Manual assembly operations are sensitive to human errors that can diminish the quality of final products. The paper shows an application of human reliability analysis in a realistic manufacturing context to identify where and why manual assembly errors occur. The techniques SHERPA and HEART were used to perform the analysis of human reliability. Three critical tasks were selected for analysis based on quality records: (1) installation of three types of brackets using fasteners, (2) fixation of a data cable to the assembly structure using cushioned loop clamps and (3) installation of cap covers to protect inlets. The identified error modes with SHERPA were: 36 action errors, nine selection errors, eight information retrieval errors and six checking errors. According to HEART, the highest human error probabilities were associated with assembly parts sensitive to geometry-related errors (brackets and cushioned loop clamps). The study showed that perceptually engaging assembly instructions seem to offer the highest potential for error reduction and performance improvement. Other identified areas of action were the improvement of the inspection process and workers’ provision with better tracking and better feedback. Implementation of assembly guidance systems could potentially benefit worker’s performance and decrease assembly errors.

Objectives: This paper briefly describes the history of ergonomics in Cuba and also presents some ergonomic interventions carried out in major economic sectors, focused on reducing musculoskeletal risk factors. Methods: Five studies concerning musculoskeletal risk factors were reviewed comparing the results of various ergonomic tools. Cuban legislation related to occupational health as well as statistics available on musculoskeletal disorders were examined. Results: The reviewed studies were carried out using such universally recognized assessment tools as RULA, Strain Index, OWAS and NIOSH equations as well as human movement analysis software. The interventions presented are examples of a proactive approach to the improvement of workers' health. Musculoskeletal disorders are responsible for the second highest rate of total permanent disability in the Cuban work force. Conclusions: The prevailing approach to workers' health in terms of musculoskeletal disorders is basically reactive rather than proactive despite the commitment of the Cuban Government to the subject and a set of rules established to accomplish this goal. Simple tools for conducting a systematic evaluation of working conditions are needed in our context.

This study was conducted in a warehouse at a vaccine production centre where improvement to existing storage and working conditions were sought through the construction of a new refrigerated store section (2-8C°). Warehousing tasks were videotaped and ergonomics analysis tools were used to assess the risk of developing MSDs. Specifically, these tools were the Rapid Entire Body Assessment (REBA) and the NIOSH equation. The current plant layout was sketched and analyzed to find possible targets for improvement trough the application of general work space design and ergonomics principles. Seven of the eight postures evaluated with REBA had a total score between 8 and 10, meaning a high risk, and only one was at a medium risk level. Nine of the eleven manual material handling tasks analyzed with the NIOSH equation had a Lifting Index between 1.14 and 1.80 and two had a recommended weight limit of 0kg, indicating a need for job redesign. Solutions included the redesign of shelves, the design of a two-step stair and a trolley with adjustable height; also, changes in work methods were proposed by introducing a two-workers lifting strategy and job rotation, and, finally, a restructuring of plant layout was completed.

BACKGROUND: Fatigue and workload experienced by aircraft de-icing personnel have been largely neglected in occupational health and safety research. OBJECTIVE: To provide an initial assessment of fatigue and workload among de-icing ground crews. METHODS: Company records were used to reveal possible relationships between different variables (age, seniority, truck type, and work shift). A group of 20 volunteer participants (17 men and 3 women) rated their level of fatigue before and after one shift using the Samn-Perelli fatigue scale. Workload was evaluated using the NASA-TLX method at the end of the shift. RESULTS: The average fatigue experienced by de-icing worker was significantly greater (P = 0.043) for the technicians in open-basket trucks than for the ones in trucks with a cabin (4.43 vs 3.37). Furthermore, there was a significant age difference (P = 0.048) in the perceived level of fatigue (4.1 vs 3.1), with younger workers (< 30 years) reporting a higher level than older workers (30 years). Overall NASA-TLX score were not significant (P > 0.05) for any of the factors tested: type of truck, shift and age. CONCLUSIONS: The results suggest that particular attention should be paid to young technicians and technicians working in open-basket trucks, since the fatigue levels reported in association with these factors were higher.

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