Whole-body vibration and ergonomics toolkit

Transcription

1 Health and Safety Executive Whole-body vibration and ergonomics toolkit Phase Prepared by the Health and Safety Laboratory for the Health and Safety Executive 28 RR62 Research Report

2 Health and Safety Executive Whole-body vibration and ergonomics toolkit Phase A M Darby BSc(Hons) MSc CPhys MInsP Health and Safety Laboratory Harpur Hill Buxton SK7 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 n 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; to invite recommendations on how the toolkit detailed in the report can be improved for the vehicles and occupations of interest; and 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

3 Crown copyright 28 First published 28 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, 2-6 Colegate, Norwich NR3 BQ or by to hmsolicensing@cabinet-office.x.gsi.gov.uk ii

4 CONTENTS INTRODUCTION.... Background....2 Development of the toolkit Aims of the report TOOLKIT - WHOLE-BODY VIBRATION... 3 TOOLKIT - ANTHROPOMETRIC DESIGN ASSESSMENT Taking measurements Calculating percentile ranges Suitability of the cab for a specific operator... 4 TOOLKIT - POSTURE ASSESSMENT... TOOLKIT - MANUAL HANDLING ASSESSMENT... 6 TOOLKIT - MUSCULOSKELETAL DISORDERS QUESTIONNAIRE FUTURE WORK REFERENCES APPENDICES... 2 APPENDIX A. VIBRATION DATA FOR VEHICLES IN STUDY APPENDIX B. ANTHROPOMETRIC PROFORMAE AND SPREADSHEETS 6 APPENDIX C. POSTURE ANALYSIS iii

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6 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. The objectives 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 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. v

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8 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 23/24 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 2; 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 o whole-body vibration data acquisition and analysis system; 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

9 o o o employed; HSE s Manual handling Assessment Charts (MAC) to rate severity of manual handling tasks; video analysis to assess postures and frequency of adoption; and a questionnaire (based on the validated Nordic questionnaire) recording self-reported musculoskeletal disorders (MSDs)..2 DEVELOPMENT OF THE TOOLKIT Phase 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..2. 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 263-:997) for each channel and spine response data (ISO 263-:24). In addition the analysis software now produces resampled time history and cumulative Vibration Dose Value plots for each channel of data..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 2

10 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 8 to 6 year old males and UK 8 to 6 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..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.. 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. 993), REBA (Rapid Entire Body Assessment tool) (Hignett, S. and McAtamney, L. 2) and OWAS (Ovako Working posture Analysis System) ( 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..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..2. 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..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. 3

11 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 of the project progressed, so that the full toolkit was not used on the earlier vehicles.) 4

12 2 TOOLKIT - WHOLE-BODY VIBRATION The vibration levels should be measured on the seat pan in the three orthogonal directions shown in Figure : o x-axis fore-aft relative to the seat o y-axis across (side-to-side) the seat o z-axis vertical X Z Y Figure. 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 3 minutes, or at least three cycles for cyclical work such as transporting material from a quarry face to a crusher (Darby, A. 2). The vibration exposure duration of the operator for the working day should be recorded. All measurements must be made in accordance with ISO 263:997. 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 263-:997); o VDV (ISO 263-:997); o evdv (ISO 263-:997); o crest factor (defined as the frequency weighted peak / frequency weighted r.m.s.) (ISO 263-:997); o MTVV linear (ISO 263-:997); o MTVV exponential (ISO 263-:997). 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 2; o VDV exposure for the working day (VDV exp );

13 o the working time to reach a daily VDV exposure of 7 m/s.7 (HSE s criterion for risk including significant shock exposure adopted from ISO 263-:997); o H frequency response spectrum between the seat base and seat pan for each axis and associated coherence; o Spine response parameters (ISO 263-:24); 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 imply amplification of vibration by the suspension system, values less than 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. 6

14 3 TOOLKIT - ANTHROPOMETRIC DESIGN ASSESSMENT 3. 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 mm are acceptable. Table 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 N) and an optimum knee angle for a strong pedal force (greater than N). 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 7

15 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. 8

16 Table. Vehicle Cab Anthropometric Assessment Proforma v. 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 ().. 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. 9

17 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. 8 to 6 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 is th 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 = 79 mm, min = 69 mm Forward grip reach adult male mean = 738 mm, SD = 4 mm Max z = (79 738) / 4 =.27 p = 9 th Min z = (69 738) / 4 = -.7 p = 2 th The accommodated population range is therefore 2 th to 9 th 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 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. 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..

18 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. 993). 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. 993) 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. 993) is then used to find the grand score from scores C and D. The grand score gives the action level, where: Action level is given by a grand score of 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 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.

