| 1. |
- Lin, Li-Yen, et al.
(författare)
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A laboratory validation study of comfort and limit temperatures of four sleeping bags defined according to EN 13537 (2002)
- 2013
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 1872-9126 .- 0003-6870. ; 44:2, s. 321-326
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we validated comfort and limit temperatures of four sleeping bags with different levels of insulation defined according to EN 13537. Six male subjects and four female subjects underwent totally 20 two-hour exposures in four sleeping bags at four intended testing temperatures: 11.2, 3.8, 2.1 and -9.0 degrees C. The subjective perceptions and physiological responses of these subjects were reported and analyzed. It was found that the EN 13537 defined comfort temperature and limit temperature were underestimated for sleeping bags MA3, HAG and MAM. The predictions are so conservative that further revision may be required to meet the requirements of both manufacturers and consumers. In contrast, for the sleeping bag MAO with a low level of insulation, the limit temperature defined by EN 13537 was slightly overestimated. In addition, two individual case studies (-28.0 and -32.0 degrees C) demonstrated that low toe temperatures were widely observed among the male and female subjects, although the mean skin temperatures were almost within the thermoneutrality range (32.0-34.0 degrees C). It seems that the IREQ model (ISO 11079) overestimated both the comfort and limit temperatures of the sleeping bags. Finally, traditional sleeping bags may be required to be re-designed to provide consumers both whole body comfort as well as local thermal comfort at feet/toes or users need to be made aware of the higher need for their insulation. (C) 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.
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| 2. |
- Wang, Faming, et al.
(författare)
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Effects of various protective clothing and thermal environments on heat strain of unacclimated men: The PHS (predicted heat strain) model revisited
- 2013
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Ingår i: Industrial Health. - 1880-8026. ; 51:3, s. 266-274
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Tidskriftsartikel (refereegranskat)abstract
- Five protective garments were assessed on eight unacclimated male subjects at two WBGT temperatures: 19.0 and 24.5 °C. The thermophysiological responses and subjective sensations were reported. The PHS model (ISO7933) was used for predicting thermophysiological responses for each testing scenario. It was found that there were significant differences between clothing FIRE and other clothing on thermal sensation (p<0.05). Significant differences were found on skin humidity sensation between FIRE and L, HV or MIL (p<0.001). The RPE value in FIRE is significant different with L and HV (p<0.05). At 19.0 °C WBGT, the post-exercise mean skin temperatures increased by 0.59 and 1.29 °C in MIL and CLM. In contrast, mean skin temperatures in L, HV, MIL, CLM and FIRE at WBGT=24.5 oC increased by 1.7, 2.1, 2.1, 2.8 and 3.3 °C, respectively. The PHS model presented good performance on predicted mean skin temperatures in MIL and CLM at both two thermal environments. However, the skin temperature prediction with light clothing in high humidity (RH> 80%) was weak. For thick protective clothing, the prediction on rectal temperature was greatly conservative. It is thus concluded that the PHS model is inapplicable for high insulating clothing and measurements performed in high humidity environments.
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| 3. |
- Zhao, Mengmeng, et al.
(författare)
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A Study on Local Cooling of Garments with Ventilation Fans and Openings Placed at Different Torso Sites
- 2013
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141. ; 43:3, s. 232-237
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThe aim of the study was to examine the various design features of ventilatedgarments on cooling performance. Five jackets with small ventilation units andclosable openings were designed. The ventilation units with a flow rate of 12 l/s wereplaced at five different torso sites. They were examined on a sweating thermalmanikin in four clothing opening conditions in a warm environment(Ta=Tmanikin=34 °C, RH=60 %, Va=0.4 m/s). Total torso cooling was increased by 137to 251 %, and clothing total dynamic evaporative resistance was decreased by 43 to69 %. Neither the ventilation location nor the opening design had a significantdifference on total torso cooling. The ventilation location had a significant differenceon localized intra-torso cooling, but not the opening design. When the ventilationunits were placed at the local zone where it was ventilated, that zone underwent thehighest cooling than other local zones. The study indicated that the ventilation unitsshould be placed at the region where it required the most evaporative cooling, e.g.along the spine area and the lower back. The openings could be adjusted (closed oropened) to make comfortable air pressure for the wearers but without makingsignificant difference on the whole torso cooling under this flow rate.
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| 4. |
- Zhao, Mengmeng, et al.
(författare)
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The torso cooling of vests incorporated with phase change materials: a sweat evaporation perspective
- 2013
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Ingår i: Textile Research Journal. - : SAGE Publications. - 0040-5175 .- 1746-7748. ; 83:4, s. 418-425
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Tidskriftsartikel (refereegranskat)abstract
- Cooling vests incorporated with phase change materials (PCMs) add extra insulation and restrict sweat evaporation. It is still unclear how much cooling benefit they can provide. The aim of this study was to investigate the torso cooling of the PCM vests in two hot environments: hot humid (HH, 34C, 75% relative humidity (RH)) and hot dry (HD, 34C, 37% RH). A pre-wetted torso fabric skin was used to simulate torso sweating on a thermal manikin. Three cooling vests incorporated with three melting temperatures (Tm) of PCMs were tested (Tm=21C, Tm=24C and Tm=28C). They were worn under a military ensemble (total thermal insulation 1.60 clo; evaporative resistance 0.0516 kPam2/W), respectively. In a HH environment all the three cooling vests provided effective torso cooling; in a HD environment the cooling benefit was negative. In both environmental conditions, the evaporative cooling was greatly restricted by the cooling vests. The study indicated that when wearing the protective clothing with the relatively low evaporative resistance and when sweat production was high, the cooling vests were effective in a HH environment, but not in a HD environment.
