Estimates of Thermal Conductivity for 

Unconditioned and Conditioned 

Materials Used in Fire Fighters' 

Protective Clothing

Robert Vettori

NISTIR 7279
 

NISTIR 7279

Estimates of Thermal Conductivity for 

Unconditioned and Conditioned 

Materials Used in Fire Fighters' 

Protective Clothing

Robert Vettori

Building and Fire Research Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899-8661

November 2005

U.S. Department of Commerce

Carlos M. Gutierrez, Secretary

Technology Administration

Michelle O'Neill, Acting Under Secretary of

Commerce for Technology

National Institute of Standards and Technology

William A. Jeffrey, Director

Department of Homeland Security 

Michael Chertoff, Secretary

U.S. Fire Administration 

R, David Paulison, Administrator
 iii

Table of Contents 

Table of Contents...........................................................................................................................iii 

List of Figures................................................................................................................................ iv 

List of Tables ................................................................................................................................. iv 

Abstract........................................................................................................................................... 1 

1 Introduction............................................................................................................................. 2 

2 Test Apparatus ........................................................................................................................ 2 

3 Materials ................................................................................................................................. 4 

3.1 Test Specimens ............................................................................................................... 5 

4 Experimental Procedure.......................................................................................................... 6 

5 Uncertainty.............................................................................................................................. 7 

6 Results..................................................................................................................................... 9 

7 Conclusions............................................................................................................................. 9 

8 Acknowledgements............................................................................................................... 10 

9 References............................................................................................................................. 27 
 iv

List of Figures 

Figure 1 A schematic of the Rapid-k test section...................................................................... 21 

Figure 2 Calibration values for SRM 1450c as indicated by SRM certificate.......................... 21 

Figure 3 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Three Layer AraFlo® with Chambry Face Cloth thermal liner.............. 22 

Figure 4 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Two Layer AraFlo® with GlideTM Face Cloth thermal liner.................. 22 

Figure 5 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Black FusionTM outer shell...................................................................... 23 

Figure 6 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Black Basofil® Kevlar® outer shell....................................................... 23 

Figure 7 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Crosstech® on Nomex® moisture barrier. ............................................ 24 

Figure 8 Comparison of estimated thermal conductivity between unconditioned and 

conditioned PTFE on non woven Nomex® moisture barrier. .................................... 24 

Figure 9 Comparison of estimated thermal conductivity between unconditioned and 

conditioned PBI® Kevlar® Kombat® outer shell...................................................... 25 

Figure 10 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Nomex® III DefenderTM outer shell. ...................................................... 25 

Figure 11 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Nomex® IIIA Pajama Check moisture barrier. ..................................... 26 

Figure 12 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Aralite® thermal liner............................................................................. 26 

List of Tables 

Table 1 List of test materials...................................................................................................... 4 

Table 2 Unconditioned and conditioned test specimen dimensions and densities. ................... 5 

Table 3 Apparatus settings for specific mean specimen temperatures ...................................... 6 

Table 4 Number of single layers to form stacks of material for testing..................................... 7 

Table 5 Uncertainty in Experimental Data ................................................................................ 8 

Table 6 Thermal conductivity data of unconditioned three layer AraFlo® with 

Chambry face cloth thermal liner. .............................................................................. 11 

Table 7 Thermal conductivity data of conditioned three layer AraFlo® with Chambry 

face cloth thermal liner. .............................................................................................. 11 

Table 8 Thermal conductivity data of unconditioned two layer AraFlo® with GlideTM 

face cloth thermal liner. .............................................................................................. 12 
 v

Table 9 Thermal conductivity data of conditioned two layer AraFlo® with GlideTM 

face cloth thermal liner. .............................................................................................. 12 

Table 10 Thermal conductivity data of unconditioned Black FusionTM outer shell. ................. 13 

Table 11 Thermal conductivity data of conditioned Black FusionTM outer shell. ..................... 13 

Table 12 Thermal conductivity data of unconditioned Black Basofil® Kevlar® outer 

shell............................................................................................................................. 14 

Table 13 Thermal conductivity data of conditioned Black Basofil® Kevlar® outer 

shell............................................................................................................................. 14 

Table 14 Thermal conductivity data of unconditioned Crosstech® on Nomex® 

moisture barrier........................................................................................................... 15 

Table 15 Thermal conductivity data of conditioned Crosstech® on Nomex® moisture 

barrier.......................................................................................................................... 15 

Table 16 Thermal conductivity data of unconditioned PTFE on non woven Nomex® 

moisture barrier........................................................................................................... 16 

Table 17 Thermal conductivity data of conditioned PTFE on non woven Nomex® 

moisture barrier........................................................................................................... 16 

Table 18 Thermal conductivity data of unconditioned PBI® Kevlar® Kombat® outer 

shell*........................................................................................................................... 17 

Table 19 Thermal conductivity data of conditioned PBI® Kevlar® Kombat® outer 

shell............................................................................................................................. 17 

Table 20 Thermal conductivity data of unconditioned Nomex® III DefenderTM outer 

shell*........................................................................................................................... 18 

Table 21 Thermal conductivity data of conditioned Nomex® III DefenderTM outer shell........ 18 

Table 22 Thermal conductivity data of unconditioned Nomex® IIIA Pajama Check 

moisture barrier*......................................................................................................... 19 

Table 23 Thermal conductivity data of conditioned Nomex® IIIA Pajama Check 

moisture barrier........................................................................................................... 19 

Table 24 Thermal conductivity data of unconditioned Aralite® thermal liner*. ...................... 20 

Table 25 Thermal conductivity data of conditioned Aralite® thermal liner. ............................ 20 
 1

Estimates of Thermal Conductivity for Unconditioned and Conditioned Materials Used in Fire 

Fighters' Protective Clothing 

By 

Robert Vettori 

Abstract 

Fire fighters' protective clothing provides a limited amount of thermal protection from 

environmental exposures produced by fires. This level of thermal protection varies with the 

design, materials, construction, and fit of the protective garments. Limits of thermal protection 

may be analyzed using the thermophysical properties of garment materials. However, little 

information is currently available for analyzing and predicting protective garment thermal 

performance. To address this need, a research effort was begun to measure the thermal 

properties of fire fighters' protective clothing materials. This report presents thermal 

conductivity data for ten materials used in fabricating fire fighters' protective clothing. These 

materials included: (a) outer shell fabrics, (b) moisture barriers, and (c) thermal liner battings. 