19 A Upper arm Task: Lower arm Using Table A Posture score A Wrist + Muscle + Force = Score C Wrist twist Using Table C Grand score 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 ), and it produced an action level of 2. 2

20 A 2 Task: Fork lift truck driver (reversing) Using Table A Posture score A = 2 Using Table C 4 B 4 Using Table B Posture score B = Figure 4. RULA scoring sheet for reversing posture (forklift truck driver) Figure. Reversing posture 3

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22 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 ( 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 ) a colour band (green, amber, red or purple) is given to each factor. Figure (a). Lifting Operation Assessment Guide (I) (HSE MAC tool)

23 Figure (b). Lifting Operation Assessment Guide (II) (HSE MAC tool) 6

24 Figure (c). Lifting Operation Guide (III) (HSE MAC tool) The colour code is then entered into the MAC score sheet.(figure 6). 7

25 Figure 6. MAC Score Sheet (HSE MAC tool). 8

26 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) 9

27 Figure 7(b). HSL Musculoskeletal Disorders Questionnaire (II) 2

28 7 FUTURE WORK Phase 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 2 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. 2

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30 8 REFERENCES. European Parliament and the Council of the European Union (22) Official Journal of the European Communities Directive 22/44/EC on the minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (vibration). OJ L77, , p3. 2. Control of Vibration at Work Regulations 2, ISBN , Statutory Instrument 2 No 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 3 th July 2 4. Hignett, S. and McAtamney, L. Rapid Entire Body Assessment (REBA) Applied Ergonomics 2, 3, 2-2. ISO 326-:992 Mechanical vibration - Laboratory method for evaluating vehicle seat vibration -- Part : Basic requirements 6. ISO 263-:997 Mechanical vibration and shock -- Evaluation of human exposure to whole-body vibration -- Part : General requirements 7. ISO 263-:24 Mechanical vibration and shock -- Evaluation of human exposure to whole-body vibration -- Part : Method for evaluation of vibration containing multiple shocks 8. McAtamney, L. and Corlett, E. N. Rula a survey method for the investigation of workrelated upper limb disorders. Applied Ergonomics 993, 24(2), and (manual handling). (OWAS) 23

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32 APPENDICES 2

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34 APPENDIX A. VIBRATION DATA FOR VEHICLES IN STUDY Appendix A. Site visit Equipment Item Type Serial number or Section ID (w/o nitrile Transducer B&K pad) Transducer B&K Calibrator B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Data recorder TEAC RD3T 7237 Analysis system Pulse Analysis system MatLab Program vdv2_4 Figure A. Tipper truck 27

35 Site/meas. no. / Vehicle: Renault 37 dci (tipper truck) Measurement date: 2/2/2 Seat: ISRI, no model number Tape/ID no: /8 self adjusting air suspension Analysis length : 2 seconds Task: Depot to construction site to golf course Freq. increment:.2 Hz (transporting soil) RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS).2.6. SEAT factor (VDV)..6.6 Exposure duration: 9:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).47 (z direction) Time to action value :4:47 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ).9 (x direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

36 Site/meas. no. / Measurement date: 2/2/2 Tape/ID no: /8 Vehicle: Renault 37 dci (tipper truck) Seat: ISRI, no model number Freq. increment:.2 Hz x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response x coherence. Coherence.... Acc. PSD (m/s²)²/hz... y seat y seat base Magnitude. y frequency response y coherence. Coherence.... Acc. PSD (m/s²)²/hz... z seat z seat base Magnitude. z frequency response z coherence. Coherence

37 Site/meas. no. / Vehicle: Renault 37 dci (tipper truck) x seat y seat z seat x base y base z base x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 3

38 Site/meas. no. /2 Vehicle: Renault 37 dci (tipper truck) Measurement date: 2/2/2 Seat: ISRI, no model number Tape/ID no: 2/ self adjusting air suspension Analysis length : 2 seconds Task: Golf course to Paddington to golf course Freq. increment:.2 Hz (transporting soil) RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)..6.3 SEAT factor (VDV) Exposure duration: 9:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).9 (z direction) Time to action value 6:22:4 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 3.9 (z direction) Time to 7 m/s.7 9::3 Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

39 Site/meas. no. /2 Measurement date: 2/2/2 Tape/ID no: 2/ Vehicle: Renault 37 dci (tipper truck) Seat: ISRI, no model number Freq. increment:.2 Hz x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response. Coherence x coherence.... Acc. PSD (m/s²)²/hz... y seat y seat base Magnitude. y frequency response y coherence. Coherence.... Acc. PSD (m/s²)²/hz... z seat z seat base Magnitude. z frequency response z coherence. Coherence

40 Site/meas. no. /2 Vehicle: Renault 37 dci (tipper truck) x seat y seat z seat x base y base z base x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 33

41 Site/meas. no. /3 Vehicle: Renault 37 dci (tipper truck) Measurement date: 2/2/2 Seat: ISRI, no model number Tape/ID no: 2/2 self adjusting air suspension Analysis length : 9 seconds Task: Golf course to Paddington Freq. increment:.2 Hz (empty) RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)...3 SEAT factor (VDV) Exposure duration: 9:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).67 (z direction) Time to action value 4:8: Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 2.4 (z direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

