Thermal Protective Performance of Single-Layer and Multiple-Layer Fabrics Exposed to Electrical Flashovers

2009 ◽  
pp. 59-59-23 ◽  
Author(s):  
MW King ◽  
X Li ◽  
BE Doupe ◽  
JA Mellish
Keyword(s):  
Single Layer ◽  
Thermal Protective Performance ◽  
Multiple Layer ◽  
Protective Performance

Research on Thermal Protective Performance of Thermal Insulation and Flame-Retardant Protective Clothing

2013 ◽  
Vol 796 ◽  
pp. 607-612
Author(s):  
Fei Fei Li ◽  
Chun Qin Zheng ◽  
Guan Mei Qin ◽  
Xiao Hong Zhou
Keyword(s):  
High Temperature ◽  
Flame Retardant ◽  
Thermal Insulation ◽  
Protective Clothing ◽  
Thermal Protection ◽  
Single Layer ◽  
Woven Fabric ◽  
Standard Requirement ◽  
Thermal Protective Performance ◽  
Protective Performance

Thermal insulation and flame-retardant (TIFR) protective clothing, which has good thermal protective performance (TPP), could protect people from high-temperature or flame in casting industry, the petrochemical industry, fire industry and et al. That is, TIFR protective clothing must have certain function of slowing or restraining heat transmission, and insulating radiant heat and convection heat from high temperature heat source. The construction of TIFR protective clothing is being developed from single layer to multi-layer fabrics made by flame-retardant (FR) fibre. In this paper, based on TPP-206 tester, the TPP coefficient of single and multi-layer fabrics with flame-retardant were measured, and the TPP of TIFR protective clothing was analyzed. TPP coefficient of single fabrics included the FR viscose non-woven fabric do not meet the standard. That of all of multi-layer fabrics meet the standard requirement, and the FR viscose/wool blended fabric is not suitable for fire fighter. It is significant and the most observable effect to put the PTFE membrane between the outer layer and the insulating layer. It could improve the overall thermal protection performance.

scholarly journals Evaluation of the Effective Microstructure Parameter of the Microwave Emission Model of Layered Snowpack for Multiple-Layer Snow

2021 ◽  
Vol 13 (10) ◽  
pp. 2012
Author(s):  
Yue Yu ◽  
Jinmei Pan ◽  
Jiancheng Shi
Keyword(s):  
Process Model ◽  
Mean Squared Error ◽  
Weighted Average ◽  
Single Layer ◽  
Microwave Emission ◽  
Emission Model ◽  
Snow Layer ◽  
Optimal Method ◽  
Microstructure Parameter ◽  
Multiple Layer

Natural snow, one of the most important components of the cryosphere, is fundamentally a layered medium. In forward simulation and retrieval, a single-layer effective microstructure parameter is widely used to represent the emission of multiple-layer snowpacks. However, in most cases, this parameter is fitted instead of calculated based on a physical theory. The uncertainty under different frequencies, polarizations, and snow conditions is uncertain. In this study, we explored different methods to reduce the layered snow properties to a set of single-layer values that can reproduce the same brightness temperature (TB) signal. A validated microwave emission model of layered snowpack (MEMLS) was used as the modelling tool. Multiple-layer snow TB from the snow’s surface was compared with the bulk TB of single-layer snow. The methods were tested using snow profile samples from the locally validated and global snow process model simulations, which follow the natural snow’s characteristics. The results showed that there are two factors that play critical roles in the stability of the bulk TB error, the single-layer effective microstructure parameter, and the reflectivity at the air–snow and snow–soil boundaries. It is important to use the same boundary reflectivity as the multiple-layer snow case calculated using the snow density at the topmost and bottommost layers instead of the average density. Afterwards, a mass-weighted average snow microstructure parameter can be used to calculate the volume scattering coefficient at 10.65 to 23.8 GHz. At 36.5 and 89 GHz, the effective microstructure parameter needs to be retrieved based on the product of the snow layer transmissivity. For thick snow, a cut-off threshold of 1/e is suggested to be used to include only the surface layers within the microwave penetration depth. The optimal method provides a root mean squared error of bulk TB of less than 5 K at 10.65 to 36.5 GHz and less than 10 K at 89 GHz for snow depths up to 130 cm.

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 Experimental study on moisture transfer through firefighters' protective fabrics in radiant heat exposures

2017 ◽  
Vol 21 (4) ◽  
pp. 1665-1671 ◽  
Author(s):  
Meng Chen ◽  
Fanglong Zhu ◽  
Qianqian Feng ◽  
Kejing Li ◽  
Rangtong Liu
Keyword(s):  
Heat Flux ◽  
Moisture Transfer ◽  
Radiant Heat ◽  
Positive Influence ◽  
Heat Radiation ◽  
Radiant Heat Flux ◽  
Thermal Protective Performance ◽  
Protective Fabrics ◽  
Protective Performance ◽  
Radiation Time

The effects of absorbed moisture on thermal protective performance of fire-fighters? clothing materials under radiant heat flux conditions were analyzed in this paper. A thermal protective performance tester and temperature sensor were used to measure the temperature variations for the facecloth side of four kinds of commonly used flame retardant fabrics in several radiant heat exposures, which varied in moisture content. Experimental results showed that, all of the temperature profiles of these four kinds of moistened fabrics under different radiant heat flux conditions presented the same variation trend. The addition of moisture had a positive influence on the thermal protective performance during the constant temperature period when heat radiation time was more than 60 seconds. As the heat radiation time increased beyond 500 seconds, the thermal protective performance of moistened fabrics became worse than that of dried fabrics in general.

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