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EN
Compression bandage (CB) as a porous material should provide both graduated pressure and thermal comfort properties to enable air permeability, heat transfer, and liquid perspiration out of the human body. The main factors affecting thermal comfort properties are the temperature difference between environment and skin, yarns’ structure and material, fabric thickness, porosity, areal density, number of fabric layers, trapped air, and fabric structure. Thermal resistance (Rct) and water vapor resistance (Ret) are evaluated for four types of woven CBs. All bandage types were applied at the range of extension (10–80%) using both two- and three-layer bandaging on thermal foot model (TFM). Rct values are compared with measured results by the Alambeta instrument, whereas Ret test is performed on the Permetest device. Thermal resistance is significantly decreased when increasing the bandage extension from 10 to 40%, then it is slightly increased by increasing the extension from 40 to 60%, after that it is decreased especially at 80% extension due to lower bandage thickness and higher compression.
PL
W artykule przedstawiono wyniki badań mikroklimatu obuwia ochronnego wyznaczonego na termicznym modelu stopy. Stwierdzono, że w obuwiu ochronnym z podnoskami kompozytowymi stopa jest lepiej wentylowana z uwagi na paroprzepuszczalny charakter materiału w okolicy palców, w porównaniu do obuwia z podnoskami metalowymi. Izolacyjność obuwia była lepsza w przypadku występowania w obuwiu podnosków metalowych. Wartości odchylenia standardowego potwierdziły mały rozrzut wyników pomiarów; wartości względnego błędu przypadkowego wartości średniej (przy p=0,95) potwierdziły dobrą dokładność przyrządu pomiarowego.
EN
This paper presents investigation results of microclimate parameters of protective footwear for a thermal foot model. The standards harmonized with the Directive 89/686/EEC are currently used for assessing protective properties. They concern only assessment of hygienic materials used in manufacturing [1-6]. An alternative can be tests on a thermal foot model fit in terms of the feasibility of five variants of construction protective footwear (with high upper) [7-9]. The study was performed on the thermal foot model which ensures the release of water in a manner similar to human sweat glands and heat dissipation by conduction, convection and radiation in proportions similar to those at different speeds of real sweat, different time use of the footwear and different possibilities of simulated movement of the foot. The test method includes monitoring the simulated release of moisture in seven segments and heat release in nine independent isothermal zones (Figs. 3, 4). Based on the results, it was found that the footwear with a composite toe cap foot (Fig. 1) was better ventilated (Fig. 5) because of permeable material around the fingers, compared to the footwear with a steel toecap (Fig. 2). There was greater loss of insulation for the footwear with a composite toecap with and without a function of perspiration (Fig. 6). The values of standard deviations and variation coefficients confirmed the small scattering of measurements, the values of the relative random error of the mean (at p = 0.95) confirmed the good accuracy of the measuring instrument (Tables 5, 6).
PL
Artykuł prezentuje opis dotychczas stosowanych metod w ocenie komfortu użytkowania obuwia ochronnego z uwzględnieniem modelu sztucznej stopy. Opisano postęp jaki dokonał się od lat 30-tych 20 wieku w zakresie poziomu technicznego ich konstrukcji na podstawie danych literaturowych. Podkreślono zalety wykonywania badań komfortu użytkowania z wykorzystaniem termicznego modelu stopy oraz zwrócono uwagę, że wyniki mogą być szeroko wykorzystywane zarówno w badaniach naukowych jak i przez producentów obuwia do szybkiej jego weryfikacji na etapie projektowania. W publikacji wskazano kierunki technicznego rozwoju modeli ii aplikacji badawczych.
EN
Description of existing methods in evaluation of protective footwear comfort including the thermal foot model is presented in the paper. The progress made throughout the 30-ties XX century in the technical level of their design on the basis of literature data is described. Starting with the first model developed in Primasens in the 80-ties the models currently under development are overvieved. The paper broadly describes the first study in the protective shoe conducted at Lund University since 1999. Advantages of comfort testing using a thermal foot model of the rate were emphasized and it was noted that the results can be widely used in both research and footwear manufacture to assess fast the microclimate parameters in the shoe at the stage of the design. Future directions in terms of their technical development and research opportunities are also identified in the paper. Seven years lasting the standardization work concerning to attempts to include to the series ISO standards the insulating protective footwear properties study and methods of their determination by means of the thermal foot model are also presented.
EN
The use of physiological data from human tests in modelling should consider background data, such as activity, environmental factors and clothing insulation on the whole body. The present paper focuses on local thermal comfort of feet with special attention on the effects of physical changes of footwear thermal properties. An alternative test method is available for footwear thermal testing besides the standard method. The possibility to use insulation values acquired on a thermal foot model in practice is shown here. The paper describes the correlation between cold and pain sensations, and foot skin temperatures of the subjects and relates these to insulation measured on a thermal foot model. Recommendations are made for footwear choice according to environmental temperature.
EN
This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of the thermal foot method, the latter should be preferred for testing.
EN
The present European Standard for footwear testing (Standard No. EN 344:1992; European Committee for Standardization [CEN], 1992) classifies footwear thermally by a temperature drop inside the footwear during 30 min at defined conditions. Today, other methods for footwear thermal testing are also available. The aim of this study was to compare EN 344:1992 with a thermal foot method. Six boots were tested according to both methods. Additional tests with modified standard tests were also carried out. The methods ranked the footwear in a similar way. However, the test according to standard EN 344:1992 is a pass-or-fail test, whereas data that is gained from the thermal foot method gives more information and allows further use in research and product development. A change of the present standard method is suggested.
7
Content available Effect of Sweating on Insulation of Footwear
EN
The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands wassupplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19-25% (30-37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.
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