42 Site/meas. no. /3 Measurement date: 2/2/2 Tape/ID no: 2/2 Vehicle: Renault 37 dci (tipper truck) Seat: ISRI, no model number Freq. increment:.2 Hz x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response x coherence. Coherence.... Acc. PSD (m/s²)²/hz... y seat y seat base Magnitude. y frequency response y coherence. Coherence.... Acc. PSD (m/s²)²/hz... z seat z seat base Magnitude. z frequency response z coherence. Coherence.... 3

43 Site/meas. no. /3 Vehicle: Renault 37 dci (tipper truck) x seat y seat z seat x base y base z base x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 36

44 Appendix A.2 Site visit 2 Equipment Item Type Serial number or Section ID (w/o nitrile Transducer B&K pad) Transducer B&K Calibrator B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Data recorder TEAC RD3T 7327 Analysis system Pulse Analysis system MatLab Program vdv2_4 Figure A.2 Transit van 37

45 Site/meas. no. 2/ Vehicle: VW Diesel Transit LT3 TDi Measurement date: 2/4/2 Seat: Conventional, no identification Tape/ID no: /9 Analysis length : 246 seconds Task: Driving from HSL, Buxton to Freq. increment:.2 Hz edge of Newcastle-under-Lyme RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)... SEAT factor (VDV)..2. Exposure duration: :: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).34 (z direction) Time to action value :47:9 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 9.3 (z direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

46 Site/meas. no. 2/ Measurement date: 2/4/2 Tape/ID no: /9 Vehicle: VW Diesel Transit LT3 TDi Seat: Conventional, no identification Freq. increment:.2 Hz x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response. Coherence... x coherence. y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence

47 Site/meas. no. 2/ Vehicle: VW Diesel Transit LT3 TDi x seat y seat z seat x base y base z base x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 4

48 Appendix A.3 Site visit 3 Equipment Item Type Serial number or Section ID (w/o nitrile Transducer B&K pad) Transducer B&K Calibrator B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Data recorder TEAC RD3T 7327 Analysis system Pulse Analysis system MatLab Program vdv2_4 Figure A.3 Fork lift truck Figure A.4 Fork lift truck (cab) 4

49 Site/meas. no. 3/ Vehicle: Yale 32 counterbalance lift truck Measurement date: 2//2 Seat: Conventional, no identification Tape/ID no: /6 Analysis length : 28 seconds Task: Driving round yard Freq. increment:.2 Hz RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS) SEAT factor (VDV) Exposure duration: 4:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).49 (z direction) Time to action value 4::42 Time to limit value 2:39:48 VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 4. (z direction) Time to 7 m/s.7 8:27:2 Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

50 Site/meas. no. 3/ Measurement date: 2//2 Tape/ID no: /6 Vehicle: Yale 32 counterbalance lift truck Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat.. Acc. PSD (m/s²)²/hz... y seat.. Acc. PSD (m/s²)²/hz... z seat.. 43

51 Site/meas. no. 3/ Vehicle: Yale 32 counterbalance lift truck x seat y seat z seat x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 44

52 Site/meas. no. 3/2 Vehicle: Yale 32 counterbalance lift truck Measurement date: 2//2 Seat: Conventional, no identification Tape/ID no: /7 Analysis length : 29 seconds Task: Simulated loading and unloading Freq. increment:.2 Hz RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS) SEAT factor (VDV) Exposure duration: 4:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).27 (x direction) Time to action value 3:3:46 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 8.2 (x direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

53 Site/meas. no. 3/2 Measurement date: 2//2 Tape/ID no: /7 Vehicle: Yale 32 counterbalance lift truck Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat.. Acc. PSD (m/s²)²/hz... y seat.. Acc. PSD (m/s²)²/hz... z seat.. 46

54 Site/meas. no. 3/2 Vehicle: Yale 32 counterbalance lift truck x seat y seat z seat x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 47

55 Appendix A.4 Site visit 4 Equipment Item Type Serial number or Section ID (w/o nitrile Transducer B&K pad) Transducer B&K Transducer B&K (borrowed from L. Beirne) Calibrator B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Data recorder TEAC RD3T 7327 Analysis system Pulse Analysis system MatLab Program vdv2_4 Force gauge Mecmesin Advanced Force Gauge KN33266 Figure A. Road repair depot tipper truck () Figure A.6 Road repair depot tipper truck (2) 48

56 Site/meas. no. 4/ Vehicle: Leyland DAF tipper truck (Y746 HKY) Measurement date: 22//2 Seat: Conventional, no identification Tape/ID no: / Analysis length : seconds Task: Driving from depot at Chapel-en-le-Frith Freq. increment:.2 Hz to Goyt valley RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS).9.2. SEAT factor (VDV) Exposure duration: 6:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).6 (z direction) Time to action value 4::39 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 7.4 (z direction) Time to 7 m/s.7 :2: Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

57 Site/meas. no. 4/ Measurement date: 22//2 Tape/ID no: / Vehicle: Leyland DAF tipper truck (Y746 HKY) Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat back.. x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response. Coherence x coherence.... y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence....

