Heat strain in chemical protective clothing in hot-humid environment:Effects of clothing thermal properties

Heat strain experienced by individuals wearing chemical protective clothing(CPC)is severe and dangerous especially in hot-humid environment.The development of material science and interdisciplinary studies including ergonomics,physiology and heat transfer is urgently required for the reduction of heat strain.The aim of this paper was to study the relationship among clothing thermal properties,physiological responses and environmental conditions.Three kinds of CPC were selected.Eight participants wore CPC and walked(4 km/h,two slopes with 5%and 10%)on a treadmill in an environment with(35±0.5)℃ and RH of(60±5)%.Core temperature,mean skin temperature,heart rate,heat storage and tolerance time were recorded and analyzed.Physiological responses were significantly affected by the clothing thermal properties and activity intensity in hot-humid environment.The obtained results can help further development of heat strain model.New materials with lower evaporative resistance and less weight are necessary to release the heat strain in hot-humid environments.

Study on Protective Clothing against SARS Using PTFE/Poly(ether-ester) Membrane

By means of texturing with organic conductive fiber, and then being treated with JAM-Y1 anti-bacteria agent, in the end, treated with the XL-550 waterproof agent, the PET fabric has permanent antistatic, anti-bacteria and waterproof and anti-oil properties. The PET fabric was laminated with PTFE membrane by paste dot coating, and then coated by Poly(ether-ester) solution in a direct process. The filter efficiency of NaCl aerosol, penetration property of poliomyelitis virus in liquid and animalcule in air of PET fabric laminated with PTFE membrane are measured. The properties show that the PET fabric laminated with PTFE membrane can separate SARS virus in air and liquid. The protective mechanism is also discussed in the article.

Structure and Properties of Polytetrafluorethylene and Polyurethane Layered Membrane for Protective Clothing

This paper presents a new idea for intensifying protective and stretch recovery properties of micro porous polytetrafluorethylene and hydrophilic polyurethane (PTFE/PU) layered membrane through a co-stretching process. The structure and properties of co-stretching PTFE/PU layered membrane and coated PTFE/PU layered membrane by means of directly coating the PU on the PTFE membrane were investigated using Electron Microscope, Universal Materials Testing Machine, and the water vapor permeability (WVP) was measured according to absorption method of water vapor of GB/T 12704-91. Contrasted to PU coating process, the PU membrane on the co-stretching PTFE/PU membrane is nonporous because of heat treatment process, which can prevent the SARS virus from permeating the Co-stretching PTFE/PU membrane. The stretch and recovery properties of the Co-stretching PTFE/PU membrane is at least 66% after being stretched to 50% of its original length in transverse directions and that of the coated PTFE/PU membrane is 52%. The WVP of the Co-stretching PTFE/PU membrane is 13 523 g/24 h·m^2. The results suggest that when Co-stretching PTFE/PU membrane is laminated to a stretchable fabric, the fabric would have excellent stretch and recovery properties while waterproof and being permeable to water vapor. So, the Co-stretching PTFE/PU membrane laminated fabric will be a comfortable protective clothing material.

Numerical Estimation of the Thermal Response of Thermal Protective Clothing-Air Gap-Human Skin Micro-system

Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing under high temperature is the key work to investigate the thermal insulation of thermal protective clothing. A coupling model composed of thermal protective clothing,air gap and human skin is established and the temperature of the micro-system is numerically solved via the finite element method( FEM).Especially,the heat transfer of air gap located between clothing and human skin considering conduction and radiation is established while the human skin layers involve the effect of blood perfusion. Then the effect of thermophysical properties( thermal conductivity and volumetric capacity) of fabric and thickness of fabric and air on the thermal response of the micro-system is elucidated and compared.The results indicate that the volumetric heat capacity of fabric is the key parameter to affect the thermal shielding performance of thermal protective clothing,and the thicker fabric thickness and air gap thickness can improve the thermal protective properties of the micro-system.

