Broad Lane, Sheffield, S3 7HQ Telephone: +44 (0)114 2892000 Facsimile: +44 (0)114 2892500

The Development of the Risk Filter and Risk Assessment Worksheets for HSG60(rev)

HSL/2002/34

Project Leader: David Riley Author(s): R Graves (Human Factors & Work Design), K Way

(Better Working Environment Division 7), D Riley Science Group: Human Factors

© Crown copyright

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ACKNOWLEDGEMENTS

The authors acknowledge the considerable time and effort put into this project by the many volunteers from within industry, academia and ergonomics consultancies who helped during the development of the risk assessment tools. Without their help and dedication this project would not have been possible. In particular, we would like to acknowledge the contribution of Ann Brooks, Margaret Hanson, and Glyn Smyth, who worked alongside HSE and HSL in developing the ULD risk assessment filter and worksheets.

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CONTENTS

1 INTRODUCTION .............................................................................................................................1 1.1 AIMS ..........................................................................................................................................1 1.2 OVERVIEW ...............................................................................................................................2 1.3 REPORT STRUCTURE.............................................................................................................3

2 METHODOLOGY FOR DEVELOPMENT OF THE RISK ASSESSMENT TOOL ................5 2.1 PHASE ONE...............................................................................................................................5 2.2 PHASE TWO..............................................................................................................................5 2.3 PHASE THREE..........................................................................................................................6

3 LITERATURE REVIEW .................................................................................................................7 3.1 AIMS ..........................................................................................................................................7 3.2 METHOD ...................................................................................................................................7 3.3 FINDINGS AND DISCUSSION................................................................................................7 3.4 EVIDENCE BASE FOR RISK ASSESSMENT ......................................................................11 3.5 RISK FACTORS ......................................................................................................................11 3.6 CONCLUSIONS.......................................................................................................................13

4 DEVELOPMENT AND EVALUATION OF PROTOTYPE TOOLS........................................15 4.1 INITIAL ASSESSMENT TOOL DEVELOPMENT................................................................15 4.2 STAKEHOLDER WORKSHOP ..............................................................................................15 4.3 FURTHER DEVELOPMENT OF THE TOOL USING THE HSE IND (G) 171 (L) FORMAT.18 4.4 FIRST ROUND CONSULTATION.........................................................................................20 4.5 POST CONSULTATION RESULTS AND REVISION..........................................................20 4.6 EVALUATION OF FORMAT OPTIONS ...............................................................................21 4.7 USABILITY ASSESSMENT AND APPRAISAL...................................................................22 4.8 FINAL ROUND CONSULTATION........................................................................................23 4.9 SUMMARY..............................................................................................................................23

5 GENERAL DISCUSSION AND CONCLUSIONS ......................................................................25

6 APPENDICES..................................................................................................................................26 6.1 LITERATURE REVIEW SUMMARY TABLE ......................................................................27 6.2 PROTOTYPE TOOL................................................................................................................40 6.3 BODY PART SPECIFIC CHECKLISTS.................................................................................42 6.4 WORKSHOP PROGRAMME AND DELEGATE LIST.........................................................45 6.5 AMENDED RISK ASSESSMENT TOOL - OVERVIEW ......................................................48 6.6 AMENDED RISK ASSESSMENT TOOL - WORKSHEETS.................................................50 6.7 RISK ASSESSMENT FILTER ................................................................................................56 6.8 REVISED RISK ASSESSMENT WORKSHEETS .................................................................58 6.9 FINAL HSG60(REV) RISK ASSESSMENT FILTER AND WORKSHEETS .......................63

7 REFERENCES ................................................................................................................................72

8 BIBLIOGRAPHY............................................................................................................................74

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EXECUTIVE SUMMARY

OBJECTIVE In the context of revising the Health and Safety Executive (HSE) guidance document on Upper Limb Disorders (ULDs) - Work-related upper limb disorders: a guide to prevention, HS(G)60, 1990: • Develop a new risk assessment ‘tool’ which could be used by employers and others to

identify ULD risk factors in work activities, to assess the degree of risk and more importantly to take action to reduce or eliminate ULD risks.

The risk assessment tool forms part of a seven stage management approach which underpins the new guidance. AIMS • Review current literature on risk assessment tools to identify strengths and weaknesses; • Identify user needs regarding risk assessment for ULDs; • Develop an assessment method that assists non-expert users in identifying and assessing the

risk of ULDs in the workplace; • Develop material to assist in decisions on controlling the risk of ULDs in the workplace; • Ensure the assessment method is based on scientific evidence where possible; • Ensure the assessment method has adequate usability characteristics; • Ensure the assessment method meets the above specification and user requirements (e.g.

Easily photocopied, minimal length, etc.,.) MAIN FINDINGS Literature Review : • Li and Buckle (1998) emphasised the paucity of epidemiological criteria to establish the

point(s) where musculoskeletal risks should be controlled; • From an update of Li and Buckle’s (1999) review, it does not appear that checklist

developments have moved on substantially; • It can be argued that non-specialist users wish for checklist tools that are quick and clear to

use, user friendly, designed with tick/check boxes, easy to learn, have limited paperwork and no unnecessary data collection, and are specific to the task/job under consideration.

• At a scientific level, checklists appear to have limitations but their development and use has occurred because of user requirement (as above);

• There will be elements of subjectivity in tool application despite care in trying to develop tools which provide an objective means of identifying and assessing musculoskeletal injury risks;

• All such approaches will need an element of knowledge or training or both in order to be most effective and reliable;

• Any checklist tool developed for non-specialist users needs to be simple to use but not lacking in sensitivity, such that low risk jobs are not unnecessarily identified for detailed risk assessment;

• In relation to ULDs, the OSHA (2000) basic screening tool emulates, in part, the original two part 1994 HSE checklist. The first part involved a short one page filter followed by more detailed checklist to try to help identify suspected risk factors;

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• Examination of the ULD risk identification part of the OSHA (2000) screening tool shows that it attempts to help the user identify combinations of exposure, repetition, awkward postures and force. In principle, this type of checklist could be a useful start in developing a Risk Assessment Tool for the HSE, assuming the criteria could be justified.

Development of Risk Assessment Tools: From the outcomes of a workshop and initial evaluation exercises, a two-part format was adopted: • Part 1- This would be a simple one -page initial assessment approach to be referred to as a

‘Filter’. This would include simple questions on exposure factors, frequency etc., warning signs, and provide a section to identify static components. Each risk factor would be referenced in the main body of the HS(G)60 document.

• Part 2 - The second part would be described as a ‘Worksheet’ and be more detailed. This would enable a more explanatory assessment of risks in the workplace to be made, with suggested solutions.

Conclusions The Risk Filter and Assessment Worksheets provide an example of an assessment method that can be used as part of the 7-stage risk management approach outlined in HSE’s guidance on ULDs (HSE 2002). The Risk Filter sets out an approximate threshold below which the risk of ULDs is likely to be low. This threshold is not absolute. The guidelines in the Risk Filter and Worksheets are provided as an aid to risk assessment and have been developed from the scientific literature and from expert opinion. As such, they are not precise exposure limits, but are intended to be used alongside the published guidance (HSE 2002), to identify potential risks and possible measures to reduce them. The tools are not intended to quantify risk but rather to identify risk factors for ULDs and to translate this into positive action to control risks to a level that is as low as reasonably practicable. In designing the tools, the emphasis has been on ease of use by non-specialists, and the consultative process has helped to ensure that the needs of a wide range of users have been considered. The tools provide guidance for assessing and minimising risks through positive action, which, it is hoped, will aid compliance with the law and make the workplace safer.

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1 INTRODUCTION

The Health and Safety Executive (HSE) has recently revised the guidance document on Upper Limb Disorders (ULDs) - Work-related upper limb disorders: a guide to prevention HSG60 (HSE, 1990). At an early stage in planning the revision, a need was identified for a new risk assessment tool that could be used by employers and others to identify ULD risk factors in work activities, to assess the degree of risk and more importantly to take action to reduce or eliminate ULD risks. The risk assessment tool forms part of a seven stage management approach that underpins the new guidance. The 1990 checklist (HSE, 1990) consisted of narrative questions with prompts and guiding principles, and was intended to help a range of users and provide a combination of outcomes. It seemed to be a comprehensive checklist but, unfortunately, had not been validated. The specification for the new tool required that it should be in the form of a risk assessment tool or aid that could be used by non-specialists to help in risk reduction and assist decisions on control measures. It was intended that the tool should draw on the best features of existing tools used by specialists while maintaining a useable format that would support wide application in industry. In formulating the risk assessment tools, the following considerations/specifications were made:

A two stage approach - The first stage involving some type of screening, and the second, a more detailed assessment of risk factors, perhaps with indications of means of control;

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To target the tool especially at non-specialists who are unlikely to have expert or trained help; Any tools would need to be set in the context of the broader ULDs management document; To help with the steps needed to approach problem solving (i.e. do I have a problem?) as well as some simple means of guiding the user through the process of assessing risk and taking action. A decision support aid component was considered as well as technical content to help identify musculoskeletal risk. Approaches based on flow charts were considered due to previous experience showing them to be effective in decision making (Graves et al, 2000).

This report describes the process of developing this tool. A particular strength of the approach taken was the involvement of stakeholders (health and safety professionals, employer and employee representatives, consultants etc.,) throughout the process. For the purposes of this report the ULD risk assessment tool will be referred to as ‘the risk assessment tool’ or simply ‘the tool’. 1.1 AIMS The aims of the project were to:

Review current literature on risk assessment tools to identify strengths and weaknesses; Identify user needs regarding risk assessment for ULDs; Develop an assessment method that assists non-expert users in identifying and assessing the risk of ULDs in the workplace;

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Develop material to assist in decisions on controlling the risk of ULDs in the workplace;

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Ensure the assessment method is based on scientific evidence where possible; Ensure the assessment method has adequate usability characteristics; Ensure the assessment method meets the above specification and user requirements (e.g. easily photocopied, minimal length, etc.,)

1.2 OVERVIEW There are many methods available to assess risk of upper limb disorders, often developed by experts for experts. There is a view that these approaches are of limited use to non-experts/ergonomists because they do not take account of the restrictions on the expertise, technical capability, and time available to those involved in assessing working conditions, especially in small companies. Furthermore, for those at company level the priority is to collect information in order to improve working conditions rather than scientifically quantify risks (Malchaire and Cock, 1999). The four-stage approach suggested by Malchaire and Cock (op cit.) outlined in Table 1, provides a useful framework for comparison of the characteristics of different types or ‘levels’ of assessment tools. The model outlines stages, of increasing complexity, to be used successively by people with different levels of expertise. The initial stage involves screening of complaints and/or musculoskeletal disorders (MSDs) and a rapid inspection of working conditions. It should be easy to understand and use, preferably by the workers, and not be time consuming. The outcome of this leads to a decision on whether there should be a more detailed evaluation. This philosophy is similar to that provided by the first part of the simple assessment procedure introduced by the HSE’s booklet in 1994 (INDG 171). This procedure contained two categories of potential risk factors. The first was frequent or forceful or awkward specified actions. The second was evidence of signs of ULDs. This approach also accords with the use of the US Occupational Safety and Health Administration’s Basic Screening Tool (OSHA, 2000) to review risk factors for those areas of the body affected by the MSD incident (once an employee reports MSD or MSD signs and symptoms). The Malchaire and Cock (op cit.) suggested that the second stage involves observation (see Table 2). This can be used by company officials without training in MSDs using a checklist to assess working conditions. This covers aspects such as posture, forces and repetition that may contribute to increased risk of MSDs. If observation does not help identify possible solutions, a more detailed analysis should be carried out. This increases the level of knowledge required. Lastly, expertise is applied in the fourth stage, where specialised techniques are used in complex cases. The assessment tools described in this report can be classified within the first two parts of this four-stage approach - Screening and Simple Observation. It is important to note that the described assessment tools are not, nor do they claim to be, phase three or four type tools. This decision was based on the need for the assessment to be able to be used by non-experts and also due to the limited time available for trials and development. These tools are intended to be simple and straightforward, aiming to assist employers etc., in recognising risk factors, assessing the risk for the purpose of meeting statutory obligations, i.e. level of assessment commensurate with likely degree of risk, and most importantly, identifying control options and acting to eliminate or reduce risk.

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1.3 REPORT STRUCTURE An iterative process was followed in developing the tool. This provided for the input of potential users at several stages and this has provided valuable feedback on the structure and presentation of the tool. This report looks at the process of developing the tool and the criteria adopted in defining risk factors and assessment criteria (evidence base) and the outcomes of the user evaluation exercises. The report is divided into five sections (plus Appendices):

(1) Introduction and overview

(2) Method of development of the risk assessment tool

(3) Literature review

(4) Evidence for risk assessment tool content

(5) Risk assessment tool structure and development

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Table 1. Characteristics of the different stages

Phase I Phase II Phase III Phase IV “SCREENING” “OBSERVATION” “ANALYSIS” “EXPERTISE”

WHEN? All cases If problem Difficult cases Complex cases HOW?

Simple observations

Qualitative Observations

Quantitative observations Specialised Techniques

COST?

