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Using a thermal manikin to determine evaporative resistance and thermal insulation : A comparison of methods

Toma, Róbert LU ; Kuklane, Kalev LU ; Fojtlín, Miloš ; Fišer, Jan and Jícha, Miroslav (2021) In Journal of Industrial Textiles 50(9). p.1493-1515
Abstract
Heat transfer from the human body, especially through the evaporation of sweat from the skin, is often restricted when protective clothing is used, which may result in overheating. For this reason, it is important to consider the parameters of protective clothing as input data in physiological models, such as predicted heat strain. The two most important parameters are thermal insulation and evaporative resistance with clothing area factor strongly influencing both. These parameters were determined for two clothing ensembles using a (dry) non-sweating thermal manikin. First, the clothing area factor was determined using the photographic method. Second, thermal insulation was measured in both static and dynamic conditions, and multiple... (More)
Heat transfer from the human body, especially through the evaporation of sweat from the skin, is often restricted when protective clothing is used, which may result in overheating. For this reason, it is important to consider the parameters of protective clothing as input data in physiological models, such as predicted heat strain. The two most important parameters are thermal insulation and evaporative resistance with clothing area factor strongly influencing both. These parameters were determined for two clothing ensembles using a (dry) non-sweating thermal manikin. First, the clothing area factor was determined using the photographic method. Second, thermal insulation was measured in both static and dynamic conditions, and multiple equations for predicting dynamic thermal insulation from static ones were evaluated. Third, methodology for measuring evaporative resistance based on pre-wetted skin was adopted and multiple corrections were assessed. Finally, sensitivity analyses were completed using PHS to determine the impact of different equations on the duration limited exposure. For the thermal insulation measurements, we found that predictive equation (32) from ISO 9920 was the most accurate, but choosing the correct equation for protective clothing proved challenging. Although a manikin’s surface temperature is widely used for calculating evaporative resistance, the skin temperature should be used instead, since it is correct from a physical point of view and there is a difference of up to 15% in the results. Because these measures are used in thermal risk analyses conditions, a high degree of accuracy and a knowledge of the inputs must be guaranteed. (Less)
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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Industrial Textiles
volume
50
issue
9
pages
1493 - 1515
publisher
SAGE Publications
external identifiers
  • scopus:85078632527
ISSN
1528-0837
DOI
10.1177/1528083719900672
language
English
LU publication?
yes
id
f33a0e9a-1f36-48b9-9f30-0205d9048eca
date added to LUP
2021-06-01 16:52:46
date last changed
2022-04-27 02:14:26
@article{f33a0e9a-1f36-48b9-9f30-0205d9048eca,
  abstract     = {{Heat transfer from the human body, especially through the evaporation of sweat from the skin, is often restricted when protective clothing is used, which may result in overheating. For this reason, it is important to consider the parameters of protective clothing as input data in physiological models, such as predicted heat strain. The two most important parameters are thermal insulation and evaporative resistance with clothing area factor strongly influencing both. These parameters were determined for two clothing ensembles using a (dry) non-sweating thermal manikin. First, the clothing area factor was determined using the photographic method. Second, thermal insulation was measured in both static and dynamic conditions, and multiple equations for predicting dynamic thermal insulation from static ones were evaluated. Third, methodology for measuring evaporative resistance based on pre-wetted skin was adopted and multiple corrections were assessed. Finally, sensitivity analyses were completed using PHS to determine the impact of different equations on the duration limited exposure. For the thermal insulation measurements, we found that predictive equation (32) from ISO 9920 was the most accurate, but choosing the correct equation for protective clothing proved challenging. Although a manikin’s surface temperature is widely used for calculating evaporative resistance, the skin temperature should be used instead, since it is correct from a physical point of view and there is a difference of up to 15% in the results. Because these measures are used in thermal risk analyses conditions, a high degree of accuracy and a knowledge of the inputs must be guaranteed.}},
  author       = {{Toma, Róbert and Kuklane, Kalev and Fojtlín, Miloš and Fišer, Jan and Jícha, Miroslav}},
  issn         = {{1528-0837}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{9}},
  pages        = {{1493--1515}},
  publisher    = {{SAGE Publications}},
  series       = {{Journal of Industrial Textiles}},
  title        = {{Using a thermal manikin to determine evaporative resistance and thermal insulation : A comparison of methods}},
  url          = {{http://dx.doi.org/10.1177/1528083719900672}},
  doi          = {{10.1177/1528083719900672}},
  volume       = {{50}},
  year         = {{2021}},
}