The move towards a green economy, with increased demands for renewable energy, recycling and organically produced food, brings with it new jobs and rapidly changing ways of working. With these come health and safety and ergonomics challenges, but much can and should be done to design equipment and work areas to allow staff to work comfortably and to reduce risks to their health.
In the push towards environmental protection, it is important not to forget the health risks that workers in these industries may be exposed to, to design these out as far as possible, and to manage residual risks. Occupational health professionals and ergonomists will be needed in future to provide advice in industries including energy production, recycling industries and organic farming.
As part of the 2007 agreement by EU member states to secure 20% of all Europe’s energy from renewable sources by 2020, the UK set a target of 15% of UK energy to be produced from renewables by 2020.1 Since starting from a baseline of only 1% in 2005, it is clear that there will be a rapid scaling up of the industry over the coming years. Currently, the most commercially viable renewable source for the UK is wind power, although tidal power also appears promising. Land and planning restrictions mean that offshore wind farms are the main focus of activity for the wind sector; this is creating some of the largest infrastructure projects in the world, with a potential investment required of more than £100bn.2
It is projected that to meet the government’s target, there will be more than 6,000 offshore wind turbines installed on the UK continental shelf by 2020. At their peak, more than 300 turbines will be installed each year and it is estimated that more than 50,000 jobs will be created in the industry.3
This rapid up-scaling presents both technical and human challenges; in these relatively early stages of growth of the industry, it is important that the ergonomics issues affecting the construction, installation and maintenance, and ultimate decommissioning, of the turbines are considered.
The size of masts, blades and turbines presents a challenge for the operators involved in construction. Blades may be up to 70m long (turbines are more efficient with longer blades) and could be 3m wide. With their curvature, access to the internal and external faces during construction may require stretching and leaning, while also using tools.
Clearly, prolonged periods spent in these postures poses a risk of musculoskeletal injury. Access platforms that do not come into contact with the blades are required, and they need to be positioned and used correctly to avoid over-reaching when working.
Construction of large masts presents significant engineering challenges, particularly offshore. Training and good communication methods are essential when using the heavy machinery required, as well as good visibility from the machines for the operators.
Access to the turbine
Most of the maintenance work required on the mast will be undertaken at the turbine. The first generation of on-shore masts were built with internal ladder access to the turbine. Since these masts could be 60-80m high, this was clearly a considerable height for operators to climb, particularly since two or three journeys might be required to take the maintenance equipment to the turbine.
Intermediate platforms were provided to enable operators to rest, but this was clearly a fatiguing task, with risks of falls, as well as discomfort or errors due to fatigue. To reduce this risk, limits have been set on how much operators can climb each day. Winches have also been used both to transport equipment and components, and to assist operators in the climb (by attaching the harness to the winch). More recent designs of mast have included internal lifts, particularly on the much taller (for example, 160m) offshore turbines.
Due to varying sea conditions, access to the mast itself is a significant challenge off shore. Normal access is via a door at the base of the mast. Due to sea swell this has to be approximately 20m above calm sea level, and an external ladder allows access from sea level to the door. Operators are brought by boat to the base of the mast, the boat is held in place against the ladder (by throttling the engine), and operators climb from the boat onto the ladder; equipment also has to be transferred. With sea swell, this can be a risky manoeuvre.
Clearly there are only some sea conditions in which this can be undertaken, although it is possible that work pressures may mean that risks are taken. This is perhaps more likely when removing operators at the end of the maintenance task, if sea conditions have deteriorated.
Alternative means of transfer, such as being able to secure the boat to the mast, or having a flexible walkway that could be attached to the mast, are likely to reduce risk, and their installation should be investigated.
Maintenance at the turbine
The turbine housing is designed with standing areas for operators, but awkward postures are likely to be required when working on the turbines; limited space may be available for access to some parts, requiring operators to stretch, twist, crouch or work overhead. In addition, some of the component parts (eg, bearings) can be heavy, potentially presenting manual handling risks on top of the potential postural constraints. Some tasks will require working inside the blades (eg, installing temperature sensors on the blades), where operators may have to work in particularly constrained postures. As far as possible, turbines, their housing and the blades should be designed to facilitate maintenance.
