Standard Practice for Evaluating Thermal Conductivity of Gasket Materials

SIGNIFICANCE AND USE
5.1 This practice is designed to compare related materials under controlled conditions and their ability to maintain a minimum amount of thermal conductance. Test results should be correlated with field results in order to predict heat transfer properties in particular applications.  
5.2 This practice may be used as a routine test when agreed upon by the user and the producer.
SCOPE
1.1 This practice covers a means of measuring the amount of heat transfer quantitatively through a material or system.  
1.2 This practice is similar to the Heat Flow Meter System of Test Method C518, but modified to accommodate small test samples of higher thermal conductance.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
30-Jun-2014
Technical Committee
Drafting Committee
Current Stage
Ref Project

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation: F433 − 02 (Reapproved 2014)
Standard Practice for
Evaluating Thermal Conductivity of Gasket Materials
ThisstandardisissuedunderthefixeddesignationF433;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially corrected Footnote 6 in July 2014.
2 2
1. Scope m (or ft ), per unit temperature gradient in the direction
perpendicular to an isothermal surface °C/m (or °F/in.). The
1.1 This practice covers a means of measuring the amount
k-factor is expressed W/m·K (Btu·in./h·ft ·°F).
of heat transfer quantitatively through a material or system.
3.2 Symbols:
1.2 This practice is similar to the Heat Flow Meter System
of Test Method C518, but modified to accommodate small test 2
k = thermal conductivity, W/m·K (Btu·in./h·ft ·°F)
2 2
samples of higher thermal conductance.
C = thermal conductance, W/m ·K (Btu/h·ft ·°F)
∆x = sample thickness, mm (in.)
1.3 The values stated in SI units are to be regarded as the
2 2
A = sample cross-sectional area, m (ft )
standard. The values given in parentheses are for information
q = heat flow, W (Btu/h)
only.
φ = heat flow transducer output, mV
1.4 This standard does not purport to address all of the
N = heat flow transducer calibration constant,
2 2
safety concerns, if any, associated with its use. It is the
W/m ·mV (Btu/h·ft ·mV)
2 2
responsibility of the user of this standard to establish appro-
Nφ = heat flux, W/m (Btu/h·ft )
priate safety and health practices and determine the applica-
∆T = temperature difference, °C (°F) or mV
bility of regulatory limitations prior to use.
T = temperatureoflowersamplesurface,°C(°F)or
mV
2. Referenced Documents
T = temperature of upper sample surface, °C (°F)
2.1 ASTM Standards:
or mV
T = temperature of HFT surface facing sample,° C
C518Test Method for Steady-State Thermal Transmission
h
Properties by Means of the Heat Flow Meter Apparatus (°F) or mV
T = temperature of upper heater surface facing
D2214Test Method for Estimating the Thermal Conductiv-
c
sample, °C (°F) or mV
ityofLeatherwiththeCenco-FitchApparatus(Withdrawn
T = temperature, °C (°F)
2008)
δ = total temperature drop across interfaces be-
F104Classification System for Nonmetallic Gasket Materi-
tweensampleandadjacentsurfaces,°C(°F)or
als
mV
ρ = coefficient of thermal resistance at interfaces,
3. Terminology
2 2
m ·K/W (h·ft ·°F/Btu)
3.1 Definitions:
α = correction constant
3.1.1 thermal conductivity, k, of a solid material—the time
subscript s = unknown sample
rate of steady heat flow, watts (or Btu/h), through a unit area,
subscript r = known calibration sample
4. Summary of Practice
ThispracticeisunderthejurisdictionofASTMCommitteeF03onGasketsand
is the direct responsibility of Subcommittee F03.10 on Composite Gaskets.
4.1 The sample and the heat flow transducer (HFT) are
Current edition approved July 1, 2014. Published November 2014. Originally
sandwiched between two controlled heater plates. The lower
approved in 1964. Last previous edition approved in 2009 as F433–02 (2009).
heater is set at a higher temperature than the upper plate to
DOI: 10.1520/F0433-02R14E01.
produce a flow of heat through the sample. The differential of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
these two temperatures, ∆ T, sensed by thermocouples, is
Standards volume information, refer to the standard’s Document Summary page on
amplified along with the electrical output, φ, of the HFTand is
the ASTM website.
directly proportional to the heat flow through the sample,
The last approved version of this historical standard is referenced on
2 2
www.astm.org. expressed as W/m (Btu/h·ft ). See Appendix for further
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F433 − 02 (2014)
FIG. 1 Heat Flow Meter Assembly With Water-Cooled Heat Sink
information. This recommended practice can be used for
measuring heat transfer at a hot side temperature up to 200°C
(392°F). See Figs. 1-5.
5. Significance and Use
5.1 This practice is designed to compare related materials
under controlled conditions and their ability to maintain a
FIG. 2 HFT Electrical Output and Heat Flow Section With Tem-
minimum amount of thermal conductance. Test results should perature Sensors
be correlated with field results in order to predict heat transfer
properties in particular applications.
user. (The guard heater is usually set at or near the average
sample temperature between the lower and upper heater
5.2 This practice may be used as a routine test when agreed
plates.)
upon by the user and the producer.
9.1.1 Release the compressive load, pull out the tray, and
load the sample. Care must be maintained to ensure that the
6. Apparatus
tray compartment is free of any foreign matter. Clean as
6.1 Heat Flow Transducer (HFT), with controlled heater
required.
plates, thermocouples, and an analog computer module.
