One of the areas we work in is identification of, and assessment of, hazards and risks that can result in musculo-skeletal disorders. We can provide an individual assessment of workstations where an employee is reporting symptoms and in almost all cases recommend suitable actions to remedy the situation. We take a rounded, holistic approach to our investigations. In the past we have found some interesting problems such as an individual complaining of frequent serious headaches (diagnosed as migraine attacks - he was being prescribed one of the strongest medications by his GP with no effect at all) and increased occurrence was being blamed on the workstation. The probable causes were eventually identified as very poor posture due to a lateral spinal curvature and an abnormal running pattern resulting from a childhood injury causing cervical spine problems. The increased frequency of problems coincided with a sudden increase in playing football and training, the workstation also needed some minor changes. Most are rather simpler than that!
MUSCULOSKELETAL PROBLEMS IN THE WORKPLACE
Musculoskeletal problems are not a new phenomenon. Gamekeepers thumb, housemaids knee and many others have probably been around for centuries. In the eighties the term RSI, (repetitive strain injury), came into common use, now usually replaced by WRULD or work related upper limb disorder. Before describing two case studies with very different problems let us not forget that it is not just upper limbs we are interested in. Back or spinal and lower limb problems must also be recognised and removed or controlled where they exist. Overall we can use the expression Musculo-Skeletal Disorder or MSD. The two case studies below are not complete. They do show some of the common problems with an office based word-processor and the very extensive range of factors that may need to be looked at on a factory assembly task.
A Legal duty on an employer, to take such action, exists firstly in the Health and Safety at Work etc. Act 1974 and has been supplemented by more specific duties in later Regulations. The Manual Handling Operations Regulations 1992 (L23) and the Health and Safety (Display Screen Equipment) Regulations 1992 (L26) being two examples.
Whilst these conditions are not likely to be life threatening, they can represent considerable pain and disability for the person suffering from them. They will affect the ability of the employee to work at their best and hence everyone loses out. Development of a MSD by an employee may result in time off work, reduced efficiency when they are at work, complete loss of a valued employee and possibly a legal case for compensation.
Despite all the above good reasons for identifying and removing or reducing potential MSD problems, often little is done.
There is an increasing amount of guidance available. In addition to the above two sets of Regulations (with guidance) there is also ‘A pain in your workplace’ (HSG 121) and ‘Work related upper limb disorders - a guide to their prevention’ (HSG 60). For work in the healthcare industry ‘Guidance on manual handling of loads in the health services’ provides a good starting point. All five are available from HSE Books, telephone 01787 881165.
WORD PROCESSOR WORKSTATION ANALYSIS
INTRODUCTION
This example shows typical results from a Display Screen Equipment workstation investigation where the user had been complaining of various aches and pains for up to four years. Full details of the results are not included, this being an illustration only of what can be found and what actions may be taken. The only way to make significant positive changes in this workstation was the replacement of the combined processor/keyboard/printer unit with a now more common PC or similar equipment. Interestingly, this example was found in a firm of solicitors!
A further significant finding during the investigation was the serious lack of safeguards on data. No back-up copies of documents, or the numerous standard documents in use were kept and loss through any cause would have resulted in severe problems.
The analysis consisted of direct observation of the workstation equipment and location environment, use of a standard workstation evaluation questionnaire, a self-completion questionnaire for the user and by direct discussion with the user.
The basis of the analysis was the Health and Safety (Display Screen Equipment) Regulations 1992 and associated guidance, plus other guidance. The Regulations came into force 1 January 1993 with a time allowance for workstations in use before that date. For workstations in use prior to January 1993 (as this one was) the schedule to the Regulations did not have to be complied with until 31 December 1996. However, any risks to health or safety identified as a result of the analysis (required by regulation 2) must be reduced to the lowest level reasonably practicable without this time allowance.
BACKGROUND INFORMATION
One particular employee had worked in this location in the building for approximately four years. She was about 5' 4" in stature and ecto-mesomorphic, meaning small to medium build. At about the time of the move to this work area she recalled mild aching to the back of the neck radiating up to the posterior aspect of the skull. After discussion with persons in the company the screen location was changed by removing the monitor from its native cantilever support. The monitor was relocated on a typical after-market cantilever support which allows a greater degree of movement and alternative location. At the same time a cantilever design of A4 document holder was provided.
Prior to the changes the screen was to the left of the Olivetti word-processor unit and documents being copied from were flat on the desk, again to the left of the word-processor. Such an arrangement is common and often can lead to pains in the neck or shoulders due to constant tension in the neck/upper back muscles.
After the changes the monitor was located centrally behind the word-processor with the document holder to the left and slightly lower than the screen.
For the last couple of years there was some pain to the forearms and wrists. A height adjustable wrist rest had been in use for about one year.
INVESTIGATION
Two questionnaires based on the contents of the Schedule to the ‘DSE’ Regulations were used. Such checklists are available from a number of sources and provide a structured approach to the investigation.
Overall, the workstation was typical office layout using a standard office desk. The Olivetti unit word-processor, obtained about 1991, was a combined processor and daisy wheel printer with fixed keyboard. This occupied considerable space on the desk and greatly reduced the possibilities for workstation adjustment.
The layout was reasonable given the above constraints and attempts had been made to provide equipment to reduce the problems. In addition a seat base wedge had been provided to improve posture but this should have been unnecessary as the seat base angle to the horizontal was adjustable. This was not known by the users.
