder height)

Male drivers above 1 percentile and female drivers above 34 percentile will have a greater shoulder sitting height than the seat back

Back rest width 500 (Dimension used: chest breath at nipple)


Head rest height 150 Sitting height 720 Percentile 1

70

950 0 0

0 330 0

770

730 0 0

i(Di i i )

Steering

Top of seat back to top of steer ng wheel 950 mens on used: forward gr p reach



With the seat in its lowest height setting, all male drivers will have sufficient thigh clearance available and all female drivers will have sufficient thigh clearance available

(Di i i )

Gear Lever

Top left of seat back to top of gear lever 770 mens on used: forward gr p reach


(Di i i )

Hand Brake

Top left of seat back to front of hand brake 730 mens on used: forward gr p reach


71

440 0

380 0 0

460 0 0

400 0 0

440 0 0

0400 0 0




Date of measurements: 01/11/2005 Vehicle: Yale counterbalance lift truck

British Adult Male British Adult Female Min. or Fixed Max Min Max Min. or

Fixed Max Min Max

Pedals

Knee angle 135 ° 95 ° 160 ° 140 ° 135 ° 95 ° 160 ° 140 °




Seat



Seat pan depth (front to back) 380 (Dimension used: buttock to popliteal)








Head rest height Sitting height 400

72

630 0 0

0 170 0

0

580 0 0

i(Di i i )

Steering





(Di i i )

Gear Lever

Top left of seat back to top of gear lever mens on used: forward gr p reach


(Di i i )

Hand Brake



73

350 0

485 0 0

520 0 0

610 0 0

530 0 0

0610 0 0




Date of measurements: 22/11/2005 Vehicle: Leyland DAF 55 tipper truck


Fixed Max Min Max

Pedals

Knee angle 135 ° 95 ° 160 ° 140 ° 135 ° 95 ° 160 ° 140 °




Seat











Head rest height Sitting height 610

74

900 0 0

0 230 0

590

500 0 0

i(Di i i )

Steering




With the seat in its lowest height setting, all male drivers will have sufficient thigh clearance available and all female drivers will have sufficient thigh clearance available

(Di i i )

Gear Lever



(Di i i )

Hand Brake



75

400 0

470 0 0

530 0 0

610 0 0

500 0 0

0830 0 0




Date of measurements: 22/11/2005 Vehicle: Open back transit van


Fixed Max Min Max

Pedals

Knee angle 135 ° 95 ° 160 ° 140 ° 135 ° 95 ° 160 ° 140 °




Seat











Head rest height 220 Sitting height 830

76

720 0 0

0 190 0

640

650 0 0

i(Di i i )

Steering





(Di i i )

Gear Lever



(Di i i )

Hand Brake



77

1.2

APPENDIX C. POSTURE ANALYSIS Appendix C.1 Video Proforma v.1 – Postures and Actions to identify and log

Ergonomics Section, HSL.

• Green text indicates a low risk posture unlikely to cause injury.

• Black text indicates a moderate risk posture that may cause injury to some operators if performed repetitively and with moderate to high force (relative to the muscle groups used).

• Red text indicates a high risk posture that may cause injury even through fairly low rates of repetition. These postures also present a high risk of injury if they are held static for a period significantly longer than would result from a dynamic action / movement.

Review the video and see when postures occur. It is more than likely that certain actions are associated with particular postures. If this is the case the posture can just be redefined as the action e.g. ‘Shoulder Abduction ⇒ Reaching for control lever’ or ‘Trunk Rotation ⇒ Talking to Passenger’ (to simplify the posture coding / logging process).

1.0 Trunk / Spine postures

• Measure amount of time backrest is in use

• Measure times & frequencies spent in the following (approximate) postures:

1.1 Flexion / Extension (leaning forwards and backwards respectively)

Neutral to Mild Flexion (0 to 20deg leaning forwards) Mild Flexion (20 to 45deg with full trunk support) *Moderate Flexion (20 to 60deg without trunk support) *Severe Flexion (>60deg) *- Severe and Moderate angles approaching 60 deg are likely to be a particularly high risk if held for over 1 minute

Supported Extension (<0deg – leaning backwards) Un-supported Extension(<0deg)

Lateral Bending (leaning from side-to-side)

Neutral to Moderate (0 to 20deg either side) Severe* (>20 deg) * - Severe if performed frequently as a ‘normal’ part of the vehicle operation

79

1.3 Twisting (rotation around the spines axis)

Neutral to Moderate (0 to 20 deg) Severe* (>20deg)

* - Severe if performed frequently as a ‘normal’ part of the vehicle operation. Also a particular problem if the seat has a high backrest as this will prevent the shoulders and the upper trunk rotating as easily, thus leading to greater strain in the lower back.

