Two isothermal challenges yield comparable physiological and subjective responses

Purpose Ventilated vests are developed to reduce thermal stress by enhancing convective and evaporative cooling from skin tissue underneath the vest. The purpose of this study is to investigate whether thermal stress is equal when a ventilated vest is worn compared to a no-vest situation with similar dry thermal resistance. Methods Nine healthy males walked on a treadmill (7 km h−1) for 45 min in a desert climate (34 °C, 20% relative humidity) with and without ventilated vest. Gastrointestinal temperature (Tgi), heart rate (HR), and skin temperature (Tsk) were continuously monitored. Local sweat rate (LSR) was assessed two times on six skin locations. Subjective ratings were assessed every 10 min. Results Final Tgi (37.6 ± 0.1 °C for vest and 37.6 ± 0.1 °C for no-vest), HR (133 ± 7 bpm and 133 ± 9 bpm) and mean Tsk (34.8 ± 0.7 °C and 34.9 ± 0.6 °C) were not different between conditions (p ≥ 0.163). Scapula skin temperature (Tscapula) under the vest tended to be lower (baseline to final: ΔTscapula = 0.35 ± 0.37 °C) than without vest (ΔTscapula = 0.74 ± 0.62 °C, p = 0.096). LSR at locations outside the vest did not differ with and without vest (p ≥ 0.271). Likewise, subjective responses did not differ between conditions (χ2 ≥ 0.143). Conclusions We conclude that two systems with similar dry thermal resistance and, therefore, similar required evaporation, resulted in similar thermal stress during paced walking in a hot-dry environment. Local ventilation did not alter the sweating response on locations outside the vest.

Performance attributes relevant to thermal wear comfort of hip protective garment: influence of comprising pad materials, pad thickness, pad area, and pocket fabric structure

PurposeThis study aimed to evaluate the performance attributes relevant to thermal wear comfort of the commercially available hip protective pads and materials intended for impact protection that can be used for the hip protective pad.Design/methodology/approachThe performance attributes relevant to thermal wear comfort (i.e. dry thermal resistance and evaporative resistance) of the pads were tested using MTNW Integrated Sweating Guarded Hotplate (iSGHP).FindingsIt was found that: the pad with more porous structure has more advantages in terms of evaporative resistance; the permeability index will be higher on the pad with an opening such as a segmented pad; the permeability index will be lower on the thicker and larger pad. The pocket fabric with open structure will have lower dry thermal resistance and evaporative resistance.Originality/valueThe study results showed that the properties of the utilised materials influenced thermal comfort performance. These results could be useful for designing and engineering hip protective garments.

Energy absorption and thermal comfort of segmented pad for hip protective garment

Purpose The purpose of this paper is to investigate the influence and relationship of segment area and opening area in segmented protective pad in comparison to non-segmented pad to the energy absorption and performance attributes relevant to thermophysiological wear comfort. Design/methodology/approach The compressive stress-strain curves were obtained using Instron Tester and were used to analyse the energy absorption of the pads and the segmented pad assemblies. The dry thermal resistance and evaporative resistance of the non-segmented and segmented protective pads were obtained using MTNW Sweating Guarded Hot Plate. Findings The compression test results and performance attributes relevant to thermophysiological wear comfort test result demonstrated that the area segment and opening area of segmented pad influenced their energy absorption value, dry thermal resistance value and evaporative resistance value (permeability index value). Originality/value The results are expected to be useful for design and engineering of hip impact protective garments. Hip impact protective pads are used to prevent hip fractures in elderly people as a result of fall.

An evaluation of force attenuation, comfort properties and density of materials for hip protective pads

We evaluated 15 materials for their effectiveness as hip protective pads for elderly women, including several materials used in commercially available pads and novel materials. The materials’ densities were measured, and they were tested for force attenuation (relevant to protection), permeability index (relevant to thermophysiological wear comfort) and interface pressure delivery (relevant to pressure comfort). Force attenuation values were obtained in drop impact tests. Permeability data were obtained from the dry thermal resistance and evaporative resistance of the pads tested using a sweating guarded hot plate. Interface pressure delivery values were acquired using a Salzmann pressure-measuring device MST MK IV. Experimental pads were graded, rated and ranked on their overall performance using weights applied to the four parameters. Vertically lapped nonwoven fabrics and treated knitted spacer fabrics were highly ranked and could be used as material for hip protective pads.

A new method to assess the influence of textiles properties on human thermophysiology. Part I

Purpose – The purpose of this paper is to determine the validity and inter-/intra-laboratory repeatability of the first part of a novel, three-phase experimental procedure using a sweating Torso device. Design/methodology/approach – Results from a method comparison study (comparison with the industry-standard sweating guarded hotplate method) and an inter-laboratory comparison study are presented. Findings – A high correlation was observed for thermal resistance in the method comparison study (r=0.97, p<0.01) as well as in the inter-laboratory comparison study (r=0.99, p<0.01). Research limitations/implications – The authors conclude that the first phase of the standardised procedure for the sweating Torso provides reliable data for the determination of the dry thermal resistance of single and multi-layer textiles, and is therefore suitable as standard method to be used by different laboratories with this type of device. Further work is required to validate the applicability of the method for textiles with high thermal resistance. Originality/value – This study provides the first “round-robin” data for measuring thermal resistance using a Torso device. In future publications the authors will provide similar data examining the repeatability of measurements that quantify combined heat and mass transfer.