Protective clothing and heat stress

The high level of protection required by 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. Current methods of describing evaporative heat exchange with PPC are insufficient, will overestimate evaporative heat loss and should not be recommended. More reliable measures of the resistance to evaporative heat transfer by PPC should be developed and standardized. Direct measurements of evaporative resistance of PPC may be carried. However, a more promising method appears to be the definition of evaporative resistance on the basis of the i ^cl-index for the fabric layers. The i ^cl-mdex is a permeation efficiency ratio, which in combination with clothing insulation determines the evaporative heat transfer. Current methods should be further developed to account for effects of moisture condensation and microclimate ventilation.     

3D quantification of microclimate volume in layered clothing for the prediction of clothing insulation

Garment fit and resultant air volume is a crucial factor in thermal insulation, and yet, it has been difficult to quantify the air volume of clothing microclimate and relate it to the thermal insulation value just using the information on the size of clothing pattern without actual 3D volume measurement in wear condition. As earlier methods for the computation of air volume in clothing microclimate, vacuum over suit and circumference model have been used. However, these methods have inevitable disadvantages in terms of cost or accuracy due to the limitations of measurement equipment. In this paper, the phase-shifting moiré topography was introduced as one of the 3D scanning tools to measure the air volume of clothing microclimate quantitatively. The purpose of this research is to adopt a non-contact image scanning technology, phase-shifting moiré topography, to ascertain relationship between air volume and insulation value of layered clothing systems in wear situations where the 2D fabric creates new conditions in 3D spaces. The insulation of vests over shirts as a layered clothing system was measured with a thermal manikin in the environmental condition of 20 degrees C, 65% RH and air velocity of 0.79 m/s. As the pattern size increased, the insulation of the clothing system was increased. But beyond a certain limit, the insulation started to decrease due to convection and ventilation, which is more apparent when only the vest was worn over the torso of manikin. The relationship between clothing air volume and insulation was difficult to predict with a single vest due to the extreme openings which induced active ventilation. But when the vest was worn over the shirt, the effects of thickness of the fabrics on insulation were less pronounced compared with that of air volume. In conclusion, phase-shifting moiré topography was one of the efficient and accurate ways of quantifying air volume and its distribution across the clothing microclimate. It is also noted that air volume becomes more crucial factor in predicting thermal insulation when clothing is layered.     

Clothing ventilation - update and applications

The Environmental Ergonomics Unit at the P.O.W. provided a forum for the discussion and consolidation of ideas regarding the origins, current progress and the future development of the Clothing Ventilation Index.

Crockford et al (1972) first developed the concept of clothing ventilation. The basic technique employs a trace gas dilution method for measuring the ventilation of the clothing microclimate. Ventilation is vital to the removal of sensible and insensible heat and, therefore, an important determinant of thermal comfort. Two techniques (Lotens and Havenith, 1986, 1988; Reischl et al, 1987) have subsequently been developed. The former method results in an average ventilation value for the total clothed-body surface area, whereas the latter method also takes into consideration regional changes in garment design as separate entities from the total ventilation, allowing for local modification in garment design.

The Clothing Ventilation Index is a quantitative, relatively inexpensive, fast, reliable and repeatable technique. It can be used in context, in the working environment to predict the effectiveness, preference and suitability of garments and clothing assemblies; firstly, to ensure that protective clothing is worn and used correctly, and secondly, to improve performance by minimising heat strain, sweat retention and thermal discomfort.

Further work on validating the techniques in terms of human responses to the thermal environment is required. Questions were also raised as to whether human beings or manikins should be used. The use of human beings in dynamic situations is of paramount importance; however, manikins could be used for purely physical measurements to test various assumptions in evaluating clothing ventilation. It is essential that body dimensions and posture are always specified.

The seminar enabled researchers to identify with the proposed techniques, outline the advantages and importance of the Clothing Ventilation Index and focus future studies.     

