Thermal Protective Clothing Research Articles

Lightweight, ultrahigh-strength and flame-retardant cellulose aerogel crosslinked with a reactive P/N-rich curdlan derivative.

Cellulose aerogel, recognized for its eco-friendliness, bio-sustainability and excellent thermal insulation property, holds immense potential as an insulation material. However, the application of cellulose aerogel has been hindered by its inherent drawbacks, particularly its low strength and flammability. In this study, a reactive P/N-rich curdlan derivative (NT) was synthesized and characterized. Lightweight, ultrahigh-strength and flame-retardant composite aerogels were then prepared by slow freezing, freeze-drying and chemical crosslinking methods. Composite aerogel crosslinked with 30% NT exhibited exceptional thermal insulation property with a low thermal conductivity of 33.9mW/(m·K), which rivaled the value of petroleum-based thermal insulation materials. It possessed an ultrahigh compressive modulus (0.786MPa) at low density (21.6mg/cm3), which supported >12,000 times its weight. It also displayed superior flame-retardant property, with a limiting oxygen index of up to 33.1% and a V-0 rating in the UL-94 test. This study provides a new insight into the high-value utilization of natural polysaccharide and an innovative solution to the problem of low strength and flammability of cellulose aerogel. Cellulose aerogels with ultrahigh strength, superior flame retardancy and thermal insulation property possess a promising application in the fields of construction, aerospace and thermal protective clothing as high-performance thermal insulation materials.

Analyzing thermal‐moisture comfort and thermal protective performance of phase change materials dripped protective clothing

AbstractThe objective of the study was to alleviate the thermal‐moisture comfort (TMC) of phase change material (PCM) thermal protective clothing, while simultaneously enhancing thermal protective performance (TPP) by a drip molding process. Nine types of PCM dripped fabrics were prepared by the drip molding process and served as comfort layers of thermal protective clothing. The TMC and TPP of the fabric systems were measured. A new method was proposed to balance the TMC and TPP of thermal protective clothing. The results demonstrated that the drip molding process marginally weakened the TMC while substantially enhancing the TPP of fabric systems. But the TMCs of the PCM dripped fabrics were far larger than the PCM coated fabric. Specifically, an increase in droplet diameter led to a decline in TMC and an improvement in TPP, whereas an increase in droplet interval resulted in an enhancement in TMC and a decrease in TPP. The findings obtained in this study can be used to engineer fabric systems that provide better protection for heat stress and skin burns.

Upper- vs. Whole-Body Cooling During Exercise with Thermal Protective Clothing in the Heat.

INTRODUCTION: Firefighters operating in hot environments face challenges from protective garments that restrict heat dissipation, resulting in increased core temperature, thermal discomfort, and performance decline. Cooling vests represent a viable solution. The study aim was to compare effectiveness of the same amount of cooling power to the upper body (UB) or whole body (WB) in alleviating thermoregulatory and physiological stress, enhancing cognitive function, and reducing ratings of thermal discomfort and exertion, during 60 min of exercise in a hot environment (40°C, 40% relative humidity) while wearing firefighter turnout gear.METHODS: Eight healthy individuals (27.5 ± 3 y) participated in three conditions with either no cooling (Control) or active cooling with a liquid perfused shirt (UB cooling), or with a liquid perfused shirt and pants (WB cooling). In each trial, subjects performed three sets of 15 min of stepping (20 steps ⋅ min-1) and 5 min of rest.RESULTS: Both cooling strategies were beneficial compared to having no cooling at all. Subjects could only complete two exercise bouts during Control, but they completed all three bouts with active cooling. WB cooling provided an advantage over UB cooling for core and skin temperature, and thermal comfort and sensation. The advantage in minimizing the increase in core temperature was only evident during the third exercise bout.DISCUSSION: Active cooling is advantageous under these conditions. WB cooling provided some benefits vs UB cooling during heavy intensity exercise; however, it is uncertain whether these benefits would be observed during light-to-moderate exercise, which more likely reflects an actual firefighting scenario.Mansouri F, Talebian Nia M, Villar R, Cornish SM, Giesbrecht GG. Upper- vs. whole-body cooling during exercise with thermal protective clothing in the heat. Aerosp Med Hum Perform. 2024; 95(9):659-666.

