Magda Liliana Cáceres Cáceres1; Mercedes Sanchis Almenara1; Alfonso Oltra Pastor1; Raquel Marzo Roselló1; Raquel Ruiz Folgado1; Arturo Santamaría Villena2
1Instituto de Biomecánica (IBV). Universitat Politècnica de València. Edificio 9C. Camino de Vera s/n (E-46022) Valencia. Spain
2 CEE Dr. Schneider
Contrary to what is normally thought, the safety and health of workers do not only involve experts in occupational risk management, but also all the company levels. The project performed by the company Dr. Schneider made it possible both to train risk management professionals in the assessment of ergonomic risks and to identify the actions to be taken to reduce such risks; additionally, the project also made the engineering department aware of the importance of an adequate design of the workstation (both from the dimensional and the organizational perspective) in order to reduce the risk of musculoskeletal disorders.
Tasks such as the manual assembly of pieces (an activity frequently performed at companies in the industrial sector) imply repetitive movements in defined work cycles. Repetitiveness, along with other factors such as an inadequate distribution of rest periods, application of forces or awkward postures, can lead to various musculoskeletal disorders mainly in the upper limbs. This is something that should be taken into account when designing the workstation, the production process and the parts to be assembled.
The injuries that these tasks can cause develop during a slow and cumulative process which is apparently harmless, therefore, the symptom or discomfort is usually ignored. This characteristic may lead to a chronic and incapacitating problem, which is associated, in many cases, with recurrent sick leaves of the workers or inability to return to the job where the injury occurred.
In order to avoid these problems, it is essential that all the areas of the company are aware of the problems that ergonomic risks in the workplace cause to the worker and the company, which includes the engineering department (who design the parts and the production processes), the company's doctor (who must be able to identify potential ergonomic risks in a workplace on the basis of the symptoms shown by the employee), the purchasing department (who must purchase equipment considering ergonomic criteria) and, of course, the occupational risk management professionals (who must ensure that the ergonomic risks of the workplaces are within the acceptable limits established in the current regulations).
That is why Dr. Schneider decided to train risk management professionals and engineers in how to perform an ergonomic risk assessment in the workplace and what actions can be taken to reduce the risks detected.
To carry out the training, the company decided to focus on a workstation which they knew involved ergonomic risks. The tasks performed in the selected workstation were the following:
To perform the assembly task of the pieces, the worker performs a total of 45 different technical actions. The necessary elements to perform the assembly are located around the workstation both in boxes and trays on the work table and the conveyor belt, which the worker sequentially accesses throughout the work cycle.
Some information on that workstation was collected (organizational aspects, working schedules, cycle times, images and videos, workers' opinions, etc.) in order to perform the risk assessment using the Ergo/IBV tool.
Once this information was obtained, the analysis of the ergonomic risks was carried out using the appropriate Ergo/IBV modules considering the type of tasks performed by the workers (UNE-EN 1005-5 OCRA for tasks involving repetitiveness and REBA for tasks that involved forced postures).
Figure 1. Ergo/IBV software to assess ergonomic risks
The ergonomic analysis found risk in repetitive tasks according to OCRA index (Table 1). In addition, various awkward postures were detected, especially in the upper limbs, with a medium risk level in the classification of the REBA methodology.
Table 1. Ergonomic risks detected
The results of the assessment performed clearly showed the need to take actions to reduce the ergonomic risks due to repetitiveness. This implies the need to implement changes that range from an appropriate distribution of breaks and rotations to variations in the work cycle itself. For this reason, it is important to train the engineering department so that they become aware of the influence of the production process on the risks to which workers are exposed during their workday.
Additionally, nine awkward postures with a medium level of risk were found which, according to the REBA methodology, implies a necessary action. These postures were related to the movements performed by the workers to reach the pieces that have to be assembled; therefore, the recommendations addressed the adequate distribution of the elements necessary for the task (boxes, trays, individual parts, etc.) as well as changes in the working height and the horizontal distance.
Figure 2. General recommendations to reduce risk due to awkward postures (heights and reaches)
Finally, as a complementary measure, the implementation of an Active Ergonomics program that helps to prevent musculoskeletal disorders is recommended. To do this, warm-up exercises and stretches to be done are specified considering the tasks that workers perform during their workday.
Figure 3. Example of a physical exercise included in the Active Ergonomics program
All these results were presented during a training session for risk management professionals and staff of the engineering department with the following objectives: to raise awareness of the importance of an adequate design of workstations (both from the dimensional and the work organization perspective), the importance of the problems for the workers’ health that an inadequate design of the workstation implies, as well as the importance of scheduled breaks and rotations in order to reduce the ergonomic risks to which workers are exposed. In addition, these sessions make it possible to identify innovation opportunities in the workplace thanks to the joint work of various departments that provided different views of these positions.
This project made it possible to further train the risk management professionals of CEE Dr. Schneider in the assessment of ergonomic risks and in identifying the actions to be taken to reduce the risks detected. Additionally, the engineering department became aware of the impact that the design of both workstations and work cycles can have on the workers as well as the importance of defining scheduled breaks and rotations in order to reduce the exposure of workers to tasks that involve risk of suffering musculoskeletal disorders. This way of working has been identified as a way to detect innovation opportunities in the workstations by considering the views of the different departments involved.
Company Dr. Schneider