• Identify when a jolt has caused the back to leave the backrest – this should be noted differently to a posture that is held deliberately for a period of time.

2.0 Neck

• Measure durations and frequencies of:

2.1 Flexion and Extension

Neutral to Mild Flexion (0 to 25deg - forwards tilt) Moderate Flexion (25 to 45deg) Severe Flexion (>45deg)

Extension (<0deg - backwards tilt)

2.2 Twisting (rotation to look sideways)

2.2.1 For repetitive movements (every few seconds or as part of a work cycle repeated more than twice per minute over 2 hours per day / >1/3 of work period)

Acceptable / Mild (0 to 15deg) Moderate (15 to 45deg) Severe (>45deg)

80

2.2.2 For non-repetitive movements

Acceptable / Mild (0 to 30deg) Moderate (30 to 60deg) Severe (>60deg)

3.0 Head

• Measure durations and frequencies of:

Neutral to Mild Flexion (0 to 25deg – forwards tilt) Moderate Flexion (25 to 85deg) Severe Flexion (>85deg)

Extension (<0deg – backwards tilt)

4.0 Hand / Arm Postures and Movements

4.1 Side to side Hand Movements

Ulnar deviation (>24deg sideways toward little finger) Radial deviation (>15deg sideways toward thumb)

4.2 Up and Down Hand Movements

Extension (>50deg bending hand up / backwards) Flexion (>45deg bending hand down / forwards)

4.3 Shoulder Movements

Abduction (>70 deg lifting elbow sideways and up)

81

4.4 Movement Frequencies

For a quick and initial assessment of risk refer to table 1 below. However, it should be remembered that these figures are meant to be a risk ‘threshold’ for tasks repeated continuously and fairly rhythmically for more than 2 hours per day or over 1/3 of the working period.

For short periods and providing there are adequate rest periods these frequencies may not present a significant risk. In addition, the levels of risk are greatly dependent on the extent of the motions and the forces that they apply, larger motions and higher forces = higher risk of injury:

Table 1. Frequency rates for high risk to the upper extremities. Upper Extremities Potential high risk movement

frequencies Shoulder >2.5 / minute Upper arm >10 / minute Forearm / wrist >10 / minute Finger >200 / minute

5.0 Additional considerations

5.1 Force If the force of operators’ movements is considered to be a factor that is contributing significantly to the injury risk, it would be useful to get advice from the Ergonomics section. Risk associated with force is dependant on the muscle groups being used, in combination with the postures adopted.

Note in particular the postures associated with the following operations (if relevant) • Vehicle / tasks specific visibility issues (e.g. in RoRo tugs) • Reversing the vehicle • Ingress / Egress (especially if frequent) • Reaching to any hand / foot controls or a back-seat etc. • Any in-vehicle non-driving tasks (e.g. attending to passengers, communications tasks)

5.2 Interactions between postural risk factors

There may be situations when two or more postural risk factors occur simultaneously. Postural risk factors coud also be combined with environmental risks such as extremes of temperature or shocks / jolts. Interactions like this should be noted specifically.

5.3 Leg postures

These should be assessed primarily using the spreadsheet tool.

6.0 References

ISO 11226:2000(E) – Ergonomics – Evaluation of Static Working Postures

Zacharkow (Ed). Posture: Sitting, Standing, Chair Design & Exercise. Charles C Thomas Publisher. USA.

82

Keyserling et al (1992). A checklist for evaluating ergonomic risk factors resulting from awkward postures of the legs, trunk and neck. International Journal of Industrial Ergonomics. 9. pp283-301.

Bergamasco, R et al (1998) Guidelines for designing jobs featuring repetitive tasks. Ergonomics. 41(9). Pp1364-1383

6.0 Possible Recording Methods

** Take stills of movements / postures at known angles (before or after the actual videorecording). **Put markers on points around the cab so that degrees etc can be better extimated.

83

Appendix C.2 Comments received from Ergonomist (Liz Yeomans MSc) applying Video Proforma V.1 to forklift truck video

Difficulties experienced using the Pro froma:

Trunk Postures Backrest contact time? Is this being measured via a pressure pad?If not, it’s not easy to ascertain from video. Full trunk support? Not sure I understand this. Does this refer to whether the back is in contact with the backrest? If so, then how can you have a posture with 20-45º trunk flexion and full trunk support? Or does it refer to lateral support?

RULA/REBA use 0-20º, >20 -60º, >60º as trunk flexion.