The Evaluation of Double‐Layer Clothing in a Semiconductor Manufacturing Environment

This study aims to investigate the influence of double‐layer clothing in a semiconductor manufacturing clean‐room environment. Twenty subjects including ten males and ten females participated in this study. Each subject completed four treatment combinations with four different inner pieces of clothing (i.e., 100% cotton, 70% cotton + 30% polyester, 65% polyester + 35% cotton, 100% polyester). The dependent measures included moisture absorption, skin temperature, and subjective responses in three body regions. The results indicate that wearing 100% polyester inner clothing caused a significant increase in inner microclimate relative humidity (RH; p < .01). Wearing 100% cotton inner clothing caused a significant increase in both inner microclimate RH (p < .01) and the inner clothing's moisture absorption. This was due to cotton fiber tends to trap more water molecules and allow less water vapor to pass through as compared to other types of fiber. Furthermore, wearing the blended fiber inner clothing caused lower RH in the inner and outer clothing microclimate (p < .05). Moreover, wearing 65% polyester + 35% cotton inner clothing had higher subjective comfort than did wearing 70% cotton + 30% polyester. In summary, the moisture absorption and water vapor transport characteristics of the inner clothing are the major factors affecting the comfort of wearing double‐layer clothing. © 2012 Wiley Periodicals, Inc.     

Dynamic clothing insulation. Measurements with a thermal manikin operating under the thermal comfort regulation mode

The main objective of the present work is the assessment of the thermal insulation of clothing ensembles, both in static conditions and considering the effect of body movements. The different equations used to calculate the equivalent thermal resistance of the whole body, namely the serial, the global and the parallel methods, are considered and the results are presented and discussed for the basic, the effective and the total clothing insulations. The results show that the dynamic thermal insulation values are always lower than the corresponding static ones. The highest mean relative difference [(static-dynamic)/static] was obtained with the parallel method and the lowest with the serial. For I_cl the mean relative differences varied from 0.5 to 13.4% with the serial method, from 5.6 to 14.6% with the global and from 7.2 to 17.7% with the parallel method. In addition, the dynamic tests presents the higher mean relative differences between the calculation methods. The results also show that the serial method always presents the higher values and the parallel method the lowest ones. The relative differences between the calculation methods {[(serial-global)/global] and [(parallel-global)/global]} were sometimes significant and associated to the non-uniform distribution of the clothing insulation. In fact, the ensembles with the highest thermal insulation values present the highest differences between the calculation methods.     

Thermal and cardiovascular strain imposed by motorcycle protective clothing under Australian summer conditions

Motorcycle protective clothing can be uncomfortably hot during summer, and this experiment was designed to evaluate the physiological significance of that burden. Twelve males participated in four, 90-min trials (cycling 30 W) across three environments (25, 30, 35 °C [all 40% relative humidity]). Clothing was modified between full and minimal injury protection. Both ensembles were tested at 25 °C, with only the more protective ensemble investigated at 30 and 35 °C. At 35 °C, auditory canal temperature rose at 0.02 °C min^?1 (SD 0.005), deviating from all other trials (p < 0.05). The thresholds for moderate (>38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 min (SD 20.6) and 180 min (SD 33.0), respectively. Profound hyperthermia might eventuate in ~10 h at 30 °C, but should not occur at 25 °C. These outcomes demonstrate a need to enhance the heat dissipation capabilities of motorcycle clothing designed for summer use in hot climates, but without compromising impact protection.

Practitioner’s Summary:

Motorcycle protective clothing can be uncomfortably hot during summer. This experiment was designed to evaluate the physiological significance of this burden across climatic states. In the heat, moderate (>38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 and 180 min, respectively.     

浅析服装设计中服装材料的运用、发展及趋势

服装材料是构成服装的基本要素,服装的竞争同时也是服装材料的竞争。本文通过对服装材料历史的概述,总结分析出当代服装材料发展的三大趋势:服装材料的组合与再创造、新加工方式与新原料结合的环保服装材料、高科技材料的开发与使用。     

中国青年女性服装色彩搭配美的规律初探

美的服装色彩搭配能够给人以精神上的享受,使人的身心得到放松。对于中国青年女性服装色彩搭配而言,一般都要遵循这个规律:(1)服装色彩搭配应与人的自身条件相和谐,(2)服装色彩搭配应与色彩搭配美的规律相和谐,(3)服装色彩搭配应与生活环境相和谐。了解并运用这些规律是人们通向美的最佳捷径,而这些规律与健康相结合是人们未来的必行之路。     

