| 1. |
- Broede, Peter, et al.
(författare)
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The Universal Thermal Climate Index UTCI Compared to Ergonomics Standards for Assessing the Thermal Environment
- 2013
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Ingår i: Industrial Health. - 1880-8026. ; 51:1, s. 16-24
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Forskningsöversikt (refereegranskat)abstract
- The growing need for valid assessment procedures of the outdoor thermal environment in the fields of public weather services, public health systems, urban planning, tourism & recreation and climate impact research raised the idea to develop the Universal Thermal Climate Index UTCI based on the most recent scientific progress both in thermo-physiology and in heat exchange theory. Following extensive validation of accessible models of human thermoregulation, the advanced multi-node 'Fiala' model was selected to form the basis of UTCI. This model was coupled with an adaptive clothing model which considers clothing habits by the general urban population and behavioral changes in clothing insulation related to actual environmental temperature. UTCI was developed conceptually as an equivalent temperature. Thus, for any combination of air temperature, wind, radiation, and humidity, UTCI is defined as the air temperature in the reference condition which would elicit the same dynamic response of the physiological model. This review analyses the sensitivity of UTCI to humidity and radiation in the heat and to wind in the cold and compares the results with observational studies and internationally standardized assessment procedures. The capabilities, restrictions and potential future extensions of UTCI are discussed.
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| 2. |
- Bröde, Peter, et al.
(författare)
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Deriving the operational procedure for the Universal Thermal Climate Index (UTCI)
- 2012
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Ingår i: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 1432-1254 .- 0020-7128. ; 56:3, s. 481-494
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Tidskriftsartikel (refereegranskat)abstract
- The Universal Thermal Climate Index (UTCI) aimed for a one-dimensional quantity adequately reflecting the human physiological reaction to the multi-dimensionally defined actual outdoor thermal environment. The human reaction was simulated by the UTCI-Fiala multi-node model of human thermoregulation, which was integrated with an adaptive clothing model. Following the concept of an equivalent temperature, UTCI for a given combination of wind speed, radiation, humidity and air temperature was defined as the air temperature of the reference environment, which according to the model produces an equivalent dynamic physiological response. Operationalising this concept involved (1) the definition of a reference environment with 50% relative humidity (but vapour pressure capped at 20 hPa), with calm air and radiant temperature equalling air temperature and (2) the development of a one-dimensional representation of the multivariate model output at different exposure times. The latter was achieved by principal component analyses showing that the linear combination of 7 parameters of thermophysiological strain (core, mean and facial skin temperatures, sweat production, skin wettedness, skin blood flow, shivering) after 30 and 120 min exposure time accounted for two-thirds of the total variation in the multi-dimensional dynamic physiological response. The operational procedure was completed by a scale categorising UTCI equivalent temperature values in terms of thermal stress, and by providing simplified routines for fast but sufficiently accurate calculation, which included look-up tables of pre-calculated UTCI values for a grid of all relevant combinations of climate parameters and polynomial regression equations predicting UTCI over the same grid. The analyses of the sensitivity of UTCI to humidity, radiation and wind speed showed plausible reactions in the heat as well as in the cold, and indicate that UTCI may in this regard be universally useable in the major areas of research and application in human biometeorology.
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| 3. |
- Bröde, Peter, et al.
(författare)
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Heat gain from thermal radiation through protective clothing with different insulation, reflectivity and vapour permeability
- 2010
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Ingår i: International Journal of Occupational Safety and Ergonomics. - 2376-9130. ; 16:2, s. 231-244
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Tidskriftsartikel (refereegranskat)abstract
- The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments.
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| 4. |
- Bröde, Peter, et al.
(författare)
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Thermische Beanspruchung in Schutzkleidung
- 2010
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Ingår i: Technische Überwachung. ; 51:6, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in German Grundlegende Daten zur Beurteilung der thermischen Beanspruchung während der Arbeit in Schutzkleidung wurden im europäischen Verbundprojekt THERMPROTECT (EU Contract-No. G6RD-CT-2002-00846) mit Untersuchungen des durch die Kleidung erhöhten Energieumsatzes und des Transports von Wärme und Feuchte unter Kältebelastung sowie bei Einwirkung von Wärmestrahlung erhoben. Der Eingang der hier dargestellten Resultate in international standardisierte Bewertungsverfahren soll zur Vermeidung thermophysiologischer Überbeanspruchungen beitragen.
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| 5. |
- Havenith, George, et al.
(författare)
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Evaporative Cooling: effective latent heat of evaporation in relation to evaporation distance from the skin
- 2013
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Ingår i: Journal of Applied Physiology. - 1522-1601. ; 114:6, s. 778-785
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Tidskriftsartikel (refereegranskat)abstract
- Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available which has found little use in recent literature. In this experiment a thermal manikin (MTNW, Seattle) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently allowing a direct calculation of an effective latent heat of evaporation (λeff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used and different numbers of layers were used. Tests took place in 20ºC, 0.5 m.s-1 at different humidities and were performed both dry and with a wet layer allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin λeff is close to the theoretical value (2430J.g-1), but starts to drop when more clothing is worn, e.g. by 11% for underwear and permeable coverall. When evaporation is from the underwear, λeff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base-layer) increasing towards 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of λeff was developed.