The thermal conductivity data for each material was obtained twice. Once when the material 

was new and once after the material had undergone a conditioning process of five washings and 

dryings by a contract cleaner that specializes in cleaning, decontaminating and repair of fire 

fighters' protective clothing. The thermal conductivity of individual protective clothing materials 

was measured using the test procedure specified in ASTM C 518 Standard Test Method for 

Steady-State Thermal Transmission Properties by Means of Heat Flow Meter Apparatus. 

Measurements producing estimates of thermal conductivity for a single layer of materials were 

carried out at mean test temperatures of 20 °C (68 °F), 48 °C (118 °F), 55 °C (131 °F), and 72 °C 

(162 °F). No visible physical changes were observed with any of the materials tested at these 

temperatures. For unconditioned materials, the thermal conductivity estimates ranged from 

0.034 W/m K to 0.093 W/m K. For the conditioned materials the thermal conductivity estimates 

ranged from 0.033 W/m K to 0.089 W/m K. Thermal conductivity values increased for all 

materials as mean test temperatures were increased. 

Key words: fires, fire fighters, heat transfer, protective clothing, test method, thermal analysis, 

thermal conductivity, 
 2

1 Introduction 

The thermal performance of fire fighters' protective clothing is primarily based on the 

thermophysical properties of the materials used to construct the clothing. Analysis and 

prediction of protective clothing thermal performance requires the use of numerical parameters 

for thermophysical properties for all materials used in garment construction. Currently, little 

information is available for making detailed studies of protective clothing thermal performance. 

The physical properties used for thermal analysis and predictions are: (a) thermal conductivity; 

(b) specific heat; (c) density; and (d) the thermal spectral properties of emissivity, transmissivity, 

and reflectivity [1]. This paper discusses measurements of thermal conductivity. Data collected 

on the emissivity, transmissivity, and reflectivity of materials will be described in a separate 

report [2]. 

This study builds upon the work performed by Lawson and Pinder [3]. They give estimates for 

the thermal conductivity of 10 different materials used in the construction of fire fighters' 

protective clothing. All measurements taken by Lawson and Pinder were on new or unused 

material as delivered by the manufacturer. In this study, four of the materials used by Lawson 

and Pinder and six additional materials are investigated. 

Estimates of thermal conductivity for the six additional materials were determined. Then the six 

new materials and the four materials from Lawson and Pinder were conditioned by undergoing a 

process of five washings and dryings by a contract cleaner that specializes in cleaning, 

decontaminating and repair of fire fighters' protective clothing. Many of the test methods used 

for the certification of fire fighters’ protective clothing by The National Fire Protection 

Association (NFPA) 1971 Standard on Protective Ensemble for Structural Fire Fighting [4] 

require that the material pass the test method when new and after undergoing the conditioning 

process of five washings and dryings. 

Thermal conductivity of a material relates to the rate of heat transfer through the material. Heat 

transfer by this mechanism is based on the transfer of energy of motion between adjacent 

molecules. This property will vary with the amount of heat energy that a material is exposed to 

and is therefore moderately temperature dependent. 

Thermal conductivity will change for materials as the thermal exposure changes. This study has 

developed estimates of thermal conductivity for protective clothing materials over a range of 

temperatures below where visible physical changes occur. Observed physical changes in 

materials would indicate that the materials are beginning to degrade. As a result, the steady state 

measurement of the materials would be compromised. Testing was carried out at the following 

temperatures: 20 °C (68 °F), 48 °C (118 °F), 55 °C (131 °F), and 72 °C (162 °F). 

2 Test Apparatus 

Thermal conductivity measurements were made using a commercially manufactured test 

apparatus. The apparatus used was a Holometrix, Rapid-k, Model VT400-A1

 with computer 

 

1

 Certain commercial equipment, instruments, or materials are identified in this paper in order to adequately specify 

the experimental procedure. Such identification does not imply recommendation or endorsement by the National 

Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily 

the best available for the purpose. 
 3

control and data logging. This test equipment was operated in accordance with ASTM C 518, 

Standard Test Method for Steady-State Thermal Transmission Properties by Means of Heat Flow 

Meter Apparatus [5]. 

The ASTM C 518 standard is a comparative method for measuring thermal conductivity that is 

based on apparatus calibrations obtained from a Standard Reference Material. The heat flow 

meter apparatus establishes a steady state one-dimensional heat flux through the test specimen 

that is located between two parallel plates that are controlled at constant but different 

temperatures. Fourier's law of heat conduction, Equation 1, is used to calculate thermal 

conductivity. Computer software used for calculating thermal conductivity is based on 

ASTM C 1045, Practice for Calculating Thermal Transmission Properties for Steady State 

Conditions [6]. 

Figure 1 shows the principle of the apparatus operation. A specimen is placed in the test 

chamber between the two plates. The plates attain different, but constant temperatures. Since 

there is a temperature difference across the specimen, heat flows through the specimen from the 

hotter to the cooler plate. When the apparatus reaches thermal equilibrium, the temperature of 

each plate, the temperature gradient across the specimen, and the heat flow through the specimen 

are constant. At thermal equilibrium, thermal conductivity can be measured. 

The heat flow across the specimen is given by: 

X

T

q A

Δ

Δ = λ Equation 1 

where q = heat flow W

λ = thermal conductivity of the specimen m K

W

A = area through which the heat flows 2m

ΔT = temperature difference across the specimen K

ΔX = thickness of the specimen m

The heat flow transducer measures the heat flow through the specimen. The signal of the heat 

flow transducer is a voltage which is proportional to the heat flow through the transducer. In the 

apparatus, the area of the heat flow transducer represents the area through which the heat flows 

to the transducer and is the same for all specimens. Equation 1 can be re-written in the following 

form: 
 4

T

V N

X Δ = Δ

λ Equation 2 

where V = the transducer voltage V

N = the calibration factor that relates the voltage signal of the heat flow transducer to 

the heat flux through the specimen. m V

W

2

The apparatus was calibrated using NIST Standard Reference Material (SRM) 1450c, a fibrous 

glass board insulation [7]. This SRM measured 305 mm x 305 mm (12 in x 12 in) and 24.7 mm 

(0.972 in) thick. The SRM density was 158.09 kg/m3 (9.87 lb/ft3). The primary thermal 

conductivity calibration for the SRM at 24 °C (75 °F) was 0.0334 W/m K. Figure 2 shows a 

temperature calibration plot for SRM 1450c over the range from 10 °C (50 °F) to 80 °C (194 °F). 

