Ergonomics issues and methodologies in industrially developing countries
This thesis considers the application of ergonomics in Industrially Developing Countries (IDCs) with a particular focus on rural subsistence agriculture in Ghana. The thesis had two aims, firstly to identify the need for ergonorMcs to be incorporated into international development projects. A survey of the causes and incidence of illhealth in subsistence fanning was undertaken A high incidence of occupational disorders was recorded with injuries Erom. handtools and lower back pain being endemic. This survey was followed by a checklist analysis and Participatory Rural Appraisal of agroprocessing. Ergonomics issues were identified in many agroprocessing activities. These included poor posture, repetitive motions, manual handling, and stressful work environments. Inappropriate technology transfer was widespread. Farmers behaviour when working in high ambient temperatures was investigated in the field. Whilst methodological problems were encountered and discussed, heat stress was considered a potential problem that deemed further investigation. From the surveys and field investigation, ergonorMcs problems in human work in rural subsistence agriculture were identified and a need for ergonotMcs to be incorporated into development projects was demonstrated. In the light of this, the second aim of the thesis was addressed, investigating the appropriateness of tools, methods and standards for use in IDCs with an ergonomics tool kit being developed. Following on from the field investigation into working in the heat, stratergies for assessing heat stress in tropical agriculture were assessedin terms of their validity and usability. In a simulated tropical agricultural task heat stress standards (ISO 7243 and ISO 7933) were found to be valid if over protective. It can be anticipated that the ISO 7243 can be easily used in IDCs. The usability of ISO 7933 however was questioned. As the standards failed to accommodate for solar load, solar radiation and its effects on the human thermoregulatory system were considered. Six subjects performed a step test in outdoor conditions with a solar load, repeating this in similar conditions in a thermal chamber with no solar load. The difference in sweat loss between the conditions was attributed to the increased load from solar radiation. In the conditions measured, the radiation incident on the human thermoregulatory system was 82W/M 2. Two existing models for solar radiation were validated. Subjective and objective ergonomics tools were assembled in a tool kit that was used on an ad hoc basis in the field in Ghana. A pragmatic approach to the usability of the tool kit was adopted. Drawing on practical experiences and expert analysis, it was found that simple, reliable, robust and easy to maintain equipment was most appropriate and usable in the field. Subjective rating scales proved to be difficult to use and were unreliable. Participatory rural appraisal methods were found to be simple, rapid and well suited to ergonomics research in tropical agriculture. Practical implications from the research in Ghana were discussed and recommendations made. The thesis concluded that there is a need for ergonomics interventions in IDCs with the ergonomics tool kit being generally acceptable for use in this field. The thesis concluded that there is a need for ergonormcs and that the tools, methods and standards considered were found to be generally usable, although the approach often required adapting to local circumstances whilst maintaining scientific integrity.