23 research outputs found
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A âheart rateâ-based model (PHSHR) for predicting personal heat stress in dynamic working environments
The parameter of human body metabolic rates has been popularly used for the prediction of human heat stress in hot environments. However, most modules use the fixed and estimated metabolic heat production. The aim of this study is to develop the prediction of personal heat stress in dynamic working environments. Based on the framework of the predicted heat stress (PHS) model in ISO 7933, a heart-rate based PHSHR model has been developed using the time-based heart rate index, which is suitable for prediction in situations where metabolic rates are dynamic and there are inter-individual variations. The infinitesimal time unit Îti, has been introduced into the new PHSHR model and all the terms used in the PHS model related to metabolic rates are thus redefined as the function of real-time heart rates. The PHSHR has been validated under 8 experimental combined temperature-humidity conditions in a well-controlled climate chamber. The feature of the PHSHR model is being able to calculate dynamic changes in body metabolism with exposure time. It will be useful to the identification of potential risks of individual workers so to establish an occupational working environment health and safety protection mechanism by means of simultaneous monitoring of workersâ heart rates at the personal levels, using advanced sensor technology
Thermal comfort of motion and stationary states for recreational spaces of colleges and universities in the cold regions of China
Physiological and psychological reactions of subâtropically acclimatized subjects exposed to different indoor temperatures at a relative humidity of 70%
The effects of short-term and long-term exposure to extreme cold environment on the bodyâs physiological responses: An experimental study
Comparative analysis of methods for determining the metabolic rate in order to provide a balance between man and the environment
Prioritizing Factors Associated with Thermal Stresses Imposed on Workers in Steel and Iron Casting Industries Using the Monte Carlo Simulation and Sensitivity Analysis
A Method to Protect Mine Workers in Hot and Humid Environments
Background: Work comfort studies have been extensively conducted, especially in the underground and meteorological fields resulting in an avalanche of recommendations for their evaluation. Nevertheless, no known or universally accepted model for comprehensively assessing the thermal work condition of the underground mine environment is currently available. Current literature presents several methods and techniques, but none of these can expansively assess the underground mine environment since most methods consider only one or a few defined factors and neglect others. Some are specifically formulated for the built and meteorological climates, thus making them unsuitable to accurately assess the climatic conditions in underground development and production workings. Methods: This paper presents a series of sensitivity analyses to assess the impact of environmental parameters and metabolic rate on the thermal comfort for underground mining applications. An approach was developed in the form of a âcomfort modelâ which applied comfort parameters to extensively assess the climatic conditions in the deep, hot, and humid underground mines. Results: Simulation analysis predicted comfort limits in the form of required sweat rate and maximum skin wettedness. Tolerable worker exposure times to minimize thermal strain due to dehydration are predicted. Conclusion: The analysis determined the optimal air velocity for thermal comfort to be 1.5Â m/s. The results also identified humidity to contribute more to deviations from thermal comfort than other comfort parameters. It is expected that this new approach will significantly help in managing heat stress issues in underground mines and thus improve productivity, safety, and health. Keywords: maximum sweat rate, skin wettedness, thermal comfort models, tolerable worker exposure times, underground mine environmen