These data show that the SRM's thermal conductivity has a linear relationship over the 

temperature calibration range and the range of temperatures used for testing the fire fighter 

protective clothing materials. 

3 Materials 

Ten different materials were tested in this study, see Table 1 below. All of these materials are 

currently used as components of fire fighters' protective clothing. Of the materials tested, three 

were moisture barriers, four were outer shell fabrics, and three were thermal liners. Even though 

this group of materials does not cover all of the materials currently used to fabricate fire fighters' 

protective clothing, it does represent a significant fraction of the materials presently in use. All 

materials used were received from the manufacturer rolled as bolts on thick walled paper tubes. 

Table 1 List of test materials 

Material* Use 

Three Layer AraFlo® with Chambry Face Cloth Thermal Liner 

Two Layer AraFlo® with GlideTM Face Cloth Thermal Liner 

Aralite® Thermal Liner 

Black FusionTM Outer Shell 

Black Basofil® Kevlar® Outer Shell 

PBI® Kevlar® KombatTM Outer Shell 

Nomex® III DefenderTM Outer Shell 

Crosstech® on Nomex® Moisture Barrier 

PTFE on non woven Nomex® Moisture Barrier 

Nomex® IIIA Pajama Check Moisture Barrier 

* AraFlo® is a registered trademark of Lion Apparel, Inc. 

GlideTM and FusionTM are trademarks of Safety Components Fabric Technologies, Inc. 

Aralite® is a registered trademark of Southern Mills. 

KombatTM and DefenderTM are trademarks of Southern Mills. 

Basofil® is a registered trademark of Basofil Fibers, LLC. 

Kevlar® and Nomex® are registered trademarks of E. I. Dupont. 

Crosstech® is a registered trademark of W. L. Gore and Associates. 

PBI® is a registered trademark of the Celanese Corporation. 
 5

Aralite, PBI Kevlar Kombat, Nomex III Defender, and Nomex IIIA Pajama Check were the four 

materials that were also included in the Lawson and Pinder study. 

3.1 Test Specimens 

Test specimens were cut from the rolls of materials received from the manufacturers. The 

Rapid-k test apparatus requires that specimens measure 305 mm x 305 mm (12 in x 12 in). 

Specimen outlines were marked on the materials using a felt tipped ink pen, and then each 

specimen was cut from the roll using scissors. Specimens were cut from each material and were 

stacked until they reached a height of 25 mm (1 in). The number of cut specimens varied 

between different materials based on the material's thickness. After all specimens were cut, three 

specimens were randomly selected from each set of materials. The specimen's dimensions were 

measured using a ruler for large dimensions and a micrometer for thickness. There was a 

minimum of twelve measurements made for each specimen dimension. Average dimensions 

were then calculated. In addition, each specimen was weighed using a laboratory balance to 

determine its mass. The density for each material was calculated using the collected data. See 

the results in Table 2 below. Thermal conductivity measurements were then performed on the 

test specimens using the test apparatus as described in Section 4 below. These test specimens 

were then conditioned by undergoing a process of five washings and dryings by a contract 

cleaner that specializes in cleaning, decontaminating and repair of fire fighter protective clothing. 

After this conditioning process, the test specimens were again measured and weighed and the 

density calculated. The results of these measurements on the conditioned test specimens are also 

in Table 2 below. 

Table 2 Unconditioned and conditioned test specimen dimensions and densities. 

Material Use Unconditioned 

(New) 

Conditioned 

(Washed) 

 Thickness 

(m) 

Density 

(kg/m3

) 

Thickness 

(m) 

Density 

(kg/m3) 

Three Layer AraFlo® with Chambry 

Face Cloth 

Thermal liner 0.00312 89 0.00353 80 

Two Layer AraFlo® with GlideTM 

Face Cloth 

Thermal liner 0.00223 121 0.00249 103 

Aralite® Thermal liner 0.00359 74 0.00368 70 

Black FusionTM Outer shell 0.00069 344 0.00082 293 

Black Basofil® Kevlar® Outer shell 0.00077 352 0.00083 324 

PBI® Kevlar® KombatTM Outer shell 0.00080 322 0.00079 315 

Nomex® III DefenderTM Outer shell 0.00082 317 0.00082 307 

Crosstech® on Nomex® Moisture Barrier 0.00050 335 0.00055 299 

PTFE on non woven Nomex® Moisture Barrier 0.00114 134 0.00126 117 

Nomex® IIIA Pajama Check Moisture Barrier 0.00052 317 0.00052 300 
 6

4 Experimental Procedure 

Thermal conductivity for each of the materials was measured at four different temperatures, 

20 °C (68 °F), 48 °C (118 °F), 55 °C (131 °F), and 72 °C (162 °F). These temperatures were 

selected from ASTM C 1055, Standard Guide for Heated Systems Surface Conditions That 

Produce Contact Burn Injuries [8], and cover the range of temperatures that produce burn 

injuries. The 20 °C (68 °F) temperature represents room temperature, 48 °C (118 °F) represents 

a human tissue temperature at which a first degree burn occurs, 55 °C (131 °F) is the human 

tissue temperature that is likely to cause a second degree burn [9], and 72 °C (162 °F) is the 

human tissue temperature at which an instantaneous burn injury is likely to occur. These four 

temperatures resulted in different temperature settings for each of the heat flow meter plates. 

The mean temperature for each of the test conditions was established by adjusting the thermally 

controlled apparatus plates so there would be a temperature difference of 15 °C (27 °F) between 

the plates. Apparatus plate temperature settings for each of the mean test temperatures is shown 

in Table 3 below. 