Development of a Reproducible Rating System for Sun Protective Clothing That Incorporates Body Surface Coverage

Sunlight is a known skin carcinogen. Skin cancer is the most common form of cancer in humans, and typically affects sun-exposed parts of the body. Sunny Australia and New Zealand have the highest incidence of skin cancer globally. Clothing provides a protective barrier that reduces the amount of ultraviolet radiation (UVR) reaching the skin. Australia pioneered the development of a relative ranking of the sun-protective capabilities of clothing based on the transmission of UVR through fabric. Standardized Ultraviolet Protection Factor (UPF) measurement procedures and associated labeling specifications are documented in the Australian and New Zealand Standard, AS/NZS 4399:1996. The standard was intended to enable consumers to make informed choices. Since its introduction, this standard has been adopted almost universally by the textile industry, and is still in use almost two decades on, with plans to revise it only commencing recently. However, AS/NZS 4399:1996 does not consider garment design, particularly in relation to body surface coverage. Although swim-shirts have grown in popularity in Australia since the late 1990s, particularly among children, clothing remains under-utilized as a form of sun-protection in contemporary society. Skin cancer prevention campaigns should emphasize the sun-protective benefits of clothing and collaboration with the fashion industry is urgently needed to improve the aesthetic appeal, comfort, durability and affordability of sun-protective clothing to increase its popularity in skin cancer prone populations. In light of recent evidence showing that high UPF clothing which covers more of the body surface reduces pigmented mole development in children (major risk factor for melanoma), the rating system for sun-protective clothing should incorporate body surface covered as well as the UPF of the fabric. We discuss progress towards developing a protocol for measuring the extent of coverage of sun-protective garments. Once fully evaluated and refined, the testing protocol developed from this research may influence future revisions of international standards for evaluating and classifying sun-protective clothing.

Research on the Copyright Protection Technology of Digital Clothing Effect Diagram

As a kind of digital clothing design works,digital clothing effect diagram shows fast and roughly designer intent expression and needs protection of digital copyright protection technology.A novel digital clothing effect diagram copyright protection scheme and some algorithms based on digital image watermark technology are proposed,used by two-dimensional chaotic encryption watermark generation algorithm to generate watermark data,watermark embedding algorithm twice using genetic algorithm to obtain the optimal embedding position and embedding strength,and watermark verification algorithm to determine the copyright ownership.Experimental results and analyses show that the proposed scheme and algorithms have the feasibility and effectiveness.

Effect of Phase Change Materials on the Thermal Protective Performance of the Multi-layered Fabrics Examined by TPP Tester under Flash Fire

Cotton fabrics treated with phase change materials( PCMs)were used in multi-layered fabrics of the fire fighter protective clothing to study its effect on thermal protection. The thermal protective performance( TPP) of the multi-layered fabrics was measured by a TPP tester under flash fire. Results showed that the utilization of the PCM fabrics improved the thermal protective performance of the multi-layered fabrics. The fabric with a PCM add on of 41. 9% increased the thermal protection by 50. 6% and reduced the time to reach a second degree burn by 8. 4 s compared with the reference fabrics( without PCMs). The employment of the PCM fabrics also reduced the blackened areas on the inner layers. The PCM fabrics with higher PCM melting temperature could bring higher thermal protective performance.

Effect of Air Gap under Fabric on Thermal Protective Performance Using an Improved Apparatus

The bench top test is one of the most important and effective methods to evaluate the total thermal protective performance(TPP) of firefighters' protective clothing,which is greatly influenced by the air gaps entrapped.In this paper,to investigate the effect of air gap width on TPP,a new improved apparatus with two height changeable buttons to hold the thermal sensor was developed to get a series of air gap sizes from 0 mm to 40 mm.The TPP of two types of flame-resistant outer fabrics was measured with TPP test apparatus respectively.Analysis of temperature rise with each air gap width was made to determine the effects of different air gaps on protective performance.It was indicated that air gap size had great effect on TPP of fabrics in the bench top test.An air gap width above 8 mm was suggested for the thermal protective clothing design.

