Effects of Radiant Heat and Frictional Abrasion on Thermal Protective Performance of Clothing Against High Pressurized Steam

2021 ◽  
pp. 0887302X2199350
Author(s):  
Jiazhen He ◽  
Ling Sun ◽  
Yehu Lu
Keyword(s):  
Thermal Radiation ◽  
Exposure Duration ◽  
Protective Clothing ◽  
High Performance ◽  
Specific Interaction ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Initial Increase ◽  
Radiation Conditions ◽  
Protective Performance

This study focused on changes in protective performance of steam protective clothing after exposure to conditions such as thermal radiation and frictional abrasion. Totally eight radiation conditions varying on exposure duration and times, four types of abrasion scenarios with different friction cycles and three different combined treatments were designed. Results demonstrated that any increase in radiant exposure duration or exposure times would lead to an initial increase and then a following decrease in the steam protective performance. However, the steam protective performance seemed relatively immune to the friction cycles. When thermal radiation and frictional abrasion acted together, interactions between them existed and their specific interaction highly depended on the distribution of heat exposure duration and friction cycles. Findings of this study provided insight into factors influencing steam protective performance, and could be an aid in developing high performance materials or guidelines for use and maintenance of protective clothing.

Analyzing steam transfer though various flame-retardant fabric assemblies in radiant heat exposure

2016 ◽  
Vol 47 (5) ◽  
pp. 853-869 ◽  
Author(s):  
Yun Su ◽  
Jun Li
Keyword(s):  
Thermal Radiation ◽  
Thermal Energy ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Positive Influence ◽  
Air Permeability ◽  
Fabric System ◽  
Layered Fabric ◽  
Nonfatal Injuries

Protection from steam burns is beneficial to reduce the nonfatal injuries of firefighters in firefighting and rescue operations. A new multifunctional testing apparatus was employed to study heat and steam transfer in protective clothing under low-pressure steam and low-level thermal radiation. Single-, double-, and triple-layered fabric assemblies were selected in this experiment. It is indicated that the existence of hot steam weakens the positive influence of the fabric’s thickness, but increases the importance of the air permeability on the thermal protection. The fabric assemblies entrapping moisture barrier can better resist the penetration of steam through the fabric system, and significantly improve the thermal protection in low steam and thermal radiation exposure due to the low air permeability. Additionally, the total transmitted energy ( Qe) and dry thermal energy ( Qd) under low steam and thermal radiation are dramatically larger than that under thermal radiation ( p < 0.05), while hot steam insignificantly reduces the thermal energy during the cooling ( p = 0.143 > 0.05). The understanding of steam heat transfer helps to provide proper guidance to improve the thermal protection of the firefighter’s clothing and reduce steam burns.

scholarly journals A categorization tool for fabric systems used in firefighters' clothing based on their thermal protective and thermo-physiological comfort performances

2018 ◽  
Vol 89 (16) ◽  
pp. 3244-3259 ◽  
Author(s):  
Sumit Mandal ◽  
Simon Annaheim ◽  
Andre Capt ◽  
Jemma Greve ◽  
Martin Camenzind ◽  
...  
Keyword(s):  
Performance Index ◽  
Protective Clothing ◽  
High Performance ◽  
Clustering Algorithm ◽  
Health And Safety ◽  
Thermal Protective Performance ◽  
Thermal Protective Clothing ◽  
Low Performance ◽  
Fabric System ◽  
Protective Performance

Fabric systems used in firefighters' thermal protective clothing should offer optimal thermal protective and thermo-physiological comfort performances. However, fabric systems that have very high thermal protective performance have very low thermo-physiological comfort performance. As these performances are inversely related, a categorization tool based on these two performances can help to find the best balance between them. Thus, this study is aimed at developing a tool for categorizing fabric systems used in protective clothing. For this, a set of commercially available fabric systems were evaluated and categorized. The thermal protective and thermo-physiological comfort performances were measured by standard tests and indexed into a normalized scale between 0 (low performance) and 1 (high performance). The indices dataset was first divided into three clusters by using the k-means algorithm. Here, each cluster had a centroid representing a typical Thermal Protective Performance Index (TPPI) value and a typical Thermo-physiological Comfort Performance Index (TCPI) value. By using the ISO 11612:2015 and EN 469:2014 guidelines related to the TPPI requirements, the clustered fabric systems were divided into two groups: Group 1 (high thermal protective performance-based fabric systems) and Group 2 (low thermal protective performance-based fabric systems). The fabric systems in each of these TPPI groups were further categorized based on the typical TCPI values obtained from the k-means clustering algorithm. In this study, these categorized fabric systems showed either high or low thermal protective performance with low, medium, or high thermo-physiological comfort performance. Finally, a tool for using these categorized fabric systems was prepared and presented graphically. The allocations of the fabric systems within the categorization tool have been verified based on their properties (e.g., thermal resistance, weight, evaporative resistance) and construction parameters (e.g., woven, nonwoven, layers), which significantly affect the performance. In this way, we identified key characteristics among the categorized fabric systems which can be used to upgrade or develop high-performance fabric systems. Overall, the categorization tool developed in this study could help clothing manufacturers or textile engineers select and/or develop appropriate fabric systems with maximum thermal protective performance and thermo-physiological comfort performance. Thermal protective clothing manufactured using this type of newly developed fabric system could provide better occupational health and safety for firefighters.

