ERGONOMICS IN THE WORKPLACE

ERGONOMICS IN THE WORKPLACE

Oleh : Bayu Nurwinanto

The purpose of this short guide is to provide information to the reader on the subject of Ergonomics. It also provides guidance on where to source further information. It is not within the bounds of this guidance to discuss in detail all the main aspects of knowledge in the field of Ergonomics. However efforts will be made to give the reader an understanding of different Ergonomic principles aswell as an appreciation of relevant and useful literature and textbooks, which cover the subject of Ergonomics in more detail.

The guidance is designed to assist those who deal with Ergonomic issues in a workplace setting and these include architects, designers, engineers, manufacturers, suppliers, contractors, health and safety professionals, safety representatives, employers and employees.

“Ergonomics applies information about human behaviour, abilities and limitations and other characteristics to the design of tools, machines, tasks, jobs and environments for productive, safe, comfortable and effective human use” (McCormick and Saunders 1993).

A number of factors play a role in Ergonomics; these include body posture and movement (sitting, standing, lifting, pulling and pushing), and environmental factors (noise, lighting, temperature, humidity).

THE IMPACT OF ERGONOMICS ON WORKPLACE DESIGN

The goal of Ergonomics is to provide maximum productivity with minimal cost; in this context cost is expressed as the physiological or health cost to the worker. In a workplace setting there are seldom a large number of tasks that exceed the capabilities of most of the work force. There may be jobs that will include a specific task that requires extended reaches or overhead work that cannot be sustained for long periods, by using Ergonomic principles to design these tasks; more people should be able to perform the job without the risk of injury.

Ergonomics has already been defined and its primary focus is on the design of work activity that suits the person in that it takes account of their capabilities and limitations. Matching the requirements of a job with the capabilities of the worker is the approach to be adopted in order to reduce the risks of musculoskeletal injuries resulting from handling materials manually.

Proactive Ergonomics emphasises the prevention of work related musculoskeletal disorders through recognising, anticipating and reducing risk factors in the planning stages of new systems of work or workplaces. In effect, to design operations that ensures proper selection and use of tools, job methods, workstation layouts and materials that impose no undue stress and strain on the worker. Additional costs are incurred in redesigning or modifying work processes therefore it is more cost effective to reduce risk factors at the design stage.

A proactive approach to Ergonomics will ensure that :

• Designers will receive training in ergonomics and have appropriate information and guidelines regarding risk reduction.
• Decision-makers planning new work processes should have knowledge of Ergonomics principles that contribute to the reduction or elimination of risk.
• Design strategies emphasise fitting job demands to the capabilities and limitations of workers. For example, for tasks requiring heavy materials handling, use of mechanical assist devices to reduce the need for manual handling would be designed into the process.
• Other aspects of design should be considered including load design, layout of the workplace to allow for ease of access when using mechanical aids and eliminating unnecessary lifting activities.

ERGONOMIC PRINCIPLES THAT CONTRIBUTE TO GOOD WORKPLACE DESIGN

The goal for the design of workplaces is to design for as many people as possible and to have an understanding of the Ergonomic principles of posture and movement which play a central role in the provision of a safe, healthy and comfortable work environment. Posture and movement at work will be dictated by the task and the workplace, the body’s muscles, ligaments and joints are involved in adopting posture, carrying out a movement and applying a force. The muscles provide the force necessary to adopt a posture or make a movement. Poor posture and movement can contribute to local mechanical stress on the muscles, ligaments and joints, resulting in complaints of the neck, back, shoulder, wrist and other parts of the musculoskeletal system.

Ergonomic principles provide possibilities for optimising tasks in the workplace These principles are summarised in Table below :

ERGONOMICS AND IRISH LEGISLATION

The Manual Handling of Loads Regulation

Many of the Ergonomic Principles, which have been detailed above, have been incorporated into Irish Legislation. The Safety Health and Welfare at Work (General Application) Regulations of 1993 contain regulations dealing specifically with the manual handling of loads.

The regulation is titled the Manual Handling of Loads Regulation. These regulations are likely to be remade in 2006 without substantive changes. There is detailed guidance on this regulation in the Health and Safety Authority publication Management of Manual Handling in the Workplace.

The Regulation details a definition of Manual Handling as:

“Any transporting or supporting of a load by one or more employees, and includes lifting, putting down, pushing, pulling, carrying or moving a load, which by reason of its characteristics or unfavourable ergonomic conditions, involves risk, particularly of back injury, to employees”

There is a schedule attached to the Manual Handling of Loads Regulation, which details these unfavourable ergonomic conditions or risk factors for the manual handling of loads. The Manual Handling regulations require the employer to have regard to these risk factors when assessing manual handling activities.

These risk factors mirror many of the Ergonomic principles already described in this guidance leaflet. The Regulation sets out a framework for employers to avoid or reduce manual handling activity through a risk assessment process, which takes account of the risk factors detailed in the schedule. Ideally the risk assessment process should take place at the design or planning stage of new systems of work, but must

happen as a matter of course for any existing systems of work, which involve manual handling.

Manual Handling Risk Assessment:

Risk assessment is a process which involves gaining a detailed understanding of a task being carried out, collecting all relevant technical details of the task, identifying if there are risk factors/hazards present, exploring what options or solutions are available to reduce or eliminate the risk factors/hazards and putting a plan in place to introduce agreed control measures.

IDENTIFICATION OF RISK FACTORS

The Schedule in the regulation details the unfavourable ergonomic conditions or risk factors, which should be considered as part of the risk assessment process. Figure 1 details examples of some of these risk factors. Ergonomics Research which has been conducted to identify workplace factors that contribute to the development of musculoskeletal disorders including back injury, has demonstrated the following as important risk factors:

Awkward Posture

Body postures determine which joints and muscles are used in the activity, more stress is placed on the spinal discs when lifting, lowering or handling loads with the back bent or twisted compared with when the back is straight. Activities requiring frequent or prolonged work over shoulder height can be particularly stressful.

FIGURE 1: EXAMPLES OF AWKWARD POSTURES

Forceful Exertion: Tasks that require forceful exertions place higher loads on the muscles, tendons and joints. Increasing force means increasing body demands such as greater muscle exertion. The weight of a load that has to be lifted, the height that the load has to be lifted and the frequency of lift are all factors that contribute to the level of exertion on the muscles and joints. The Regulations set no specific requirements such

as weight limits.

However there are numerical guidelines, which take account of weight, repetition and location of lifts as a means of identifying activities, which involve risk. In using the guideline weights in Figure 2, the assessor should take account of the type of work activity and have an appreciation of what realistic improvements can be put in place to avoid or reduce risk. When assessing manual handling activities it is important to keep in mind that weight is not the only factor that needs.

to be considered, other factors that should be considered include repetition, individual capacity, posture and the work environment. The Guideline Weights can be used to determine if the load is too heavy. Working outside these guidelines is likely to increase the risk of injury.

                 FIGURE 2: GUIDELINE WEIGHTS