A review of: “Medical and Scientific Aspects of Cycling”, edited by E. R. BURKE and M. M. NEWSOM,Human Kinetic Publishers,Champaign, Illinois,USA (1988), $2800, ISBN 0 87322 126 5

A common metric of assessing the evaporative cooling potential of protective clothing is to assess the rate of diffusion of water vapour through the fabric. Another mechanism that supports evaporative cooling is convective transfer. Prototype porous coveralls were constructed to promote convective air flow with 0.0024 mm (0.06 inch) holes representing nominal openings of 0, 1, 2, 5, 10 and 20% of the garment surface area (called P00, P01, P02, P05, P10 and P20). The purpose of this study was to evaluate the ability of these porous coverall configurations to support evaporative cooling. The assessment measures were critical wet bulb globe temperature (WBGT) and apparent evaporative resistance via a progressive heat stress protocol. There was a progressive increase in critical WBGT with increases in convective permeability for P00, Saratoga? Hammer, P01, work clothes and P02. There was no further increase for P05, P10 and P20. A similar pattern was found for diffusive permeability, with the exception of Saratoga? Hammer, which suggested that the convective permeability could explain evaporative cooling better than diffusive permeability.

Statement of Relevance: Protective clothing often interferes with evaporative cooling and thus increases the level of heat stress. While increased diffusion of water vapour is associated with lower evaporative resistances, the convective movement of water vapour is a dominant mechanism and better explains the role of the clothing in heat stress.     

现代服装广告的特点及常用的创意手法

服装广告作为服装企业推销产品和构筑品牌的重要手段之一,在企业的营销活动中处于重要地位。本文通过相关文献资料的阅读和服装广告案例的归纳总结,系统阐述了服装广告的特点及常用的创意手法。     

Intermittent microclimate cooling during rest increases work capacity and reduces heat stress

Requirements for special protective equipment while working in hazardous environments can present a significantly increased thermal burden and early onset of physical fatigue. Ambulatory (backpack) or tethered personal cooling can accelerate metabolic heat removal, but is often not practical from an ergonomic standpoint. The efficacy of incorporating personal cooling during non-ambulatory rest periods was evaluated in subjects (n=8) with varying levels of fitness. Treadmill work (≈475 W, 40% [Vdot]O₂max) was alternately performed for 30 min followed by 30 min of rest. Subjects walked and rested under three separate experimental conditions: (1) control (C), in which light clothing was worn; (2) CPE, in which a chemical protective ensemble (CPE) was worn, and (3) CPE plus intermittent microclimate cooling (COOL). The WBGTcondition for all trials was 31°C. During the COOL trial the subjects additionally wore a personal cooling vest which allowed for the circulation of chilled liquid over the torso during rest. Under C conditions, relatively modest changes in rectal temperature (T _re ) were observed, which stabilized over time. CPE wear resulted in a progessive rise in T _re and early fatigue. The addition of intermittent cooling during each rest cycle (COOL trial) significantly attenuated heat storage such that an oscillating, but equilibrated T _re was established and work capacity was at least doubled. Moreover, the perceived cooling effect was appreciable for all subjects. Therefore, intermittent personal cooling provided a useful means of enhancing work productivity and may have application for certain military and industrial personnel performing heavy work in hot environments. This approach should provide a practical alternative for reducing stress/fatigue when work/rest cycles are employed.     

Sobel算子在衣物纹理类型检测中的应用研究

衣物纹理是指衣物表面的纹络现象。在越来越发达的智能图像处理过程中,针对衣物纹理的检测也变得愈发平常,人们期望能够使用计算机自动识别衣物表面的纹理类型,如横竖条纹、方格及碎花等,从而进行基于纹理类型的相应操作。文中提出了一种利用Sobel算子进行梯度方向统计来实现衣物纹理类型检测的方法,其中对各纹理类型的判定依据来源于实验分析过程,经测试表明,该方法及相应判定依据能够有效地检测出衣物常见的纹理类型。     

Reducing heat stress under thermal insulation in protective clothing: microclimate cooling by a ‘physiological’ method