scholarly journals Analysis of thermal properties, water vapor resistance and radiant heat transmission through different combinations of firefighter protective clothing

2019 ◽  
Vol 69 (06) ◽  
pp. 458-465
Author(s):  
NAEEM JAWAD ◽  
ADNAN MAZARI ◽  
AKCAGUN ENGIN ◽  
HAVELKA ANTONIN ◽  
KUS ZDENEK
Keyword(s):  
Heat Flux ◽  
Water Vapor ◽  
Flux Density ◽  
Heat Flux Density ◽  
Protective Clothing ◽  
Radiant Heat ◽  
Thermal Protective Performance ◽  
Firefighter Protective Clothing ◽  
Protective Performance ◽  
Different Levels

This experimental work is an effort to seek the possibility of improvement in thermal protective performance of firefighter protective clothing at different levels of heat flux density. Improvement in thermal protective performance means enhancement in the time of exposure against the heat flux, which will provide extra time to firefighters to perform their duties without suffering from severe injuries. Four different multilayer combinations of firefighter protective clothing were investigated. Each combination consists of outer shell, moisture barrier and thermal liner. Aerogel sheet was also employed as a substitute to thermal barrier. Initially, properties like thermal resistance, thermal conductivity, and water vapor resistance of multilayer fabric assemblies were investigated. Later on these combinations were exposed to different levels of radiant heat flux density i.e. at 10, 20 and 30 kW/m2 as per ISO 6942 standard. It was noted that those combinations in which aerogel blanket was used as thermal barrier acquire greater thermal resistance, water vapor resistance and have less transmitted heat flux density values.

On the Effectiveness of Temperature-Responsive Protective Fabric Incorporated With Shape Memory Alloy (SMA) Under Radiant Heat Exposure

2019 ◽  
Vol 38 (3) ◽  
pp. 212-224 ◽  
Author(s):  
Lijun Wang ◽  
Yehu Lu ◽  
Jiazhen He
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Air Gap ◽  
Environment Change ◽  
Temperature Responsive ◽  
Thermal Insulating

To improve thermal protection of protective clothing, temperature-responsive protective fabrics incorporated with shape memory alloy (SMA) springs varying on four different deformation heights and five types arrangement modes were designed. The thermal protection was investigated under radiant heat exposure of 0.39 cal/cm2 s. The results indicated that the air gap between fabric layers produced by SMA springs effectively improved protective performance. The thermal protection of fabrics with different SAM arrangement modes and sizes showed different trends, and the interaction effects of arrangement mode and size were analyzed. Moreover, the optimized arrangement and size of SMA springs were suggested. The regression models were established to assess the relationship between the air gap and thermal protection. This study demonstrated that the combination of flame-resistant fabric with SMA was feasible to develop temperature-responsive protective clothing because it could improve thermal insulating property by producing intelligent air gaps that responded to environment change.

Studies of the thermal protective performance of fabrics under fire exposure: from small-scale to hexagon tests

2017 ◽  
Vol 88 (20) ◽  
pp. 2339-2352 ◽  
Author(s):  
Sumit Mandal ◽  
Simon Annaheim ◽  
Thomas Pitts ◽  
Martin Camenzind ◽  
René M Rossi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Radiant Heat ◽  
Air Permeability ◽  
Small Scale ◽  
Fire Exposure ◽  
Thermal Protective Performance ◽  
Flash Fire ◽  
Protective Performance ◽  
The Impact

This study aims to investigate the thermal protective performance of fabrics used in firefighters' clothing under high-intensity fire exposure. The performance of thermal protective fabric systems with different physical properties was evaluated under laboratory simulated fire exposure. Additionally, the influence of the configuration of the fire exposure tests and modes of heat transfer through the fabrics was also thoroughly investigated. The protective performance was evaluated using the standard small-scale flame [International Organization for Standardization (ISO) 9151:1995] and radiant heat (ISO 6942:2002) exposure tests. Additionally, the protective performance was evaluated under flash-fire exposure using a newly developed hexagon test. The protective performance values obtained from the small-scale (flame and radiant heat) and hexagon (flash fire) tests were compared and discussed. It has been found that a multi-layered fabric with high weight, thickness, and thermal resistance can significantly and positively affect the protective performance. If the air permeability of this fabric is high, it can show a lower protective performance; however, the impact of air permeability on the protective performance is insignificant especially in the case of the hexagon test. Notably, the protective performance can differ under two types of small-scale tests − flame and radiant heat. Also, this protective performance value is generally higher in the case of hexagon test in comparison with the small-scale tests. These differences in protective performance are mainly due to the unique configurations of these tests and/or different modes of heat transfer through the tested fabrics. The findings from this study will guide textile or materials engineers in the design and selection of materials for high performance thermal protective clothing; in turn, it will improve the occupational health and safety for firefighters.

