Effect of changing window type and ventilation strategy on indoor thermal environment of existing garment factories in Bangladesh

Abstract

This paper presents two workable solutions that can significantly improve the indoor thermal environment within the workspaces in existing ready-made garment (RMG) factories in the tropical climatic context of Bangladesh. The research involved field studies in three multi-storey factory buildings, semistructured interviews with workers and owners and simulation studies. Field data indicated that the effective window-opening size of existing buildings and limiting the ventilation strategy to occupied hours caused overheating of the indoor environment. Among a list of proposals, the building owners saw value in implementing two solutions (i.e. altering existing window type to one with a higher effective opening area and adopting a night-time ventilation strategy) in their existing buildings as well as proposed new buildings. To quantify the benefits of these two interventions, a validated simulation study on one of the buildings was conducted. The findings confirm that these two solutions can provide reductions of up to 23% in overheated hours during operational time and in so doing, improve workers' thermal comfort and well-being. IntroductionIn the tropical climatic context of Bangladesh, most of the workers in ready-made garment (RMG) factories suffer from discomfort in their workspaces and a range of health problems due to the high indoor air temperature and poor air distribution (Authors 2015; Authors 2014;Fatemi 2014). The workspaces include cutting, sewing and finishing sections. Workers' thermal discomfort also hampers productivity (Fatemi 2014), resulting in additional workload to meet production targets without any financial benefit. These workspaces, with a deep floor-plan and low ceiling heights, usually employ forced cross-ventilation using auxiliary extractor fans located on the external walls. However, the existing active ventilation strategies do not meet the thermal comfort needs of the workers with significant overheating observed in the middle part of the floor plate (Authors 2015) even in the presence a significant difference in 'wind pressure coefficient' between the inlet and outlet openings (CIBSE 2005) due to mechanical ventilation.Previous theoretical studies and empirical evidence suggest that improving the indoor thermal environment and air quality through the adaptation of available passive technologies can improve health, productivity and wellbeing of the workers in workspace offering financial benefits to both workers and factory owners (Fisk 2000;Hobday and Dancer 2013;Mahbob et al. 2011;Srinavin and Mohamed 2003). In particular, improving the thermal environment of RMG factories helps to reduce production errors up to 1.88% (Fatemi 2014), which may offer added commercial benefit to factory owners and their international buyers. In addition, effective implementation of natural ventilation in the factories can provide a natural environment for the workers and reduce electricity energy consumption and consequent greenhouse gas emissions (Wijewardane and Jayasinghe 2008). By adopting ...

Review of Window Performance in A Hot and Humid Climate

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“…Figure 15 shows the average DBT and RH recorded in the students' lecture room during one of the workshops and indicates the key period of changed physical and environmental parameters, such as students' physical exercise, switching on an electric heater, opening/closing windows for ventilation, which have direct impacts on the students' thermal comfort experience [28][29][30][31]. The subjective feedback was also observed keeping the changes of conditions in mind in addition to recorded DBT values.…”

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