58 Site/meas. no. 4/ Vehicle: Leyland DAF tipper truck (Y746 HKY) x seat y seat z seat x base y base z base x back x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 )

59 Site/meas. no. 4/2 Vehicle: Leyland DAF tipper truck (Y746 HKY) Measurement date: 22//2 Seat: Conventional, no identification Tape/ID no: /2 Analysis length : seconds Task: Driving from Goyt valley to tipping area Freq. increment:.2 Hz RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)..2. SEAT factor (VDV)..2. Exposure duration: 6:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).3 (z direction) Time to action value :23:3 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 2.4 (z direction) Time to 7 m/s.7 2:2:26 Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

60 Site/meas. no. 4/2 Measurement date: 22//2 Tape/ID no: /2 Vehicle: Leyland DAF tipper truck (Y746 HKY) Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat back.. x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response. Coherence x coherence.... y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence.... 3

61 Site/meas. no. 4/2 Vehicle: Leyland DAF tipper truck (Y746 HKY) x seat y seat z seat x base y base z base x back x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 4

62 Site/meas. no. 4/3 Vehicle: Leyland DAF tipper truck (Y746 HKY) Measurement date: 22//2 Seat: Conventional, no identification Tape/ID no: /2 Analysis length : 8 seconds Task: Dumping load and driving from tipping area Freq. increment:.2 Hz to Goyt valley RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)..2. SEAT factor (VDV)..2.3 Exposure duration: 6:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²). (z direction) Time to action value 4:3:3 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ).9 (z direction) Time to 7 m/s.7 7:48:7 Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

63 Site/meas. no. 4/3 Measurement date: 22//2 Tape/ID no: /2 Vehicle: Leyland DAF tipper truck (Y746 HKY) Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat back.. x seat Acc. PSD (m/s²)²/hz... x seat base Magnitude. x frequency response x coherence. Coherence.... y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence.... 6

64 Site/meas. no. 4/3 Vehicle: Leyland DAF tipper truck (Y746 HKY) x seat y seat z seat x base y base z base x back x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 7

65 Appendix A. Site visit Equipment Item Type Serial number or Section ID (w/o nitrile Transducer B&K pad) Transducer B&K Transducer B&K (borrowed from L. Beirne) Calibrator B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Charge amplifier B&K Data recorder TEAC RD3T 7237 Analysis system Pulse Analysis system MatLab Program vdv2_4 Figure A.7 Flat back transit van () Figure A.8 Flat back transit van (2) 8

66 Site/meas. no. / Vehicle: Ford transit LF 3 (Y99 PHL) Measurement date: 3//2 Seat: Conventional, no identification Tape/ID no: /8 Analysis length : 9 seconds Task: Driving from depot at Chapel-en-le-Frith to check Freq. increment:.2 Hz road works at Bamford RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS).2.2. SEAT factor (VDV)..3. Exposure duration: 6:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).32 (z direction) Time to action value 4:3:38 Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 7.4 (z direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

67 Site/meas. no. / Measurement date: 3//2 Tape/ID no: /8 Vehicle: Ford transit LF 3 (Y99 PHL) Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat back.. Acc. PSD (m/s²)²/hz... x seat x seat base Magnitude. x frequency response x coherence. Coherence.... y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence.... 6

68 Site/meas. no. / Vehicle: Ford transit LF 3 (Y99 PHL) x seat y seat z seat x base y base z base x back x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 6

69 Site/meas. no. /2 Vehicle: Ford transit LF 3 (Y99 PHL) Measurement date: 3//2 Seat: Conventional, no identification Tape/ID no: /9 Analysis length : seconds Task: Driving from road works at Bamford to depot Freq. increment:.2 Hz at Chapel-en-le-Frith RMS (m/s²) (Unweighted) RMS (m/s²) (ISO 263-:997) VDV (m/s.7 ) (ISO 263-:997) evdv (m/s.7 ) (ISO 263-:997) Crest factor (ISO 263-:997) MTVV linear (m/s²) (ISO 263:997) MTVV exp. (m/s²) (ISO 263:997) Seat Seat base Seat back x y z x y z x SEAT factor (RMS)..3. SEAT factor (VDV).9.3. Exposure duration: 6:: A(8) value for comparison with the exposure action (. m/s² A(8)) and limit (. m/s² A(8)) values in the Control of Vibration at Work Regulations 2 A(8) (m/s²).28 (z direction) Time to action value 9:47: Time to limit value > 24 hrs VDV for comparison with HSE's criterion for significance of shock VDVexp (m/s.7 ) 6. (z direction) Time to 7 m/s.7 > 24 hrs Spine response data for comparison with the criterion set out in ISO 263-:24, R <.8 low probability of an adverse health effect, R >.2 high probability of an adverse health effect Dx Dy Dz Sed (m/s 2 ) (m/s 2 ) (m/s 2 ) (MPa) R Age (yrs)