Very low • 10 min

Low • 2 hours

Average • 2 days

High • 2 weeks

BY WHOM? Workers and company personnel

Workers and company personnel

Workers and company personnel + Specialists

Workers and company personnel + Specialists + Experts

Expertise: Work Very high High Average Low Ergonomics Low Average High Very high

Table 2. Checklist for Stage ll: "Observation"

1. The head deviates from a neutral position: in rotation, lateral bending, flexion, extension or twisting 2. Specific postures and movements are imposed by a task 3. In some work phases, the shoulder reaches down and behind the torso with the elbow stretched 4. Some movements of the hand and forearm in the horizontal plane lead to significant shoulder rotations 5. For some movements, the elbow is at mid-torso level or above 6. Some operations require torsion of the forearm (ringing, screwing) 7. At times, the wrist deviates from the neutral position: extreme flexion or extension, radial or ulnar deviation, prosupination 8. The operator uses grips such as the following… 9. Some efforts for lifting, pushing, pulling objects or tools are greater than 2 kg 10. The operator uses tools or objects weighing more than 1 kg per hand

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2 METHODOLOGY FOR DEVELOPMENT OF THE RISK ASSESSMENT TOOL

The development of the risk assessment tool followed an iterative path. While the assessment criteria themselves remained relatively unchanged, input by consultees at the various stages provided valuable insight into the usability of the tool and had a large influence over the format. As a result, users have had significant input into the final product. Ideally, the development of such a tool would involve a series of stages as follows:

A survey of user needs; • • • • • •

Development of a prototype tool; Evaluation of the prototype by users under standardised conditions; Modification of the prototype taking account of the experimental study; Field evaluation of the prototype; Finalisation and production of the tool.

However, within the time scale imposed on this project, there was no possibility of following the whole of the above approach. Therefore, the best parts of existing tools (many of which have undergone rigorous testing) were used to develop the questions for the prototype checklist tools. These were then reviewed at various stages by a mix of ergonomics practitioners and industry representatives. This chapter provides an overview of the approach taken. Stages of development fell into three distinct phases as listed below. 2.1 PHASE ONE 2.1.1 Literature Review A literature review was conducted in order to examine existing approaches and their relative advantages and disadvantages as well as the needs of the potential users. The process and findings of the literature review are detailed in Section 3 of this report. 2.1.2 Develop prototype checklist type tools Based on the findings from the literature review, exemplar checklist tools were developed. More details of the underlying reasoning and development of the prototype tools are included in Sections 3 and 4 of this report. 2.1.3 Stakeholder workshop A peer review was conducted on 16th March 2001, managed by the Better Working Environment Division Human Factors Unit (BWED7, formerly Health Directorate D2). This review aimed to obtain the views of a group of specialists and non-specialists regarding the potential options for the risk assessment tools. Details of the outcomes of this review process can be found in Section 4 of this report. 2.2 PHASE TWO 2.2.1 Further development of a two part tool using HSE leaflet format The consensus of the consultation and peer review suggested following a similar format to that found in the HSE leaflet INDG 171 (Upper limb disorders: Assessing the Risks, 1998). This stage of development involved modifying the tool into a two part format, filter and assessment stages, like INDG 171, with an additional overview of the risk management process. A

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consideration of the work by Smyth (1994) was included in this process, and the limitations of IND(G) 171 were noted for further development of the tool. 2.2.2 Initial peer review (within HSE) The HSE’s BWED7 forwarded the updated version of the tool to the HSL Ergonomics Section, who provided comment. 2.2.3 Consultation exercise for the revision of HS(G)60 - Upper Limb Disorders

in the Workplace (Draft v2.05 13.6.01). A modified version, which had taken account of comments, was provided to HSL Ergonomics Section. A short questionnaire was developed and circulated with both the latest draft of HSG60(rev), and the revised tool for consultation to a group of industry representatives and professional ergonomists (provided by BWED7). An HSL report on the findings of this exercise was produced for the writing team (ERG/01/15). 2.3 PHASE THREE 2.3.1 Risk assessment tool revised in line with all comments received. Feedback from the consultation suggested that the filter and assessment stages were too long and possibly too complex for non-specialist users. As a result, the flow chart approach and references to particular body parts were removed from the filter leaving two options for the filter format. Two formats for the assessment stage were also compiled. 2.3.2 Further internal consultation regarding format The two prototypes of the risk filter and risk assessment were then circulated to a limited number of ergonomics professionals (10) in order to get an indication as to the usability and sensitivity of the two formats. From the results, the format for the filter and risk assessment sheets was finalised. 2.3.3 Circulate modified version of tool to users for usability assessment and

appraisal External ergonomics professionals appraised the revised Filter and Assessment sheets, which involved using both to assess three jobs/tasks each. They reported on a number of aspects of the Filter and Assessment Worksheets including usability aspects. Significant and valuable written reports were received, which were used to update the tools. 2.3.4 Final round of consultation The full draft of HS(G)60 including the Risk Filter and Risk Assessment was forwarded to consultees. Comments received that were specific to the Risk Filter and Risk Assessment were evaluated and alterations to the Risk Filter and Risk Assessment Worksheets were made, where appropriate. 2.3.5 Full review and update of Risk Filter and Risk Assessment This stage involved conducting a systematic review of the content and layout of the risk assessment tool by the drafting team (the authors, plus Clare Lawton - Ergonomics Section, HSL). The instructions, the format and the content were finalised.

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3 LITERATURE REVIEW

3.1 AIMS The aims of the literature review were to:

Identify those aids to MSD risk management used by both specialists and non-specialists including reviewing the needs of non-specialists;

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Compare and contrast the usability of MSD risk management Aids, especially for non-specialists; Provide a summary of the advantages and disadvantages to inform the HSG60(rev) drafting process.

3.2 METHOD 3.2.1 Review An abstract search was undertaken with OSH-ROM: CISDOC using the following key words in the indicated combinations; musculoskeletal, assess, check*list, (musculoskeletal) and (assess* or check*list), musculoskeletal, assess*, checklist, (musculoskeletal) and (assess* or checklist). This produced 945 abstracts that were then read and a final total of 40 abstracts selected to obtain the associated full papers. In addition, the references in the review undertaken by Li and Buckle (1999) were cross-referenced with the previously selected papers to check for any omissions. Further, the world-wide-web was searched for standards and guidance using a similar selection of keywords and terms. 3.2.2 Selection of assessment tools The papers obtained were examined and tabulated under the headings of: Types of tools; Characteristics; Types of study and application, Findings and Author. This was subsequently used to identify pen and paper based checklist techniques which might be usable by a non-specialist user (the type of checklist or tool contained in the initial 1990 HS(G)60 can be described as a pen and paper based observational technique). The initial criteria for selection were that the technique would mainly apply to the upper limb risk assessment and appeared to be usable by non-ergonomists. These techniques were then tabulated, outlining their features, field of applications, potential users and training needs. Information on the latter characteristics were obtained by reference to Li and Buckle (op cit.) and to the original papers. 3.2.3 Summary of advantages and disadvantages The selected techniques were then examined to identify their relative advantages and disadvantages. This was based on those identified by Li and Buckle (op cit.) and by reference to the original papers. 3.3 FINDINGS AND DISCUSSION Appendix 1 summarises the main findings of the literature review and its update. 3.3.1 User Requirements Non-specialist user needs are mentioned by a large number of authors, however, little is specified about what this means in practice. Table 3 (from Buckle and Li, 1996), shows broad needs obtained from focus groups. It is clear that there are contrasts between the needs of the experts and those of the practitioners.

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Table 3. (from Buckle and Li, 1996) Experts Needs Practitioners/Health and Safety

Professionals Needs (including safety reps etc)

Valid Reliable High face validity “believability” Equal balance across risk factors Comprehensive Can generalise results across plants etc. Seen as standard tool, backed by Regulatory bodies

Quick Clear User friendly Tick/Check boxes Easy to learn Limited paperwork Specific to task/job under consideration No unnecessary data collection

3.3.2 Features of existing tools At the time of the initial review, OSHA in the USA proposed a “revised ergonomics program standard” (OSHA, 2000) to reduce work-related musculoskeletal disorders in the workplace. This was adopted on November 14, 2000 but was subsequently repealed amidst competing political argument. (See the OSHA web site for details of the proposed rule, its history and associated information at, http://www.osha-slc.gov/ergonomics-standard/archive-index.html). The OSHA ergonomics standard adopts a two-stage approach. First, its main requirements applied only to jobs where a case of work-related MSD or sign or symptoms had been reported, and the job type implied exposure to ergonomic risk factors of sufficient magnitude, duration or intensity to warrant further examination. If the first stage requirements were met, a more in depth approach was applied. The “Basic Screening Tool” contained specific definitions of risk factors that could lead to a MSD hazard. The risk factors covered were: repetition, force, awkward postures, contact stress and vibration. A number of specific criteria for identifying possible job hazards and evaluating control measures were provided in the standard. Examination of the ULD risk identification part of this tool shows that it attempts to help the user identify combinations of exposure, repetition, awkward postures and force. It did allow, however, alternative methods “reasonable and appropriate for the risk factor present” to be used. In relation to ULDs, this approach emulates, in part, the HSE 1994 IND(G) 171 checklist which was also in two parts. The first part involved a short one page filter followed by a more detailed checklist to try to help identify suspected risk factors. Li and Buckle (1999) undertook an extensive review of techniques available for assessing work related MSD risks. From the review update, it does not appear that checklist developments had moved on substantially since this work was published in 1999. Table 4 is adapted from Li and Buckle (op cit) and shows selected checklist approaches for identifying upper limb MSD risk at work and their identified advantages and disadvantages.

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Table 4. Advantages and Disadvantages of Selected MSD risk checklist approaches (Adapted from Li and Buckle, 1999)

Techniques Application area Disadvantages Advantages Two page checklist (Keyserling et al. 1993)

335 manufacturing and warehouse jobs An apparent one week training requirement Checklist is an effective rapid screening tool for identifying jobs that expose workers to harmful ergonomic stresses

HAMA (Christmansson 1994) Hand/arm motion Information obtained by videotaping task, and information about force exertion is described by the observer and augmented by the worker

No reference data available for the description of the exposure level, or the description of stress in body parts other than upper limbs.

The data is linked to the specific work activity, thus the relationship between the use of the body and the design of the workplace and task can be obtained.

ULDs Checklist (HSE, 1994) General industrial Poorer than RULA and TUC checklists on static posture, local stress, psychosocial and individual risk factors (Smyth and Haslam, 1995) Has not been validated independently

Appears to identify risk for repetition, force and environmental extremes of temperature

TUC Guide (TUC, 1994)

General industrial

Has not been validated independently

Appears to identify risk for a number of factors

PLIBEL (Kemmlert and Kilbom 1987, Kemmlert 1995)

Has been applied in several studies (Vink, 1991, Jakobsson, 1993). Inter-observer reliabilities have been shown to be ‘fair to moderate’

Inter-observer reliability not high (Kemmlert 1995), it is difficult to justify the magnitude of ‘risks’ when the combination of several factors is presented within a job

The tool is useful for identifying risk factors for musculoskeletal injuries of a specific body region

Job strain index (Moore and Garg, 1995)

Distal Upper Limbs Intended to provide scores for risk factors and a risk index

Still in development Has not been validated independently

Could provide a quantitative means of screening for risk by professionals

QEC (Li and Buckle 1998) General Inter-/intra-observer reliabilities have been proven to be ‘fair to good’ for most of the assessment items.

Improvements needed with training process. ‘Score system’ needs to be validated via epidemiological studies. Relevant to change in exposure before and after ergonomic intervention only

QEC is sensitive to change in exposure before and after ergonomic intervention, is suitable for the exposure comparison; between operators doing same task, or between those doing different tasks.

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At one end of the usability and training spectrum for checklist tools, there is the rapid screening tool designed as a two-page checklist intended for a manufacturing environment (Keyserling et al., 1993). It contains questions with multiple-choice responses, it is intended to be used by plant personnel, and it is stated that it required a week of training. At the other end of this spectrum, there is the Quick Exposure Checklist (QEC) developed by Li and Buckle (1998). This was developed “to assess the change in exposure to musculoskeletal risks before and after an ergonomic intervention”. It’s target users are “practitioners” and it requires 10-15 minutes of self-learning and some practice. The authors emphasise the paucity of epidemiological criteria to establish the point(s) where musculoskeletal risks should be controlled. 3.3.3 General considerations in Ergonomics Assessments Issues that are worth noting regarding ergonomics assessments in general include:

There is not yet sufficient data to prescribe acceptable exposure limits to individual or combined risk factors, although the epidemiological literature shows increased risk of a specific type of work-related musculoskeletal disorder as exposure to a single risk factor or to the combination of risk factors increases. (Silverstein et al. 1986, 1987, Burton et al. 1989, Marras 1992, Bernard et al. 1997);

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There is not yet agreement on how measures such as repetition, force or posture should be weighted, and how the magnitude of interactions should be quantified. (Winkel and Westgaard 1992, Kilbom 1997); Most score systems adopted in these existing methods have been largely hypothetical.

3.3.4 Advantages and disadvantages of checklist approaches Li and Buckle (op cit.) highlight generic advantages and disadvantages of observational techniques that apply to checklists in general. The main advantages were:

They are simple to undertake and provide a quick answer; They are relatively inexpensive to carry out; Postural assessments can be made in a confined workplace without disruption to the workforce; They are most useful for jobs where body postures are held for longer periods of time, or the body movement follows a simple pattern that is repeated during work.

The main disadvantages included:

The optimum number of observations for low and high repetitive tasks are still unclear (Genaidy et al. 1994); Subjective judgement carried out by human observers is not exhaustive in its assessment of the physical workload of the operator (Chen et al., 1989); The observation methods lack precision, are less reproducible in dynamic work situations, and are subject to intra- and inter-observer variability (Burdof et. al, 1992). They are more suited to relatively static jobs, where body postures are held for longer periods of time, or the body movement follows a simple pattern that is repeated during work.

