5. Discussion and Conclusion
5.4 Novelties (key contributions) of the present research
The research work promotes the existing knowledge of the vibration mitigation strategies in the applied domain of the floor polishing work where the use of the vibrating polishing device is a part of the regular working life. The key novelties of this research are pinpointed hereunder.
Contribution to knowledge-base
Following the current research, adoption of awkward working posture, repetitive forceful movement, prolonged work duration, and improper working tool have been identified as some of the ergonomic stressors associated with the floor polishing work. As there was not single literature in the Indian context, which deals with the ergonomic risk factors, thereby occupational health issues and their corresponding remedial measures including ergonomic design intervention, the present research has addressed this identified research gap by design modification of the existing hand-held floor-polishing device used by construction workers.
The present research has successfully demonstrated how high level of exposure to vibration (due to use of the hand-held polishing device) in the construction sector affect the occupational health of the polishing-workers and how ergonomic design intervention can be
adopted for reduction of vibration generation and transmission to the human hand-arm system for reduced vibrational exposure and thereby ameliorating the ill-impact on occupational health.
The current research has not only identified the ergonomic stressors in the unorganized sector of construction work but also addressed the issue through systematic research and development of a redesigned polishing device with its subsequent field trial for assessing usability and acceptance by the targeted users.
Contribution to methodological perspective
Systematic research methodology has been followed in the present research staring from literature review and field survey for establishing the research need and problem statement to finally come up with innovative product design for addressing the identified problems through design, development and field-testing. Current research has demonstrated how to identify ergonomic stressors during field surveys using questionnaires and direct/ indirect (photography and videography) observations. Both qualitative and quantitative research methodologies were adopted as per the requirement of data collection. Pre-designed questionnaire to identify the drudgery of the polishing workers and standard Nordic body parts discomfort mapping for identifying pain/ discomfort were used to understand the requirement of appropriate ergonomic interventions. The REBA for postural load evaluation, quantification of vibrational exposure using Human- Vibration meter, EMG for quantification of the requirement of muscular effort, and SUS for usability evaluation were applied during polishing activities by both existing and redesigned device to demonstrate the effectiveness of the redesigned device in comparison to existing ones.
The research methodology followed in the present research work might be the foremost of its kind as regards exploration from an occupational health perspective in floor polishing work in the construction sector in India. Researchers, Designers and Engineers involved in design, development and manufacturing of hand-held vibrating equipment/ machine/ device, may adopt a similar strategy to come up with innovative product design. Thus, the standardized methodology as described and adopted in the present research could serve as the research manual for future researchers.
The complete methodology (starting from problem identification to providing appropriate solution) used in the present research may be reproduced by emulating similar exploration in various occupational sectors in order to recognize occupation specific
ergonomic stressors and suggest suitable solutions, specifically for workers of unorganized sectors.
Perspective of intervention strategies
The current research has demonstrated how to come up with an appropriate ergonomic design solution against a given problem. The detailed methodology of product design innovation has been followed here. It involves user study and market study for design limits selection; generation of product concepts following brainstorming and using Morphological chart; screening of final concept using Pugh chart; mock-ups development, prototype development; and user trial and feedback from real field condition. The intervention strategies to address each of the identified problems such as (a) use of planetary gear mechanism (by replacing compound gear) to reduce jerk and vibration; (b)use of supportive structure and vibration dampening material towards diminishing vibration transmission to hand-arm of the workers; (c) provision for the vertical adjustment of the device to accommodate polishing stone of different thickness; (d) proper casing of the device to ensure electrical safety; (e) changing the dimension and design of the handle for anthropometric and biomechanical compatibility; (f) provision of attaching the handle on both left and right side of the device for facilitating as per workers hand dominance and operational requirement; (g) supportive frame with 3 legs on the ground to avoid sustained load holding by hands; and (h) use of roller ball caster unit at the bottom of the 3 supportive legs for the smooth movement of the redesigned device on the floor-surface.
Contribution to the society
The current research has addressed the real-life problems of occupational exposure to vibration of the floor polishing workers in the unorganised sectors of construction work.
Appropriate ergonomic design intervention to ameliorate the drudgery of the unprivileged construction workers has been depicted here. The developed design intervention was tested in real field conditions to demonstrate its usability and acceptance among construction workers.
The design intervention significantly reduced exposure to vibration as well as reduced the muscular effort for polishing activities along with improved perceived comfort due to better anthropometric and biomechanical compatibility. It is expected that the mass manufacturing and implementation of the device for the polishing activities in the construction sector would be very beneficial towards the reduction of the drudgery of the unprivileged construction workers to a great extent.