Thermal Protection Performance Evaluation Based on Structural Composition Changes of the Intermediate-Layer Fabric in Thermal Protective Clothing

This study is a follow-up to ‘Research on the Development of Fabrics for Industrial and Firefighting Protective Clothing and Comparison of Flame Retardant Performance,’ focusing on the thermal protection performance of clothing designed to protect the human body from high temperatures and heat in industrial settings and fire scenarios. In this study, additional thermal protection performance tests were conducted to provide a more comprehensive analysis. Aside from the flame-retardant performance evaluation conducted according to ISO 15025 on 12 base fabrics with different yarn compositions, the following thermal performance studies were carried out: radiant heat protection (ISO 9151), convective heat protection (ISO 6942), and combined radiant and convective heat protection (ISO 17492). The heat-transfer index of the intermediate layer, which plays a crucial role in the thermal protection performance of thermal clothing, was also assessed. The results indicated that although most of the 12 base fabrics offered a certain level of thermal protection, some of them melted and failed to provide adequate thermal protection.

Effect of Orientation of Test on Radiant Protective Performance of Outer Layer of Multilayer Thermal Protective Clothing

Effect of Orientation of Test on Radiant Protective Performance of Outer Layer of Multilayer Thermal Protective Clothing

Improvement of the technology of manufacturing clothes of law enforcement agencies

Special requirements are imposed on the uniform of a serviceman due to the specific use in different conditions. Special attention is paid to the comfort of wearing, the quality of materials and construction of clothing, hygienic and tactical and technical properties. When designing thermal protective clothing, it must be borne in mind that its thermal resistance must ultimately be assessed by the cumulative insulating effect of the finished structure. This scientific article attempts an in-depth analysis of the study of the problem of choosing the best range of materials necessary for the manufacture of uniforms intended for use in law enforcement agencies. The purpose of this study is to carefully determine the optimal combination of materials that is guaranteed to ensure a high standard of quality, durability and functionality of the uniform, as well as compliance with its requirements for modern service conditions. The article analyzes various aspects that affect the choice of materials, including their strength, comfort, protective properties and aesthetic aspect. The obtained research results, in turn, are aimed at improving the process of developing and manufacturing uniforms for law enforcement agencies, which, ultimately, will lead to an increase in the level of comfort and safety for its future wearers.

Influence of the Structure of 3D Woven Fabrics on Radiation Heat Resistance and Thermophysiology Properties

The goal of this study was to investigate the influence of structural and constructional parameters of 3D fabric on two of the most significant properties of fabrics for thermal protection—resistance to radiation heat and thermophysiological properties. Today’s textile materials provide high thermal protection, but they display poor thermophysiological properties in extreme conditions. Six samples of 3D fabrics were developed using a laboratory weaving machine. The examined samples were made of identical warp, with a total of three different weft densities, and were woven in two different weaves. The conditions of the weaving process and construction were the same. EN ISO 6942:2022 and EN ISO 11092:2014 methods were used to determine the resistance of the samples to thermal radiation and thermophysiological properties. The results showed that the samples that contained folds in their structure with a larger volume of “trapped” air had better thermophysiological properties and better resistance to thermal radiation. The volume of air contained in the 3D structure was used as a thermal insulator and it did not have a negative effect on the thermophysiological properties. The described structure enabled the 3D fabric to have an optimal ratio of thermal protection and comfort, which is of crucial importance for fabrics used to make thermal protective clothing.

THE EFFECT OF AIRGAP THICKNESS ON THERMAL PROTECTIVE PERFORMANCE IN HEAT RESISTANT CLOTHING

The thermal protective performance is provided by thermal protective clothing worn by people who work in high temperature environments and is highly influenced by air gaps. In this paper, effect of air gap thickness on thermal protective performance as indicated by the time before degree burn were investigated. 3 layers of thermal protective clothing with 3 types of fabrics that have been selected will be tested using an experimental method. The research will be conducted through experimental tests using the fabric level method on a bench-scale test apparatus which is equipped with 4 thermocouples and using gas torch as a heat source. The air gap located between the layers of thermal protective clothing will be varied with different thickness in a vertical orientation. The size of the air gap used varies from 01 mm, 2.51 mm, 51 mm, and 7.51 mm. The results show that the temperature distribution in each layer of clothing from the outer shell to the thermal linear has decreased. In addition, time before degree burn which is an indicator on thermal protective performance shows a positive effect on the addition of air gap thickness where the optimum air gap thickness is shown at 7.5 mm variation. It is hoped that the results of this research can be a source or useful information in mechanical engineering, especially in the fields of thermal comfort and fire safety.