Lateral bending – what’s “frequently”? Is this more than twice per minute? RULA/REBA don’t specify angles but adds 1 to score for twisted or lateral flexion oftrunk.

Neck Posture Most of the literature (including HSG60) doesn’t distinguish between head and neck flexion. From video it’s very difficult to separate neck and head flexion especially where the subject is turning. For these purposes I would question whether “head flexion” is necessary.

There’s only limited research consensus on the recommended limits for neck flexion so the flexion bands used in the posture analysis appear to be rather arbitrary. Estimating neck/head flexion during rotating actions (such as looking behind when reversing the vehicle) is particularly difficult.

Neck flexion – REBA/RULA use 0-20º and >20º with +1 for any rotation or lateral flexion.

Neck Rotation (probably better described as head rotation).

Hand /Arm Postures Usually broken down into upper arms, lower arms and wrists Not sure why the traffic light system has been lost here.

Ulnar deviation – high risk usually considered if >45º rather than 85ºRULA/REBA add 1 to score for any radial or ulnar deviation

Wrist Flexion/Extension – Not sure where 50/45º comes from.RULA/REBA uses 0-15º and >15º.

Shoulder Movements – Not sure why only abduction is considered here. RULA/REBA adds 1 to score for any abduction.

Lower arm not considered at all?

84

Analysis of fork lift truck video (img_0129.jpeg)

Reversing Posture

Video proforma v.1 REBA RULA OWAS

Trunk flex Green 2 1 4 Trunk bend Green 0 Trunk twist Severe +1 +1 Neck flex ? Moderate 2 3 Neck twist Severe +1 +1 Head flex ? not sure -Wrist dev ? 0 Wrist flex/ext ? 1 1 Upper arm abd - 0 Upper arm flex/ext 2 2 1 Lower arm flex 2 1 Legs 1 1 Load 0 0 1

Action level 1 Action level 2 Action Low risk – Further category 2 action may be investigation Corrective necessary soon measure in

near future

REBA – Rapid Entire Body Assessment RULA – Rapid Upper Limb Assessment OWAS – Ovako Working Posture Analysis System Louhevaara V, Suurnäkki T. 1992. OWAS: a method for the evaluation of postural load during work. Institute for Occupational Health and Centre for Occupational Safety, Helsinki, p23.

General comments

I found it difficult to estimate postural angles of such narrow bandwidth from the video/photos provided. I was happier to estimate using the broader category of angles in RULA/REBA.

I was initially quite confused over the difference between neck flexion and head flexion. It’s not usual to distinguish the two in postural analysis from video.

Awkward Postures Identified from Holdsworth Video

When I reviewed the tape, I identified 3 awkward (non-neutral) postures: 1. Reversing the vehicle

Looking over left of right shoulder whilst reversing. In a cycle lasting 72 seconds, this posture was adopted on three occasions and held each time for 3 seconds. In the 60-second cycle, it was adopted 5 times and held for 2 seconds each time.

2. Bending to unload Bending the trunk and neck to check whether the forks are aligned with the pallet slots during unload from the lorry. This posture was adopted once and held for 2 seconds in a 60-second cycle.

85

3. Lateral bend Bending the trunk to the side in order to see the position of the pallet when loading into the lorry. In a 72-second cycle, this posture was adopted once and held for 4 seconds: in the following 60-second cycle it was adopted once and held for 7 seconds.

Assuming that the operator carried out this work for 8 hours a day, he/she wouldn’t exceed 2 hours a day in any of these postures. However, the reversing posture involves twisting the head and this is carried out 3-5 times per minute which could be considered repetitive. Whether it is part of a work cycle that is repeated more than twice per minute depends on how you define the work cycle in this task.

Photograph C.1 (img 0129.jpeg) Reversing posture.

Published by the Health and Safety Executive 01/08


Whole-body vibration and ergonomics toolkit Phase 1 The exact cause of back pain is often unclear but back pain is more common in jobs that involve certain tasks, one of which is driving. Driving exposes the vehicle’s occupants to whole-body vibration and in some cases shocks and jolts, factors which are believed to increase the likelihood of injury or pain in the lower back. The report describes a whole-body vibration and ergonomics toolkit that has been developed for use in assessing driving occupations.


n to provide a guide on how to approach the control of back pain due to occupational exposure to whole-body vibration and ergonomic risk factors;

n to invite recommendations on how the toolkit detailed in the report can be improved for the vehicles and occupations of interest; and

n to provide a specification for future whole-body vibration data collection activities.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the author alone and do not necessarily reflect HSE policy.

RR612

www.hse.gov.uk

whole-body vibration and ergonomics toolkit - phase 1 · pdf fileexecutive health and safety...

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