| 1. |
- Gao, Chuansi, et al.
(författare)
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The heating effect of phase change material (PCM) vests on a thermal manikin in a subzero environment
- 2008
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Ingår i: 7th International Meeting on Manikins and Modelling (7I3M).
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Konferensbidrag (refereegranskat)abstract
- The heating effects of three PCM vests (Tmelt=32, 28 and 24 °C) were tested on a thermal manikin with constant temperature at 30 ºC in a subzero environment (Ta=-4 °C, Va=0.4 m/s). The results showed that the heating effects lasted about 3-4 hours. The highest heating effects reduced heat loss for 20-30 W/m2 on the torso during the first two hours. The results also showed that the vest with higher melting/solidifying temperature had a greater and longer heating effect. Among the three wear scenarios, the PCM vest worn directly and closely over the stretch coverall without winter jacket revealed the highest heating effect on the torso.
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| 2. |
- Holmér, Ingvar
(författare)
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How is performance in the heat affected by clothing?
- 2008
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Ingår i: Bioengineering and Informatics Symposium Proceedings , Vol 1-2. ; , s. 700-705
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Konferensbidrag (refereegranskat)abstract
- Adequate heat balance is critical to human performance in the heat. If heat balance cannot be maintained, the core temperature increases and body water dehydration leads to exhaustion and limit the performance. Clothing heat transfer properties.. thermal insulation and water vapour resistance, modify heat exchange and may indirectly affect performance. Work in protective clothing quickly becomes exhaustive in impermeable garments, but can be easily completed with much less strain in permeable garments. Athletes, in particular in sports of endurance type.. may produce more than 1000 W/m(2) in an event lasting several hours. Physical examination of the heat balance of a runner reveals that a 20% lower water vapour resistance of a covering running suit allows the runner a longer run time or a higher speed per kin before critical physiological strain is reached.
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| 3. |
- Kuklane, Kalev, et al.
(författare)
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Are standard tests of cold protection by footwear relevant and valid?
- 2008
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Ingår i: 7th International Meeting on Manikins and Modelling (7I3M).
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Konferensbidrag (refereegranskat)abstract
- The present international standards for safety, protective and occupational footwear EN ISO 20344 – 20347 classify footwear as cold protective by a pass/fail test where the limits are set for an allowed 10 °C temperature drop inside the footwear at a sole location during 30 minutes at a temperature gradient of about 40 °C. In a test of five footwear including a summer sandal it was shown that all could pass the test, since performance is basically determined by the sole insulation only. The standard does not discriminate between good and poor cold protective footwear and should be replaced by a more relevant and valid test, for example with a heated foot model.
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| 4. |
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| 5. |
- Ueno, Satoru, et al.
(författare)
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Thermal insulation of occupational footwear used in Japan
- 2008
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Ingår i: ICB2008 : 18th International Congress of Biometeorology : "Harmony within nature" : 22-26 September 2008, Tokyo, Japan - "Harmony within nature" : 22-26 September 2008, Tokyo, Japan.
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Konferensbidrag (refereegranskat)abstract
- Introduction Many kinds of footwear are used for various purposes in the workplace in Japan. Careful selection of footwear is needed to protect workers from coldness and to keep the performance of workers in cold workplace where employees have to work under -20℃. On the other hand, safety boots with high heat conductivity from foot to outside are needed for the workers in hot environments. But thermal characteristics are not shown for each boots. We measured the thermal insulation values of various kinds of footwear by thermal foot manikin. Materials and methods We tested 14 kinds of Japanese protective footwear (Midori Safety) with a thin or a thick sock in climate chamber by thermal foot manikin having 8 zones. The footwear included cold protective boots(2), long rubber boots(1), safety boots(4), safety shoes(2), business shoes(1), work sneakers(1), anti-electrostatic aerated shoes (2) and sandals (1). The ambient temperature of climate chamber was 4.6±0.5℃. The air velocity near boot was 0.27±0.5m/sec. The boots were placed on a copper/zinc alloy plate in the climate chamber. When upper parts of foot manikin were not covered by footwear, muffler was wound around the foot manikin to avoid the unnecessary heat dissipation from manikin. The manikin skin temperature of each zones were set at 34℃ on the control software. Each test was run for about 80 minutes to reach steady state. The data registered during the last 10 minutes on PC were used to calculate the thermal resistance. In boot toe to L Calf data were used, in shoe foot and ankle data were used. We conform to ISO 15831 about the test methods. When the thermal resistance of the second measurement was not within the 4% difference of that of first, the third measurement was done. The temperatures on the sock at the toe tip, the mid-sole, the dorsal foot, the guard front were measured by thermocouples which were fixed by surgical tape. Results and discussion In boots, thermal insulation with thick sock was larger than that with thin sock by 0.014-0.0033 m2℃/W. The cold protective boot which had the inner sock with thick sock had the largest insulation, which was about 0.45 m2℃/W. The other kind of cold protective boot was 0.325 m2℃/W. Though the thermal resistances of normal safety boot were the same values of 0.26-0.27 m2℃/W, safety boot whose material was fibrous leather made by cutting outer layer from normal leather was relatively lower value. Common rubber boot made of polyvinyl chloride (PVC) was lowest, 0.215 m2℃/W. In shoes, the thermal insulation of work sneaker was 0.28 m2℃/W, which was larger than business shoe, aerated shoe and sandal. The larger the aeration the shoes had, the smaller the temperature insulation. Temperature on sock in toe tip was smaller in sandal and aerated shoe than non-aerated work sneaker.
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