Clearly, on a scientific level, checklists appear to have limitations. This, however, has not inhibited their development and use because, as indicated earlier, users wish to have tools that are quick and clear to use, and are “user friendly”. Inevitably, despite care in trying to develop tools that provide an objective means of identifying and assessing musculoskeletal risk, there

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will be elements of subjectivity in their operation and application. All such approaches will need an element of knowledge or training, or both. A further problem can arise in relation to the sensitivity and cost effectiveness of any checklist. Any checklist tool developed for non-specialist users needs to be simple enough to use but not end up in identifying relatively low risk jobs as requiring further assessment. 3.4 EVIDENCE BASE FOR RISK ASSESSMENT The identification of robust criteria for all stages of the risk assessment process is a problem area. Ideally criteria should be based upon epidemiological evidence to provide a “Gold Standard”. The relationships described by Silverstein et al. (1986) have been used to develop criteria by a number of authors and organisations. In practice these criteria are limited in their scope and detail and most checklists use lower levels of criteria, or a mixture of different levels. The next level can be described as a “Silver Standard”, being based on studies in the reviewed literature. The checklist described by Keyserling et al. (1992), and the RULA methodology (McAtamney and Corlett, 1993), and QEC (Li and Buckle, 1999) could be described as being of this type. Usually these methods have hypothetical scoring systems but are useful operationally. The third can be described as a “Bronze Standard,” being based on what could be termed operational criteria. The latter include those that have been applied and used because they have at least some intuitive basis and/or have been used operationally to provide practical risk identification. Examples of the latter can be found in checklists such as those developed by the HSE and the TUC. It was not possible within the timescales and resources of this study to do more than use existing checklist criteria and note the sources. Where possible, Gold and Silver Standard criteria were sought. Where these were not available, Bronze Standard criteria were used. A further complication arises from the lack of integrated criteria. Sources may indicate risk factors only in respect of one risk source, for example, repetition. The influences of other risk factors such as force or posture are less easy to define. Duration is another aspect with limited information. 3.4.1 Influences And Question Phraseology Generally, the Occupational Safety and Health Administration screening tool (2000), Li and Buckle (1999), and the State of Washington Proposed Ergonomics Rule (WAC1, 1999), provided the most up to date sources of criteria and question phraseology. Both the OSHA and WAC share similar criteria, although the latter has more detailed risk criteria. 3.5 RISK FACTORS 3.5.1 Repetition There are a number of problems in defining repetitiveness. For example there appear to be different levels dependent upon body location (see Kilbom, 1994). Kilbom cites frequencies of more than 2.5 movements per minute for the shoulder, and more than 10 for the upper arm, elbow forearm and wrist as presenting a high risk. Li and Buckle expressed some reservations about the difficulty of assessing repetition. Highly repetitive tasks have been defined as those with a work cycle time less than 30 seconds or with more than 50% of the cycle time involved in performing the same motion pattern. However, a

1 State of Washington Proposed Ergonomics Rule, WAC 296-62-051

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work cycle may not exist in many work situations, or if it does, work cycle time may vary. It was felt that this makes it difficult to assess within a limited observation period. As an alternative, it has been suggested that the repetition should be assessed on the basis of perceived movement rates (i.e., number of times repeating similar motion per minute). Kilbom (op cit.) suggested a movement rate of more than 10 times per minute increased risk, and work undertaken for more than 60 minutes as repetitive. Bjelle et al., 1981 indicate that highly repetitive arm and shoulder movement increases the risk of shoulder tendon disorders. Li and Buckle are not convinced that epidemiological studies have provided sufficient information to define the frequency at which repetitive shoulder movements should be regarded as having increased risk. In addition they said it was not clear how such terms as ‘frequent’ or ‘very frequent’ should be defined. They decided that these terms would be defined by describing the pattern or manner of the arm movement, rather than by the number of times the arm moved within a given period. As Li and Buckle found that movement rates of 11 and more per minute could be assessed reliably, these criteria were used for the wrist for the present checklist but with the phraseology used in the QEC. A similar approach was used for defining shoulder/arm movement. In addition the phraseology used by OSHA was included to provide extra questions to ensure as many options were covered as possible. 3.5.2 Working Postures In relation to wrist postures, there appears to be enough evidence of the increased risk associated with awkward wrist/hand postures, especially in combination with force, repetition and duration. For example, the prevalence of wrist problems is associated with activities where the wrist is deviated beyond 15° or 20° from its ‘neutral’ or straight position. Li and Buckle felt that it was difficult for an observer to assess whether the wrist was beyond 15° or 20° from its neutral position during work. Their questions differentiated posture on the basis of either “almost a straight wrist, or, with a deviated or bent wrist position”. Their experimental studies reported that this approach was successful. As static postures are considered to increase risk, some assessment of this was needed. Working above shoulder height (and by implication leading to at least static and awkward postures, possibly with force) is recognised widely as a risk factor for shoulder ULDs. The existing question set was extended to take account of the Smyth (op cit.) study by including questions about risk to the shoulder, neck and about static postures. For neck posture two types of question were used. The first related to assessing how the task was performed i.e. with the head/neck bent or twisted excessively, occasionally or continuously for more than 2 hours total per workday. The second was in terms of how the visual demands of the task requiring the worker to view fine details, and so by implication require a bent neck to achieve this (from the QEC). 3.5.3 Force The original INDG 171 section on force was expanded. In addition, a further section on local force and stress was added to reflect risk factors identified by Keyserling et al (1993). The force magnitude criteria were based upon those found in OSHA and WAC. 3.5.4 Duration As was seen earlier, defining risk associated with duration posed a problem. OSHA used “more than 2 consecutive hours per workday” as a definition of duration as applied to repetition, force and awkward postures. WAC tended to use 4 hours when dealing with the influence of an

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individual risk factor such as repetition. Where the WAC includes combinations of risk factors, the duration values quoted tend to be less. For example, with the wrists bent 30° or more, the duration is defined as more than 3 hours total per workday. Li and Buckle state that epidemiological studies have shown that when the daily exposure time exceeds 4 hours, the rates of WMSD complaints increase in the back, shoulder/neck particularly for seated tasks such as driving and VDU operation. For simplicity, a compromise value of 2 hours (consecutive or total) based on the above references was used, depending upon the risk factor. 3.5.5 Work Environment Criteria for vibration were based on HSE’s portfolio of guidance related to vibration (HS(G)88, HS(G)170, Video 'Hard to Handle', CD-ROM 'The Successful Management of Hand-arm Vibration', INDG 338 and ID 246/31). This states a recommended action level of 2.8 m/s² A(8). 3.5.6 Psychosocial Factors The psychosocial or work organisation questions were based on Li and Buckle’s (op cit.) QEC questionnaire phraseology that they reported to be effective in identifying organisational pressure factors. Additional questions were added where it was felt that established psychosocial factors had not been adequately covered. 3.5.7 Individual Differences The questions relating to individual differences are intended to prompt assessors to look at these issues, but also to discourage them from placing unnecessary emphasis on the worker being a member of a certain group. The tool recommends that expert assistance be obtained if individual differences are believed to be a risk factor. In these cases a functional assessment of the individual in question would be required to ascertain whether the individual difference is, indeed a risk factor for injury or not. Issues such as gradual return to work are also recognised. 3.6 CONCLUSIONS

Li and Buckle (1998) emphasised the paucity of epidemiological criteria to establish the point(s) where musculoskeletal risks should be controlled.

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From an update of Li and Buckle’s (1999) review, it does not appear that checklist developments have moved on substantially. It can be argued that non-specialist users wish for checklist tools that are quick and clear to use, user friendly, designed with tick/check boxes and easy to learn, with limited paperwork, have no unnecessary data collection, and be specific to task/job under consideration. At a scientific level, checklists appear to have limitations but their development and use has occurred because of user requirement (as above). There will be elements of subjectivity in tool application despite care in trying to develop tools that provide an objective means of identifying and assessing musculoskeletal injury risks. All such approaches will need an element of knowledge or training or both in order to be most effective and reliable. Any checklist tool developed for non-specialist users needs to be simple to use but not lacking in sensitivity, such that low risk jobs are not unnecessarily identified for detailed risk assessment. In relation to ULDs, the OSHA basic screening tool emulates, in part, the original two-part 1994 HSE checklist. The first part involved a short one page filter followed by more detailed checklist to try to help identify suspected risk factors.

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Examination of the ULD risk identification part of the OSHA screening tool shows that it attempts to help the user identify combinations of exposure, repetition, awkward postures and force. In principle, this type of checklist could be a useful start in developing a Risk Assessment Tool for the HSE, assuming the criteria could be justified.

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4 DEVELOPMENT AND EVALUATION OF PROTOTYPE TOOLS

4.1 INITIAL ASSESSMENT TOOL DEVELOPMENT Appendix 2 shows the checklist approach. This was designed as a flow chart to provide an aide memoir / overview of the management of MSD risk. The intention was, with appropriate instructions and training, to lead the user through questions to help them decide which risk assessment routes should be followed. This was felt to be important because there is an overlap between ULD, DSE and Manual Handling Risk management. The flow of the questions was intended, first of all, to direct the user to the appropriate type of risk assessment. Next, both symptoms and types of work were used as decision points to highlight when there was the possibility of ULD risk. Even if these were negative, work organisation factors were used as the next stage to try to help identify possible overall factors that could increase risk of ULDs. Finally, industries shown by epidemiological studies to have an increased incidence of ULDs, were used as a screening question to help focus the user. If any of the questions indicated possible ULD risk, the user was directed to further screening flowcharts to help them assess risk in relation to specific body areas. Appendix 3 shows the flowcharts that were developed using, in part, some OSHA criteria. 4.2 STAKEHOLDER WORKSHOP A workshop was held on 16th March 2001, to give stakeholders an early opportunity for input into the development process. Invited attendees included a mix of industry and union representatives as well as a number of ergonomics experts. Appendix 4 shows the programme for the day, and a list of invited attendees. 4.2.1 Options presented to the workshop Table 5 provides an overview of the topics that were presented to the group for discussion and consensus at the workshop.

Table 5. 1. All MSD issues should be:

a) Integrated into one checklist i.e. whole body, ULDs and DSE together b) ULDs by themselves c) Some other combination

2. Ergonomics training is a prerequisite for use of checklists 3. Initiating action should be by:

a) Incidents, complaints b) Surveillance such as body mapping and discomfort c) Types of job d) Presence of known ergonomic hazards such as repetitive work etc.,

4. Risk assessment for non-specialists should involve a) Simple screening b) Two staged approach – screening and more complex assessment c) More than two stages

5. Can Psycho-social factors be assessed a) At a simple screening stage? b) At another stage, please specify?

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As well as these specific questions being posed, participants were requested to identify the good points, the concerns and possible improvements for the assessment tool options presented at the workshop. 4.2.2 Summary of responses Table 6 summarises some of the reactions to the overview risk assessment option (Appendix 2.)

Table 6. Good Points Concerns Improvements Proactive as well as reactive Has clear layout and structures Industry used to flow diagrams Could be useful prompt for manager/ supervisor Would be better as a general overview not exclusive to HS(g)60 to direct user to appropriate regulations etc., Approach might be useful at the first level of Risk Management Process

All questions to be answered by users - no employee input Ambiguous conclusion on risk level No guidance on frequency/force Industry jobs list Work organisation issues not included Not comprehensive enough

Couch questions for employee involvement Improve conclusion statement Improve sequencing Step one, ask people Possibly QEC model driven by someone engaging with workers Could be broken into two, start with questions dealing with frequent/ forceful/ awkward etc., Could be modified to get to frequent/forceful etc. Include force, repetition, awkward angles, vibration, hot and cold Remove industry job list

Table 7 summarises the reactions to the checklists for specific body areas (Appendix 3). It is interesting to note that the group with a high proportion of industry-based representatives was more comfortable with the overview and flow chart approach. The other groups, with a high proportion of professional health and safety, academic and ergonomics representatives found it less acceptable. The review of the OSHA based checklist showed similar results (i.e. industry based representatives were favourable). Examination of some of the comments on the specialists’ worksheets and overview papers indicates that some of the latter reservation was down to detail rather than the principle involved, as well as favouring a tick box approach. Some of this may be the result of having the existing HSE leaflet IND (G) 171 (L) approach which is checklist based. This conflict can only be resolved by user trials.

Table 7. Good Points Concerns Improvements Pictograms; Leads to a solution Gives guidance Clear/visible Prescriptive values

Not multifactorial Appears too prescriptive with values (HSE reservation), although industry likes this Not comprehensive Problem of feedback loop Problem with hazards and solutions Possible managerial shortcut to solutions Work in between tasks - miss important issues? Angles are difficult to estimate Did not like flow chart approach Did not like symptom driven approach Production, Feedback loop needed, symptoms driven Hazard driven

Improve conclusion statement Encourage employee involvement in questions Improve sequencing Use a list Words better than diagrams Need to look back at existing HSE IND (G) 171 (L), i.e. HSE leaflet is closer but incomplete, it might be a way forward with single questions and potential solutions More familiar with the existing HSE leaflet IND (G) 171 (L), so use this approach, plus pictograms

One group at the workshop argued for an approach similar to that used in the QEC. The QEC was developed as a tool to determine changes to exposure to risk factors relating to ergonomic

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interventions (Li and Buckle, op cit.). The questions were developed in user trials with health and safety professionals. 4.2.3 Key Outcomes

In relation to the design of the risk assessment approach for non-specialists, the majority favoured a two-stage approach including a simple filter stage, followed by a more detailed stage. Initial questions give a broad view of risk factors, followed up with a more comprehensive assessment.