Although environmental conditions were not ideal they were not considered to warrant any major changes.
RECOMMENDATIONS
1. The user of the workstation examined was given personal instruction in the correct method of adjustment, based on an introduction to the potential risks involved with not doing so. It was strongly recommended that similar information was given to the remaining users. A number of videos exist that satisfy much of the requirements.
Poor organisation of workspace and adjustment of chairs are common reasons for musculo-skeletal problems developing.
2. A major problem was lack of space on the desk top. This restricted the amount of reorganisation possible. The ideal would be larger desks, at least 5' by a depth of 4'. Without incurring the expense of complete replacement, a single additional desk to allow additional space for both workstations in this location would have allowed much greater personal reorganisation. A side table of similar height to the desks would also have allowed considerable extra space and was a further option.
3. The further major problem was the design of the equipment ie. word-processor, in use. Where these combined units exist there is hardly ever the ability to adjust and organise to the best positions for each user. In the case of this workstation the available positions of keyboard, monitor, and document holder were restricted.
The best adjustments possible were made during the workstation analysis but the ideal solution would be replacement with either stand-alone PC based systems or a networked server system with individual monitor/keyboard workstations. Either option would also allow the use of larger monitors with clearer displays.
4. The monitors in use did not allow adjustment of both contrast and brightness and would not comply with the requirements of the schedule at the end of 1996. Whilst this was not considered to be a serious problem in the workstation examined, modern monitors have high definition displays, are very stable and the larger sizes allow much quicker working, especially when complex word-processing software is in use as would probably happen if the system was changed.
DOMESTIC OVEN ASSEMBLY
BACKGROUND
This example shows the range of possible contributing factors to the problems that developed and extensive range of possible solutions.
Since the introduction of cooker assembly, a number of operatives had experienced and reported various musculo-skeletal complaints. These included locations at neck/ back/shoulders, arms, wrists, knees or combinations of these.
During the previous year a number of changes had been made to the workstations, various component changes had been tried, different screw fasteners, screwdriver design etc. It was in view of the improvements made but the musculo-skeletal problems remaining that the investigation was called for.
TASK DESCRIPTION
Cooker oven assembly was carried out at six assembly stations supplied by conveyor feeders. The cooker internal structure was placed on a transit baseboard which was also fitted with a component box holding the remaining parts of the oven assembly.
At each station two operatives worked as a team. The most accomplished team was able to assemble about 50 units per shift whilst a new team still gaining experience was working at about 30 - 35 units. Extensive training of each team, of up to 3 months, was necessary to allow a flexible assembly line. They were able to assemble any model of oven required.
Although extensive training was carried out there were obvious differences in the final team organisation of assembly. Some teams had set tasks per person and did not vary from this regime, other teams would switch tasks. The most productive team had set tasks per person and worked in a highly coordinated way. This increased level of individual task practice would account in part for the higher efficiency, but would also tend to concentrate any potential problems from individual task elements.
INITIAL OBSERVATIONS
From the observations of the assembly, and discussion prior to this, the following possible problem areas for investigation were identified:
A.component design;
B.component accuracy of fit;
C.order of assembly;
D.fastener design and ease of initial location then insertion, plus related component design;
E.stability of oven assembly on transit board;
F.height of assembly conveyor and assembly workstation;
G.air powered screwdriver design;
H.individual adopted work posture;
I.use of pinch grip for electrical connector insertion;
J.team assembly organisation and task allocation;
K.speed of assembly and rest breaks;
L.type of gloves used;
M.environmental conditions
After direct observation of assembly a number of key issues were considered of primary importance, these were:
• the number and location of screw fasteners;
• the posture adopted for fastener insertion and its relationship to individual stature;
• screwdriver design relative to the location of the fastener, i.e. vertical or horizontal;
ACTIONS
A three stage action plan was proposed.
STAGE ONE
This included:
1. sorting out the problem of base panel distortion which made assembly difficult at times, resulting in excessive pressure being required to locate screw holes;
2. re-assess the screw fastener specification. Variation in screw thread root size has been identified as one problem with insertion;
3. reduce the number of screw fasteners. This is subject to a BSI or BEAB approval for design change. If agreed the number of fasteners will reduce by 18 making a significant reduction to the problems created by location and insertion pressures;
4. consideration of substitution of zero insertion force (ZIF) electrical connectors for some of those in use;
5. reintroduce a pistol grip design driver for use with horizontal fasteners. This had been tried but using a modified, existing automatic straight driver. This was rejected because of operator dislike - probably due to weight and unwieldiness. A proper pistol design was needed;
6. associated with the above, all operatives to be properly trained and instructed in which driver to use for individual fasteners, and the correct posture to adopt, ie hand orientation;
7. a check was to be made to see if the air hose to the drivers could be reduced in size to reduce the weight and resistance to movement;
8. the use of sliding rail or spring type hose supports to supplement the above was to be investigated;
9. BS5750 procedures had been written. Short additional instructions on assembly method, order and including items from above were needed;
STAGE TWO
A structured form of individual health monitoring was to be introduced. This would take the form of weekly or fortnightly questionnaires allowing pain/discomfort recording on body representative diagrams, and development of personal history.
STAGE THREE
Once health monitoring was in place, observation of individuals could take place. Individual problems could be considered in light of their stature and build, work methods, team organisation and use of equipment. This stage would involve on-site direct observation, video recording of work activities, interviews with operatives, off-site video analysis and reporting.
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