All masts sway to some extent, but the degree of sway increases with height, and is particularly exaggerated on offshore masts (depending on the anchorage method). This brings the risk of movement-induced illness, with associated reduction in performance or risk of errors. Scheduling maintenance tasks to avoid excessive wind conditions may help to reduce this, but it is not technically possible to eliminate sway. There may be a need to screen potential operators for a tendency towards motion sickness.
Some masts (for example, ‘sway’ style offshore masts, which can be installed in deeper waters) are designed to tilt 5-8°,4 which presents challenges for operators working on a tilting platform (eg, tools needing to be secured rather than placed on the floor).
Masts need to be designed to consider the need to rescue operators if required. This would usually be from the top of the mast, and is likely to necessitate the use of a helicopter and winch, with associated safety risks, particularly involving lowering a winch man onto the small and potentially moving turbine structure, in adverse weather conditions. Hatches of a suitable size are required to allow external access to the turbine area, and clearly effective means of communication are required between masts and the control centre.
Offshore hotel ships
The size of offshore wind farms (typically in excess of 100 turbines, and forthcoming fields will be significantly larger) and their distance from shore means that maintenance workers are likely to stay in hotel ships close to the field.
Again, transfer methods and movement-induced illness need to be considered for those spending a considerable amount of time in ships. Many of the issues faced in the offshore oil and gas industry concerning shift patterns are similar to those in the offshore wind industry, and lessons can therefore be shared; these are important considerations to ensure operators can work safely and with minimal health effects.
Skills and training
The speed of the scaling up of the construction, installation and maintenance of masts and turbines means the rapid need for a skilled workforce. The demand for construction to meet the set targets is likely to result in time pressures; these inevitably lead to challenges around training, competence of staff, availability of materials, and being able to keep to the prescribed work methods. The UK’s first offshore wind turbine training tower was opened in March 2010 to help technicians develop the skills that will be required to install and maintain offshore wind turbines.5
When undertaking maintenance on a turbine, operators typically work in pairs. Since their work cannot be directly supervised, creating a culture where operators behave safely will be crucial to ensuring their health and safety. Training and safe systems of work will be essential and, again, much can be learned from the oil and gas industry. However, the rapid increase in the number of workers in the wind energy industry will present pressures. Ergonomists and other health and safety specialists have an important role to play in ensuring health and safety standards and assisting with behaviour change.
Domestic wind turbines
While large-scale wind turbines have been considered here, the issue of installation and maintenance of domestic wind turbines, typically by small scale contractors, should not be overlooked. Issues about access to sites, working at height (their size means there will be no internal access to the turbine), and competence and training of contractors, mean there are health and safety issues to be considered.
Tidal power generation is also likely to pose health and safety risks, particularly concerning maintenance of a moving unit where sea swell will be considerable. Again, much can be learned from the offshore oil and gas industry about divers working under water, but more work may be needed to consider the potential impact on health of underwater maintenance activities undertaken on a moving structure.
The growth in the recycling of domestic and commercial waste has increased dramatically over the past 15 years. Over a similar period, the manual handling risks associated with domestic refuse collection have been significantly reduced with the introduction of wheelie-bins. However, kerbside box collections of household recycling re-introduces a lifting and carrying element to waste collection that the use of wheelie bins had largely eliminated. Sorting of recyclables from kerbside boxes into collection vans (as happens in many councils) requires manual handling of boxes from the ground, and lifting individual items or tipping the contents into stillages or containers, with the potential for awkward postures.
One council estimates that each recycling van collects about six tons of materials each day, typically with three operators (including the driver) manually handling this material.6 This council estimates that the average weight of each box (containing glass and cans) is 8kg, and each bag of paper is 4kg. While these weights are not excessive, the repeated handling (about two boxes every minute) and the awkward postures that can be required to sort materials pose a risk of musculoskeletal injury.
An HSE review of sickness absence data,7 found that (although data were limited) the average number of days’ absence per employee per year was higher for local authority drivers, loaders and operators in the waste and recycling industries (13.2 days) compared with the average absence for all local authority employees (9.6 days). Altogether, 21% of all absences were due to musculoskeletal disorders (MSDs), but 46% of long-term absences (ie, 20 working days or more) for drivers, loaders and operators were due to MSDs.