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A split between those favouring whole body and DSE checklists, as opposed to those who wanted to concentrate on ULDs, raised questions about how both could be accommodated. All groups considered that using the checklists should not require ergonomics training. This indicates a simple approach is needed which could favour concentrating on a ULD only checklist. However, there would be a need to ensure that other risks were dealt with and this might be accommodated by an overview approach to the risk assessment. Some training is needed but should be minimised. Pictograms are needed to help users judge body angles etc., must minimise costs to business of training. Tool must be self-explanatory if possible, incorporating prompts for inexperienced users. All groups wanted psychosocial factors to be considered at an early stage. There were provisos, however, such as the need for careful question design and keeping the ideas simple. A need for a clear link to the management approach in the revised HSG60 (HSE, 2002). SMEs need an approach that will identify key risks and possible control options in about 10 minutes. Users will need worked examples in accompanying guidance. Need a job-based approach, feeding through to control measures, initiating action at the time of the assessment. Larger organisations, e.g. manufacturing may need the possibility of a more detailed breakdown of risk so that they can consider job/task design. Need to get people at all levels involved in assessment process. The tool should raise awareness and facilitate such discussion. Build in a review stage to close the loop. Consider personal factors; past history of ill health, new employees, pregnant workers etc. The tool should be outcome-based rather than hazard-based. The tool should assess severity of risk factors - red/amber/green system? User requirements need to be defined for various groups – these are not well defined at present.

4.2.4 The Way Forward The results of the workshop and the checklist formats were discussed within the HSE. It was recognised that the decision aid option had technical merits in leading the user towards solutions, but would need extensive user studies. Within the timescales and resources available, the HSE felt that the best way forward was to develop the format in the existing HSE leaflet IND (G) 171 (L). This could be linked with a simple flow chart that would lead the user through decisions relating to specific risk assessments under the Manual Handling Operations (MHO) Regulations and the Display Screen Equipment (DSE) Regulations (1992), etc.

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4.3 FURTHER DEVELOPMENT OF THE TOOL USING THE HSE IND (G) 171 (L) FORMAT

The risk assessment tools were revised where possible, in line with issues raised at the workshop, as well as by taking into account weaknesses identified in studies. 4.3.1 HSE Leaflet Weaknesses Smyth’s (op cit.) findings are of particular importance in relation to any IND(G) 171 weaknesses. This study found that shoulder, neck and static postures were not identified by a majority of experts and non-experts with the IND(G) 171 checklist. Further, local stress, psychosocial, individual differences and some environmental risk factors were not identified. It seems that there is something about the questions that do not help the user highlight these risks. Examination of IND(G) 171 showed that shoulder and neck postures are not mentioned specifically. Also, static postures were not identified successfully throughout. Besides these, examination of IND(G) 171 shows that there is a heading which refers to “Awkward or Static Posture”. Those questions, which could be interpreted as referring to static posture shown below, do not appear to be clear enough to help the user identify static postures:

Cramped body position, and/or not enough space to change posture? Arms stretched or overhead for long periods?

In relation to local stress, psychosocial, and individual differences, it is not surprising that these factors are not easily identified by IND(G) 171. There are no clear questions covering these areas. Although the study by Smyth (op cit.) was limited in size, it provides some clear indications of the performance of IND(G) 171 by non-specialists in an environment with limited training. In the absence of a proper study of Risk Assessment Tools generally, the IND(G) 171 format, updated in the light of these findings, would appear to provide a sound basis for the HSG60(rev) risk assessment. To improve its sensitivity, the update would need to take account of the following risk factors:

Shoulders; • • • • • • •

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• •

Neck; Static postures; Localised stress/force; Psychosocial issues; Work environment issues; Individual differences.

This would have the following benefits:

It is similar to the existing risk assessment approach, i.e. familiar to many; It would obviate the need for a new revision and publishing a separate document.

The disadvantages are:

It would be advisable to produce a learning aid/supporting text to accompany it; There are assumptions about its usability that would need user trials to resolve.

4.3.2 Overview page with first stage filter Appendix 5 shows the reviewed prototype overview of the MSD Risk Assessment and Management Actions. This was designed as a flow chart to help the user select the appropriate

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route. It allows the user to carry out a DSE or MHO risk assessment and be guided by key questions to pick up potential ULD risks. It also includes a risk filter. The set of questions (in the box to the right of the DSE and MHO prompts) relating to complaints of discomfort etc., was intended to ensure that risk factors not picked up by either the DSE or Manual Handling assessments would stimulate further action. The set of questions relating to the workers seeming to have difficulty keeping up with the work and workers finding the work stressful were designed to pick up organisation influences. These questions were based on those used in the QEC. If DSE and MHO activities could be excluded, the user would continue to the next set of questions that were intended to highlight task based risk factors. In addition, further questions were included to cover symptoms and organisational factors. These questions were based on those used in the QEC. The next part of the flow chart was based on the original HS(G)60 (HSE, 1990) risk management process. It was modified to emphasise workforce involvement. At an early stage the user was encouraged to undertake what was termed an initial risk assessment by using the “checklist overleaf” (see next section). If the use of the checklist indicated risks then the users were expected to follow the rest of the risk management flowchart. 4.3.3 Second Stage Risk Assessment Tool The prototype Risk Assessment Tool was modified as a result of internal HSE consultation. The overall Risk Assessment Tool front pages and the top of each page reminded the user to undertake the assessment in conjunction with the workers. The format of the Risk Assessment Checklist followed the IND(G) 171 booklet, but with additional questions to cover the areas where Smyth (op cit.) identified weaknesses. In addition, pictograms were included (see Appendix 6). Risk Assessment Checklist started with questions about Repetition, in contrast to Force which was the first consideration in IND(G) 171. The importance of repetitiveness as a risk factor relates back to the strength of epidemiological evidence. The latter indicates that there is the most valid exposure-effect relationship between workplace risk factors for repetitiveness, especially in relation to tendon/ nerve disorders. There were further additions to the Risk Assessment Tool. These included questions about poor workstation design. These were intended to make the assessment process more comprehensive and took account of the TUC checklist deficiencies. The section on hand tool design was intended to cover issues not dealt with satisfactorily in the original IND(G) 171. Smyth (op cit.) identified limitations of IND(G) 171 in relation to local stress, psychosocial, and individual differences. As these sections were revised, questions were added to take account of these factors. The original IND(G) 171 section on Force was expanded. In addition, a further section on Local Force and Stress was added to reflect risk factors identified by Keyserling et al (1993) and the force criteria were based upon those found in OSHA and WAC. The section concerning risks associated with work for long periods without breaks or changes of activity (Section G), was extended from the original IND(G) 171. It was designed to help identify some psychosocial risk factors as well as general work pressure. Li and Buckle argued that the literature suggested no single psychosocial or work organisational factor is a predominant cause of ULDs. However, they state that time pressure and machine-paced jobs have been found to significantly correlate with lack of job satisfaction, fatigue and mental or physical health of workers. In addition they suggest that perception of Stress is related to how a

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person perceives and experiences the work system. So if a person “tells you that he is loaded and effortful, then he is loaded and effortful whatever the behavioural and performance measures may show” (Moray et al., 1979, cited in Li and Buckle). In order to assess both time pressure and stress, questions were added based on the QEC. These were phrased to encourage the user to ask the worker their perceptions. The section dealing with Work Organisation Arrangements was expanded from the original IND(G) 171. Further questions from sources such as the TUC checklist were included. Poor Environmental Conditions was expanded to include criteria such as examples of temperature. The vibration criteria were taken from the OSHA checklist. Finally, the section on Individual and Personal Factors was expanded to take account of previous illness or injuries.

4.4 FIRST ROUND CONSULTATION A modified version, amended in line with the comments, was provided to HSL. A questionnaire was developed and circulated with both the newest version of HSG60(rev), and the Tool, for external consultation. The consultation and comments gathering process was achieved using both a short questionnaire incorporating rating scales and also by providing a copy of the draft for marking up and return. The questions were based upon the purpose of the document as stated in the introduction, with some additional questions covering other aspects such as technical content and to what extent it is perceived to be helpful in managing ULDs. Consequently, this exercise was mainly concerned with gaining a wider view of the suitability and content of the draft, rather than examining its effectiveness in use, i.e. it does not examine the usability of the risk assessment checklist, as such. A total of 32 consultation packs were sent out, after approaching a group of around 40 potential consultees. This included a wide range of internal and external stakeholders from a cross section of industry as well as health and safety/ergonomics professionals. Some further consultation was performed to get feedback from other key stakeholders including the Occupational Health Advisory Committee (OHAC) working party. This part of the process was managed by BWED 7. Comments that applied to the risk assessment and filter were compiled and a detailed evaluation of the comments relating to the checklist was conducted. A more detailed listing of this process and the associated findings are reported elsewhere (ERG/01/15). 4.5 POST CONSULTATION RESULTS AND REVISION Revisions made in this phase were driven by comments received from the consultation exercise. There were mixed views on the Risk Assessment Tool. Positive comments about the design included:

Useful in breadth • • •

Bullet points incorporated into checklist Good use of figures to support key points

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Negative comments about the design included:

Too long • • • •

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Ways of controlling risk not adequate Solutions not clear and incomplete Looks daunting

Clearly it seems difficult to balance all views. The results do, however, indicate that a simpler form of risk assessment tool was wanted. The evaluation exercise was of limited value in assessing the risk assessment tool because it was not specifically directed at the tool, but the whole document. It should be noted also that the main context document had not been properly “married“ to the risk assessment tool at this stage. Further, as no usability trials were undertaken the comments are likely to reflect personal views rather than applied usability issues. After internal HSE and HSL consultation, it was decided that the tool should be shortened. Further, the constraint of following the IND(G) 171 format as closely was lifted, but it was agreed that the prototype assessment should still be in two parts. Part 1: This would be a simple one page initial assessment approach similar to that produced by Graves in 1994, to be referred to as a ‘Filter’. This would be modified to include exposure factors, re-order the frequency etc., risk factors, include warning signs, and provide a section to identify static components. Each risk factor would be referenced in the main body of the HSG60(rev) document. Part 2: The second part would be described as a ‘Worksheet’ and be more detailed. This would enable a more explanatory assessment of risks in the workplace to be made, with suggested solutions. It should be noted that at the start of this process, the relevant section of HSG60(rev) was redrafted to better reflect the details of the risk assessment process. 4.6 EVALUATION OF FORMAT OPTIONS Feedback from the consultation exercise suggested that the Filter and Worksheets in their current form were too long and complex for non-specialist users. As a result, the flow chart approach and references to particular body parts were removed from the Filter leaving two options for its format. Two prototype formats of the Risk Assessment Worksheets were also compiled. These two options were then circulated to a limited number of ergonomics professionals (10) with a questionnaire on aspects of usability. Questions centred on which of the two formats were:

Easier to use; Easier for non-specialists to use.

For the Filter, additional questions were asked regarding:

Thoroughness of observation; Accuracy of prediction (i.e. in predicting the need for further risk assessment).

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4.6.1 Results and Discussion - Filter Results from this exercise indicated a clear preference for one format. If this format were to be applied, however, a number of changes would be required in order for the Filter to suitably predict the need for further risk assessment. As in the HSE Guidance on the Manual Handling Operations Regulations 1992 (L23, 1998), the filter prototypes were designed with the purpose of avoiding ‘wasted time and effort’. The use of the filter will only be worthwhile, therefore, where the relevance of the risk factors can be determined quickly, i.e. within 10 minutes. If it is not clear from the outset that this can be done, it is better to opt immediately for the more detailed risk assessment. This purpose sets the aims of the Filter – a quick, user-friendly tool that will enable non-specialists to determine whether there is a need for a full risk assessment. The feedback on usability of the Filter suggested that there was preference for the simple decision criterion of: ‘If you answer yes to any of the steps, you should make a full risk assessment of the task.’ This decision criterion however, led to problems with sensitivity of prediction regarding the need for a full risk assessment. Risk factors of psychosocial factors and lighting, for example, could be present in isolation in a workplace, and the filter would indicate the need for a full ULD risk assessment (e.g. a worker performing tasks in a stressful environment but with no physical risk factors for ULD being present). This was an obvious sensitivity shortcoming of the Filter, as almost all tasks that the Filter might be applied to would lead to the decision that a full risk assessment was required. In other words, the Filter was not filtering. As a result the following options were considered:

Including all risk factors but using a different decision criterion; • • Using the decision criterion highlighted in usability questionnaire results, but

focusing only on the stronger risk factors for ULD injury/illness. The decision was made to maintain the initial criterion for the Filter and to include only risk factors for which there was considered strong evidence to suggest that their presence (in isolation of other risk factors) would increase the risk of ULDs. The resultant version of the Risk Filter can be found in Appendix 7. 4.6.2 Results and Discussion – Risk Assessment Worksheets Results for the two versions of the risk assessment checklist were mixed with no clear preference for one version over the other. However, the comments made were incorporated into a modified format. The revised format can be found in Appendix 8. 4.7 USABILITY ASSESSMENT AND APPRAISAL Three independent ergonomics practitioners were requested to provide an appraisal of the revised risk assessment sheets and filter. The appraisal required application of the Filter and Worksheets to at least three jobs/tasks per professional. They were asked to report on how well the assessment methodology worked in practice, the instructions, the effectiveness or otherwise of the Filter, the effectiveness of the Worksheets in identifying areas where there is a risk of ULDs, and generally any problems with the sensitivity and specificity of the package. This exercise was extremely valuable in that it identified a number of issues in relation to the usability as well as some other outcomes. Key issues raised in reports received from each of the professionals included:

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Some minor formatting and layout issues; • • •

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Confirmed differences in sensitivity in the two levels of assessment; Poor shoulder and neck postures were not well targeted with the questions (including reaching); There was no place to record work scheduling/rest breaks; Suggestions to clarify potential points of misunderstanding (particularly for non-specialist users); More emphasis was needed to encourage users to consider the combination of risk factors in coming to a conclusion regarding the level of risk; Many other useful but minor points (as well as issues that had already undergone significant consideration and review and where decisions had already been made).