Validity of a noninvasive estimation of deep body temperature when wearing personal protective equipment during exercise and recovery

Background:Deep body temperature is a critical indicator of heat strain.However,direct measures are often invasive,costly,and difficult to implement in the field.This study assessed the agreement between deep body temperature estimated from heart rate and that measured directly during repeated work bouts while wearing explosive ordnance disposal(EOD)protective clothing and during recovery.Methods:Eight males completed three work and recovery periods across two separate days.Work consisted of treadmill walking on a 1%incline at 2.5,4.0,or 5.5 km/h,in a random order,wearing EOD protective clothing.Ambient temperature and relative humidity were maintained at 24℃and 50%[Wet bulb globe temperature(WBGT)(20.9±1.2)℃]or 32℃and 60%[WBGT(29.0±0.2)℃]on the separate days,respectively.Heart rate and gastrointestinal temperature(TGI)were monitored continuously,and deep body temperature was also estimated from heart rate(ECTemp).Results:The overall systematic bias between TGI and ECTemp was 0.01℃with 95%limits of agreement(Lo A)of±0.64℃and a root mean square error of 0.32℃.The average error statistics among participants showed no significant differences in error between the exercise and recovery periods or the environmental conditions.At TGI levels of(37.0–37.5)℃,(37.5–38.0)℃,(38.0–38.5)℃,and>38.5℃,the systematic bias and±95%Lo A were(0.08±0.58)℃,(–0.02±0.69)℃,(–0.07±0.63)℃,and(–0.32±0.56)℃,respectively.Conclusions:The findings demonstrate acceptable validity of the ECTemp up to 38.5℃.Conducting work within an ECTemp limit of 38.4℃,in conditions similar to the present study,would protect the majority of personnel from an excessive elevation in deep body temperature(>39.0℃).

Protective Performance of Woven Fabrics against Heat Radiation

In this paper,the protective performance of woven fab-rics against heat radiation is studied from the view offabric structure.As indices reflecting the protective per-formance against heat radiation,the heat emissivity andthe transmissivity of different fabrics are measured.It ispointed out that structure changes of common textiles af-fect their transmission to heat radiation while have littleinfluence on their absorption or reflection to heat radi-ation except fabrics surfaces are aluminized.Double-layer weave is proved to be an effective fabric weave forreducing the trasmissivity.It helps increase the densityand tightness while keeps the comfort of woven fabrics atthe same time.

Modeling Thermal Protective Performance of Multilayer Fabrics for Firefighters

This paper is to report a prediction model for thermal protective performance of multilayer fabrics based on Matlab neural network toolbox. Then a back propagation (BP) neural network model is developed to predict thermal protective performance of multilayer fabrics for firefighters. The network consists of twelve input nodes, six hidden nodes, and one output node. The inputs are weight, thickness, density of warp and weft, limited oxygen index (LOI), and heat conductivity of each-layer fabric. Thermal protective performance (TPP) rating of multilayer fabrics is the output. In this paper, the data from the experiments are used as learning information for the neural network to develop a reliable prediction model. Finnally the model performance is verified, and the proposed model can be applied to predict the thermal protective performance of multilayer fabrics for firefighters.

军用防护服发展现状与趋势

军用防护服在军事作战和应急救援中发挥着重要作用,因而对其特殊环境下的防护性能提出了更高的要求。从防护服的色彩、面料、结构3个方面介绍军用防护服的主要功能,其中,面料是军用防护服的核心组成部分,直接关系到防护能力和作战效能,高性能纤维材料在军用防护服中已得到广泛应用。结合研究现状,提出未来军用防护服的发展趋势,将聚焦于高性能纤维材料、智能可穿戴材料和环保材料的综合应用,进而为军用防护服设计的系统研究提供一定的参考。

国内外防电弧服开发及性能评价体系研究

文章介绍了防电弧服的分类和款式,阐述了防电弧材料及影响电弧防护性能的因素,对比分析了国内外防电弧服性能评价标准体系和测试技术。在此基础上,从功能性、舒适性和标准3个方面对防电弧服的未来发展进行了展望。

热防护服散热性的数学模型仿真

为了探求热防护服的散热规律和在高温环境中工作的极限,根据傅里叶热传导定律,用微元法和有效差分法建立了热防护服在高温条件下的“外界环境-织物层-皮肤”散热数学模型并进行仿真模拟,然后将穿着相同防护服的恒温假人放置在与数学模型中假设温度一致的实验室温度下进行实测,并采用DS18B20温度传感器测量出假人表面温度进行比对验证。结果表明:实测假人皮肤温度为43.71℃,与模型仿真结果43.99℃的误差仅为0.28℃。研究结果说明建立的热传导散热模型具有较高准确度,能够对热防护服的散热防护效果进行仿真预测与合理评价,可为在较短的研发周期内设计散热效果更好的热防护服提供借鉴。