Mechanical strength recognition and classification of thermal protective fabric images after thermal aging based on deep learning

Objectives. Currently, numerous studies have focused on testing or modeling to evaluate the safe service life of thermal protective clothing after thermal aging, reducing the risk to occupational personnel. However, testing will render the garment unsuitable for subsequent use and a series of input parameters for modeling are not readily available. In this study, a novel image recognition strategy was proposed to discriminate the mechanical strength of thermal protective fabric after thermal aging based on transfer learning. Methods. Data augmentation was used to overcome the shortcoming of insufficient training samples. Four pre-trained models were used to explore their performance in three sample classification modes. Results. The experimental results show that the VGG-19 model achieves the best performance in the three-classification mode (accuracy = 91%). The model was more accurate in identifying fabric samples in the early and late stages of strength decline. For fabric samples in the middle stage of strength decline, the three-classification mode was better than the four-classification and six-classification modes. Conclusions. The findings provide novel insights into the image-based mechanical strength evaluation of thermal protective fabrics after aging.

Numerical investigation of the influence of thermal protective fabric deformation on heat transfer from thermal radiant heat to human skin

Operators in thermal hazardous environments are more susceptible to burns during physical motion due to the potential deformation of thermal protective clothing. To study the influence of fabric deformation on heat transfer, a model of a three-layer thermal protective fabric system with stretching and compression deformation throughout the heat exposure and cooling phases was established and coupled with a skin heat transfer model to predict skin burns. Changes in the thermophysical properties of the fabric with deformation and skin tissue based on body location were considered. To verify the accuracy of the model, a modified radiant protective performance tester capable of simulating fabric deformation was applied. The relative error between the prediction results of the model and the experimental results does not exceed 4.68 %. The results demonstrate that stretching or compression deformation of the fabric increases heat transfer to the skin, and compression deformation generates a greater thermal hazard by accelerating the discharge of stored energy. Fabric deformation accelerates skin burns in all body parts, especially in the arms and legs. The findings of this research can provide a theoretical basis for understanding the frequent occurrence of skin burns associated with body motion and provide guidance for the design of thermal protective clothing to enhance the partial thermal protective performance.

A Multifunctional Approach to Optimizing Woven Fabrics for Thermal Protective Clothing

This paper presents a detailed exploration of the development and characterization of multifunctional dual-purpose woven fabrics for thermal protective clothing. Through this research, 69 woven fabric prototypes have been carefully designed and produced, integrating various raw materials, yarn, and woven fabric construction parameters, with the aim of optimizing thermal protection properties while ensuring comfort and durability. The analysis led to the identification of two optimal woven fabric samples, which, upon further testing, exhibited exceptional dimensional stability, crease recovery, tear resistance, as well as abrasion and water resistance. Furthermore, the thermal properties were evaluated, demonstrating exceptional flame resistance, limited heat transmission, and high thermal insulation. Additionally, the study evaluated dynamic thermal properties, contact conductive heat transfer, air permeability, water vapour resistance, and thermal resistance of two clothing systems constructed from selected woven fabrics. Statistical analysis confirms significant differences between clothing systems, highlighting the influence of yarn composition and fabric structure on thermal performance and comfort, where one system exhibits better thermal insulation characteristics suitable for colder environments while the other excels in breathability for warmer climates. The developed woven fabrics meet high standards for protective clothing against heat and flame, surpassing currently available comparable woven fabrics on the market in terms of efficacy and performance. This research provides insights into the intricate balance between protection, comfort, and durability of woven fabrics, contributing to advancements in protective textile technology.