Table 3 Apparatus settings for specific mean specimen temperatures 

Plate TMEAN = 20 °C TMEAN = 48 °C TMEAN = 55 °C TMEAN = 72 °C 

Upper 27.5 °C 55.5 °C 62.5 °C 79.5 °C 

Lower 12.5 °C 40.5 °C 47.5 °C 64.5 °C 

The specimen thickness was changed for certain sets of tests to obtain thermal conductivity 

values for estimating the single layer thickness of each protective clothing material. The Rapid-k 

apparatus is not capable of measuring thermal conductivity of a single layer thickness of a fabric 

or other protective garment material. Therefore, a test plan was developed to produce data 

forming a linear relationship for thermal conductivity relative to specimen thickness. This 

method would allow for calculating an estimate of thermal conductivity for a single thickness or 

layer of material. The following procedure was used to develop these estimates. This procedure 

was done on the material when it was first received from the manufacturing and then repeated 

after it had undergone the conditioning process. 

An approximately 25 mm high stack of each material was constructed by placing single 

layers of the same material on top of each other. Each stack of material was tested at 

each of the given mean test temperatures, and the thermal conductivity was recorded. 

For the next set of tests, 1/3 of the materials layers were removed leaving a stack 

consisting of 2/3 of the original number of material layers. Each stack of material was 

again tested at each of the mean test temperatures with the thermal conductivity being 

recorded. 

The final series of tests were conducted with the material thickness consisting of 1/3 of 

the original layers of material. Again each stack of material was tested at each of the 

mean temperatures, and the thermal conductivity was measured. 
 7

Table 4 below provides information on the number of layers used to obtain the test thickness for 

each stack of materials. 

Table 4 Number of single layers to form stacks of material for testing 

 Thickness 

Material Full Thickness 2/3 1/3 

Three Layer AraFlo® with Chambry Face Cloth 11 8 4 

Two Layer AraFlo® with GlideTM Face Cloth 16 10 5 

Aralite® 9 6 3 

Black FusionTM 55 36 18 

Black Basofil® Kevlar® 37 24 12 

PBI® Kevlar® KombatTM 34 23 11 

Nomex® III DefenderTM 35 23 12 

Crosstech® on Nomex® 64 42 21 

PTFE on non woven Nomex® 28 18 9 

Nomex® IIIA Pajama Check 61 39 19 

Three replicate tests were conducted on each of the materials, at each mean temperature setting, 

and each specimen stack thickness. Before material specimens can be tested, SRM 1450c is used 

to calibrate the test apparatus at the four selected mean test temperatures. Calibration values for 

SRM 1450c are shown in Figure 2. Calibration using the SRM provides the apparatus computer 

program with a reference thermal conductivity for the mean temperature setting. This reference 

value is calculated from the response of the apparatus heat flow meter. After the calibration is 

completed and verified, testing is begun. The mass of each test specimen stack is measured and 

recorded. The specimen stack is placed into the test apparatus and positioned on the lower plate. 

The test apparatus is closed by raising the lower plate and specimen until the specimen's top 

surface is in direct contact with the upper plate. The specimen and lower plate are locked into 

place. A transducer attached to the lower plate of the apparatus provides a measurement of 

specimen thickness, and specimen density is calculated using the mass data developed earlier. 

The test apparatus remains in an automatic mode throughout the test period when the specimen 

reaches a steady-state temperature condition. At this point, the computer program calculates and 

records the specimen's thermal conductivity. 

5 Uncertainty 

Measurement uncertainty for thermal conductivity with the ASTM C 518 test apparatus and 

procedure is significantly affected by the calibrations with SRM 1450c. Uncertainty values for 

SRM 1450c were reported to be less than ±2 % of the mean certified value across the 

temperature range used for certification [7]. A series of replicate comparative calibration tests 

was carried out during this study to better characterize test variability using the Rapid-k and 

SRM 1450c. These calibration tests were conducted at each of the four test temperature settings, 

20 °C (68 °F), 48 °C (118 °F), 55 °C (131 °F), and 72 °C (162 °F). Results from these tests 

showed the following maximum deviations from the certified SRM values: 1 % at 20 °C (68 °F), 

1 % at 48 °C (118 °F), 2 % at 55 °C (131 °F), and 5 % at 72 °C (162 °F). These calibration data 
 8

indicate that measurement uncertainty is increasing as test temperatures are increased. This 

uncertainty becomes a component of uncertainty for thermal conductivity measurements reported 

in this document. The Rapid-k test apparatus precision reported by the manufacturer indicates 

that apparatus reproducibility is on the order of ±1 % [10]. Additionally, inter-laboratory 

imprecision reported in the ASTM C 518 standard, for thermal conductivity measurements using 

various types of insulating materials, ranged from 1.9 % to 10.5 % at a two standard deviation 

level. 

There are different components of uncertainty in the thickness and mass of the materials data 

reported here. Uncertainties are grouped into two categories according to the method used to 

estimate them. Type A uncertainties are those which are evaluated by statistical methods, and 

Type B are those which are evaluated by other means [11]. Type B analysis of systematic 

uncertainties involves estimating the upper (+ a) and lower (- a) limits for the quantity in 

question such that the probability that the value would be in the interval (± a) is essentially 

100 percent. After estimating uncertainties by either Type A or B analysis, the uncertainties are 

combined in quadrature to yield the combined standard uncertainty. Multiplying the combined 

standard uncertainty by a coverage factor of two results in the expanded uncertainty which 

corresponds to a 95 percent confidence interval. 

Components of uncertainty are tabulated in Table 5 below. Some of these components, such as 

temperature elements, are derived from instrument specifications, while other components, such 

as mass and dimensional measurements include past experience. 

Table 5 Uncertainty in Experimental Data 

Component Standard 

Uncertainty 

Combined Standard 

Uncertainty 

Total Expanded 

Uncertainty 

Temperature 

 Repeatability 

 Random 

± 2 % 

± 2 % 

± 3 % ± 6 % 

Volume 

 Thickness 

 Length 

 Width 

± 1 % 

± 1 % 

± 1 % 

± 2 % ± 4 % 

Mass 

 Repeatability 

 Random 

± 1 % 

± 1 % 

± 1 % ± 3 % 

Density 

 Volume 

 Mass 

± 4 % 

± 3 % 

± 5 % ± 10 % 

Thermal Conductivity 

 Calibration 

 Repeatability 

 Random 

± 5 % 

± 2 % 

± 4 % 

± 7 % ± 13 % 
 9

6 Results 

Data from each of the test conditions, temperature and number of material layers, were reduced 

by linear regression, and the single layer thermal conductivity was estimated using the generated 

linear equation for each material and condition combination. Test results for both unconditioned 

and conditioned materials are shown in Table 6 through Table 25. These data show that the 

average thermal conductivity values generally increased as exposure temperature increases for 

both unconditioned and conditioned materials. The uncertainty associated with each of the 

single layer thermal conductivity values was determined by a method described by Natrella [12]. 