70 Site/meas. no. /2 Measurement date: 3//2 Tape/ID no: /9 Vehicle: Ford transit LF 3 (Y99 PHL) Seat: Conventional, no identification Freq. increment:.2 Hz Acc. PSD (m/s²)²/hz... x seat back.. Acc. PSD (m/s²)²/hz... x seat x seat base Magnitude. x frequency response x coherence. Coherence.... y seat Acc. PSD (m/s²)²/hz... y seat base Magnitude. y frequency response y coherence. Coherence.... z seat Acc. PSD (m/s²)²/hz... z seat base Magnitude. z frequency response z coherence. Coherence

71 Site/meas. no. /2 Vehicle: Ford transit LF 3 (Y99 PHL) x seat y seat z seat x base y base z base x back x-axis: time (minutes) y-axis (left): unweighted accel. (m/s²) y-axis (right): cumulative VDV (m/s.7 ) 64

72 APPENDIX B. ANTHROPOMETRIC PROFORMAE AND SPREADSHEETS Appendix B. 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 6

73 Anthropometric Cab Design Assessment for Driving Occupations Version.2 Body dimensions taken from Peebles & Norris, 998, 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 Min Max Min Max Measure pedal force accurately using a force dynamometer Angle (degrees) 3 9 Alternatively simply place a kg weight on H point height 4 4 the pedals and note whether it moves them down H point to heel 6 99 Buttock to heel Pedals Accommodated leg length Z Score Z Score Z Score Corrected Z Score Corrected Percentile 3 Percentile Required force < N (kg) Required force < N Males between and percentile Females between can sit with the recommended knee angle (9 to 3 degrees) can sit with the recomm Required force > N (kg) Required force > N Males between and 3 percentile Females between can sit with the recommended knee angle ( 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 8 Gap B = Horizontal, wheel set as close to driver as possible and seat as for back as possible Top wheel Z Score -.8. **although the reach zone ranges may be satisfied, the position of the pedals will Z Score Z Score Corrected primarilly determine the seat position and therefore the required wheel position / potential grip distances Z Score Corrected Percentile 93 Dimension used is Forward Grip Reach Percentile The smallest male who can reach the far edge of the steering wheel is. percentile With the seat as far back as possible, a male of 93. percentile can reach the back of the steering wheel Bottom wheel - backrest Step. Set seat up so that small (th %ile) male is in comfortable pedal zone (ideally approximately degrees) (use spreadsheet cells to calculate position) then measure Gap A Step 2. Set seat up so that large (9th %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 th %ile male Bottom wheel - backrest 38 Gap B = Horizontal, wheel set as close to driver as possible and seat set for 9th %ile driver Bot wheel Z Score **If wheel is not adjustable, do seat adjustments and take measurements Z Score Z Score Corrected Dimension used is Back of elbow to grip Z Score Corrected Percentile 7 Percentile Small (th %ile) drivers have adequate space available between the seat back and the near edge of the wheel when seating is adjusted If Gap B = <4mm adjust wheel to check that 4mm can be made available. If it can, clearance is adequate for most drivers if 4mm cannot be made available, some larger drivers may find there is not sufficient space between the wheel and the seat If Gap B = >4mm 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 2 Gap B = vertical distance when seat fully up and wheel fully raised Wheel to pan Z Score **must remember though that between these positions the potential gap may be much greater Z Score Z Score Corrected Dimension used is thigh depth Z Score Corrected Percentile 9 Percentile 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 9th %ile comfortable pedal zone position and measure the gap again. If it is greater than 98mm, the clearance is likely to be adequate during normal use for larger drivers 66

74 Gear Lever Min Max Measure distance between near shoulder point and the mid point of the gear lever grip Gear Lever Seat to lever 7 8 Min shoulder point = 86mm above seat pan (& seat adjusted to %ile comfort pedal zone) Seat to lever Z Score Max shoulder point = 683mm above seat pan (& seat adjusted to 9%ile comfort pedal zone) Z Score Z Score Corrected Dimension used is forward grip reach Z Score Corrected Percentile 7 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 7 8 Min shoulder point = 86mm above seat pan (& seat adjusted to %ile comfort pedal zone) Seat to lever Z Score Max shoulder point = 683mm above seat pan (& seat adjusted to 9%ile comfort pedal zone) Z Score Z Score Corrected Dimension used is forward grip reach Z Score Corrected Percentile 7 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 Pan height Z Score Z Score Z Score Corrected Z Score Corrected Percentile 36 Percentile Small drivers (th %ile and smaller) should be able to adjust the seat to a comfortable height Some taller drivers (9%ile and above) will have difficulty adjusting the seat so that their legs can bend at approximately 9 degrees Min Max Min and Max if appropriate (e.g. if back height can be adjusted) Pan depth 6 Pan depth Z Score Z Score Z Score Corrected Z Score Corrected Percentile 3 Percentile Pan width Pan width Z Score -..9 Z Score Z Score Corrected -..9 Z Score Corrected Percentile 46 7 If any of these max. distances are calculated as < 9%ile, Percentile Back height 6 6 some larger drivers may not find the seat comfortable Back height Z Score Z Score Z Score Corrected Z Score Corrected Percentile 2 2 Percentile Back width 3 Back width Z Score high backrest not always useful, especially if drivers are turning around frequently Z Score Z Score Corrected Z Score Corrected Percentile Percentile Head rest Head rest Sitting height 6 6 Sitting height Z Score Z Score Z Score Corrected Z Score Corrected Percentile Percentile It may be useful to build a simple th and 9th %ile leg (2 jointed lengths of wood) - taking into account shoe depth to make setting up the seat in approximate th and 9th %ile pedal comfort zones quiker and more straightforward A model like this could also incorporate joint angles (9, 3 and degrees) 67