These comments were reviewed and applied to the assessment tool where appropriate. The review was undertaken, firstly by the working group responsible for the development of the risk assessment tool (consisting of 4 ergonomists), and secondly by the broader HS(G)60 writing group ( a multi-disciplinary team). 4.8 FINAL ROUND CONSULTATION

The final evaluation stage consisted of the full draft of HS(G)60 including the Risk Filter and Risk Assessment Worksheets being forwarded to 68 internal and external consultees comprising a cross-section of industry representatives, health and safety, ergonomics and occupational health professionals. Comments were received back from 35 consultees. Comments specific to the Risk Filter and Worksheets were considered and alterations were made where appropriate. Lastly, the working group conducted a question-by-question review, looking at issues of consistency and layout of the Filter and Worksheets. The content, format and instructions were then finalised. The final versions of the filter and worksheets are presented in Appendix 9. They are also available on the HSE website (http://www.hse.gov.uk/msd/risk.htm). 4.9 SUMMARY The Filter and Worksheets provide an example risk assessment method that can be utilised as part of the seven stage management approach outlined in HSG60(rev). The aim of the tool is not to quantify risk, but to identify workplace risk factors for ULDs and to translate to this into action (i.e. controlling risks to a level that is as low as reasonably practicable). The tool specifically avoids attempting to quantify the risk of ULDs due to the difficulties inherent in designing such a tool for non-specialist users. The tool aims to provide guidance for assessing and minimising the risk through positive action that encourages compliance with the law and makes the workplace safer. The content of the Risk Filter and Risk assessment Worksheet is based on three primary sources: OSHA; WAC; and the work of Li and Buckle. The format of the tool has been driven by extensive stakeholder and expert input. The two-stage approach allows users to avoid unnecessary effort by identifying only those tasks that present a significant risk of ULD, thereby focusing assessment efforts on the higher risk tasks. In order for the Risk Filter to have enough sensitivity so as not to identify all tasks as requiring further assessment, psychosocial and individual factors have been excluded at this stage. This does not mean that they are not important risk factors, but simply that they are not enough to stimulate a full assessment if they are present in the absence of physical risk factors for injury. The Risk Filter sets out an approximate threshold below which the risk of ULDs is likely to be low. This threshold is not absolute. The guidelines in the Risk Filter and Worksheets are provided as an aid to risk assessment. They have been developed from the scientific literature

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and from expert opinion. As such, they are not precise exposure limits, but are intended to help in identifying the potential risks and possible measures to reduce them. The advantage of providing values in the risk assessment criteria is that it gives at least some indication to employers about what aspects of a task should be considered to present greatest risk as far as ULDs are concerned. However, building such a feature into a simple risk filter and worksheet is difficult due to the complex interaction of risk factors. A good example of the difficulty in choosing quantitative figures can be seen in the ‘2 hour’ value for duration. It would be unrealistic to suggest that the 2-hour period is a limit that can be applied anything but pragmatically. Consideration of the combination of risk factors and their varying intensity would obviously effect the duration of exposure that is likely to be problematic in terms of presenting an increased risk of ULD.

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5 GENERAL DISCUSSION AND CONCLUSIONS

The two-stage approach in the Risk Filter and Risk Assessment Worksheets (HSE, 2002), allows users to prioritise ULD risk assessment by initially filtering out low risk tasks. In order for the Risk Filter to operate effectively psychosocial and individual factors have been excluded in the initial screening but are fully assessed in the second stage of the risk assessment process. This does not mean that they are not considered important risk factors but simply that they are not felt to be sufficient to trigger a full ULD assessment if none of the physical risk factors for injury are present. It is important to note that the Risk Filter sets out an approximate threshold below which the risk of ULDs is likely to be low. This threshold is not absolute. The guidelines in the Risk Filter and Worksheets are provided as an aid to risk assessment and have been developed from the scientific literature and from expert opinion. As such, they are not precise exposure limits, but are intended to be used alongside the published guidance (HSE 2002), to identify potential risks and possible measures to reduce them. There are advantages in providing some numerical guidance values for users. Firstly, they provide an indication to employers about aspects of tasks that potentially pose a higher risk and secondly, assist in prioritising actions to control the risks identified. A similar concept is raised by Fallentin et al. (2001) who state:

“The dilemma for the quantitative standards is a conflict between the intention of providing numerical acceptance criteria differentiating between hazardous and safe jobs, and the paucity of scientifically well founded data allowing such quantitative risk estimates to be established.”

Buckle and Devereux (1999), however, argue that although exposure-response relationships are difficult to ascertain, the current knowledge base does allow us to identify workers at high risk of ULD. Lastly, as HSE’s current policies place emphasis on evaluating interventions made in the area of MSDs, it is foreseeable that the guidance document, including the Risk Filter and Risk Assessment Worksheets will undergo a further process of evaluation. It can be concluded that the Risk Filter and Risk Assessment Worksheets provide an example of a risk assessment methodology that can be utilised as part of the seven stage management approach outlined in HSE’s guidance on ULDs (HSE 2002). The tools are not intended to quantify risk but rather to identify risk factors for ULDs and to translate this into positive action to control risks to a level that is as low as reasonably practicable. In designing the tools, the emphasis has been ease of use by non-specialists and the consultative process has helped to ensure that the needs of a wide range of users have been considered. The tools provide guidance for assessing and minimising risks through positive action, which, it is hoped, will aid compliance with the law and make the workplace safer.

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6 APPENDICES

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6.1 LITERATURE REVIEW SUMMARY TABLE

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Types of tool(s) Tool characteristics Study type and application Findings Author A workplace screening checklist

A worksite screening checklist

Identification of ergonomic risk factors for musculoskeletal disorders in the nursery industry. Survey - interviews with nursery managers and supervisors, identification of ergonomic risk factors by the use of a worksite screening checklist, and scrutiny of workers' injury and illness records.

Evidence of risk factors and musculoskeletal disorders similar to those reported in other industries, and highlighted priority job tasks for intervention

Meyers, J.M., Miles, J.A., Faucett, J., Janowitz, I., Tejeda, D.G., Kabashima, J.N., American Industrial Hygiene Association Journal; Feb. 1997, Vol.58, No.2, p.121-126.

Simple observational instrument for general surveillance of ergonomic exposure hazards

A checklist to score jobs according to postural stress (comprising factors of posture, force and repetition).

Investigate musculoskeletal pain in relation to postural stressors. A random sample of workers (n=155) were interviewed with regard to pain and various potential confounders and effect modifiers. Exposure-response relationships were examined in defined factory floor occupations

Years on the job, force and a summed unnatural posture score was significantly associated with pain in the trapezius region Overall unnatural posture score significantly associated with musculoskeletal pain at any anatomical site. None of the explanatory variables were associated with back pain.

Schierhout, G.H., Myers, J.E., Bridger, R.S., International Journal of Industrial Ergonomics; Aug. 1993, Vol.12, p.3-11.

Ovako Working Posture Analysing System (OWAS)

Postural analysis and risk

Working postures and work activities of mechanics in 42 garages in the Netherlands were observed and recorded using an extended version of the OWAS Observations of working postures in garages

Four particular activities cause poor working postures, although the load of three of these can be substantially reduced if a vehicle lift is used work methods can substantially reduce the daily ergonomic load, although some activities still impose harmful working postures

Kant, I., Notermans, J.H.V., Borm, P.J.A., Ergonomics; Feb. 1990, Vol.33, No.2, p.209-220.

28

Types of tools Tool characteristics Study type and application Findings Author Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms

The questions are forced choice variants and may be either self-administered or used in interviews. They concentrate on symptoms most often encountered in an occupational setting.

Standardised questionnaires for the analysis of musculoskeletal symptoms in an ergonomic or occupational health context are presented.

The reliability of the questionnaires is acceptable. Specific characteristics of work strain are reflected in the frequency of responses to the questionnaires.

Kuorinka, I., Jonsson, B., Kilbom, A., Vinterberg. H., Biering-Sorensen, F,., Andersson, G., Jorgensen, K., Applied Ergonomics; Sep. 1987, Vol.18, No.3, p.233-237. Illus. 8 ref.

Exposure assessment strategies for work-related risk factors for musculoskeletal disorders.

Considers the related topic of the critical time window of risk factors for musculoskeletal disorders.

Discusses the design of assessment strategies for work-related risk factors for musculoskeletal disorders. Suggests that the parameters of an exposure variable should address the three principal exposure dimensions: intensity, frequency, and duration.

Strategies depend on the risk factors of interest, features of the measurement device, feasibility considerations, and variation at the workplace.

Burdorf, A., Beek, A.,van-der Scandinavian Journal of Work Environment and Health. 1999, vol.25, supp.4, p.25-30.

Reproducibility of a self-report questionnaire for upper extremity musculoskeletal disorder risk factors.

Visual-analogue and categorical scales were designed to represent responses relating to primary work as well as second job and hobbies or non-work activities.

Discusses a self-report questionnaire developed to evaluate the potential for assessment of possible risk factors for musculoskeletal disorders. Seventy-one tree nursery workers completed the scales twice in consecutive weeks, and the findings were evaluated. industry or temporary and seasonal work

Results show potential for future application of similar scales in industry or temporary and seasonal work to evaluate exposure to upper extremity risk factors.

Spielholz, P., Silverstein, B., Applied Ergonomics. Oct. 1999, vol.30, no.5, p.429-433.

29

Types of tools Tool characteristics Study type and application Findings Author In Musculoskeletal Epidemiology Are We Asking The Unanswerable In Questionnaires On Physical Load.

Questionnaires On Physical Load

Considers the challenges of trying to establish a robust exposure assessment strategy in musculoskeletal epidemiology. Discusses the contribution made by using.

Concludes that while assessment calls for creative approaches combining different methods and measurement techniques, there is a role for use of questionnaires in the assessment of physical load at work.

Burdorf, A., Beek, A.J.,van-der Scandinavian Journal of Work Environment and Health. Apr. 1999, vol.25, no.2, p.81-83.

Preventing work-related musculoskeletal disorders.

Describes user-friendly tools to assess musculoskeletal risk.

Discusses the issue of work-related musculoskeletal disorders. Provides a definition of the term and analyses the size of the problem. Describes ways in which interventions in work systems are being used to prevent work-related musculoskeletal disorders.

Briefly describes how guidance has been published in the form of European directives and Health and Safety Commission regulations and guidance.

David, G., Safety and Health Practitioner. Jul. 1999, vol.17, no.7, supplement, p.4-6. Both are based on an ergonomics approach to risk assessment and identifying solutions.

Interview versus questionnaire for assessing physical loads in the population-based MUSIC-NORRTAELJE study.

Presents the Music-Norrtaelje study which aims to find health risk factors which cause low back pain, neck/shoulder disorders and other musculoskeletal problems. The study period was three years between 1993 to 1996 and data was collected via questionnaire. Looks at a typical working day, assesses energy expenditure, work postures, manual material handling for work and leisure time.

Wiktorin, C., Vingard, E., American Journal of Industrial Medicine. May 1999, vol.35, no.5, p.441-445.

30

Types of tools Tool characteristics Study type and application Findings Author Current techniques for assessing physical exposure to work-related musculoskeletal risks,

emphasis on posture-based methods.

Methods are critically reviewed. The applications of these techniques in ergonomic and epidemiological studies are considered, and their advantages and shortcomings are highlighted. A strategy that considers both the ergonomics experts' view and the practitioners' needs for developing a practical exposure assessment tool is then discussed.

Physical exposure to risks for potential work-related musculoskeletal injuries has been assessed using a variety of methods, including pen and paper based observation methods, videotaping and computer-aided analysis, direct or instrumental techniques, and various approaches to self-report assessment.

Li, G., Buckle. P., Ergonomics. May 1999, vol.42, no.5 p.674-695.

An improved musculoskeletal discomfort assessment tool.

self-reported musculoskeletal assessment tool - may be particularly useful in prioritising ergonomic intervention for these disorders.

A self-reported musculoskeletal assessment tool was administered to employees of a public utility company. Results were analysed to determine if the self-reports could adequately predict whether or not an employee reportedly sought medical or therapeutic treatment for a work-related discomfort.

As a result of this exercise an easy to administer, self-reporting discomfort tool was developed and validated based upon a large industrial population. It is anticipated that this tool will be useful in auditing and surveillance for musculoskeletal disorders.

Marley, R.J., Kumar, N., International Journal of Industrial Ergonomics. Jan. 1996, vol.17, no.1 p.21-27.

31

Types of tools Tool characteristics Study type and application Findings Author Assessment of risk factors for development of work-related musculoskeletal disorders (rsi).

Combines a video image of the worker performing the task with superimposed quantitative information on risk factors. Contains methodology; rationale for the quantities displayed and workplace examples.

Describes an approach to assessing exposure to risk factors for development of work-related chronic musculoskeletal disorders (repetitive strain injuries) of upper limbs and low back. Continuous monitoring with both muscle activation and video is useful for identifying risk factors for both acute and chronic injuries in many workplaces.