The effect of the conditioning process caused an increase in material thickness in seven out of 

the 10 materials. One moisture barrier, Nomex® IIA Pajama Check, and two of the outer shell 

materials, Nomex® III Defender and PBI® Kevlar® Kombat®, did not show an increase in 

thickness. All materials showed a decrease in density. This decrease in density was caused by a 

combination of increase in the material thickness along with some loss of actual material in the 

conditioning process. 

Except for the Black FusionTM outer shell material, there did not appear to be any significant 

difference between unconditioned and conditioned materials. This would indicate that the 

insulative properties of the materials are essentially the same before and after this conditioning 

process. Figure 3 through Figure 12 compare unconditioned versus conditioned thermal 

conductivities for each material at the four temperatures for which thermal conductivity was of 

interest. A possible reason for the difference in the Black FusionTM results may be the increase 

in material thickness after under going the conditioning process. Black FusionTM thickness 

increased approximately 17%, the greatest increase of any material. 

As a comparison, the following are thermal conductivity values reported for some other similar 

materials. Cotton, 0.071 W/m K [13] and 0.0716 W/m K [14]; wool felt, 0.0519 W/m K [15]; 

wool 0.0540 W/m K [13] and 0.0528 W/m K [14]; protective clothing shell fabric, 

0.0470 W/m K [16]; mineral fiber blanket 0.038 W/m K [17]. Thermal conductivity values for 

these materials generally fall within the range measured for materials studied in this project. 

7 Conclusions 

Ten materials typically used in the fabrication of fire fighters' protective clothing were tested to 

develop thermal conductivity estimates. Thermal conductivity was measured twice for all 

materials. Once when the material was new and once after the material had undergone a 

conditioning process of five washings and dryings by a contract cleaner that specializes in 

cleaning, decontaminating and repair of fire fighters' protective clothing. These fire fighters' 

protective clothing materials included outer shell fabrics, moisture barriers, and thermal liner 

batting. Thermal conductivity was measured using a commercially manufactured test apparatus. 

Testing followed procedures presented in ASTM C 518. The materials were tested at a mean 

room temperature of 20 °C (68 °F) and across a range of temperatures, 48 °C (118 °F), 55 °C 

(131 °F), and 72 °C (162 °F), known to produce burn injuries in humans. 

Thermal conductivity values generated in this study along with the work of Lawson and Pinder 

will provide an initial set of data of actual protective clothing materials that may be used by 
 10

computer models for predicting the thermal performance of fire fighters' protective clothing. 

Although this data is over a limited temperature range, some differences were measured. In 

general, little difference was measured between conditioned and unconditioned materials over 

this temperature range. It would be of interest to determine the thermal conductivity at greater 

temperatures, but below the temperature where material degradation begins. Current computer 

based heat transfer models also require input data for specific heat, emissivity, transmissivity, 

and reflectivity. Additional work is being conducted to develop these thermal properties for fire 

fighters' protective clothing. 

8 Acknowledgements 

Appreciation is extended to Mr. Robert T. McCarthy of the United States Fire Administration for 

assistance provided during this project. The United States Fire Administration provided funding 

for the National Institute of Standards and Technology, Building and Fire Research Laboratory 

to study the thermal properties of fire fighters' protective clothing. Appreciation is extended to 

Mr. Donald Aldridge of Lion Apparel for supplying the six additional materials. 
 11

Table 6 Thermal conductivity data of unconditioned three layer AraFlo® with 

Chambry face cloth thermal liner. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 11 0.0331 0.0333 0.0339 0.0334 

 8 0.0335 0.0339 0.0339 0.0338 

 4 0.0335 0.0335 0.0337 0.0335 

 1 0.034±0.001

48 11 0.0361 0.0351 0.0376 0.0363 

 8 0.0393 0.0380 0.0379 0.0384 

 4 0.0402 0.0393 0.0398 0.0397 

 1 0.041±0.002

55 11 0.0370 0.0346 0.0381 0.0366 

 8 0.0408 0.0395 0.0390 0.0398 

 4 0.0447 0.0413 0.0420 0.0427 

 1 0.045±0.003

72 11 0.0426 0.0426 0.0404 0.0419 

 8 0.0431 0.0425 0.0421 0.0426 

 4 0.0495 0.0449 0.0459 0.0468 

 1 0.049±0.003

Table 7 Thermal conductivity data of conditioned three layer AraFlo® with 

Chambry face cloth thermal liner. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 11 0.0344 0.0350 0.0339 0.0344 

 8 0.0340 0.0337 0.0334 0.0337 

 4 0.0343 0.0340 0.0341 0.0341 

1 0.034±0.001

48 11 0.0385 0.0393 0.0371 0.0383 

 8 0.0381 0.0371 0.0379 0.0377 

 4 0.0404 0.0403 0.0401 0.0403 

1 0.041±0.002

55 11 0.0379 0.0370 0.0365 0.0372 

 8 0.0384 0.0373 0.0385 0.0381 

 4 0.0430 0.0424 0.0425 0.0426 

1 0.045±0.002

72 11 0.0380 0.0368 0.0418 0.0389 

 8 0.0431 0.0360 0.0427 0.0406 

 4 0.0466 0.0467 0.0456 0.0463 

1 0.049±0.005
 12

Table 8 Thermal conductivity data of unconditioned two layer AraFlo® with GlideTM 

face cloth thermal liner. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 16 0.0355 0.0351 0.0356 0.0354 

