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No sweat: easy ways to cool Bangladesh garment factories

Mohataz Hossain

Mohataz Hossain’s study into why air quality in Bangladesh clothing factories is so poor, and his guidelines to improve it, is of value to manufacturers as well as workers and was shortlisted in the RIBA President’s Awards for Research

Research methods to gather evidence and propose design guidelines.
Research methods to gather evidence and propose design guidelines. Credit: Mohataz Hossain

The major branded clothing we wear is usually made in the garment factories where workers labour all day long to produce quality products. In the tropical climate of Bangladesh, the workers of these factories suffer from thermal discomfort and a range of health issues due to indoor high temperature and lack of uniform airspeed. As one clothing worker said: ‘We usually feel tired at our workstations due to uncomfortable thermal environment.’ But the factory owners don’t seem to know how to help. ‘We are aware of workers’ low productivity and thermal discomfort. We added more ceiling-fans. But we could not improve their working environment without knowing the feasible solution,’ said one. There must be a knowledge gap, which is one of the main reasons why I commenced this research as an architect.

Being trained as an architect and academic in Bangladesh, I got involved in investigating ready-made garment (RMG) factories as a graduate student researcher with my colleagues at Bangladesh University of Engineering and Technology (BUET) in 2009. As a part of a collaborative research project, I focused on the clothing workers’ comfortable lighting environment and its impact on increasing their work efficiency. From my colleagues’ research, I found that workers’ thermal discomfort also hampers their work productivity.

Starting my PhD research, funded by ‘Commonwealth Scholarship Commission in the UK, at the University of Nottingham in 2013, I found that previous studies provided too little field evidence or viable design guidelines for multi-story garment factories in Bangladesh. While designing a garment factory, architects and engineers tend to use mechanical fans to extract the indoor hot air by positioning them at either side of the deep floor-plates – around 30-35m apart – of multi-storey buildings, and provide ceiling fans for workers’ thermal comfort. They follow local codes and regulations, but these codes usually lacked field evidence. In a developing country such as Bangladesh, air-conditioning factories is not feasible due to high electrical energy demand and associated running costs.

So I investigated workable design solutions to improve indoor environments at RMG factories. My objectives included establishing thermal comfort guidelines and testing designs with an evidence-informed approach. With support from my PhD supervisors, colleagues, friends and relevant stakeholders in the UK and Bangladesh, I conducted extensive field investigations in three case study buildings during the three seasons of the tropical climate of Bangladesh in 2015. My overall research involved scientific data monitoring, questionnaire surveys among 900 workers across various seasons and case studies, focus group discussions, interviews with factory owners and computer-based simulations. This research was extended in 2019 with further analyses, validations and simulations using the latest versions of software such as IESVE 2019.

Thermal comfort guidelines for clothing workers to improve three types of workspace environment during the warm-humid season.
Thermal comfort guidelines for clothing workers to improve three types of workspace environment during the warm-humid season. Credit: Mohataz Hossain

My significant findings are all evidence-based. These include possible causes of high indoor temperatures and thermal discomfort, workers’ adaptive comfort range and preferred airspeed, workable building width and potential passive ventilation design guidelines to improve both existing and new buildings.

Scientific field evidence and analyses of the environmental data from all three case study buildings revealed that the tendency to design with limited effective openings, such as sliding windows, and a ventilation strategy limited to occupied hours only, influence the indoor work environment and prevent the mechanical fans from working effectively. Thermal images, scientific data and group discussions revealed that workspaces with different activities – such as cutting, sewing and finishing – have varied thermal environments so demand different ventilation rates and comfortable airspeeds. For example, workers highlighted that ‘ceiling fans do not help as they bring down hot air to our workstations’.

Workers’ preferred adaptive temperature and airspeed ranges according to climate and type of work were established through the analysis of subjective votes from workers.  They prefer more personalised control on their comfort, avoiding the ceiling fans. The maximum distance between their workstation and ventilation-inlets should be 18m. Among a range of proposed solutions, the most viable for owners of the case study buildings were to use a nighttime cooling strategy and to modify the existing window type to one with a higher effective opening areas. This applied to both new and existing buildings.

Passive ventilation design proposal for new garment factories.
Passive ventilation design proposal for new garment factories. Credit: Mohataz Hossain

The most exciting part of the project is the extended simulation results – endorsed by field data. Results confirmed that the above solutions can reduce hours worked in high temperatures. Moreover, additional comfort and airspeed can be provided by designing stack induced ventilation through shafts, changing workstation arrangements including lighting layouts and adapting low heat-emitting lights. Consequently, clothing workers can enjoy improved working environments and manufacturering industries can have a more diversified architecture with sustainable solutions in Bangladesh and other countries.

Mohataz Hossain is lecturer in environmental architecture and technology at Sheffield Hallam University

His research Improving Workspace Environment for Garment Factories in Bangladesh: Design Guidelines for Clothing Workers’ Thermal Comfort was shortlisted in the RIBA President’s Awards for Research

See the other winners of President’s Medals and President’s Awards



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