Performance of Thermal Protective Clothing upon Exposure to Hot Liquid Splash

  • Author / Creator
    Farzan Gholamreza
  • This study mainly involved an experimental evaluation of transient heat transfer through thermal protective fabric systems, in particular the convection heat transfer between hot water and the fabric systems. The main objective of this thesis was to gain a fundamental understanding of the heat and mass transfer mechanisms associated with protective clothing systems when exposed to hot water and other fluids and during the cooling period immediately afterwards. For this purpose, five interrelated studies were performed. The fabric systems selected for this thesis represent thermal protective garments worn by firefighters and other workers. In this study, the thermal protective performance of the fabric system was evaluated upon exposure to hot water, drilling fluid, canola oil steam and high level radiation. In addition, an instrumented spray mannequin was used in order to see the effect of fabric system’s properties, garment design and hot water flow on the thermal performance of the garments. A detailed study of the hydrodynamics of the hot water flow on the surface of the fabric, in depth water penetration through the fabric system, the parameters which influence heat and mass transfer through the fabric system and their effects on thermal performance of the fabric was also conducted. The results indicate that stored thermal energy contributes significantly to second degree burns and can reduce the level of protection expected from the studied fabrics. In hot water exposures, the liquid starts spreading radially from the stagnation point until there is a sudden increase in the fluid height. This phenomenon is termed a hydraulic jump. The position of the hydraulic jump on the surface of the fabric and the area of the supercritical region are a function of experimental variables as well as physical properties of the fabric system. This affects the thermal performance of the fabric systems. Among the studied physical properties of fabrics, air permeability and fabric surface energy are dominant factors in the effective protection against hot liquid since resistance to mass transfer is shown to be the key factor for reducing the amount of transmitted and discharged thermal energy to the skin in bench scale and full scale tests. The results from the full-scale tests also show that garment fit and garment style, such as pocket style, have a great influence on the performance of the garments during the cooling period. Also, this study suggests possible modifications to the existing bench top and full scale test methods and equipment. These modifications could be used in the existing standards, in order to better predict the thermal protection provided by thermal protective clothing systems considering the stored energy effects and the hydrodynamics of hot liquid flow. In order to address the contribution of the stored energy in a bench scale fabric and a full-scale garment test, new predictive parameters were introduced. These parameters reveal the thermal response of protective clothing during the cooling period of the garment where heat transfer is influenced by the garment/fabric properties and/or the liquid flow. In addition, a predictive stored energy model and a burn evaluation model were proposed in order to determine the minimum exposure time for prediction of second degree burn in the cooling period. The proposed stored energy model calls for the use of only one test to predict the minimum exposure time to second degree burn. The findings obtained from this research will enable the engineering of textile materials to provide improved safety for firefighters and industrial workers under a wider range of conditions.

  • Subjects / Keywords
  • Graduation date
    Spring 2018
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
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