 10 0.0352 0.0353 0.0354 0.0353 

 5 0.0353 0.0349 0.0361 0.0354 

1 0.035±0.001

48 16 0.0389 0.0389 0.0384 0.0387 

 10 0.0401 0.0404 0.0406 0.0404 

 5 0.0415 0.0405 0.0422 0.0414 

1 0.043±0.001

55 16 0.0388 0.0395 0.0383 0.0388 

 10 0.0416 0.0418 0.0423 0.0419 

 5 0.0443 0.0423 0.0445 0.0437 

1 0.046±0.001

72 16 0.0402 0.0405 0.0407 0.0405 

 10 0.0439 0.0437 0.0447 0.0441 

 5 0.0494 0.0458 0.0491 0.0481 

1 0.051±0.002

Table 9 Thermal conductivity data of conditioned two layer AraFlo® with GlideTM 

face cloth thermal liner. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 16 0.0355 0.0358 0.0345 0.0353 

 10 0.0356 0.0352 0.0351 0.0353 

 5 0.0353 0.0362 0.0347 0.0354 

1 0.036±0.001

48 16 0.0381 0.0385 0.0389 0.0385 

 10 0.0406 0.0408 0.0409 0.0408 

 5 0.0418 0.0424 0.0420 0.0420 

1 0.044±0.001

55 16 0.0374 0.0390 0.0392 0.0386 

 10 0.0416 0.0420 0.0422 0.0419 

 5 0.0440 0.0445 0.0451 0.0445 

1 0.047±0.001

72 16 0.0387 0.0412 0.0385 0.0395 

 10 0.0413 0.0449 0.0441 0.0434 

 5 0.0482 0.0485 0.0501 0.0490 

1 0.053±0.003
 13

Table 10 Thermal conductivity data of unconditioned Black FusionTM outer shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 55 0.0587 0.0604 0.0597 0.0596 

 36 0.0592 0.0606 0.0619 0.0606 

 18 0.0588 0.0586 0.0655 0.0610 

1 0.062±0.005

48 55 0.0662 0.0637 0.0677 0.0659 

 36 0.0678 0.0695 0.0695 0.0689 

 18 0.0702 0.0691 0.0768 0.0720 

1 0.075±0.005

55 55 0.0682 0.0665 0.0698 0.0682 

 36 0.0750 0.0724 0.0722 0.0732 

 18 0.0755 0.0737 0.0831 0.0774 

1 0.082±0.006

72 55 0.0729 0.0660 0.0724 0.0704 

 36 0.0803 0.0769 0.0777 0.0783 

 18 0.0835 0.0819 0.0921 0.0858 

1 0.093±0.007

Table 11 Thermal conductivity data of conditioned Black FusionTM outer shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 55 0.0579 0.0555 0.0562 0.0565 

 36 0.0585 0.0559 0.0564 0.0569 

 18 0.0567 0.0552 0.0552 0.0557 

1 0.056±0.002

48 55 0.0602 0.0602 0.0607 0.0604 

 36 0.0655 0.0650 0.0636 0.0647 

 18 0.0663 0.0649 0.0654 0.0656 

1 0.069±.0.002

55 55 0.0599 0.0610 0.0632 0.0613 

 36 0.0686 0.0673 0.0654 0.0671 

 18 0.0701 0.0686 0.0692 0.0693 

1 0.074±0.003

72 55 0.0559 0.0586 0.0622 0.0589 

 36 0.0717 0.0677 0.0653 0.0682 

 18 0.0761 0.0751 0.0752 0.0754 

1 0.083±0.005
 14

Table 12 Thermal conductivity data of unconditioned Black Basofil® Kevlar® outer 

shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 37 0.0594 0.0613 0.0614 0.0607 

 24 0.0594 0.0589 0.0603 0.0596 

 12 0.0611 0.0599 0.0594 0.0601 

 1 0.060±0.002

48 37 0.0675 0.0670 0.0676 0.0674 

 24 0.0671 0.0673 0.0689 0.0680 

 12 0.0721 0.0708 0.0704 0.0711 

 1 0.072±0.002

55 37 0.0702 0.0695 0.0698 0.0698 

 24 0.0725 0.0702 0.0721 0.0718 

 12 0.0769 0.0758 0.0755 0.0761 

 1 0.078±0.002

72 37 0.0689 0.0687 0.0685 0.0687 

 24 0.0761 0.0752 0.0763 0.0762 

 12 0.0838 0.0838 0.0825 0.0834 

 1 0.090±0.001

Table 13 Thermal conductivity data of conditioned Black Basofil® Kevlar® outer 

shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 37 0.0583 0.0604 0.0604 0.0597 

 24 0.0590 0.0593 0.0604 0.0596 

 12 0.0599 0.0563 0.0570 0.0578 

1 0.057±0.003

48 37 0.0637 0.0658 0.0660 0.0652 

 24 0.0676 0.0676 0.0688 0.0680 

 12 0.0709 0.0671 0.0682 0.0687 

1 0.071±0.004

55 37 0.0666 0.0678 0.0689 0.0678 

 24 0.0703 0.0701 0.0730 0.0711 

 12 0.0749 0.0711 0.0720 0.0727 

1 0.076±0.005

72 37 0.0656 0.0656 0.0690 0.0667 

 24 0.0747 0.0768 0.0787 0.0767 

 12 0.0823 0.0809 0.0792 0.0808 

1 0.089±0.009
 15

Table 14 Thermal conductivity data of unconditioned Crosstech® on Nomex® 

moisture barrier. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 64 0.0490 0.0492 0.0501 0.0493 

 42 0.0488 0.0491 0.0488 0.0489 

 21 0.0492 0.0496 0.0491 0.0493 

 1 0.049±.0.001

48 64 0.0564 0.0548 0.0575 0.0561 

 42 0.0555 0.0552 0.0561 0.0556 

 21 0.0575 0.0570 0.0570 0.0572 

 1 0.057±0.002

55 64 0.0588 0.0569 0.0578 0.0576 

 42 0.0581 0.0577 0.0582 0.0580 

 21 0.0612 0.0600 0.0599 0.0604 

 1 0.061±0.002

72 64 0.0591 0.0557 0.0572 0.0573 

 42 0.0617 0.0615 0.0614 0.0615 

 21 0.0658 0.0652 0.0651 0.0654 

 1 0.069±0.002

Table 15 Thermal conductivity data of conditioned Crosstech® on Nomex® moisture 

barrier. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 64 0.0475 0.0467 0.0479 0.0473 