Comparison between the human physiological sweat and pre-wetting method on the heat and mass transfer of thermal protective clothing under radiant exposure

In this study, a thorough investigation of human sweating behavior was conducted to ensure an accurate evaluation of the thermal protection performance of garments, addressing the lack of existing standardized methods. Three fabrics were compared at different sweating rates under radiant exposure, focusing on exploring heat and mass transfer mechanisms using the traditional pre-wetting method and the innovative continuous sweating method. It was found that the pre-wetting method was effective in situations where fabrics experienced transient moisture absorption, whereas the continuous sweating method excelled in scenarios requiring continuous moisture supply before saturation and was used to estimate liquid moisture transfer. In particular, for materials with low hygroscopicity, the pre-wetting method resulted in 86.24 kJ/m2 more absorbed thermal energy at the skin surface compared with the continuous sweating method, with a sweat rate of 10 μL/min/cm2, highlighting the tendency of the pre-wetting method to overestimate the thermal protective performance. Conversely, for fabrics with high hygroscopicity and testing with high sweat rate, a 32.81% reduction in absorbed thermal energy on the skin surface was observed when the continuous sweating method was used in place of the pre-wetting method, significantly reducing operational risks. This study provides valuable guidance in selecting appropriate sweat simulation methods to evaluate the thermal protection performance based on specific environmental conditions, and provides critical insights for further studies on heat and moisture transfer.

Predicting the thermal protective performance of flame-retardant fabric based on machine learning

PurposeThe purpose of this study is to predict the thermal protective performance (TPP) of flame-retardant fabric more economically using machine learning and analyze the factors affecting the TPP using model visualization.Design/methodology/approachA total of 13 machine learning models were trained by collecting 414 datasets of typical flame-retardant fabric from current literature. The optimal performance model was used for feature importance ranking and correlation variable analysis through model visualization.FindingsFive models with better performance were screened, all of which showed R2 greater than 0.96 and root mean squared error less than 3.0. Heat map results revealed that the TPP of fabrics differed significantly under different types of thermal exposure. The effect of fabric weight was more apparent in the flame or low thermal radiation environment. The increase in fabric weight, fabric thickness, air gap width and relative humidity of the air gap improved the TPP of the fabric.Practical implicationsThe findings suggested that the visual analysis method of machine learning can intuitively understand the change trend and range of second-degree burn time under the influence of multiple variables. The established models can be used to predict the TPP of fabrics, providing a reference for researchers to carry out relevant research.Originality/valueThe findings of this study contribute directional insights for optimizing the structure of thermal protective clothing, and introduce innovative perspectives and methodologies for advancing heat transfer modeling in thermal protective clothing.

A Hollow Structure of Thermal Barrier for Thermal Protective Clothing

A Hollow Structure of Thermal Barrier for Thermal Protective Clothing

Effects of air gap and compression on the dual performance of multilayer thermal protective clothing under low radiant heat

An air gap in thermal protective clothing (TPC) plays an important role in determining heat transfer, but it may also increase the amount of stored thermal energy that would discharge to the skin after exposure, especially when the TPC suffers compression. To investigate the effect of air gap and compression on the dual thermal protective performance (TPP), thermal hazardous performance (THP) and overall thermal protective performance (OTPP) of TPC, nine air gap configurations with different sizes and positions and five compression levels were designed in this study. Regression models were established to explore the relationships among air gap size, compression and THP for different air gap positions. The results demonstrate that increasing the air gap size without exceeding 12 mm not only significantly enhances the TPP by impeding heat transfer from the heat source to the fabric system during exposure but also decreases the THP by reducing heat discharge from the fabric system to the sensor even when compression is applied. Although an inner air gap contributes more to increasing the TPP during exposure than an outer air gap, it may also bring about severe stored energy discharge when compression is applied. It suggests that a larger air gap size should be divided into individually separate air gaps within different fabric layers to reduce the heat transfer during exposure as well as lower the stored thermal energy discharge after exposure.

Investigation of the influence of the environment on the electrical properties of textile clothing materials

Investigation that Elevated levels of static electricity build-up on the surfaces of work clothes, different technological structures, and polymeric materials can cause disruptions to the techno-bio system, resulting in adverse physiological effects in humans, accidents caused by humans, and environmental disasters. Under conditions of low temperatures, electrostatic charge on polymeric materials is intensively generated. Synthetic materials have an increased ability to electrify. The processes were studied the mechanisms of the occurrence of a electricity an polymer materials of clothing in winter. The logical structure of the model of the formation of an electrostatic field on the surface of polymer materials of objects in environmental conditions during a snowstorm has been developed. A set of materials for experimental thermal protective clothing was investigated. The findings from the investigation into the process of electrification in the layers of materials used to make thermally protective clothing are gathered and given. As follows from the graphs, the limiting value of the electrostatic field strength can occur already with an external field of 15000 V/m. The formation of charges is facilitated by the physical conditions of the snowstorm electrification in the system of polymer structures.