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| 6. |
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| 7. |
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| 8. |
- Kuklane, Kalev, et al.
(författare)
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Insulation of traditional Indian clothing: Estimation of climate change impact on productivity from PHS (predicted heat strain) model
- 2014
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Ingår i: Achieving Sustainable Construction Health and Safety : proceedings of CIB W099 International Conference, 2-3 June 2014, Lund University, Sweden - proceedings of CIB W099 International Conference, 2-3 June 2014, Lund University, Sweden. - 9789176230053 ; , s. 234-244
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Konferensbidrag (refereegranskat)abstract
- Major databases on western clothing and their thermal properties are available, but information on non-western clothing is lacking. A recent ASHRAE project 1504 TRP, Extension of the Clothing Insulation Database for Standard 55 and ISO 7730 dealt with the issue. Simultaneously, a co-operation study at Indian workplaces allowed us to acquire some sets of the traditional clothes used at construction sites in Chennai area. The work was related to mapping of present work conditions in order to allow predictions and measures to be taken if the mean temperature of the work environment would rise. We selected ISO 7933 on predicted heat strain (PHS) as a tool to estimate productivity loss in physical work. PHS criteria are related to reaching safe body core temperature limit of 38 °C or excess water loss. 3 sets of clothing were investigated: 2 female sets of traditional clothes (churidar and saree) modified as used at construction site (added shirt and towel to protect traditional clothes and hair), and a male set commonly used at the construction sites. The clothing insulation and evaporative resistance were measured on thermal manikins. The climatic conditions were based on weather statistics, and metabolic heat production was based on field observations at work places and the ISO 8996:2004 tables (Ergonomics of the thermal environment — Determination of metabolic rate). For the future scenarios all basic parameters were left the same except the air temperature was increased by 2 °C. Adding the protective layer on female clothing did increase clothing insulation by 25-31 % and evaporative resistance by 10-18 % respectively. This affected the performance showing lower capacity to maintain work pace already under present climatic conditions. Further increase in mean air temperature may decrease the productivity by 30-80 % depending on the parameter that is observed (limited exposure time or lower work load), and on the earlier capacity to carry out the tasks. The present evaluation may have several limitations related to the PHS model's boundaries, and validation of the presented method application is needed.
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| 9. |
- Lundgren Kownacki, Karin, et al.
(författare)
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CLOTHING INSULATION AND THERMAL COMFORT IN AFRICA: CURRENT STANDARDS AND APPLICABILITY
- 2014
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Ingår i: Proceedings of Ambience 14&10i3m : Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland - Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland. - 2342-4540. - 9789521532696 ; 1
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Konferensbidrag (refereegranskat)abstract
- Background: The adoption of air conditioning (AC) is growing rapidly in developing countries across the world which puts a high burden on electricity distribution systems. This development is mostly driven by income growth and building design, but also due to increasing outdoor temperatures and to provide indoor thermal comfort. Current indoor thermal comfort standards are based on western clothing (in terms of the ASHRAE Standard 55 and ISO 7730). However, due to different clothing practices in regions such as Africa, providing comfortable indoor environments may differ significantly. For optimal design and achieving energy savings of AC systems, accounting for different clothing practices is fundamental. Methods: The research presented is based on a project aimed at the extension of the ASHRAE Standard 55 database to include non-western clothing. The paper focuses on the African clothing tested on thermal manikins. Three sets of female clothing and five sets of male clothing were measured. The ISO7730:2004 standard which uses the PMV/PPD indices was used to assess the optimal indoor temperature (assessed between 20-30 °C). The occupant was considered acclimatized with low activity (120 W), with an air velocity of 0.2 m/s, no additional heat radiation and a relative humidity of 50 %. Results and Conclusion: The optimal indoor temperature for both women (PMV: -0.09, PPD: 5 %) and men (PMV: 0.1, PPD: 5 %) was found to be 24 °C. Considering better ventilation and evaporation in African clothing the comfort temperatures could be even higher. In conclusion, sub-optimal indoor thermal conditions are being adopted in Africa resulting in lower indoor air temperatures than required, causing an unnecessary waste of energy from AC systems and affecting the thermal comfort of the occupants.
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| 10. |
- Wang, Faming, et al.
(författare)
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CLOTHING REAL EVAPORATIVE RESISTANCE DETERMINED BY MEANS OF A SWEATING THERMAL MANIKIN: A NEW ROUND-ROBIN STUDY
- 2014
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Ingår i: Proceedings of Ambience 14&10i3m : Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland - Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland. - 2342-4540. - 9789521532696 ; 1
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Konferensbidrag (refereegranskat)abstract
- The previous round-robin (RR) study on clothing evaporative resistance (Ret) has shown that the repeatability and reproducibility of clothing Ret measurements on sweating manikins were rather low. To further examine and enhance the measurement accuracy, a new strict but feasible test protocol was proposed and thoroughly examined in a new round-robin test. Eight laboratories participated in this study and three types of sweating manikins were used. Six clothing ensembles including body mapping cycling wear, light summer workwear, typical spring and autumn clothing for people living in subtropical regions, cold protective clothing and functional Gore-Tex coverall were selected. The measurement repeatability and reproducibility are analysed. The ultimate goal of the RR study is to provide solid support for amending ASTM F2370 standard and/or drafting a new ISO/EN standard.
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