 42 0.0481 0.0489 0.0490 0.0487 

 21 0.0480 0.0482 0.0478 0.0480 

1 0.049±0.001

48 64 0.0553 0.0529 0.0542 0.0541 

 42 0.0561 0.0558 0.0565 0.0561 

 21 0.0561 0.0565 0.0557 0.0561 

1 0.057±0.002

55 64 0.0558 0.0533 0.0567 0.0553 

 42 0.0582 0.0575 0.0577 0.0578 

 21 0.0604 0.0589 0.0592 0.0595 

1 0.062±0.002

72 64 0.0492 0.0507 0.0546 0.0515 

 42 0.0599 0.0590 0.0578 0.0589 

 21 0.0648 0.0648 0.0630 0.0642 

1 0.070±0.004
 16

Table 16 Thermal conductivity data of unconditioned PTFE on non woven Nomex® 

moisture barrier. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 28 0.0336 0.0334 0.0332 0.0334 

 18 0.0334 0.0335 0.0335 0.0335 

 9 0.0340 0.0338 0.0344 0.0341 

1 0.034±0.001

48 28 0.0372 0.0372 0.0361 0.0368 

 18 0.0384 0.0387 0.0389 0.0386 

 9 0.0397 0.0392 0.0400 0.0396 

1 0.041±0.001

55 28 0.0373 0.0383 0.0369 0.0375 

 18 0.0400 0.0400 0.0402 0.0399 

 9 0.0420 0.0412 0.0417 0.0416 

1 0.044±0.001

72 28 0.0409 0.0392 0.0388 0.0396 

 18 0.0428 0.0428 0.0435 0.0429 

 9 0.0457 0.0444 0.0450 0.0450 

1 0.048±0.002

Table 17 Thermal conductivity data of conditioned PTFE on non woven Nomex® 

moisture barrier. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 28 0.0336 0.0333 0.0334 0.0334 

 18 0.0334 0.0327 0.0338 0.0333 

 9 0.0332 0.0334 0.0337 0.0334 

1 0.033±0.001

48 28 0.0398 0.0377 0.0380 0.0385 

 18 0.0388 0.0375 0.0397 0.0387 

 9 0.0393 0.0392 0.0390 0.0392 

1 0.039±0.002

55 28 0.0386 0.0365 0.0387 0.0380 

 18 0.0398 0.0397 0.0398 0.0398 

 9 0.0409 0.0414 0.0410 0.0411 

1 0.043±0.001

72 28 0.0409 0.0370 0.0385 0.0388 

 18 0.0413 0.0421 0.0417 0.0417 

 9 0.0444 0.0453 0.0451 0.0449 

1 0.047±0.002
 17

Table 18 Thermal conductivity data of unconditioned PBI® Kevlar® Kombat® outer 

shell*. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 34 0.0575 0.0583 0.0579 

 23 0.0564 0.0564 0.0564 

 11 0.0509 0.0508 0.0509 

 1 0.048±0.003

48 34 0.0668 0.0655 0.0622 

 23 0.0671 0.0672 0.0671 

 11 0.0686 0.0686 0.0686 

 1 0.070±0.001

55 34 0.0644 0.0645 0.0645 

 23 0.0669 0.0670 0.0669 

 11 0.0705 0.0706 0.0706 

 1 0.073±0.001

72 34 0.0675 0.0676 0.0676 

 23 0.0755 0.0755 0.0755 

 11 0.0786 0.0780 0.0783 

 1 0.084±0.005

 * Data from Lawson and Pinder [3] 

Table 19 Thermal conductivity data of conditioned PBI® Kevlar® Kombat® outer 

shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 34 0.0552 0.0586 0.0572 0.0568 

 23 0.0474 0.0553 0.0548 0.0525 

 11 0.0496 0.0528 0.0571 0.0532 

1 0.051±0.007

48 34 0.0606 0.0637 0.0628 0.0624 

 23 0.0539 0.0623 0.0628 0.0597 

 11 0.0594 0.0630 0.0689 0.0637 

1 0.063±0.008

55 34 0.0604 0.0660 0.0644 0.0639 

 23 0.0567 0.0662 0.0659 0.0630 

 11 0.0631 0.0666 0.0737 0.0678 

1 0.069±0.009

72 34 0.0552 0.0647 0.0662 0.0637 

 23 0.0849 0.0730 0.0714 0.0764 

 11 0.0702 0.0782 0.0798 0.0761 

 1 0.084±0.014
 18

Table 20 Thermal conductivity data of unconditioned Nomex® III DefenderTM outer 

shell*. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 35 0.0519 0.0512 0.0516 

 23 0.0495 0.0494 0.0495 

 12 0.0497 0.0498 0.0498 

 1 0.049±0.002

48 35 0.0604 0.0593 0.0599 

 23 0.0599 0.0599 0.0599 

 12 0.0622 0.0620 0.0621 

 1 0.063±0.002

55 35 0.0611 0.0584 0.0598 

 23 0.0627 0.0618 0.0623 

 12 0.0653 0.0655 0.0654 

 1 0.068±0.003

72 35 0.0617 0.0613 0.0615 

 23 0.0655 0.0650 0.0653 

 12 0.0683 0.0682 0.0683 

 1 0.072±0.001

 * Data from Lawson and Pinder [3] 

Table 21 Thermal conductivity data of conditioned Nomex® III DefenderTM outer 

shell. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 35 0.0508 0.0516 0.0518 0.0514 

 23 0.0507 0.0491 0.0502 0.0500 

 12 0.0498 0.0466 0.0499 0.0488 

1 0.048±0.002

48 35 0.0579 0.0557 0.0561 0.0565 

 23 0.0587 0.0558 0.0581 0.0575 

 12 0.0592 0.0555 0.0596 0.0581 

1 0.059±0.003

55 35 0.0583 0.0581 0.0590 0.0585 

 23 0.0615 0.0590 0.0612 0.0606 

 12 0.0625 0.0586 0.0627 0.0613 

1 0.063±0.003

72 35 0.0554 0.0576 0.0597 0.0575 

 23 0.0663 0.0645 0.0659 0.0655 

 12 0.0682 0.0655 0.0689 0.0676 

 0.073±0.004
 19

Table 22 Thermal conductivity data of unconditioned Nomex® IIIA Pajama Check 

moisture barrier*. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 61 0.0463 0.0466 0.0464 