Gives information on chronic low-level loading not easily identified with observational methods, also quantified information necessary for exposure measures in epidemiological studies

Wells, R., Moore, A., Applied Ergonomics. Jun. 1994, vol.25, no.3, p.157-164.

Reducing the risk of musculoskeletal disorders. Method

First step is risk identification/assessment. Suggested methods for risk identification are: general observations; employee discussions; employee questionnaires; review of medical data; quantitative evaluations; job consistency methods; fatigue considerations Data then converted to information for risk analysis.

Describes a method for reducing the risk of musculoskeletal disorders. Recommendations are formulated following by their implementation. Once the programme is established, monitoring and evaluation should be conducted to determine long term effectiveness.

Concludes that this S-step method provides a basic framework for implementation of an ergonomics programme in an organisation, however an ergonomics specialist may be required in some cases.

Fragala, G,. Professional Safety. Sep. 1992, vol.37, no.9, p.22-25.

32

Types of tools Tool characteristics Study type and application Findings Author Upper limb disorders: assessing the risks.

Guidance and checklists

CA: Health and Safety Executive SO: 1994. 21pp. (IND(G)171(L)).

The Scientific Basis for Making Guidelines and Standards to Prevent Work-Related Musculoskeletal Disorders

Heavy physical work, manual handling, repetitive work, static work, and upper arm abduction were related to neck disorders.

The scientific basis of occupational regulations aimed at the prevention of work related musculoskeletal disorders was discussed. Risk assessment was based on strong scientific evidence derived from epidemiological studies on human populations and experimental studies in the laboratory. Numerous epidemiological studies, including cross sectional, case control, and prospective studies, were reviewed. In general, regulatory actions were founded on risk assessment and risk management Ergonomic standards aimed at cumulative trauma disorders and all work related musculoskeletal disorders were developed in the US.

Shoulder disorders were encountered in the food industry, industrial assembly industry, and construction and ship building industry, possibly due to heavy work loads and vibration exposure. Manually strenuous jobs, repetitive work, tasks requiring high grip force, and vibration exposures were associated with elbow, wrist, and hand disorders. Experimental studies used biomechanical modelling, psychophysical criteria, and physiological measurements to determine the influence of exposures on musculoskeletal health.

Viikari, Juntura, ERA Ergonomics, Vol. 40, No. 10, p 1097-1117.

33

Types of tools Tool characteristics Study type and application Findings Author Observational Methods for Analysing Working Postures in Agriculture

The four main steps of an observational method were observation, classification, coding, and analysis. Observational methods included OWAS, WOPALAS, TRAM, PWSI, Graf's method, AET, EWA, PLIBEL, ARBAN, RULA, the Keyserling system, VIRA, PEO, HAMA, and Stetson's method

The observational strategies used for analysing working postures in agriculture were reviewed. The observational method of choice depended on the nature of the work situation, the work environment, the part(s) of the body being studied, and desired accuracy. Observations were either conducted at the workplace or videotaped. OWAS, WOPALAS, TRAM, ARBAN, PWSI, and Graf's method were time sampled methods. Real time sampling methods included VIRA, PEO, Keyserling's, Stetson's, and Forman's method. AET, EWA, PLIBEL, RULA, HAMA, and the Cube model were task sampled methods.

Real time, continuous observations were the most accurate. The validity, reliability, and sensitivity of the observational methods were considered highly important. Other factors to be considered when using an observational method included reactivity, availability, and usefulness. Most of the observational methods currently in use were computerized. The author concludes that most observational methods must be improved before they can be applied to agricultural posture assessment in the field.

Pinzke, S., Journal of Agricultural Safety and Health, Vol. 3, No. 3, p 169-194.

Predictors of Work Disability in Work-Related Upper-Extremity Disorders

Fibromyalgia Impact Questionnaire (FIQ). Modified Stanford Health Assessment Questionnaire (SHAQ)

The characteristics of work related upper extremity disorders were investigated in order to determine the predictors of work disability. A total of 106 consecutive patients were examined between January 1994 and May 1996 at two rehabilitation clinics in New Zealand. Occupational and medical history information was obtained and self-rating disability questionnaires were completed.

Best predictor of current work hours was the score on FIQ. Other suitable predictors of disability included the SHAQ, weeks of absence, passive flexion of the affected wrist, and neck stiffness or pain during movement. FIQ and SHAQ scores were highly correlated, with a coefficient of 0.70. The self-rated scores were also well correlated with several objective measurements, such as wrist flexion and grip.

Friedman, P.J., Journal of Occupational and Environmental Medicine, Vol. 39, No. 4, p.339-343.

34

Types of tools Tool characteristics Study type and application Findings Author Evaluation of Symptom Surveys for Occupational Musculoskeletal Disorders

The goal of the Nordic Musculoskeletal Questionnaire (NMQ) was to be a simple standardized questionnaire that could be used as a screening method for musculoskeletal disorders as part of ergonomic programs and epidemiological studies of musculoskeletal disorders.

The usefulness of two symptom surveys was evaluated through a review of the literature on the acceptability, validity, and reliability of the NMQ and by presenting new analyses which assess the validity and reliability of the NIOSH symptom survey. Reliability was assessed through test retest methods and inter item correlations between similar questions. Validity was assessed by comparison with results from physical examination assessments of workers and self reports of workers seeking medical care.

The evaluation of the validity of both these symptom surveys focused on evidence for a relationship between reports of discomfort and other objective measures of impairment, such as physical examination manoeuvres. Both reliability and validity were acceptable for the purposes of workplace ergonomics programs. Implications for use of these surveys for prevention and treatment outcomes research are discussed.

Baron, S, Hales, T., Hurrell, J., American Journal of Industrial Medicine, Vol. 29, No. 6, p. 609-617. .

An Improved Musculoskeletal Discomfort Assessment Tool

Pictograph of 25 different body regions on which the subjects were asked to rate the frequency of musculoskeletal pain during the previous year and the severity of the discomfort according to an 11 point scale.

The questionnaire package was administered to 797 employees, 587 males, of a public utility company in the northwestern US. An examination of the distribution of the subjects who reported that they had or had not sought treatment and frequency at which musculoskeletal discomfort was reported enabled classifying the subjects into three zones: those 'very likely', 'somewhat likely', and 'not likely' to seek treatment.

The frequency of experiencing musculoskeletal discomfort and the severity of the symptoms were significantly associated with the probability of seeking treatment The authors conclude that this approach can be effectively used as a surveillance tool for proactive ergonomic management. After the initial assessment, the tool can also be utilised to conduct regular audits to monitor worker perceptions or help evaluate the effectiveness of changes in work design.

Marley, R.J., Kumar, N., International Journal of industrial Ergonomics, Vol. 17, No. 1, p.21-27.

35

Types of tools Tool characteristics Study type and application Findings Author A Method Assigned for the Identification of Ergonomic Hazards - PLIBEL

A checklist for the identification of ergonomic hazards in the workplace

Literature was reviewed to make an association between defined work characteristics and occupational musculoskeletal disorders. Relevant items were placed into the checklist, the checklist was field tested for validity at 200 workplaces through workplace observations and against a well documented existing method (AET). Reliability was evaluated by having 24 ergonomically skilled people perform four assessments using PLIBEL.

The reliability test yielded fair to moderate agreement. The checklist did not make use of graded steps; rather it required only dichotomous answers. PLIBEL analysis was directly related to the individual observed worker, and not to the job and workplace, as was done in AET. The author concludes that the continued use of PLIBEL would probably increase the understanding of ergonomics hazards at workplaces and improve ergonomic working conditions.

Kemmlert, K., Applied Ergonomics, Vol. 26, No. 3, p.199-211.

The Strain Index: A Proposed Method to Analyse Jobs for Risk of Distal Upper Extremity Disorders

A methodology for performing a semi quantitative job analysis, using physiology biomechanical, or psychophysical critical threshold response; epidemiological data; or a combination.

Physiology, biomechanics, and epidemiology were used in developing the Strain Index. The scientific basis for the Strain Index was discussed and presented with six task variables considered in the methodology. The method relied on multiplicative interactions between these variables, which were intensity of exertion, duration of exertion per cycle, efforts per minute, wrist posture, speed of exertion, and duration of task per day. Application of the Strain Index was described.

Preliminary testing indicated that the Strain Index could be effective in analysing jobs and predicting hazard potential. Limitations of the Index included; its application only to distal upper extremity; and it predicted a spectrum of morbidity, not specific disorders. The Index was able to predict primarily disorders of the muscle/tendon units and carpal tunnel syndrome (CTS) and assessed the job as opposed to individual workers performing the job. It did not account for mechanical compression, Needs further refinement, and validation, and evaluation in future studies.

Moore, J.S., Garg, A., American Industrial Hygiene Association Journal, Vol. 56, No. 5, p.443-458.

36

Types of tools Tool characteristics Study type and application Findings Author Development of Observational Methods for Estimation of Exposure to Workplace Postural Stress

An observational instrument for measurement of workplace ergonomic stressor exposure - to assess static loading (posture), force and repetitious elements of their work..

South African workers from four labour intensive manufacturing industry jobs were observed using the instrument to assess the static loading (posture), force and repetitious elements of their work. Other factors such as extreme temperature, piece rate, precision requirements, mental concentration and seasonality were investigated as potential confounders and effect modifiers. Statistical analyses were used to interpret reports of musculoskeletal pain.

The authors conclude that the observational instrument meets the objectives for capacity, versatility and generality, Additional research is needed to determine adequate measures of postural constraint, repetition, and to investigate the effects of using composite measures for exposure characterization.

Schierhout, G.H., Bridger, R.S., Myers, J.E., Occupational Medicine, Vol. 44, No. 5, p.262-266, 1994.

A Checklist for Evaluating Ergonomic Risk Factors Associated with Upper Extremity Cumulative Trauma Disorders

Checklist for evaluating ergonomic risk factors of repetitiveness, localised mechanical stress, forceful exertions, awkward posture, and tool use.

A 42 month longitudinal study was carried out in a large automotive corporation with a total of 335 jobs from four sites. The evaluations were compared with an expert evaluation using two way contingency tables.

There was general agreement between the checklist results and the expert results. The authors conclude that the checklist is an effective rapid screening tool for identifying jobs that expose workers to harmful ergonomic stresses.

Keyserling, W.M., Stetson, D.S., Silverstein, B.A., Brouwer, M.L., SO: Ergonomics, Vol. 36, No. 7, p.807-831, 1993.

37

Types of tools Tool characteristics Study type and application Findings Author RULA: A Survey Method for the Investigation of Work-Related Upper Limb Disorders

A rapid screening technique known as rapid upper limb assessment (RULA) consisted of observing workers through several work cycles and recording the movements made, identifying muscular efforts that were associated with each working posture and force exertion, and recording the relation of each working posture to the work equipment and furniture.

The data were coded using diagrams of body postures and scored using scales developed from published studies on the relationships between neck, trunk, and upper limb motions and symptoms in these body parts. The total scores were used in conjunction with UK HSE guidelines for preventing upper limb musculoskeletal disorders to generate action levels. The technique was applied to 16 experienced video display terminal (VDT) operators performing a 40 minute data entry task. The subjects were asked to rate any perceived symptoms of pain in the neck, trunk, upper and lower arm, and wrist while performing the task. The RULA scores for these body parts were compared with the subjects' symptom scores.

The RULA scores were significantly related to self reported pain in the neck and lower arm, but not for the trunk, upper arm, or wrist. The authors conclude that the RULA technique rapidly assesses loading on the neck, trunk, and upper limbs. It requires no special equipment. It should be useful for evaluating risk factors for upper limb disorders caused by repetitive work.

McAtamney, L., Corlett, E.N., SO: Applied Ergonomics, Vol. 24, No. 2, p.91-99, 1993.

Occupational and Individual Risk Factors for Shoulder-Neck Complaints: Part I - Guidelines for the Practitioner

Guidelines for assessing occupational and individual risk factors for shoulder/neck injuries were presented.

These guidelines were targeted to occupational health and safety personnel, production engineers, safety controllers, and management personnel responsible for planning new work tasks and analysing the acceptability of occupational shoulder/neck exposure. The recommendations were derived from physical exposure/chronic effect and individual factor/chronic effect relationships documented in the research literature.

Estimation of physical exposure to tasks which may produce shoulder/neck injuries included evaluation of exposure levels, exposure repetitiveness, and exposure durations. Introduction of time limits was recommended to avoid negative effects of physical inactivity or to reduce exposure levels in individuals subjected to maximum physical activity.

Winkel, J., Westgaard, R., International Journal of Industrial Ergonomics, Vol. 10, Nos. 1-2, p.79-83, 1992.

38

Types of tools Tool characteristics Study type and application Findings Author Exposure Variables in Ergonomic Epidemiology

The exposure variables were divided into five main categories: posture, motion/repetition, material handling, work organisation, and external factors.

This review presented exposure variables used in ergonomic epidemiology, particularly those that concern mechanical trauma to the musculoskeletal system occurring at the workplace. The topics discussed included exposure definition, exposure assessment, exposure variables, dose assessment, and exposure evaluation for epidemiological studies of work related musculoskeletal disorders.

These variables can be expressed as peak measure, time average, intensity, or cumulative exposure. No consensus currently exists on how different exposure variables should be pooled and interpreted as single estimates of cumulative exposure. The author suggests for future studies that exposure be described by different exposure variables giving an exposure profile and not by a single estimate of the exposure

Hagberg, M., American Journal of Industrial Medicine, Vol. 21, No. 1, p.91-100, 42 1992. .

