Abstract
Aim: The purpose of this study is to develop and verify a mathematical model, which identifies the thermal condition of a firefighter whilst wearing heat protective clothing at different temperature levels. The model is intended for predicting and analyzing the thermal condition of the body and determination of a firefighter’s maximum operating endurance.
Introduction: The work of a firefighter is accompanied by considerable risk to health and life. Effects from heat and physical exertion often reach critical limits of human endurance. Similarly, materials used in protective clothing may become ineffective beyond certain parameters. Consequently, exposure beyond such parameters leads to overheating of the body and causes burns. In order to increase the firefighter’s operational safety, it is important to know endurance limits for specified operating conditions, within which a firefighter is expected to perform and not exceed such limits. The time constraint is dependent on a range of factors, such as: characteristics of heat protective clothing (amount, type of material used and thickness of layers), temperature, humidity, speed of airflow surrounding the clothing and work load.
Methodology: The simultaneous modelling of a firefighter’s body temperature and clothing intended to protect from the effects of heat, allows for an evaluation of many aspects relating to the work of a firefighter and factors which influence the thermal condition of his/her body. This kind of modelling facilitates the determination of a firefighter’s maximum performance duration in given circumstances and to develop a configuration of new clothing providing protection against the effect of heat. Simultaneously, it is possible to analyze comfort levels and parameter limits for human body temperatures, which on average range within 37,2-38°C. Additionally, modelling will enable a reduction in the number of expensive tests for textile content of protective clothing, performed for different environmental conditions and nature of work of a firefighter during operations.
Results: Reported study results relating to temperature levels in spaces beneath layers of protective clothing for volunteers taking part in research, who performed physical exercises of varying intensity, were utilised to verify the proposed model. Body temperature test results, for volunteers attired in protective clothing and engaged in physical activity at room temperature of varying degrees, were very close to the results obtained from model calculations. Variations did not exceed 2°C.
Conclusions: The study facilitated the development of a two dimension model revealing the heat exchange in protection clothing, taking into account thermal processes and thermoregulation mechanisms of the human body, at different physical exertion levels, including internal heat release, permeability of textiles, and heat dissipation through breathing and perspiration.
Keywords: safety at work, thermal condition of a firefighter’s body dressed in heat protective clothing, modelling, experimental research