scholarly journals Characterizing the Tensile Strength of the Fabrics Used in Firefighters’ Bunker Gear under Radiant Heat Exposure

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 296
Author(s):  
Nur-Us-Shafa Mazumder ◽  
Sumit Mandal ◽  
Robert J. Agnew ◽  
Adriana Petrova ◽  
Lynn M. Boorady ◽  
...  
Keyword(s):  
Heat Flux ◽  
Tensile Strength ◽  
National Fire Protection Association ◽  
Single Layer ◽  
Radiant Heat ◽  
Radiant Heat Flux ◽  
Thermal Hazards ◽  
Fabric System ◽  
Four Levels ◽  
The Impact

More than 60,000 firefighters’ injuries were reported by the National Fire Protection Association in the U.S. in 2019. Inadequate protection by bunker gear could be a reason for most of the injuries. Firefighters repeatedly encounter thermal hazards due to their job responsibilities. Degradation could occur on bunker gear fabric during thermal exposure. It has been found that the presence of moisture affects performance as well, which may come from wearers’ sweat. Proper evaluation of the tensile strength of the fabrics used in bunker gear could provide information essential for maintenance the overall integrity of the gear. An evaluation of the tensile strength of fabrics when exposed to 10, 15, and 20 kW/m2 radiant heat flux in the presence of moisture is reported. In each fabric system, a total of sixty-four different samples were prepared for four different types of fabric and four levels of moisture which were exposed to three different radiant heat flux for five minutes. Heat flux and moisture levels have significant impact on tensile strength. The effect of moisture on tensile strength in a three-layered fabric system is higher than that for a single layer fabric. An understanding of the impact of heat and moisture on fabric strength has been achieved.

scholarly journals Лучистый тепловой поток от возбужденных атомов в высокочастотном ионном двигателе

2021 ◽  
Vol 47 (4) ◽  
pp. 45
Author(s):  
В.К. Абгарян ◽  
М.В. Абгарян ◽  
А.Б. Надирадзе ◽  
В.В. Нигматзянов ◽  
А.А. Семенов
Keyword(s):  
Heat Flux ◽  
Radio Frequency ◽  
Spontaneous Emission ◽  
Discharge Plasma ◽  
Radiant Heat ◽  
Numerical Calculations ◽  
Radiant Heat Flux ◽  
Ion Thrusters

The radiant heat flux coming from the discharge plasma on the surfaces of radio frequency ion thrusters is considered. Spontaneous emission of photons is formed when the excitation of plasma atoms and ions is removed. The distributions of the densities of the heat flux brought by radiation to the surface in the thrusters are calculated. The distributions can be used in numerical calculations of temperatures in thrusters design.

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.

Development of a pyrolysis model for oriented strand board: Part II—Thermal transport parameterization and bench-scale validation

2021 ◽  
pp. 073490412110366
Author(s):  
Junhui Gong ◽  
Hongen Zhou ◽  
Hong Zhu ◽  
Conor G McCoy ◽  
Stanislav I Stoliarov
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Loss Rate ◽  
Oriented Strand Board ◽  
Mass Loss Rate ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Controlled Atmosphere ◽  
Radiant Heat Flux ◽  
Pyrolysis Model

Oriented strand board is a widely used construction material responsible for a substantial portion of the fire load of many buildings. To accurately model oriented strand board fire response, kinetics and thermodynamics of its thermal decomposition and combustion were carefully characterized using milligram-scale testing in part I of this study. In the current work, Controlled Atmosphere Pyrolysis Apparatus II tests were performed on representative gram-sized oriented strand board samples at a range of radiant heat fluxes. An automated inverse analysis of the sample temperature data obtained in these tests was employed to determine the thermal conductivities of the undecomposed oriented strand board and condensed-phase products of its decomposition. A complete pyrolysis model was formulated for this material and used to predict the mass loss rates measured in the Controlled Atmosphere Pyrolysis Apparatus II experiments. These mass loss rate profiles were predicted well with the exception of the second mass loss rate peak observed at 65 kW m−2 of radiant heat flux, which was underpredicted. To further validate the model, cone calorimeter tests were performed on oriented strand board at 25 and 50 kW m−2 of radiant heat flux. The results of these tests, including both mass loss rate and heat release rate profiles, were predicted reasonably well by the model.

Radiant heat flux modelling for wildfires

2020 ◽  
Vol 175 ◽  
pp. 62-80 ◽  
Author(s):  
James E. Hilton ◽  
Justin E. Leonard ◽  
Raphaele Blanchi ◽  
Glenn J. Newnham ◽  
Kimberley Opie ◽  
...  
Keyword(s):  
Heat Flux ◽  
Radiant Heat ◽  
Radiant Heat Flux

Radiant heat flux to external surfaces from escaping and extrusive flashover flames

2003 ◽  
Vol 217 (2) ◽  
pp. 247-256 ◽  
Author(s):  
A Chen ◽  
J Francis
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Current Practice ◽  
Radiant Heat ◽  
Vertical Surface ◽  
Radiant Heat Flux ◽  
Hot Gas

Current practice when predicting safe separation distances between buildings is to assess the radiant hazard posed by flames and hot gas visible across the vent. The vent is treated as a radiating vertical surface with a representative temperature. A method is proposed for calculating the radiant heat flux to external surfaces from hot gas and extrusive flame emerging from a vent in a compartment wall containing post-flashover fire. An experimental study has been made to examine the validity of the method for extrusive flames unaffected by wind.

scholarly journals Response of stone wool–insulated building barriers under severe heating exposures

2018 ◽  
Vol 36 (4) ◽  
pp. 315-341 ◽  
Author(s):  
Blanca Andres ◽  
Karlis Livkiss ◽  
Juan P Hidalgo ◽  
Patrick van Hees ◽  
Luke Bisby ◽  
...  
Keyword(s):  
Heat Flux ◽  
Large Scale ◽  
Air Entrainment ◽  
Radiant Heat ◽  
Mechanical Degradation ◽  
Radiant Heat Flux ◽  
System A ◽  
Radiant Panel ◽  
Stone Wool ◽  
Temperature Exposure

This article presents the experimental results of stone wool–layered sandwich constructions, with either steel or gypsum claddings, tested under four different heating exposures: 7 kW/m2 incident radiant heat flux exposure, 60 kW/m2 incident radiant heat flux exposure, parametric time–temperature curve exposure and ISO 834 standard time–temperature exposure. The test apparatus used were a movable radiant panel system, a mid-scale furnace (1.5 m3) and a large-scale furnace (15 m3). The results show that reduced-scale tests are capable of reproducing the heat transferred through the construction at large scale provided there is limited mechanical degradation. The results indicate that the availability of oxygen is fundamental to the fire behaviour of the sandwich composites tested. Reactions occurring in stone wool micro-scale testing, such as oxidative combustion of the binder or crystallisation of the fibres, have a limited effect on the temperature increase when wool is protected from air entrainment.

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