 39 0.0470 0.0472 0.0471 

 19 0.0431 0.0431 0.0431 

 1 0.042±0.004

48 61 0.0535 0.0537 0.0536 

 39 0.0577 0.0575 0.0576 

 19 0.0579 0.0574 0.0577 

 1 0.060±0.004

55 61 0.0547 0.0549 0.0548 

 39 0.0574 0.0571 0.0573 

 19 0.0599 0.0597 0.0598 

 1 0.062±0.001

72 61 0.0568 0.0558 0.0563 

 39 0.0613 0.0610 0.0612 

 19 0.0643 0.0637 0.0640 

 1 0.068±0.002

 * Data from Lawson and Pinder [3] 

Table 23 Thermal conductivity data of conditioned Nomex® IIIA Pajama Check 

moisture barrier. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 61 0.0457 0.0487 0.0468 0.0471 

 39 0.0465 0.0472 0.0465 0.0467 

 19 0.0465 0.0465 0.0467 0.0466 

1 0.046±0.002

48 61 0.0522 0.0514 0.0532 0.0523 

 39 0.0542 0.0529 0.0535 0.0535 

 19 0.0549 0.0548 0.0547 0.0548 

1 0.056±0.001

55 61 0.0535 0.0509 0.0552 0.0532 

 39 0.0555 0.0553 0.0564 0.0557 

 19 0.0581 0.0577 0.0574 0.0578 

1 0.060±0.003

72 61 0.0499 0.0461 0.0548 0.0503 

 39 0.0589 0.0593 0.0607 0.0596 

 19 0.0635 0.0622 0.0616 0.0624 

1 0.069±0.006
 20

Table 24 Thermal conductivity data of unconditioned Aralite® thermal liner*. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 9 0.0355 0.0353 0.0354 

 6 0.0352 0.0351 0.0352 

 3 0.0354 0.0354 0.0354 

 1 0.035±0.001

48 9 0.0380 0.0385 0.0383 

 6 0.0409 0.0409 0.0409 

 3 0.0427 0.0430 0.0428 

 1 0.045±0.001

55 9 0.0386 0.0385 0.0386 

 6 0.0411 0.0411 0.0411 

 3 0.0444 0.0444 0.0444 

 1 0.046±0.001

72 9 0.0420 0.0420 0.0420 

 6 0.0447 0.0446 0.0447 

 3 0.0475 0.0476 0.0476 

 1 0.049±0.001

 * Data from Lawson and Pinder [3] 

Table 25 Thermal conductivity data of conditioned Aralite® thermal liner. 

Experiment 

Temperature 

(°C) 

Number 

of 

Layers 

Measurement 

#1 

(W/m K) 

Measurement 

#2 

(W/m K) 

Measurement 

#3 

(W/m K) 

Average 

(W/m K) 

Estimate for 

one layer 

(W/m K) 

20 10 0.0344 0.0346 0.0345 0.0345 

 7 0.0342 0.0343 0.0343 0.0343 

 4 0.0344 0.0341 0.0338 0.0341 

1 0.034±0.001

48 10 0.0357 0.0374 0.0385 0.0372 

 7 0.0395 0.0386 0.0385 0.0389 

 4 0.0399 0.0398 0.0396 0.0398 

1 0.041±0.002

55 10 0.0356 0.0367 0.0391 0.0372 

 7 0.0411 0.0399 0.0398 0.0403 

 4 0.0418 0.0418 0.0416 0.0417 

1 0.044±0.002

72 10 0.0364 0.0418 0.0411 0.0398 

 7 0.0438 0.0415 0.0439 0.0431 

 4 0.0453 0.0454 0.0451 0.0453 

 1 0.048±0.004
 21

Hot Plate

Cold Plate

Specimen

Thickness

Heat

Flow

Heat Flow

Transducer

Figure 1 A schematic of the Rapid-k test section. 

0.030

0.033

0.036

0.039

0.042

0.045

0 10 20 30 40 50 60 70 80 90

Temperature (o

C)

Thermal Conductivity (W/m K)

Figure 2 Calibration values for SRM 1450c as indicated by SRM certificate. 
 22

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Chambry un-conditioned Chambry conditioned

Figure 3 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Three Layer AraFlo® with Chambry Face Cloth thermal liner. 

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Glide Face un-conditioned Glide Face conditioned

Figure 4 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Two Layer AraFlo® with GlideTM Face Cloth thermal liner. 
 23

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Black Fusion un-conditioned Black Fusion conditioned

Figure 5 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Black FusionTM outer shell. 

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (oC)

Thermal Conductivity

(W/m K)

Black Basofil Kevlar un-conditioned

Black Basofil Kevlar conditioned

Figure 6 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Black Basofil® Kevlar® outer shell. 
 24

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (oC)

Thermal Conductivity

(W/m K)

Cross Tech on Nomex un-conditioned

Cross Tech on Nomex conditioned

Figure 7 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Crosstech® on Nomex® moisture barrier. 

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

PTFE un-conditioned PTFE conditioned

Figure 8 Comparison of estimated thermal conductivity between unconditioned and 

conditioned PTFE on non woven Nomex® moisture barrier. 
 25

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

PBI Kevlar un-conditioned PBI Kevlar conditioned

Figure 9 Comparison of estimated thermal conductivity between unconditioned and 

conditioned PBI® Kevlar® Kombat® outer shell. 

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Nomex III un-conditioned Nomex III conditioned

Figure 10 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Nomex® III DefenderTM outer shell. 
 26

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Nomex III A Pajama Check un-condtioned

Nomex III A Pajama Check conditioned

Figure 11 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Nomex® IIIA Pajama Check moisture barrier. 

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

0 20 40 60 80

Temperature (o

C)

Thermal Conductivity

(W/m K)

Aralite un-conditioned Aralite conditioned

Figure 12 Comparison of estimated thermal conductivity between unconditioned and 

conditioned Aralite® thermal liner. 
 27

9 References 

 

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Book Company, New York 1973. 
 28

 

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