75 Appendix B.2 Anthropometric spreadsheets for vehicles in study WBV Anthropometric Design Assessments v4 Body dimensions taken from PeopleSize 2 Professional Version 2. Project number: JR483 Site: Date of measurements: 2/4/2 Vehicle: Renault tipper truck Min. or Fixed British Adult Male Max Min Max Min. or Fixed British Adult Female Max Min Max Pedals Knee angle H-point vertical height Projection of H-point to heel point (horizontal) Accommodated hip to ankle distance For light pedal force ( < N ) 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 ( > N ) male drivers above percentile and female drivers above percentile may not have sufficient leg room to adopt a knee angle in the optimum range Seat Seat pan height at front 4 4 (Dimension used: popliteal height) Male drivers above percentile and female drivers above 3 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 percentile and female drivers below percentile may find the seat pan too deep (front to back) Seat pan width 4 4 (Dimension used: hip breadth) Male drivers above 98 percentile and female drivers above 87 percentile may find the seat pan too narrow Back rest height 6 6 (Dimension used: sitting shoulder height) Male drivers above 9 percentile and female drivers above 8 percentile will have a greater shoulder sitting height than the seat back Back rest width 4 4 (Dimension used: chest breath at nipple) Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow Head rest height 2 Sitting height

76 Steering Top of seat back to top of steering wheel (Dimension 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) 2 2 (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 Gear Lever Top left of seat back to top of gear lever 4 4 (Dimension used: forward grip reach) Male drivers below percentile and female drivers below 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 percentile and female drivers below percentile may have difficulty reaching the hand brake from a neutral posture 69

77 WBV Anthropometric Design Assessments v4 Body dimensions taken from PeopleSize 2 Professional Version 2. Project number: JR483 Site: 2 Date of measurements: 2/4/2 Vehicle: Transit British Adult Male British Adult Female User Max Min Max User Max Min Max Pedals Knee angle H-point vertical height Projection of H-point to heel point (horizontal) Accommodated hip to ankle distance For light pedal force ( < N ) 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 ( > N ) male drivers above 2 percentile and female drivers above 9 percentile may not have sufficient leg room to adopt a knee angle in the optimum range Seat Seat pan height at front (Dimension used: popliteal height) Male drivers above 7 percentile and female drivers above 99 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 percentile and female drivers below percentile may find the seat pan too deep (front to back) Seat pan width (Dimension used: hip breadth) Male drivers above 99 percentile and female drivers above 94 percentile may find the seat pan too narrow Back rest height 7 7 (Dimension used: sitting shoulder height) Male drivers above percentile and female drivers above 34 percentile will have a greater shoulder sitting height than the seat back Back rest width (Dimension used: chest breath at nipple) Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow Head rest height Sitting height Percentile 7

78 Steering Top of seat back to top of steering wheel 9 9 (Dimension 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) (Dimension used: thigh depth) 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 Gear Lever Top left of seat back to top of gear lever (Dimension used: forward grip reach) Male drivers below 79 percentile and female drivers below 96 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 4 percentile and female drivers below 76 percentile may have difficulty reaching the hand brake from a neutral posture 7

79 WBV Anthropometric Design Assessments v4 Body dimensions taken from PeopleSize 2 Professional Version 2. Project number: JR483 Site: 3 Date of measurements: //2 Vehicle: Yale counterbalance lift truck Min. or Fixed British Adult Male Max Min Max Min. or Fixed British Adult Female Max Min Max Pedals Knee angle H-point vertical height Projection of H-point to heel point (horizontal) Accommodated hip to ankle distance For light pedal force ( < N ) male drivers above 93 percentile and female drivers above 99 percentile may not have sufficient leg room to adopt a comfortable knee angle For strong pedal force ( > N ) male drivers above percentile and female drivers above 2 percentile may not have sufficient leg room to adopt a knee angle in the optimum range Seat Seat pan height at front (Dimension used: popliteal height) Male drivers above 28 percentile and female drivers above 86 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 percentile and female drivers below percentile may find the seat pan too deep (front to back) Seat pan width (Dimension used: hip breadth) Male drivers above 99 percentile and female drivers above 9 percentile may find the seat pan too narrow Back rest height 4 4 (Dimension used: sitting shoulder height) Male drivers above percentile and female drivers above percentile will have a greater shoulder sitting height than the seat back Back rest width (Dimension used: chest breath at nipple) Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow Head rest height Sitting height