An HSE-commissioned study into manual handling in kerbside collection and sorting of recyclables8 identified musculoskeletal risks due to the postures adopted (lifting above shoulder height) when tipping boxes into hoppers or stillages (both when sorting from kerbside and on-vehicle), as well as the manual handling risks when lifting from ground level and carrying to the collection van. Box weights were increased with larger boxes and boxes without lids (where the contents could become heavy due to rain). Handle design affected how operators picked up and tipped the boxes, and they weren’t always designed to take account of operators wearing gloves, making them more difficult to use.
Other factors that increased the risk of injury, were box weight and carrying distance. Box weight can be controlled to some extent by providing smaller boxes with a smaller carrying capacity (40L boxes, which tended to equate to a loaded weight of approximately 12kg), and by increasing collection frequency from fortnightly to weekly. The potential to use small wheeled bins for recyclables (which could be automatically emptied into the van) should also be considered. Sorting recyclable materials (typically paper, glass and cans) on the vehicle requires repetitive movements, with the potential for twisting. A range of different vehicles are used for kerbside collection and sorting; the designs of some offer clear postural advantages.
The use of large wheelie bins for communal recycling works well in areas of high population density (eg, city centre flat living), and also allows the collection to be automated, but this is only viable with some housing areas or at communal centres.
The HSE has provided guidance in this area9 and has an on-going programme of work including review of the ergonomics design of waste receptacles, the design of vehicles and the systems of work used for kerbside sorting, with the aim of reducing musculoskeletal injury.
After collection, much of the processing and sorting of recyclables is done mechanically, although there may be musculoskeletal risks due to repetitive movements in any residual hand-sorting.
Conveyor belts need to be designed to consider the reach and clearance of operators.
Other health and safety hazards issues exist in the recycling industry, such as noise, slips, trips and falls, workplace transport, and handling hazardous materials, although some of these hazards are exported; many electronic goods sent for recycling (with associated toxic substances) are exported to countries where labour is cheaper.
Over the past decade, an increased awareness of the environmental impact of large-scale chemical dependent farming has led to a greater demand for organic produce. Inevitably, organic agriculture is more labour-intensive than other forms of farming, and the postures adopted in work may pose musculoskeletal risks.
In organic farming, weed control may be partly undertaken by manual weeding. For the few weeks when plants are small and most vulnerable to being overwhelmed by weeds, plant beds on commercial farms are weeded by staff using a bed weeder – a trailer frame on which a row of four to eight operators lie, side-by-side and face down on massage type benches (ie, with a hole for their faces so they can see what they are doing).
While being pulled over the plant beds, operators hand pick the weeds from around the young plants. This practice improves the musculoskeletal posture as compared with bending or squatting to weed, but there are risks of neck discomfort, and discomfort due to being pulled over an uneven surface. Appropriate head support and design of the frame on which they lie (with sufficient cushioning to reduce the effect of the uneven ground) would help to reduce discomfort: rest breaks to allow workers to change posture are also important to reduce the risk of discomfort.
This article has provided an overview of some of the emerging ergonomics risks with new industries; the challenge now is to address these to protect the health of the workforce.
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Margaret Hanson is a fellow of the Institute of Ergonomics and Human Factors. She has a strong interest in environmental issues, and gave the Donald Broadbent Memorial Lecture on ‘Green Ergonomics: embracing the challenges of climate change’ at the IEHF annual conference in April 2010.
1 Offshore wind power: big challenge, big opportunity, (2008), The Carbon Trust
2 Information presented by the Crown Estates at Offshore Wind Supply Chain Share Fare, 4th February 2010
3 Statistics presented by the Crown Estates at Offshore Wind Supply Chain Share Fare, 4th February 2010
6 Personal communication to the author
7 Holmes, E (2009), Review of sickness absence data in the waste and recycling industry, HSE, RR 750
8 Oxley, L, Pinder, ADJ and Cope, MT (2006), Manual handling in kerbside collection and sorting of recyclables, HSL/2006/25