An innovative ergonomic design of classroom desktop- chair and its analysis based on anthropometric measurements at tertiary institutions. case study: Uasin-Gishu County, Kenya

Abstract

The design of classroom desktop-chairs (one size fits all) in many institutions is usually done with no consideration of anthropometric. This may cause musculoskeletal disorders and affect learning effectiveness due to sitting for a long time in awkward position. The main objective of this research was to use the concept of innovative ergonomics to design and analyse a classroom desktop-chair for students in Uasin- Gishu County. The specific objectives were: to collect anthropometric data for students from four selected tertiary institutions; to design a desktop-chair using the collected anthropometric measurements and to analyse the desktop-chair design using RULA ergonomic analytical tool. The sample size of 382 was determined according to Homkhiew et al. (2012). Anthropometric data was collected from a total of 382 students of both genders from four selected institutions within Uasin-Gishu County. The selected institutions for the survey were Moi University (MU), University of Eldoret (UoE), Rift Valley Technical Training Institute (RVTTI) and The Eldoret National Polytechnic (TENP). All fourteen (14) anthropometric measurements were taken (stature, sitting height, shoulder height, popliteal height, hip breadth, elbow height, buttock popliteal length, buttock knee length, thigh clearance, eye height, shoulder breadth, knee height, body mass and forearm fingertip length) from students with the help of anthropometric tools. The research applied fundamental engineering principles of product design and was carried out in compliance with ISO 7250-1:2017. The anthropometric data from four subject institutions were compared using one-way ANOVA analysis. The data obtained was analysed using Minitab 17.0 statistical package, to get the mean, standard deviation, minimum, maximum, 5 th , 50 th and 95 th percentiles. Using the collected anthropometric data, a students’ desktop-chair was proposed. The engineering design software, SolidWorks 2019, was used to develop four different conceptual designs of the desktop-chair from which one option was selected through Concept Scoring Method (CSM). To select the best option, relevant data was collected from students through a survey. The best selected desktop-chair concept was analysed using ergonomic software, Computer-Aided Three-dimensional Interactive Application (CATIA) based on Rapid Upper Limb Analysis (RULA). The tests results were failed to reject the null hypothesis (e.g., popliteal height p = 0.39), which meant that there was no significant difference among the anthropometric data sets. The analysed anthropometric data set was used to design, an innovative ergonomically suitable classroom desktop-chair. The results show that the proposed desktop-chair design gave better result where the final score was reduced from 4 to 1, which meant the chances of musculoskeletal disorders could be reduced. In conclusion, one type of ergonomically suitable classroom desktop-chair design was proposed to improve the match between classroom desktop-chairs dimensions and students' anthropometric characteristics. Further work on prototyping, usability and durability testing should be carried out.