Determination of Clothing Evaporative Resistance on a Sweating Thermal Manikin in an Isothermal Condition: Heat Loss Method or Mass Loss Method?

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Bibliographic Details
Title:	Determination of Clothing Evaporative Resistance on a Sweating Thermal Manikin in an Isothermal Condition: Heat Loss Method or Mass Loss Method?
Authors:	Wang, Faming¹, Gao, Chuansi¹, Kuklane, Kalev¹, Holmér, Ingvar¹
Source:	Annals of Occupational Hygiene. Oct2011, Vol. 55 Issue 7, p775-783. 9p.
Subjects:	Prevention of psychological stress, Physics -- Methodology, Body temperature regulation, Heat, Research methodology, Research funding, Symptoms
Abstract:	This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing evaporative resistance conducted in an isothermal condition (Tmanikin = Ta = Tr). Five vocational clothing ensembles with a thermal insulation range of 1.05–2.58 clo were selected and measured on a sweating thermal manikin ‘Tore’. The reasons why the isothermal heat loss method generates a higher evaporative resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of evaporative heat energy taken from the environment. It was found that clothing evaporative resistance values by the heat loss option were 11.2–37.1% greater than those based on the mass loss option. The percentage of evaporative heat loss taken from the environment (He,env) for all test scenarios ranged from 10.9 to 23.8%. The real evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing evaporative resistance, it is suggested that manikin measurements on the determination of clothing evaporative resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing evaporative resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use. [ABSTRACT FROM AUTHOR]
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Database:	Engineering Source

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Abstract:	This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing evaporative resistance conducted in an isothermal condition (Tmanikin = Ta = Tr). Five vocational clothing ensembles with a thermal insulation range of 1.05–2.58 clo were selected and measured on a sweating thermal manikin ‘Tore’. The reasons why the isothermal heat loss method generates a higher evaporative resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of evaporative heat energy taken from the environment. It was found that clothing evaporative resistance values by the heat loss option were 11.2–37.1% greater than those based on the mass loss option. The percentage of evaporative heat loss taken from the environment (He,env) for all test scenarios ranged from 10.9 to 23.8%. The real evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing evaporative resistance, it is suggested that manikin measurements on the determination of clothing evaporative resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing evaporative resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use. [ABSTRACT FROM AUTHOR]
ISSN:	00034878
DOI:	10.1093/annhyg/mer034