Heat stress caused by protective clothing limits work time. Performance improvement of a microclimate cooling method that enhances evaporative and to a minor extent convective heat loss was tested. Ten male volunteers in protective overalls completed a work-rest schedule (130 min; treadmill: 3 × 30 min, 3 km/h, 5% incline) with or without an additional air-diffusing garment (climatic chamber: 25°C, 50% RH, 0.2 m/s wind). Heat loss was supported by ventilating the garment with dry air (600 l/min, ?5% RH, 25°C). Ventilation leads (M ± SD, n = 10, ventilated vs. non-ventilated) to substantial strain reduction (max. HR: 123 ± 12 b/min vs. 149 ± 24 b/min) by thermal relief (max. core temperature: 37.8 ± 0.3°C vs. 38.4 ± 0.4°C, max. mean skin temperature: 34.7 ± 0.8°C vs. 37.1 ± 0.3°C) and offers essential extensions in performance and work time under thermal insulation.     

A study on local cooling of garments with ventilation fans and openings placed at different torso sites

The aim of the study was to examine the various design features of ventilated garments on cooling performance. Five jackets with small ventilation units and closable openings were designed. The ventilation units with a flow rate of 12 l/s were placed at five different torso sites. They were examined on a sweating thermal manikin in four clothing opening conditions in a warm environment (T_a = T_manikin = 34 °C, RH = 60%, V_a = 0.4 m/s). Total torso cooling was increased by 137–251%, and clothing total dynamic evaporative resistance was decreased by 43–69%. Neither the ventilation location nor the opening design had a significant difference on total torso cooling. The ventilation location had a significant difference on localized intra-torso cooling, but not the opening design. When the ventilation units were placed at the local zone where it was ventilated, that zone underwent the highest cooling than other local zones. The study indicated that the ventilation units should be placed at the region where it required the most evaporative cooling, e.g. along the spine area and the lower back. The openings could be adjusted (closed or opened) to make comfortable air pressure for the wearers but without making significant difference on the whole torso cooling under this flow rate.Relevance to industryHeat strain is frequently reported in hot environments, especially for those industries, such as construction, mining and steel. Clothing equipped with the small ventilation units could circulate the ambient air around the body and thus decrease heat strain and improve productivity.     

Heat stress in chemical protective clothing: porosity and vapour resistance

Heat strain in chemical protective clothing is an important factor in industrial and military practice. Various improvements to the clothing to alleviate strain while maintaining protection have been attempted. More recently, selectively permeable membranes have been introduced to improve protection, but questions are raised regarding their effect on heat strain. In this paper the use of selectively permeable membranes with low vapour resistance was compared to textile-based outer layers with similar ensemble vapour resistance. For textile-based outer layers, the effect of increasing air permeability was investigated. When comparing ensembles with a textile vs. a membrane outer layer that have similar heat and vapour resistances measured for the sum of fabric samples, a higher heat strain is observed in the membrane ensemble, as in actual wear, and the air permeability of the textile version improves ventilation and allows better cooling by sweat evaporation. For garments with identical thickness and static dry heat resistance, but differing levels of air permeability, a strong correlation of microclimate ventilation due to wind and movement with air permeability was observed. This was reflected in lower values of core and skin temperatures and heart rate for garments with higher air permeability. For heart rate and core temperature the two lowest and the two highest air permeabilities formed two distinct groups, but they did not differ within these groups. Based on protection requirements, it is concluded that air permeability increases can reduce heat strain levels allowing optimisation of chemical protective clothing. STATEMENT OF RELEVANCE: In this study on chemical, biological, radiological and nuclear (CBRN) protective clothing, heat strain is shown to be significantly higher with selectively permeable membranes compared to air permeable ensembles. Optimisation of CBRN personal protective equipment needs to balance sufficient protection with reduced heat strain. Using selectively permeable membranes may optimise protection but requires thorough consideration of the wearer's heat strain.     

