Study of ergonomic needs in designing and manfacturing of furniture for Sri Lanka : case study of chairs used in teritary education institutes

Abstract

Teachers, learners, and educational materials are considered basic ingredients of the teaching and learning process, but the physical environment in which learning occurs where furniture has become an important component of learning environment is often neglected. A study by Thariq et al (2004 under review) on chair dimensions showed that various government tertiary education institutes in Sri Lanka provide various design dimensions to manufacture lecture hall chair, for a same user population to perform a same particular task. The same study concluded that the presently used lecture hall chairs would not match body dimensions of users therefore would be unhealthy and uncomfortable for the user population. From the findings of the study they recommended to measure the body dimensions of students of tertiary education institutes and thereby to develop dimensions to design healthy and comfortable institutional chairs. Abeysekara (1985), based on the anthropometric survey among workers population carried out in Sri Lanka recommended dimensions for work seat. Abeysekara's (1985) recommendations are based on the anthropometric measurements of Sri Lankan worker population, which may not match the recent student population of tertiary education institutes and needs are also different between workers and students. The design dimensions presently used in Sri Lanka to manufacture chairs are not based on the anthropometric characteristics of Sri Lankan user population instead it has been copied from British Standards and modified (Abeysekara, 2003). An ergonomic survey in Sri Lanka conducted by Abeysekara (1996), an ergonomic expert, shows that the common problem observed in the places (indoors) was the mismatch regarding the works and their operating level, whether standing or seated. Many research works revealed the consequences of mismatch of furniture to the users. Evans et al (1988) concluded in a study, as bad posture associated with badly designed chairs and tables, unfitting to children, in schools are factors which may affect academic performance and physical development of school children. Though this study is relevant to schoolchildren the same is applicable for the students of the tertiary education institutes. A study by Balaque et al (1988) showed a surprisingly high proportion of school students reported suffering from musculoskeletal discomfort and low back pain. This is of great concern because the strongest predictor of having future back pain is often considered to be a previous history of such symptoms. A small body of research has implicated the mismatch between school furniture and body size as a causative factor for musculoskeletal discomfort and low back pain amongst school students (Floyd and Ward 1969, Mandal 1982, Parcells et al 1999). Colombini et al (1985) reported the increasing number of people spends their working days sitting down, many of them complain back and neck pain. Almost half of the population of the industrialized world is thought to be suffering from some form of back complaint, many of them are related to poor seat design (Mandel, 1985). The chairs currently used in Sri Lankan tertiary education institutes do not follow ergonomic design criteria i.e. matching to the body sizes of the users and the material comfort characteristics of seat surface and backrest. In designing chairs, concern to the task to be performed, localizing ergonomic criteria i.e. matching the chairs to the users and integrating material characteristics of seat surface and backrest according to user comfort are necessary to develop good 2 posture that would ensure functional efficiency, ease of use, comfort, health and safety and quality of working life. Therefore an understanding of the anthropometric characteristics of the user population and the user comfort to the material characteristics of seat surface, and backrest are important to design and construct healthy and comfortable chairs for tertiary education institutes.