Study the environmental impact on mobile electronics in a heat-protective sewing shell

The environment (Winter cold) affects both the individual and the equipment and communications needed to support workflow or general communication. Therefore, the issue of providing thermal conditions in which the communication device is located while a person stays in the cold is relevant. To protect such devices from premature cooling, they are placed in special parts of clothing. Model-ling and research of thermal insulation properties of garment parts for protection from cold of mobile communication devices will allow to establish effective parameters of thermal insulation structure. Such parameters will allow to develop and manufacture warm clothes with special details, which will maintain the performance and increase the time of stable operation of mobile communication devices necessary for a person in cold conditions. The geometrical model and the model mesh were developed. According to the results of numerical model-ling, the dependence of temperature in the thermal pocket on the ambient temperature was obtained, taking into account the presence or absence of the heating plate. The results of numerical modelling of model calculations al-lowed to theoretically justify by zoning and heating power the system of artificial thermoregulation in thermal protective clothing with integrated electronic devices.

The environment and ergonomics of clothing in the design of a human comfort system

During the time of stay in the city outside the closed premises during the periods of seasonal cooling, for a human thermal protection is provided by clothing. Clothing for protection from the cooling environment in the city is considered comfortable if its weight and dimensions do not limit a person in a given route and specificity of movement and does not draw attention to their own thermal sensations (i.e., the thermal balance of a person does not go out of the biophysical norm). Effective smart thermal protective clothing requires the inclusion in the thermoregulation system of consideration of individual human activity, which to some extent depends on the weight of the garment. Paper shows the proposed schematic diagram of the concept of operation of the functional system of smart thermal protective clothing. On the basis of the developed models and established functional relations for the proposed structure of smart thermal protective clothing, studies of its thermal effect depending on the properties of the clothing have been carried out. The developed functional models of connections of input and output parameters of biotechnical system “man-clothing-environment” allowed to reveal regularities of influence of clothing parameters and its weight on thermal comfort of a person in it.

The heat and moisture transfer model of firefighter protective clothing

This paper presents a model of heat and moisture transfer through multilayer firefighter protective clothing, which for the first time has taken into account all the major heat and moisture transport mechanisms including conductive and convective heat transfer, two-flux radiative heat transfer, moisture bulk flow, moisture absorption/desorption by fibers, moisture diffusion and phase change. The model was solved by Crank–Nicolson scheme of the finite difference method. Numerical analysis showed that our model can accurately predict the second-degree burn time with an error ranging from 0.37% to 3.55% for different types of clothing assemblies. With this model, the distributions of heat and moisture within the protective clothing system are elucidated and the relative importance of key clothing parameters on thermal protection better understood. It revealed that the thickness of the moisture barrier layer has the greatest influence on the skin burn time. This study is significant in providing a theoretical framework for optimizing the design of thermal protective clothing.

STUDY OF THE AIR PERMEABILITY INDICATOR OF A PACKAGE OF MATERIALS OF THERMAL CLOTHING FOR CHILDREN WITH A DIAGNOSIS OF CP

This article reports the results of breathability tests on upper materials, nonwoven insulation materials, lining materials, and material packs. The importance of air permeability values for packages of materials of thermal protective clothing for children diagnosed with cerebral palsy (CP) is substantiated. Objects and methods for studying the air permeability of materials are defined and described. The method according to State Standard ISO 9237–2013 was used to assess the properties of air permeability of materials. A method for calculating the predicted values of the air permeability of packages of materials is also given. The article analyses the results of air permeability of packages of materials obtained both theoretically and experimentally. The article compares the values of the air permeability of the packages of materials with the previous study of the packages of materials on the total thermal resistance. Conclusions are drawn about the requirements for air permeability of packages of materials for thermal protective clothing for children with cerebral palsy.