39

6.2 PROTOTYPE TOOL

40

41

6.3 BODY PART SPECIFIC CHECKLISTS

42

Checklist A Symptoms in hand/ wrist/ arm

NO

POSSIBLE RISKCheck why task is donethis wayProvide support or toolSee Solutions A4

Is any part of the hand / wristused to a hammer?More than 10 timesorFor more than 2 hours total per work day?

Gripping an unsupportedobject weighing 10 lbs. ormore per hand orsimilar forceFor more than 2 hours total per work day

Repeating similar patterns ofmotion11 or more times per minuteFor more than 2 hoursconsecutively per work day

RISK COULD BE LOWReassess if there are jobchanges or reportedsymptoms

Are hand tools with highvibration used?More than 30 min total per work dayorAre hand tools with moderatevibration used more than 2hours total per work day

STARTSymptoms in hand / wrist/

arm

Notes• Observe work for more than one operation or cycle• Work day means equivalent of an 8 hour shift

Is the task carried outw ith a bent w rist?For more than 2 hours perwork day

POSSIBLE RISKCheck why posture ispoor

-Tool design- Machine design

See Solutions A1

POSSIBLE RISKCheck why task is donethis wayProvide toolSee Solutions A2

Pinch gripping an unsupportedobject weighing 2 lbs or more?orApplying 2 lbs pinch force formore than 2 hours total per work day?

2 lbs. pinch force or moree.g. holding small binder clipopen

POSSIBLE RISKCheck why task is donethis wayProvide toolSee Solutions A3

10 lbs. of similar force e.g.crushing the sides of analuminium coke can

POSSIBLE RISKCheck why task is donethis wayIncrease task variety androtate to jobs usingdifferent musclesSee Solutions A5

As part of checking job, andfinding solutions, carry out amore detailed assessment usingtools in Appendix D

REASSESSReturn to Overviewof MSD RiskManagement

Examples include: jig saw s,grinders, and sanders

POSSIBLE RISKCheck vibration type/levels and provideinsulationSee Solutions A6

Examples include:chainsaw s, jack hammers,percussive tools, rivet ing orchipping hammers

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

YES

43

Checklist B Symptoms in arm/ neck

Is the task being carried outwith the hands above heador elbows above theshoulderFor more than 2 hourstotal per work day

STARTSymptoms in arm/ neck

–YES–––––

POSSIBLE RISKCheck why task is donethis way and why postureis poor

- Workplace design- Machine design

See Solutions B1

NO

Notes• Observe work for more than one operation or cycle• Work day means equivalent of an 8 hour shift

NO

POSSIBLE RISKCheck why task is donethis way and why postureis poor

- Workplace design- Machine design

See Solutions B2

NO

NO

Repeating similar patternsof motion 11 or more timesper minuteFor more than 2 hoursconsecutively per work day

Working with the neck bent or twistedFor more than 2 hours total per work day

As part of checking job, and findingsolutions, carry out a more detailedassessment using tools in Appendix D

NO

––––––––––––––YES–––––

––––––––––YES–––––

RISK COULD BE LOWReassess if there are jobchanges or reported symptoms

REASSESSReturn toOverview of MSDRisk Management

Does the task involvelif t ing 25 lbs. above theshouldersOrAt arms lengthmore than 25 times perwork day

Do the visual demands ofthe task require the workerto view fine details

POSSIBLE RISKCheck why task is donethis way and why postureis poor

- Workplace design- Machine design

See Solutions B3

POSSIBLE RISKCheck why task is donethis way and why postureis poor

- Workplace design- Machine design

See Solutions B4

POSSIBLE RISKCheck why task is donethis way

Increase task varietyand rotate to jobs usingdifferent musclesSee Solutions B5

––––––––––––––––––––––––––––YES–––––

–––––––––––––––––––––––––––YES–––––

44

6.4 WORKSHOP PROGRAMME AND DELEGATE LIST

45

HS(G)60 Checklist Workshop 16th March 2001

HSE, St Dunstan’s House

Southwark

PROGRAMME

10:30 Registration and Coffee 10:40 10:40 Introduction to day Len Morris 10:50 10:50 Outline of development of HSG(60) Rod Graves 11:10 MSD Assessment Approach Key Issues 11:10 Group Discussions – Approaches to Risk Syndicates 12:15 Assessment 12:15 Feed back Syndicate Reporters 13:00 Working Lunch 13:10 13:10 Group Discussions - Checklist Options Syndicates 14:45 14:45 Group Feedback (including tea) Syndicate Reporters 15:20 Summary 15:30 End Rod Graves Len Morris

46

HS(G)60 Checklist Workshop 16th March 2001

HSE, St Dunstan’s House

Southwark

DELEGATE LIST AND SYNDICATE GROUPS

Name Organisation Len Morris HSE Ron McCaig HSE Rod Graves Heriot Watt University Nick Monnery Nat West Steve Baker TRW Bill Bennett Ladbrokes Colin MacKay HSE Trevor Shaw HSE Chris Quarrie HSE Mike Gray HSE Martyn Peel HSE Sarah Tapley HSE Jackie Mee HSE Malcolm Darvill HSE CIA Representative CIA Wendy Morris Inst. for Occ. Ergonomics Alan Vogan Tokheim UK Ltd Nigel Bryson GMB Clare Friend HSE Margaret Hanson Inst. of Occ. Medicine Roger Haslam Loughborough University Andy Nicholson Hu-Tech Associates Peter Buckle University of Surrey

Group A Group B R Graves L Morris M Darvill C Friend S Tapley P Buckle A Nicholson G Frith S Baker M Smith N Bryson Group C Group D T Shaw C MacKay C Quarrie M Peel W Morris M Gray R Haslam M Hanson N Monnery B Bennett J Mee

47

6.5 AMENDED RISK ASSESSMENT TOOL - OVERVIEW

48

49

6.6 AMENDED RISK ASSESSMENT TOOL - WORKSHEETS

50

RISK FACTOR Are there any factors in the job th

A RAPID, AWKWARD OR FREQthan 2 consecutive hours in a wo

1

Repeating • the same motions every few • a cycle of motions involving

twice per minute 2

• shoulder/arm movement - regpauses or almost continuous arm

• Wrist/hand repetitive movemsimilar repeated motion patterns 11 or

B AWKWARD OR STATIC POSDoes job involve:

1 Awkward movements such as; • twisting or rotation of wrist • movement of wrist from side• very bent fingers and wrist, • deviated or bent wrist? • pinch grips i.e. between thumb and finger

2 Hands and wrists frequently in theKeeping the same or similar postuhour

3 Arm movements beyond a comforShoulders raised or held awkward

4 For more than 2 hours total per wo• Work at awkwardly high or l

stooping, or reaching up)? • Arms stretched or overhead f• Is the task being carried out

with the hands above head elbows above the shoulder

5 6

Performing the task, with the headexcessively, occasionally or contihours total per work day? The visual demands of the task refine details

7 Poor posture for any other reason?

at make ULUENT M

rkday - Do

seconds a body part

ular arm m movementent - the tas

more timesTURE

to side

same postre for perio

table rangely rk day

ow height (

or long per

/neck bent nuously for

quiring the

Ds likely, such as: RISK?

IF YES POSSIBLE SOLUTIONS

RECOMMENDATION(S) FOR ACTION(S) / DATE ACTION TAKEN

OVEMENT For more es job involve:

or parts more than

Yes Yes

• Try to achieve self-pacing • Re-plan tasks e.g. break up repetition

cycles

ovement with some k is performed with

per minute?

Yes Yes Yes

• Spread movement across both hands • Add extra activities to job, to give variety. • Consider automation / use of power tools • New piecework/ bonus systems to reduce

pressure to work faster

.

Yes Yes Yes Yes Yes

Redesign

• workstation • handling of components • controls, and/ or • tool grasping areas

ure without change ds of greater than one

Yes Yes

Change nature of task leading to unchanging posture(s)

? Yes Yes

Move materials or controls to more convenient position near to body

crouching,

iods?

Yes Yes Yes Yes

Check

• reaches for smaller operators • nature of task that makes operator reach

awkwardly

or twisted more than 2

worker to view

Yes Yes

Check need for better seating -adjustable to correct height for individual, footrests etc, Check height of work locations Provide vision enhancement aids such as magnifying glasses

Yes Ensure training in good working techniques and posture

51

RISK FACTOR Are there any factors in the job that make ULDs likely, such as:

RISK?

IF YES POSSIBLE SOLUTIONS

RECOMMENDATION(S) FOR ACTION(S) / DATE ACTION TAKEN

C 1 POOR WORKSTATION DESIGN Does job involve workstation features where;

1 The work surface is not at; • top of chest height for precision work • mid chest height for assembly work with hand support • just below elbow height for work with free hand movements • waist height for heavier work requiring force

Yes Yes Yes Yes

Worksurface; 10-20cm above elbow height 5-7cm above elbow height at or just below elbow height 10-30cm below elbow height

23

• A seat is provided but it is NOT being used • Operator has to stand at the task (no opportunity to sit)

Yes Yes

45

• Operators lean away from the back support WHILE performing task

• Operators feet lack support the thighs not horizontal to the floor or - the legs restricted by furniture or equipment

Yes Yes

Ensure enough adjustment Provide feet support, remove parts restricting posture

6 The seat: • restricts the operator from working at the correct height • is not height adjustable • has unpadded surfaces • digs into the back of the operators knees • is fixed so the operator is not able to turn to the side if required

Yes Yes Yes Yes Yes

Improve space available to worker. Provide adjustable workstation (especially chair) for workers who are above or below average height or shape

7 The operator’s posture is restricted by; • the need to see the work locations? (VDU screen, displays,

fingers, workpieces, etc)

• the position of the machine or equipment being operated? (e.g. leaning to • operate a control or tool) • obstruction to the legs (no knee room) • foot or leg controls awkwardly placed

Yes Yes Yes Yes Yes

D 2 POOR HANDTOOL DESIGN 3 Does job involve a handtool which is:

1 2 3

Too large or small to be gripped easily Too short (not as wide as the palm) or poorly shaped

• pressure points on the hand • reducing the amount of contact area with the hand

Difficult to grasp due to a smooth surface or ill-fitting gloves

Yes Yes Yes Yes Yes

Redesign tool handles to achieve even distribution of force across hand Guide - round handle best Diameters approximately 34mm (men) and 30mm (women)

4 5

Causing jerky actions, shock, vibration or reaction torque - operator has to increase effort to control it Cannot be used in either the left or right hand

Yes Yes

Power grip preferable to pinch grip Straight rather than bent wrists. Replace hand tools with power tools

6 Requiring frequent finger operations or pressure on a trigger or button. Yes Reduce squeezing forces by using weaker springs in triggers etc.,

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RISK FACTOR Are there any factors in the job that make ULDs likely, such as:

RISK?

IF YES POSSIBLE SOLUTIONS

RECOMMENDATION(S) FOR ACTION(S) / DATE ACTION TAKEN

E NEED FOR A LOT OF FORCE Does job involve:

1 Strong force at the same time as awkward movements or posture, e.g. • bent wrists, • work with arms raised or • fully extended

Yes Yes Yes Yes

Redesign workstation, e.g. • reposition components to reduce reaching • move controls to better position. • bring work components nearer

2 Performing the task (single or double handed), with forceful use of • hand/forearm muscles for more than 2 hours total per work day or • the maximum force exerted by one hand involves

• pinch gripping unsupported object weighing 0.9 kgs (2 lbs.) plus or

• 0.9 kgs (2 lbs.) plus e.g. holding small binder clip open • gripping an object weighing 10 lbs. or more or • 10 lbs. of similar force e.g. crushing the sides

of an aluminium coke can

Yes Yes Yes Yes Yes

• Redesign job, workstation, and/ or tools to

avoid over-use of the hand or forearm • Maintain tools e.g. keep them sharp and

lubricated for ease of use • Check component handling, weights and

sizes

3 45

• Trying to make do with ill-fitting components by forcing them into place?

• Using any part of the hand / wrist to hammer? • Using the tip of a finger/ thumb/ hand as a pressing or pushing

tool?

Yes Yes Yes

Improve quality of components Provide suitable tools for fitting them

6 Wearing gloves, and these hinder gripping? Yes

7 Gripping objects with a wide finger-hand grasp Yes

8 Tools not ideal for repetitive or frequent use - particularly if squeezing, twisting, or hammering actions required?

Yes

Replace domestic or DIY hand tools with tools designed for repetitive industrial use.

9 Using equipment designed for a larger or stronger person (e.g. women using tools designed for men)?

Yes

Redesign equipment or tool (e.g. counter-balancing to reduce force required) Provide powered version.

F LOCAL FORCE AND STRESS Does job involve:

1 Hard or sharp objects, tools or parts of the workstation putting localised pressure:

• on the back or side of the fingers? Yes • palm or base of the hand? Yes • forearm or elbow? Yes

• armpit? Yes • any other part of the body Yes

RISK FACTOR Are there any factors in the job that make ULDs likely, such as

RISK?

