Thermal Comfort Of Workers Research Articles

Analysis of thermal comfort and threshold range of airflow supply parameters for different types of work in humid-heat coal mines

For the purpose of investigating the effects of various factors as to the thermal comfort of miners, obtaining the most comfortable threshold range of air supply parameters. Five types of jobs with moderate and light labor intensity were selected for the study. The effects of labor intensity, environmental parameters and thermal resistance of clothing on the thermal comfort of miners were analyzed using PMV-PPD index, air motion and temperature difference. Under the same environment, moderate manual workers showed more satisfactory thermal comfort than light manual workers. In a humid and hot mine, the degree of influence of environmental parameters on thermal comfort of workers is ranked as: temperature > humidity > wind speed. Considering the influence of thermal environment and dust on people, the temperature of 27–30 °C, humidity of 40–50% and wind speed of 1.5–2.5 m/s are an optimal combination of ventilation parameters that can simultaneously satisfy human comfort and low energy consumption. The worker can compensate the temperature by adjusting the heat resistance value of the garment. 0.38–2.12clo clothing thermal resistance value, can compensate the temperature range of 27–30 °C. These findings can provide a reference for reducing energy consumption and improving human thermal comfort.

Investigating the short-term cognitive abilities under local strong thermal radiation through EEG measurement

Local Strong Thermal Radiant environment is widely present in industrial buildings, resulting in reduced cognitive abilities and thermal comfort for workers who perform monitoring operations. However, the effect is difficult to quantify, especially for jobs that are near hyperthermal radiant sources. In this study, ten young male subjects were directly exposed to five different radiation panel temperatures for 60 min, i.e., 100, 150, 200, 250, and 300 °C, at 0.8 m from the radiant panel. Subjects were asked to perform cognitive tasks and subjective questionnaires and monitor 16 channels of EEG signals in a chamber. Based on the assessment of the EEG characteristics, the impacts of Local Strong Thermal Radiant on cognitive abilities and EEG are investigated. The results indicated that cognitive abilities were improved while the radiant temperature was below 250 °C. As the radiation temperature increases, the normalized power of β activity and α activity increases, and the vigilance and frontal EEG asymmetry increase. When it reaches 300 °C, all these features decrease and show an inverted “U” shape. The Local Strong Thermal Radiant arouses β activity and motivation for a short period and enhances cognitive abilities. The thermal comfort scores and thermal sensation scores rise with increasing temperature. Several international standards and literature can verify the findings of this study. This study's findings provided a foundation for assessing the cognitive abilities and inducing the mental states of hyperthermal radiant environment young workers to advance effective safety management in the industrial workshop.

The Effects of Clothing Insulation and Acclimation on the Thermal Comfort of Underground Mine Workers

Excessive heat exposure is among the health and safety hazards that have adverse effects on the mine workers. The very nature of the underground climate makes it a convenient avenue for heat generation and accumulation from several heat sources including autocompression, equipment, and heat from strata. This study investigated the effects of clothing insulation and acclimation on the thermal comfort of mine workers who are exposed to heat in underground working environments. Several clothing ensembles have been considered to analyze the effect of the thermal resistance of clothing on the thermal comfort of workers. To investigate the impact of the clothing insulation, the thermal comfort limit of an underground miner was calculated in the form of maximum allowable exposure time for an 8-h shift. Parametric analyses were subsequently performed using an already developed thermal comfort model using MATLAB software. The results demonstrate that clothing insulation has a significant effect on the thermal comfort of mine workers. Increase in the clothing insulation decreases the maximum allowable exposure time of mine workers. This is especially true for the new and non-acclimated workers. Since acclimatized workers can tolerate a higher level of the dehydration and are capable of losing more water by sweat per shift, the maximum allowable exposure time for the acclimated workers are higher than non-acclimated workers. These analyses have shown that acclimated workers can have more continuous work per shift compared with non-acclimated workers. For example, in an environmental condition with clothing that a non-acclimated worker cannot work more than 5 h, an acclimated worker can work a full 8-h shift.

Evaluation of Thermal Comfort for Workers at the Construction Site in a Block-Modular Building Made of Sandwich Panels

The purpose of this work is to assess the thermal comfort of a block-modular building on the construction site. The experimental studies for determining the thermal conditions of the cabins in the winter and the summer time of the city of Zhengzhou was carried out at different locations of the modular house made of sandwich panels for determining the category of living comfort. The variations of air temperature and relative humidity in the cabin were analyzed. The difference between outdoor and indoor air temperatures, as well as the changes in air temperature and heat flux on the internal surface of the different walls of the building by their location relative to the cardinal directions were considered. Reasons for decreasing the comfort in the room and the attenuation of the experimental amplitude of the outdoor temperature fluctuations in the enclosing structure as well as the thermal properties of enclosing structures of the block-modular building under different climatic conditions were studied. It is shown that it is necessary to take into account the reflection of heat inside the premises and their ventilation when designing enclosing structures of mobile buildings. It is revealed that in the winter period for energy saving it is necessary to increase in addition thermal characteristics of the western wall of domestic buildings.

<b>Human thermal comfort and architectural volume

It has been questioned what influence the architectural variables have on the workers’ thermal comfort since the building is a barrier between both the external and internal environments. This article presents the findings of an applied research that correlated the analytical thermal comfort of workers with the architectural volume of the workspace. We used the Confortimetro Sensu ® equipment and the software Analysis CST 2.1 ® for measuring thermal variables and calculating the analytical comfort of workers. The research was applied in different thermal conditions and different space volumes. The statistical results of this sample did not provide evidence to support the assertion of a correlation between architectural volume of spaces and thermal comfort of workers.

Measuring Thermal Stress of Dairy Cattle Based on Temperature Humidity Index (THI) in Tropical Climate

Thermal comfort for workers is very important factor to increase their performance, as well as the comfort level of dairy cattle will influence in milk productivity. The purposes of the paper is to measure the level of heat stress and then use the information to design the dairy cattle house for increasing thermal comfort. The research is started with literature review of heat stress and early survey of environment condition e.g. temperature, wind speed and relative humidity. The next step is using the information to determine the temperature humidity index (THI) level for dairy cattle with maximum THI = 86 and 84 (moderate stress). The 3D CAD model and Computational Fluid Dynamic (CFD) simulation are employed to looking for solution for reducing the discomfort thermal of dairy cattle. A scenario (fan) air conditioning to get better condition of thermal comfort have been successfully presented with final THI index = 76 and 78 (mild stress). Finally, the paper shows how to reduce heat stress of cattle house by installation 3 exhaust fans in tropical climate.

A Field Study on Thermal Comfort of Traditional Metal Processing Factories

A traditional metal processing factory is a hot workplace. Previously, the rationality of the work-rest time regimen and the hazard of workload on employee health have been evaluated; however, thermal comfort of workers in such a hot workplace has not been discussed. This paper uses the standard new effective temperature as the thermal environment index to investigate the neutral temperature, preferred temperature, and comfortable temperature range. The doors and windows in traditional metal processing factories are always open; therefore, the neutral temperature is almost the same as the neutral temperature in semi-outdoor and outdoor environments. In addition, the preferred temperature is slightly higher than the neutral temperature. We also discovered that the comfortable temperature range in traditional metal processing factories is larger than that in office environments, but smaller than that in semi-outdoor and outdoor environments.