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Influence of the Fabric Properties on the Protective Performance of Flame Resistant Clothing during the Body Movement

  • Ahmed Ghazy
Article
  • 24 Downloads

Abstract

Getting exposed to a flash fire can be a deadly situation until the worker manages to escape from the fire location. The movement of the worker induces his protective clothing to move periodically inwards and outwards with respect to the body, which significantly influences the protective performance of the clothing. In addition, fabric properties, particularly, fabric thickness and backside emissivity have also a crucial effect on heat release from the clothing to the body and eventually on the protection provided by the clothing. This paper investigates the effect of a variation in the thickness of Kevlar®/PBI form 0.3 mm to 1.8 mm and a variation in its backside emissivity from 0.9 to 0.1 on the protective performance of the fabric for a mean air gap of 3 mm between the clothing and body and a periodic motion amplitude ranges from 0.5 mm to 3 mm and a periodic motion frequency ranges from 0 rps to 4 rps. The results showed that the improvement in the clothing protective performance made by increasing the fabric thickness and/or decreasing the fabric backside emissivity is boosted by increasing the periodic motion frequency and reduced by increasing the periodic motion amplitude.

Keywords

Flame resistant fabrics Thermal protective performance Clothing periodic motion Conduction-radiation heat transfer Finite volume method 

List of Symbols

C

Heat capacity (J/kg K)

cP

Specific heat at constant pressure (J/kg K)

cv

Specific heat at constant volume (J/kg K)

\( \hat{e} \)

Unit vector in coordinate direction

f

Frequency (1/s)

h

Convective heat transfer coefficient (W/m2K)

I

Intensity (W/m2)

k

Thermal conductivity (W/mK)

P

Pre-exponential factor (1/s)

\( q^{\prime\prime} \)

Heat flux (W/m2)

\( \overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\rightharpoonup}$}} {r} \)

Position vector (m)

R

Ideal gas constant (J/mol K)

rps

Revolutions per second

\( \hat{s} \)

Unit vector in a given direction

T

Temperature (K)

t

Time (s)

y

Linear vertical coordinate (m)

Greek Symbols

\( \varphi \)

Quantitative measure of skin damage

\( \Delta E \)

Activation energy of skin (J/kmol)

\( \Delta \varOmega^{l} \)

Control angle

ε

Emissivity

\( \gamma \)

Extinction coefficient of the fabric (1/m)

\( \rho \)

Density (kg/m3) or surface reflectivity

\( \sigma \)

Stefan-Boltzmann constant, 5.67 × 10−8 (W/m2K4)

\( \omega \)

Blood perfusion rate (m3/s)/m3 of human tissue

Subscripts

air

Air

amb

Ambient conditions

b

Human blood/black body

cnv

Convection heat transfer

cr

Human body core

ep, ds, sc

Epidermis, dermis, subcutaneous human skin layers

exp

Exposure

fab

Fabric

fl

Flame

g

Hot gases

hot

Hot air gap

R

Radiation heat transfer

Superscript

A

Apparent

Notes

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Mechanical Engineering Department, College of EngineeringJouf UniversitySakakaSaudi Arabia

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