A new simplified model for evaluating thermal environment and thermal sensation: An approach to avoid occupational disorders

- Comfort evaluation studies are time-consuming, expensive and difficult to implement.
- Simplified models for evaluating the thermal environment are needed.
- EsConTer index is an interesting method for studying thermal comfort of a space.
- The colour maps represent useful and intuitive means to know the thermal environment.
- This study proposes a new simplified model, based on colour scale and EsConTer index.

Thermal heat stress is a cause of many occupational disorders that disrupt worker performance and the quality of work and, in extreme cases, can lead to death. In the industrial context, thermal discomfort is cited as one of the major causes of dissatisfaction in workplaces when people are exposed to extremely hot or cold thermal environments. Given the time that people spend in their workplaces, studies evaluating the comfort of the thermal environment are becoming increasingly important. However, comfort evaluation studies are time-consuming and for many organizations become expensive and difficult to implement due to the lack of a simplified model for evaluating the thermal environment of workplaces and the thermal sensations of their occupants.This paper aims to show the possibility of assessing the thermal patterns of industrial spaces and consequently identifying the most critical areas in terms of thermal comfort, using thermal indexes supported by real data collected using inexpensive measuring tools. This study was carried out in two Portuguese industrial manufacturing facilities with different characteristics, evaluating the thermal environment and the workers' thermal sensation in the season of spring. The data related to environmental parameters were collected using two similar measuring instruments, Testo 435-4 and Center 317- temperature humidity meter, while the workers' thermal sensations were collected using a thermal sensation colour scale that is aligned with the ASHRAE seven-point thermal sensation scale. The results were reproduced in colour maps based on MatLab algorithms, using the calculation formula of three thermal indexes, EsConTer (a new index), THI, and PPD.The applied methodology, using the EsConTer index, proved to be an interesting method for easily studying thermal environments and predicting the thermal comfort of an indoor space. Moreover, the representation of thermal indexes in colour maps is an informative approach, prompting recommendations and development actions with the aim of providing more comfortable, safer, and healthier work conditions, and minimizing occupational disorders. Indeed, the practical results were appreciated by the Health and Safety Department of each industry in order to develop measures that improve the occupational health of the occupants to prevent work accidents and work-related disorders.Accordingly, the methodology applied in this work, using a colour scale with the EsConTer index, proposes a new, simplified model for thermal stress risk evaluation, aiming to minimize difficult and time-consuming investigations to identify thermal comfort problems in workplaces. The coloured maps generated by MatLab algorithms proved to be a useful tool to visualize the thermal pattern of an environment, and consequently to identify thermal comfort problems.

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