IF YES POSSIBLE SOLUTIONS

RECOMMENDATION(S) FOR ACTION(S) / DATE ACTION TAKEN

G WORK FOR LONG PERIODS WITHOUT BREAKS OR CHANGES OF ACTIVITY: Does Job involve:

1 No: • changes to work routine or variation of tasks? • breaks or infrequent breaks?

Yes Yes

Vary tasks to provide changes in activity Check there are adequate rest breaks Check that breaks are taken, especially if work involves continuous effort such as holding tools, or rapidly repeated movements

2 Worker not able to have short pauses when desired?

Yes Redesign work to make short pauses possible

3 No:• mechanism for dealing with seasonal volumes of work and/or • provision for sudden changes in workload?

Yes

4 The worker is (when asked); • having difficulty keeping up with this work • finding the work medium to highly stressful • finding the visual demands of the task high

Yes Yes Yes

5 Lack of variety of tasks; • to avoid monotony? • and no job rotation?

Yes Yes

6 Lack of interest to the person?

Yes

7 The number of deadlines not being minimised?

Yes

8 Lack of monitoring individual workloads to prevent overload?

Yes

H WORK ORGANISATION ARRANGEMENTS Does job involve:

1 Employer not realising the extent of skill needed for its operations? Yes 2 Supervisors not trained in all aspects of ULDs? Yes 3 Workers not trained:

• in the correct skills? • trained in all aspects of ULDs?

Yes Yes

Provide training in skills, posture, and warning symptoms for all those at risk

4 Overtime being worked, but not organised to minimise risk of ULDs? Yes 5 Job structure not preventing pressures on the individual from becoming

too great? Yes

6 Lack of a scheduled tool maintenance programme, including knives being kept sharp

Yes

7 Staff and operators not being consulted when work changes are made? Yes 8 Poor social support Yes

54

RISK FACTOR Are there any factors in the job that make ULDs likely, such as

RISK?

IF YES POSSIBLE SOLUTIONS

RECOMMENDATION(S) FOR ACTION(S) / DATE ACTION TAKEN

I POOR ENVIRONMENTAL CONDITIONS Is work carried out:

1 In dim light, shadow or flickering light? Yes Provide better lighting so that awkward postures are not adopted to see properly

2 In cold or similar adverse conditions? Cold (e.g., in handling frozen food) may increase the risk of ULDs

Yes Warm the working environment Provide well designed protective clothing that does not affect posture or grip

3 • with the hands always exposed to a temperature of lower than 21 degrees centigrade

• cold air blowing over the hands?

Yes Yes

Provide well designed protective gloves

4 With tools that vibrate? • hand tools with high vibration used more than 30 min total per

work day (examples include chainsaws, jack hammers, percussive tools, riveting or chipping hammers)

• hand tools with moderate vibration used more than 2 hours total per work day examples include jig saws, grinders, and sanders

Yes Yes Yes

Do job another way to avoid need for high vibration tools Provide vibration-absorbing grip Minimise vibration by proper maintenance

J 4 INDIVIDUAL AND PERSONAL FACTORS 5 Are the following factors present?

1 Previous illnesses or injuries that might be important?

Yes Check with occupational health

2 No special arrangements for new employees (or those returning to work after a long break)

Yes

3 People are having to work at full pace immediately they start (or resume) the job?

Yes Gradually build up to normal work pace

4 No training in risk of ULDs and ways employees can reduce risks? Yes Provide training in skills, posture, and warning symptoms for all those at risk

Allow recruits to build up their work rate sensibly as they gain experience

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6.7 RISK ASSESSMENT FILTER

56

57

6.8 REVISED RISK ASSESSMENT WORKSHEETS

58

59

60

61

62

6.9 FINAL HSG60(REV) RISK ASSESSMENT FILTER AND WORKSHEETS

63

64

65

66

67

68

69

70

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7 REFERENCES

Bjelle, A.l., Hagberg, M., Michaelson, G. (1981). Occupational and individual factors in acute shoulder-neck disorders among industrial workers. British Journal of Industrial Medicine, 38, 356-363. Buckle, P. Li, G. (1996). User needs in exposure assessment for musculoskeletal risk assessment. In: L. Starker and C. Pollock (Des). Virtual Proceedings of cyber 1996: The First International Cyberspace Conference on Ergonomics. URL http://www.curtin.edu.au/conference/cyberg/ Curtain University of Technology. Fallentin, N., Viikari-Juntura, E., Waersted, M., Kilbom, A. 2001. Evaluation of physical workload standards/guidelines from a Nordic perspective. Scandinavian Journal of Work, Environment & Health, 27 Supplement 2. Graves, R.J. (1994) Upper Limb Disorder Checklist, Human Factors & Work Design. Edinburgh. Graves, R.J. Sinclair, D.T. Jamieson, D.W. Watt, M. Ratcliffe, B. Doherty, S. (2000) Development and evaluation of diagnostic support aids for upper limb disorders. Contract Research Report 280/200. ISBN 0 7176 1824 2. HSE Books, Sudbury. Health & Safety Executive. (1998) Manual Handling: Guidance on Regulations - Manual Handling Operations 1992, L23. HSE Books. Health & Safety Executive. (1990) Work-related upper limb disorders: A guide to prevention. Health and Safety Executive. HMSO Books, London. Health & Safety Executive. (1994) Upper limb disorders: Assessing the Risks. Health and Safety Executive. HMSO Books, London. Health & Safety Executive. (1998) Upper limb disorders: Assessing the Risks. HSE leaflet INDG 171. Health & Safety Executive (2002), Upper Limb Disorders in the Workplace. HSG60(rev) HSE Books. ISBN 0-7176-1978-8. Kemmlert, K. (1995) A method assigned for the identification of ergonomic hazards – PLIBEL, Applied Ergonomics, vol.26, no.3, p.199-211. Kemmlert, K. and Kilbom, Å. (1987), Method for identification of musculoskeletal stress factors which may have injurious effects. Paper presented at XIth World Congress on the Prevention of Occupational Accidents and Diseases. Stockholm, pp401-404. Keyserling, W.M., Brouwer, M., Silverstein, B.A. (1992) A Checklist for Evaluating Ergonomic Risk Factors Resulting from Awkward Postures of the Legs, Trunk and Neck International Journal of Industrial Ergonomics, vol. 9. no. 4, pp. 283-301. Keyserling, W.M., Stetson, D.S., Silverstein, B.A., Brouwer, M.L. (1993) A Checklist for Evaluating Ergonomic Risk Factors Associated with Upper Extremity Cumulative Trauma Disorders Ergonomics, vol. 36, no. 7, pp. 807-831. Kilbom Å. (1994b) Repetitive work of the upper extremity: Part I. Guidelines for the practitioner; Part II. The scientific basis (knowledge base) for the guide. International Journal of Industrial Ergonomics, 14, 51-86.

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Kilbom, Å. (1994a) Assessment of physical exposure in relation to work-related musculoskeletal disorders - what information can be obtained from systematic observations? Scand J Work Environ Health, 20, Special issue: 30-45. Lawton, C. and Riley, D. (2001) HSL Reactive Support Report. Consultation exercise for the revision of HS(G) 60 - Working title: Upper limb disorders in the workplace. (ERG/01/15). Li, G., Buckle, P. (1998). Quick Exposure Checklist (QEC). (HSE contract research report no. 251/1999) Health and Safety Executive. HMSO Books, London. Li, G., Buckle, P. (1999). Current techniques for assessing physical exposure to work-related musculoskeletal risks, with emphasis on posture-based methods. Ergonomics, vol. 42, no. 5 p. 674-695. Malchaire, J.B., Cock, N.A. (1999). Risk prevention and control strategy for upper limb musculoskeletal disorders. UTB Newsletter, no. 11-12. Marley, R.J., Kumar, N. (1996). An Improved Musculoskeletal Discomfort Assessment Tool International Journal of Industrial Ergonomics, vol. 17, no. 1, p.21-27. McAtamney, L., Corlett, E.N. (1993). RULA: A Survey Method for the Investigation of Work-Related Upper Limb Disorders, Applied Ergonomics, vol. 24, no. 2, p. 91-99. Moore, J.S., Garg, The Strain Index: A Proposed Method to Analyze Jobs for Risk of Distal Upper Extremity Disorders, A. American Industrial Hygiene Association Journal, Vol. 56, No. 5, p.443-458. Moray, N., Johansen, J., Pew, R., Rasmussen, J., Sanders, A.F. Wickens, C.D. (1979). Report of the experimental psychology group. In: Mental workload: its theory and measurement (ed. N. Moray), New York: Plenum. Occupational Safety and Health Administration’s (OSHA, 2000), United States Department of Labor. Silverstein, B.A., Fine, L.J., Armstrong, T.J. (1986). Hand wrist cumulative trauma disorders in industry. British Journal of Industrial Medicine, 43, 11, 779-784. Smyth, M.G. (1994). An investigation of the 1994 Health and Safety Executive check-list’s effectiveness in identifying risk factors associated with the development of work-related upper limb disorders. Loughborough University of Technology. Smyth, G. and Haslam, R. (1995). Identifying risk factors for the development of work related upper limb disorders. In: Contemporary Ergonomics 1995, edited by S. A. Robertson (Taylor & Francis: London), pp. 440-445. Trade Union Congress (1994), TUC Guide to Assessing WRULDs Risks. College Hill Press, London. WAC 296-62-051 (1999), State of Washington Proposed Ergonomics Rule, State of Washington Department of Labor and Industries.

73

8 BIBLIOGRAPHY

Baron, S., Hales, T., Hurrell, J. (1996) Evaluation of symptom surveys for occupational musculoskeletal disorders, American Journal of Industrial Medicine, Vol. 29, No. 6, p. 609-617. Burdorf, A., Beek, A.J, van-der. (1999) Exposure assessment strategies for work-related risk factors for musculoskeletal disorders, Scandinavian Journal of Work Environment and Health, vol.25, supp.4, p.25-30. Burdorf, A., Beek, A.J., van-der. (1999) In musculoskeletal epidemiology Are we asking the unanswerable in questionnaires on physical load, Scandinavian Journal of Work Environment and Health, vol.25, no.2, p.81-83. David, G. (1999) Preventing work-related musculoskeletal disorders, Safety and Health Practitioner, vol.17, no.7, supplement, p.4-6. Fragala, G. (1992) Reducing The Risk Of Musculoskeletal Disorders, Professional Safety, vol.37, no.9, p.22-25. Friedman, P.J. (1997) Predictors of Work Disability in Work-Related Upper-Extremity Disorders, Journal of Occupational and Environmental Medicine, Vol. 39, No. 4, p.339-343. Hagberg, M. (1992). Exposure variables in ergonomic epidemiology, American Journal of Industrial Medicine, Vol. 21, No. 1, p.91-100. Kant, I., Notermans, J.H.V., Borm, P.J.A. (1990) Observations of working postures in garages using the Ovako Working Posture Analysing System (OWAS) and consequent workload reduction recommendations, Ergonomics, Vol.33, No.2, p.209-220. Keyserling, W.M., Stetson, D.S., Silverstein, B.A., Brouwer, M.L. (1993) A checklist for evaluating ergonomic risk factors associated with upper extremity cumulative trauma disorders, Ergonomics, Vol. 36, No. 7, p.807-831. Kuorinka, I., Jonsson, B., Kilbom, A., Vinterberg. H., Biering-Sorensen, F., Andersson, G., Jorgensen, K. (1987) Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms, Applied Ergonomics, Vol.18, No.3, p.233-237. Li, G., Buckle. P. (1999) Current techniques for assessing physical exposure to work-related musculoskeletal risks, with emphasis on posture-based methods, Ergonomics, vol.42, no.5 p.674-695. Marley, R.J., Kumar, N. (1996) An improved musculoskeletal discomfort assessment tool, International Journal of Industrial Ergonomics, vol.17, no.1 p.21-27. McAtamney, L., Corlett, E.N. (1993). RULA: A survey method for the investigation of work-related Upper Limb Disorders, Applied Ergonomics, Vol. 24, No. 2, p.91-99. Meyers, J.M., Miles, J.A., Faucett, J., Janowitz, I., Tejeda, D.G., Kabashima, J.N. (1997). Ergonomics in agriculture: Workplace priority setting in the nursery industry, American Industrial Hygiene Association Journal, Vol.58, No.2, p.121-126. Pinzke, S. (1997) Observational Methods for Analyzing Working Postures in Agriculture Journal of Agricultural Safety and Health, Vol. 3, No. 3, p 169-194.

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Schierhout, G.H., Myers, J.E., Bridger, R.S. (1993) Musculoskeletal pain and workplace ergonomic stressors in manufacturing industry in South Africa, International Journal of Industrial Ergonomics, Vol.12, p.3-11. Schierhout, G.H., Bridger, R.S., Myers, J.E. (1994) Development of observational methods for estimation of exposure to workplace postural stress, Occupational Medicine, Vol. 44, No. 5, p.262-266, 1994. Spielholz, P., Silverstein, B. (1999) Reproducibility of a self-report questionnaire for upper extremity musculoskeletal disorder risk factors, Applied Ergonomics, vol.30, no.5, p.429-433. Viikari, Juntura, E. R. A. (1997) The scientific basis for making guidelines and standards to prevent Work-Related Musculoskeletal Disorders, Ergonomics, Vol. 40, No. 10, p 1097-1117. Wells, R., Moore, A. (1994) Assessment of risk factors for development of WORK-RELATED MUSCULOSKELETAL DISORDERS (RSI), Applied Ergonomics, vol.25, no.3, p.157-164. Wiktorin, C., Vingard, E. (1999) Interview versus questionnaire for assessing physical loads in the population-based MUSIC-NORRTAELJE study, American Journal of Industrial Medicine, vol.35, no.5, p.441-445. Winkel, J., Westgaard, R. (1992) Occupational and individual risk factors for shoulder-neck complaints: Part II - The scientific basis (literature review) for the guide, International Journal of Industrial Ergonomics, Vol. 10, Nos. 1-2, p.79-83.