Quantitative assessment of the thermal stored energy in protective clothing under low-level radiant heat exposure

2017 ◽  
Vol 88 (24) ◽  
pp. 2867-2879 ◽  
Author(s):  
He Jiazhen ◽  
Chen Yan ◽  
Wang Lichuan ◽  
Li Jun
Keyword(s):  
Energy Storage ◽  
Thermal Resistance ◽  
Thermal Energy ◽  
Protective Clothing ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Air Gap ◽  
Heat Fluxes ◽  
Total Thermal Resistance ◽  
Fabric System

In addition to direct thermal energy from a heating source, a large amount of thermal energy stored in clothing will continuously discharge to the skin after exposure. Therefore, thermal protective clothing may have a dual effect on human skin in reality. An experimental investigation was conducted to study the energy storage within 15 different combinations of clothing layers exposed to low heat fluxes ranging from 2.5 kW/m2 to 8.5 kW/m2. The energy storage process, the distribution of energy storage, and variables critically impacting energy storage, including fabric layers, air gap under clothing, thermal resistance and heat source intensity were discussed. It is demonstrated that the weight and thickness of the fabric are dominating factors affecting energy storage. For a multilayer fabric system, 36–57% of the total amount of energy is stored in the outer shell. The neighboring layer proves to be very important for the energy storage in an individual fabric. The air gap that exists between the fabric and the skin exerts an influence on the energy storage within fabric layers. In addition, a linear correlation is observed between the energy storage and the total thermal resistance of a fabric system. The research findings will be brought to researchers to better understand the mechanism and factors associated with energy storage and help develop new fabric combinations in order to minimize heat transmission to the skin.

scholarly journals Thermal Protective Performance of Firefighters’ Clothing Under Low-Intensity Radiation Heat Exposure

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hualing He ◽  
Zhicai Yu ◽  
Chunbo Zhang ◽  
Minhua Li
Keyword(s):  
Protective Clothing ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Test Methods ◽  
Stored Energy ◽  
Radiation Heat ◽  
Low Intensity ◽  
Fabric System ◽  
Protective Performance ◽  
Intensity Radiation

AbstractThe stored energy provided by the fabric assemblies will greatly influence the thermal protection performance (TPP) of firefighters’ protective clothing under low-intensity radiation heat exposure. In this study, two test methods, namely radiant protective performance (RPP) and stored energy test (SET), were used to investigate the TPP of the fabric assemblies. The results indicated that TSET value was lower than TRPP value because of the release of the stored energy in the fabric assemblies after heat exposure. Increasing the fabric layer numbers, air gap between the fabric assemblies would increase the time of TRPP and TSET, indicating that the thermal stored energy weakened the TPP of the firefighters’ protective clothing. Moreover, the TRPP and TSET of the fabric system would be increased when the moisture barrier was cut in the fabric combination system. These findings suggested that stored energy should be considered in analyzing the TPP of fabric assemblies..

A model of heat transfer in firefighting protective clothing during compression after radiant heat exposure

2016 ◽  
Vol 47 (8) ◽  
pp. 2128-2152 ◽  
Author(s):  
Yun Su ◽  
Jiazhen He ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Parametric Study ◽  
Protective Clothing ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Heat Transfer Model ◽  
Air Gap ◽  
Transfer Model ◽  
Skin Burn ◽  
Contact Heat

This paper presents an experiment-based, multi-medium heat transfer model to study thermal responses of multi-layer protective clothing with an air gap exposed to thermal radiation and hot contact surface. The model considers the dynamical changes of air gap, each layer’s fabric thickness, and air content contained in the fabric due to the pressure applied. The fabric heat transfer model developed from this study was incorporated into a human skin burn model in order to predict skin burn injuries. The predicted results from the model were well in agreement with the experimental results. A parametric study was conducted using various contact temperatures and applied pressures and design variables of firefighting protective clothing, such as physical properties of fabric layers and air gap sizes. It was concluded from the parametric study that resistance to transmission of injurious levels of heat decreases as the test temperature and contact pressure increase, and the contact heat transfer can weaken the importance of air gap under radiant heat flux(8.5 kW/m2) for 60 s and compression (pressure: 3 kPa, temperature: 316℃) for 60 s. The findings obtained in this study can be used to engineer fabric systems that provide better protection for contact heat exposure.

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