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| 5. |
- Gao, Chuansi, et al.
(författare)
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Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective
- 2012
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Ingår i: Indoor Air. - : Hindawi Limited. - 0905-6947. ; 22:6, s. 523-530
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedAbstract The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. PRACTICAL IMPLICATIONS: Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home.
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| 6. |
- Kuklane, Kalev, et al.
(författare)
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Parallel and serial methods of calculating thermal insulation in European manikin standards
- 2012
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Ingår i: International Journal of Occupational Safety and Ergonomics. - 2376-9130. ; 18:2, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- Standard No. EN 15831:2004 provides 2 methods of calculating insulation: parallel and serial. The parallel method is similar to the global one defined in Standard No. ISO 9920:2007. Standards No. EN 342:2004, EN 14058:2004 and EN 13537:2002 refer to the methods defined in Standard No. EN ISO 15831:2004 for testing cold protective clothing or equipment. However, it is necessary to consider several issues, e.g., referring to measuring human subjects, when using the serial method. With one zone, there is no serial–parallel issue as the results are the same, while more zones increase the difference in insulation value between the methods. If insulation is evenly distributed, differences between the serial and parallel method are relatively small and proportional. However, with more insulation layers overlapping in heavy cold protective ensembles, the serial method produces higher insulation values than the parallel one and human studies. Therefore, the parallel method is recommended for standard testing.
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| 7. |
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| 8. |
- Wang, Faming, et al.
(författare)
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Effect of temperature difference between manikin and wet fabric skin surfaces on clothing evaporative resistance: how much error is there?
- 2012
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Ingår i: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 1432-1254 .- 0020-7128. ; 56, s. 177-182
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Tidskriftsartikel (refereegranskat)abstract
- Clothing evaporative resistance is one of the inherent factors that impede heat exchange by sweating evaporation. It is widely used as a basic input in physiological heat strain models. Previous studies showed a large variability in clothing evaporative resistance both at intra-laboratory and inter-laboratory testing. The errors in evaporative resistance may cause severe problems in the determination of heat stress level of the wearers. In this paper, the effect of temperature difference between the manikin nude surface and wet textile skin surface on clothing evaporative resistance was investigated by both theoretical analysis and thermal manikin measurements. It was found that the temperature difference between the skin surface and the manikin nude surface could lead to an error of up to 35.9% in evaporative resistance of the boundary air layer. Similarly, this temperature difference could also introduce an error of up to 23.7% in the real clothing total evaporative resistance (R ( et_real ) < 0.1287 kPa m(2)/W). Finally, it is evident that one major error in the calculation of evaporative resistance comes from the use of the manikin surface temperature instead of the wet textile fabric skin temperature.
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| 9. |
- Wang, Faming, et al.
(författare)
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Localised boundary air layer and clothing evaporative resistances for individual body segments.
- 2012
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 55:7, s. 799-812
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Tidskriftsartikel (refereegranskat)abstract
- Evaporative resistance is an important parameter to characterise clothing thermal comfort. However, previous work has focused mainly on either total static or dynamic evaporative resistance. There is a lack of investigation of localised clothing evaporative resistance. The objective of this study was to study localised evaporative resistance using sweating thermal manikins. The individual and interaction effects of air and body movements on localised resultant evaporative resistance were examined in a strict protocol. The boundary air layer's localised evaporative resistance was investigated on nude sweating manikins at three different air velocity levels (0.18, 0.48 and 0.78 m/s) and three different walking speeds (0, 0.96 and 1.17 m/s). Similarly, localised clothing evaporative resistance was measured on sweating manikins at three different air velocities (0.13, 0.48 and 0.70 m/s) and three walking speeds (0, 0.96 and 1.17 m/s). Results showed that the wind speed has distinct effects on local body segments. In contrast, walking speed brought much more effect on the limbs, such as thigh and forearm, than on body torso, such as back and waist. In addition, the combined effect of body and air movement on localised evaporative resistance demonstrated that the walking effect has more influence on the extremities than on the torso. Therefore, localised evaporative resistance values should be provided when reporting test results in order to clearly describe clothing local moisture transfer characteristics. Practitioner Summary: Localised boundary air layer and clothing evaporative resistances are essential data for clothing design and assessment of thermal comfort. A comprehensive understanding of the effects of air and body movement on localised evaporative resistance is also necessary by both textile and apparel researchers and industry.
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| 10. |
- Wang, Faming, et al.
(författare)
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Validation of the physiological model of sleeping bags defined in EN13537 (2002)
- 2012
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Ingår i: ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedIn this study, we validated comfort and limit temperatures of four sleeping bags with different levels of insulation defined according to EN 13537. Six male subjects and four female subjects underwent totally 20 two-hour exposures in four sleeping bags at four intended testing temperatures: 11.2, 3.8, 2.1 and -9.0 °C. The subjective perceptions and physiological responses of these subjects were reported and analysed. It was found that the EN 13537 defined comfort temperature and limit temperature were underestimated for sleeping bags MA3, HAG and MAM. The predictions are so conservative that further revision may be required to meet the requirements of both manufacturers and consumers. In contrast, for the sleeping bag MA0 with a low level of insulation, the limit temperature defined by EN 13537 was slightly overestimated. Finally, traditional sleeping bags may be required to be redesigned to provide consumers both whole body comfort as well as local thermal comfort at feet/toes or users need to be made aware of the need for their better insulation.
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