| 61. |
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| 62. |
- 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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| 63. |
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| 64. |
- Holmér, Ingvar, et al.
(författare)
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Minute volumes and inspiratory flow rates during exhaustive treadmill walking using respirators
- 2007
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162. ; 51:3, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- Air flow rate through filters and face masks is one important determinant of the final protection factor of a respiratory protective device in use. Respiratory minute volumes and instantaneous breath flow rates were measured in eight subjects during treadmill work using three types of filtering respirators and one control breathing mask. Work comprised five consecutive bouts of walking at 5 km/h with an increase in elevation of the treadmill by 5% every 5 min and a final walk at 6 km/h and 22.5%. Three subjects managed to complete 5 min at the final work rate. Minute ventilation increased in a curvilinear manner with oxygen uptake and reached 88 +/- 20 and 93 +/- 20 l/min at 5 km/h (20%) with the control mask and a half mask with filter (SP), respectively. Mean peak inspiratory flow rate (PIEFR) was 273 +/- 39 for Control and 300 +/- 36 for SP at the same work rate. Two power assisted, positive pressure filter respirators (SA and SE) produced higher mask minute volumes at any given work rate compared to respiratory minute volumes in control and SP. PIFR in SA and SE were equal to or lesser than SP. During standardized speech communication, minute volumes decreased. In contrast, PIFR increased by about 100% at low work rates and about 30% at 5 km/h (20%) compared to no speech condition, reaching a highest value of 414 +/- 46 l/min for SE. Filter testing is made at a constant flow rate of 95 l/min, a condition that eventually needs to be reconsidered in order to ensure a relevant and valid function test.
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| 65. |
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| 66. |
- Holmér, Ingvar, et al.
(författare)
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Protection against cold
- 2005
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Ingår i: Textiles in Sport. - 1855739224 ; , s. 262-286
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 67. |
- Holmér, Ingvar
(författare)
-
Protective clothing in hot environments
- 2006
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Ingår i: Industrial Health. - 1880-8026. ; 44:3, s. 404-413
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Forskningsöversikt (refereegranskat)abstract
- The high level of protection required by personal protective clothing (PPC) severely impedes heat exchange by sweat evaporation. As a result work associated with wearing PPC, particularly in hot environments, implies considerable physiological strain and may render workers exhausted in a short time. Recent development of algorithms for describing the heat transfer, accounting for pumping and wind effects, comprises improvement of the prediction of thermal stress. Realistic corrections can then be made to the available measures of thermal insulation and evaporative resistance of a given clothing ensemble. Currently this information is incorporated in international standards for assessment of thermal environments. Factors, such as directional radiation and wetting of layers, were studied in a recently completed EU research project. The development of advanced thermal manikins and measurement procedures should provide better measures for predictive models. As with all methods and models, the results need validation in realistic wear trials in order to prove their relevance and accuracy.
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| 68. |
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| 69. |
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| 70. |
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