80 Steering Top of seat back to top of steering wheel (Dimension used: forward grip reach) At the limits of adjustment males below percentile, and females below 2 percentile may have difficulty reaching the far edge of the steering wheel Seat pan to steering wheel (vertical) 7 7 (Dimension used: thigh depth) With the seat at lowest height setting male drivers above 62 percentile may not have sufficient thigh clearance and female drivers above 6 percentile may not have sufficient thigh clearance Gear Lever Top left of seat back to top of gear lever (Dimension used: forward grip reach) Male drivers below percentile and female drivers below percentile may have difficulty reaching the gear lever from a neutral posture Hand Brake Top left of seat back to front of hand brake 8 8 (Dimension used: forward grip reach) Male drivers below percentile and female drivers below percentile may have difficulty reaching the hand brake from a neutral posture 73

81 WBV Anthropometric Design Assessments v4 Body dimensions taken from PeopleSize 2 Professional Version 2. Project number: JR483 Site: 4 Date of measurements: 22//2 Vehicle: Leyland DAF tipper truck Min. or Fixed British Adult Male Max Min Max Min. or Fixed British Adult Female Max Min Max Pedals Knee angle H-point vertical height Projection of H-point to heel point (horizontal) Accommodated hip to ankle distance For light pedal force ( < N ) male drivers above 9 percentile and female drivers above 99 percentile may not have sufficient leg room to adopt a comfortable knee angle For strong pedal force ( > N ) male drivers above percentile and female drivers above 3 percentile may not have sufficient leg room to adopt a knee angle in the optimum range Seat Seat pan height at front 3 3 (Dimension used: popliteal height) Male drivers above percentile and female drivers above 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 27 percentile and female drivers below percentile may find the seat pan too deep (front to back) Seat pan width 2 2 (Dimension used: hip breadth) Male drivers above 99 percentile and female drivers above 99 percentile may find the seat pan too narrow Back rest height 6 6 (Dimension used: sitting shoulder height) Male drivers above 9 percentile and female drivers above 8 percentile will have a greater shoulder sitting height than the seat back Back rest width 3 3 (Dimension used: chest breath at nipple) Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow Head rest height Sitting height

82 Steering Top of seat back to top of steering wheel 9 9 (Dimension 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) (Dimension used: thigh depth) 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 Gear Lever Top left of seat back to top of gear lever 9 9 (Dimension used: forward grip reach) Male drivers below percentile and female drivers below 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 percentile and female drivers below percentile may have difficulty reaching the hand brake from a neutral posture 7

83 WBV Anthropometric Design Assessments v4 Body dimensions taken from PeopleSize 2 Professional Version 2. Project number: JR483 Site: Date of measurements: 22//2 Vehicle: Open back transit van Min. or Fixed British Adult Male Max Min Max Min. or Fixed British Adult Female Max Min Max Pedals Knee angle H-point vertical height Projection of H-point to heel point (horizontal) Accommodated hip to ankle distance For light pedal force ( < N ) 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 ( > N ) male drivers above 2 percentile and female drivers above 6 percentile may not have sufficient leg room to adopt a knee angle in the optimum range Seat Seat pan height at front 4 4 (Dimension used: popliteal height) Male drivers above percentile and female drivers above 3 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 3 percentile and female drivers below 32 percentile may find the seat pan too deep (front to back) Seat pan width 3 3 (Dimension used: hip breadth) Male drivers above 99 percentile and female drivers above 99 percentile may find the seat pan too narrow Back rest height 6 6 (Dimension used: sitting shoulder height) Male drivers above 9 percentile and female drivers above 8 percentile will have a greater shoulder sitting height than the seat back Back rest width (Dimension used: chest breath at nipple) Male drivers above 99 percentile and female drivers above 99 percentile will find the seat back too narrow Head rest height 22 Sitting height

84 Steering Top of seat back to top of steering wheel (Dimension used: forward grip reach) At the limits of adjustment males below 32 percentile, and females below 67 percentile may have difficulty reaching the far edge of the steering wheel Seat pan to steering wheel (vertical) 9 9 (Dimension used: thigh depth) With the seat at lowest height setting male drivers above 87 percentile may not have sufficient thigh clearance and female drivers above 87 percentile may not have sufficient thigh clearance Gear Lever Top left of seat back to top of gear lever (Dimension used: forward grip reach) Male drivers below percentile and female drivers below 4 percentile may have difficulty reaching the gear lever from a neutral posture Hand Brake Top left of seat back to front of hand brake 6 6 (Dimension used: forward grip reach) Male drivers below percentile and female drivers below 7 percentile may have difficulty reaching the hand brake from a neutral posture 77