John G. Fox (1931-2004)

The effectiveness of intermittent, microclimate cooling for men who worked in US Army chemical protective clothing (modified mission-oriented protective posture level 3; MOPP 3) was examined. The hypothesis was that intermittent cooling on a 2 min on–off schedule using a liquid cooling garment (LCG) covering 72% of the body surface area would reduce heat strain comparably to constant cooling. Four male subjects completed three experiments at 30°C, 30% relative humidity wearing the LCG under the MOPP 3 during 80 min of treadmill walking at 224 ± 5 W · m^?2. Water temperature to the LCG was held constant at 21°C. The experiments were; 1) constant cooling (CC); 2) intermittent cooling at 2-min intervals (IC); 3) no cooling (NC). Core temperature increased (1.6 ± 0.2°C) in NC, which was greater than IC (0.5 ± 0.2°C) and CC (0.5 ± 0.3°C) ( p < 0.05). Mean skin temperature was higher during NC (36.1 ± 0.4°C) than IC (33.7 ± 0.6°C) and CC (32.6 ± 0.6°C) and mean skin temperature was higher during IC than CC ( p < 0.05). Mean heart rate during NC (139 ± 9 b · min^?1) was greater than IC (110 ± 10 b · min^?1) and CC (107 ± 9 b · min^?1) ( p < 0.05). Cooling by conduction (K) during NC (94 ± 4 W · m^?2) was lower than IC (142 ± 7 W · m^?2) and CC (146 ± 4 W · m^?2) ( p < 0.05). These findings suggest that IC provided a favourable skin to LCG gradient for heat dissipation by conduction and reduced heat strain comparable to CC during exercise-heat stress in chemical protective clothing.     

从符号的角度来透视人们的着装行为

在个体着装行为的背后,服装首先是作为一种符号进入人们的识别系统的。不同的服装传达的意义不同,服装的这种符号意义是在"服装符号"被解读的过程中,也就是在交流的过程中得以实现的。本文是从符号的角度来看人们的着装行为,用符号的理论来解释着装行为,探讨了服装符号的能指与所指;服装中展现出的符号,这也是人们着装行为的依据;最后阐述了服装符号的运用。     

Layering garments during rest and exercise in the cold (8°C): wearer responses and comparability with selected fabric properties

How garments contribute to performance of the clothing system during wear is of interest, as is understanding the value of using fabric properties to inform end-use characteristics. To investigate the influences of layering upper-body garments, four fabrics were used to construct two first-layer garments (wool and polyester) and two outer-layer garments (wool and membrane laminate). Over six sessions, 10 moderately trained males wore each first-layer garment as a single layer and in combination with each outer-layer garment while resting, running and walking in cold environmental conditions (8 ± 1°C, 81 ± 4% RH). Here, the type of garment arrangement worn (fabric type or number of layers) had little influence on heart rate, core body temperature and change in body mass. Weighted mean covered skin temperature was warmer and weighted mean next-to-skin vapour pressure was typically higher (following the onset of exercise) with two layers versus one. Differences among fabrics for individual properties were typically overstated compared to differences among corresponding garments for physiological and psychophysical variables under the conditions of this study. These findings inform the interpretation of particular fabric properties and highlight issues to be acknowledged during development/refinement of fabric test methods.

Practitioner Summary: We examined the way in which selected fibre, fabric and garment (layering) characteristics contribute to performance of the clothing system during wear under cold conditions. Selected properties of the constituent fabrics were found to provide limited insight into how garments perform during wear under the conditions of this study.     

结合层次分割和跨域字典学习的服装检索

目的 针对现有的跨场景服装检索框架在服装躯干部分检索问题上,因服装款式识别优化存在服装信息丢失和跨场景款式识别的问题,提出一种新的服装分割方法和基于跨域字典学习的服装款式识别。方法 首先,提出基于超像素融合和姿态估计相结合的方法分割出完整的服装,用完整的服装进行检索可以最大限度地保留服装信息。然后,在服装款式识别时,通过学习服装商品数据集与日常服装图像数据的中间数据集字典,使其逐渐适应日常服装图像数据的方式,调节字典的适应性,进而提高不同场景下的服装款式识别的准确性。另外,由于目前国际缺少细粒度标注的大型服装数据库,本文构建了2个细粒度标注的服装数据库。结果 在公认的Fashionista服装数据集及本文构建的数据库上验证本文方法并与目前国际上流行的方法进行对比,本文方法在上下装检索中精度达到62.1%和63.4%,本文方法在服装分割、款式识别,检索方面的准确度要优于当前前沿的方法。结论 针对现有的跨场景服装检索框架分割服装不准确的问题,提出一种新的层次服装过分割融合方法及域自适应跨域服装款式识别方法,保证了服装的完整性,提高了跨场景服装检索及款式识别的精度,适用于日常服装检索。