隔绝式化学防护服研究现状及发展趋势

当前全球危险化学品事故频发,生化威胁日益严重,国内对于防护装备的需求不断增长。基于此背景,文章介绍了传统和新型隔绝式化学防护服的常用材料,探讨了目前国内外化学防护服的研究现状,归纳了相关工艺及特点。结合实际应用场景,分析了当前隔绝式化学防护服存在的缺陷及相关问题,并展望其未来的发展趋势,为其研发和应用提供依据。

基于可穿戴设备医用防护服微环境监测系统的研究

随着全球气温不断升高,生态环境不断变化,重大传染病疫情时有发生。个体防护装备是医护人员避免生物污染危害的直接防护屏障,但长期穿戴专业的医用防护服装备会导致体表温度升高、大量出汗、虚脱等状况。为此,基于一次性医用防护服设计一种监测系统,以实时监测一次性防护服内的温湿度、二氧化碳含量及穿着人员的心率和血氧饱和度等数据。针对穿戴者长时间在污染区域作业,与外界通信受限的问题,搭建物联网云平台并采用无线传输技术实现作业人员与后方控制人员的信息交互,提高了一次性防护服的安全性和控制能力。针对微环境的温湿度、二氧化碳浓度及人体的心率和血氧饱和度等设定不同的阈值,随着工作的进行,通过微环境参数的改变来触发报警系统。所设计的监测系统满足设备向小型化发展的要求,方便医护人员穿戴,且获取监测数据后能及时通过物联网上传。

新修定的化学防护服国家标准解析

为厘清化学防护服国家标准修订后的情况,通过分析我国化学防护服国家标准发展历史,研究国外化学防护服标准,重点针对修订后的GB 24539—2021《防护服装化学防护服》的变化,从化学防护服的分类、性能要求、试验方法等方面对该标准加以解读。分析发现:GB 24539—2021将相关标准进行整合,对化学防护服的分类进行了较大的调整和更新,删除了非气密型化学防护服-ET,增加了气密型化学防护服、有限泼溅化学防护服和织物酸碱类化学防护服;相应地,性能要求也产生了较大变化,主要包括服装整体防护性能、服装面料防护性能及服装面料理化性能;GB 24539—2021中的大部分试验方法沿用了之前相关标准中的试验方法,但也进行了相应的改进和完善,主要包括试样预处理条件和试验环境条件、化学防护服向内泄漏率测试方法、化学防护服液密性能测试方法、化学防护服面料耐磨损性能测试方法和耐屈挠破坏性能测试方法。

心电信号在智能服装领域发展应用

探讨心电信号在智能服装领域的应用进展。阐述了心电信号的产生机理、采集以及分析方法。结合心电信号对心理情绪和生理状态的反映,分析了心电信号在智能情绪识别服、智能健康监测服和智能防护服领域的应用。讨论了目前基于心电信号监测的智能服装系统研究的重难点――提高智能心电信号检测设备的采集准确性和洗涤耐用性。最后,总结了心电信号技术在智能服装领域应用现状以及有待解决的问题。

环保理念下的绿色可持续服装设计探究

文章以当前可持续服装设计为研究前提,运用案例分析法对可持续服装设计进行了探究。首先,对可持续设计理念与时尚行业的结合进行了分析,其次,总结了符合服装可持续设计的四项措施,即设计理念的转变、新材料的运用、零浪费设计、再循环设计。最后,探讨了可持续设计在服装设计行业的应用现状,并且分析了目前可持续服装设计存在的问题以及未来的发展方向,为从事可持续服装设计的人员提供了理论依据。

基于人体工效学对一次性医用防护服的评价研究

从人体工效学角度对防护服进行测试是防护服性能评价的重要内容。针对目前市场中通用的连脚式、非连脚式一次性医用防护服,募集了30名志愿者作为受试者,分别穿着这2类防护服进行包括关节活动范围、操作灵活性和主观评价等主客观测评。结果表明,穿着2类防护服均对人体踝关节屈伸、内收-外展的活动范围产生了限制影响,踝关节内外旋角度被增大,膝关节外展角度亦明显增大;穿着连脚式防护服对人体四肢活动的自由度产生了限制影响,穿着非连脚式防护服则对人体躯干屈伸动作产生了较大限制影响。