85 78

86 APPENDIX C. POSTURE ANALYSIS Appendix C. Video Proforma v. 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).. Trunk / Spine postures Measure amount of time backrest is in use Measure times & frequencies spent in the following (approximate) postures:. Flexion / Extension (leaning forwards and backwards respectively) Neutral to Mild Flexion ( to 2deg leaning forwards) Mild Flexion (2 to 4deg with full trunk support) *Moderate Flexion (2 to 6deg without trunk support) *Severe Flexion (>6deg) *- Severe and Moderate angles approaching 6 deg are likely to be a particularly high risk if held for over minute Supported Extension (<deg leaning backwards) Un-supported Extension (<deg).2 Lateral Bending (leaning from side-to-side) Neutral to Moderate Severe* ( to 2deg either side) (>2 deg) * - Severe if performed frequently as a normal part of the vehicle operation 79

87 .3 Twisting (rotation around the spines axis) Neutral to Moderate Severe* ( to 2 deg) (>2deg) * - 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. Neck Measure durations and frequencies of: 2. Flexion and Extension Neutral to Mild Flexion ( to 2deg - forwards tilt) Moderate Flexion (2 to 4deg) Severe Flexion (>4deg) Extension (<deg - backwards tilt) 2.2 Twisting (rotation to look sideways) 2.2. For repetitive movements (every few seconds or as part of a work cycle repeated more than twice per minute over 2 hours per day / >/3 of work period) Acceptable / Mild Moderate Severe ( to deg) ( to 4deg) (>4deg) 8

88 2.2.2 For non-repetitive movements Acceptable / Mild Moderate Severe ( to 3deg) (3 to 6deg) (>6deg) 3. Head Measure durations and frequencies of: Neutral to Mild Flexion ( to 2deg forwards tilt) Moderate Flexion (2 to 8deg) Severe Flexion (>8deg) Extension (<deg backwards tilt) 4. Hand / Arm Postures and Movements 4. Side to side Hand Movements Ulnar deviation Radial deviation (>24deg sideways toward little finger) (>deg sideways toward thumb) 4.2 Up and Down Hand Movements Extension Flexion (>deg bending hand up / backwards) (>4deg bending hand down / forwards) 4.3 Shoulder Movements Abduction (>7 deg lifting elbow sideways and up) 8

89 4.4 Movement Frequencies For a quick and initial assessment of risk refer to table 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 /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. Frequency rates for high risk to the upper extremities. Upper Extremities Potential high risk movement frequencies Shoulder >2. / minute Upper arm > / minute Forearm / wrist > / minute Finger >2 / minute. Additional considerations. 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).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..3 Leg postures These should be assessed primarily using the spreadsheet tool. 6. References ISO 226:2(E) Ergonomics Evaluation of Static Working Postures Zacharkow (Ed). Posture: Sitting, Standing, Chair Design & Exercise. Charles C Thomas Publisher. USA. 82

90 Keyserling et al (992). A checklist for evaluating ergonomic risk factors resulting from awkward postures of the legs, trunk and neck. International Journal of Industrial Ergonomics. 9. pp Bergamasco, R et al (998) Guidelines for designing jobs featuring repetitive tasks. Ergonomics. 4(9). Pp Possible Recording Methods ** Take stills of movements / postures at known angles (before or after the actual video recording). **Put markers on points around the cab so that degrees etc can be better extimated. 83

91 Appendix C.2 Comments received from Ergonomist (Liz Yeomans MSc) applying Video Proforma V. 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 2-4º trunk flexion and full trunk support? Or does it refer to lateral support? RULA/REBA use -2º, >2-6º, >6º as trunk flexion. Lateral bending what s frequently? Is this more than twice per minute? RULA/REBA don t specify angles but adds to score for twisted or lateral flexion of trunk. Neck Posture Most of the literature (including HSG6) 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 -2º and >2º with + 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 >4º rather than 8º RULA/REBA add to score for any radial or ulnar deviation Wrist Flexion/Extension Not sure where /4º comes from. RULA/REBA uses -º and >º. Shoulder Movements Not sure why only abduction is considered here. RULA/REBA adds to score for any abduction. Lower arm not considered at all? 84

92 Analysis of fork lift truck video (img_29.jpeg) Reversing Video proforma v. REBA RULA OWAS Posture Trunk flex Green 2 4 Trunk bend Green Trunk twist Severe + + Neck flex? Moderate 2 3 Neck twist Severe + + Head flex? not sure - Wrist dev? - Wrist flex/ext? - Upper arm abd - Upper arm flex/ext 2 2 Lower arm flex 2 Legs Load Action level Low risk action may be necessary Action level 2 Further investigation soon Action category 2 Corrective measure in near future REBA Rapid Entire Body Assessment RULA Rapid Upper Limb Assessment OWAS Ovako Working Posture Analysis System Louhevaara V, Suurnäkki T 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:. 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 6-second cycle, it was adopted 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 6-second cycle. 8

93 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 6-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- 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. (img 29.jpeg) Reversing posture. Published by the Health and Safety Executive /8