9.1.2 Push the tray back into the chamber with a ball and
plunger locking the tray into position.
7. Test Specimen
9.1.3 Closethetestsectiondoorandswitchtheaircontrolto
7.1 The sample size shall be a 50.8-mm (2-in.) diameter
“stack clamped.” The sample holder is now raised automati-
disk 60.25 mm (60.010 in.) from 2.29 to 12.7 mm (0.090 to
cally until the sample is clamped in place between the upper
0.500 in.) thick.
and lower heaters. The compressive load can be adjusted by
controllingtheairpressureattherearoftheunit.Apressureof
8. Conditioning
0.345 MPa (50 psi) is the recommended maximum and should
8.1 Condition the cut specimens in accordance with their
bespecifiedbyboththeproducerandusertoensurerepeatable
classification, as required in Classification F104.
results.
9.1.4 Allow from 1 to 2 h for the reading to stabilize. Read
9. Procedure
the sample thermal conductance and temperature directly from
digital meters on the front panel.The instrument has stabilized
9.1 Testtemperaturesaresuggestedfrom100to175°C(212
when the temperature indicated changes by no more than
to347°F)orwhateverisagreeduponbetweentheproducerand
65%⁄h and the conductance indicated changes no more than
62%⁄h.
The sole source of supply of the apparatus known to the committee at this time
is Holometrix, Inc., 25 Wiggins Avenue, Bedford, MA 01730–2323. If you are 10. Report
aware of alternative suppliers, please provide this information toASTM Headquar-
10.1 The report shall include the following:
ters. Your comments will receive careful consideration at a meeting of the
responsible technical committee, which you may attend. 10.1.1 Sample conditioning procedure,
´1
F433 − 02 (2014)
FIG. 3 Location of Thermocouples to Produce a Temperature Gradient Through the Test Sample
FIG. 4 The Hot and Cold Sample Surface Temperature Differential Amplified with the HFT Output, Divided Electronically, and Displayed
Digitally
FIG. 5 Clarification of Fig. 4 Showing the Calibration to Obtain the Correction Constant Correct Value Before Testing an Unknown
Sample
10.1.2 Ambient temperature, 12. Keywords
10.1.3 Sample hot side temperature, T ,
h
12.1 comparative thermal conductance; heat flow; thermal
10.1.4 Sample cold side temperature, T ,
c
conductance
10.1.5 Sample temperature drop, T −T ,
h c
10.1.6 Average sample temperature, (T + T )/2,
h c
10.1.7 Sample thickness, ∆x,
10.1.8 Thermal conductivity, k, and
10.1.9 Compressive load.
11. Precision and Bias
11.1 The precision of the practice is expected to be within
65%.
´1
F433 − 02 (2014)
APPENDIXES
(Nonmandatory Information)
X1. GENERAL INFORMATION
X1.1 Ifatestspecimenintheformofadiskisheldbetween X1.2 The heat flow per unit area is measured with a heat
two flat surfaces, each controlled at a different temperature, a
flow transducer, a sensitive device producing an electrical
flowofheatpassesthroughthesamplefromthehottothecold
output that is directly proportional to the heat flux, q/A. If the
surface.The thermal conductivity is determined by the follow-
output of the heat flow transducer (HFT) is called φ than the k
ing equation:
-factor can be calculated from:
q ∆x
∆x
k 5 W/m·K or Btu·in./h·ft ·°F (X1.1)
@ # @ #
k 5 Nφ (X1.2)
A ∆T
∆T
where:
X1.3 In this equation φ, ∆T, and ∆x can be measured by
q = heat flow through the sample, watt (Btu/h),
simple means, while the calibration constant, N, can be
2 2
A = cross-sectional area of the sample, m (ft ),
determinedbytestingasampleofknownthermalconductivity.
∆x = sample thickness, mm (in.), and
∆T = temperature difference across the sample, °C (°F).
X2. CALCULATIONS
X2.1 After thermal equilibrium has been established, the X2.1.4 The calibration sample must have a set of thermo-
various sensors may be read and recorded. Data reduction is couples installed in grooves in the upper and lower surfaces.
dependent upon the positions of the thermocouples for mea- During calibration the following results are obtained:
suring the sample ∆T, as follows:
∆x
r
k 5 Nφ (X2.5)
r r
∆T
X2.1.1 If thermocouples are installed in the sample surface
r
then:
where:
∆T 5 T 2 T ~mV! (X2.1)
1 2
∆T 5 T 2 T (X2.6)
r 1 2
NOTE X2.1—The sample thickness must be adjusted to account for the
thermocouples being slightly below the surface, see Fig. 2.
X2.1.5 From the various thermocouple readings we can
calculate the total interfacial temperature drop as follows:
X2.1.2 Acalibration run must first be made using a calibra-
tion standard of known thermal conductivity, k . This proce-
r
δ 5 T 2 T 2 ∆T (X2.7)
~ !
h c r
r
dure is identical to the procedure for the unknown sample as
The interfacial temperature drop, δ, is proportional to the
follows:
heat flux, Nφ as follows:
X2.1.2.1 k-factor, unknown sample: r
δ 5 ρNφ (X2.8)
∆x r
s
k 5 Nφ (X2.2)
s s
∆T
s
where ρ is a proportionality constant and depends mostly on
the surface conditions and on the applied pressure on the test
X2.1.2.2 k-factor, known sample:
stack. It is assumed that ρ remains essentiality constant from
∆x
r
k 5 Nφ (X2.3) test to test so long as the applied pressure remains the same.
r r
∆T
r
The contact coe
...


This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: F433 − 02 (Reapproved 2009) F433 − 02 (Reapproved 2014)
Standard Practice for
Evaluating Thermal Conductivity of Gasket Materials
This standard is issued under the fixed designation F433; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially corrected Footnote 6 in July 2014.
1. Scope
1.1 This practice covers a means of measuring the amount of heat transfer quantitatively through a material or system.
1.2 This practice is similar to the Heat Flow Meter System of Test Method C518, but modified to accommodate small test
samples of higher thermal conductance.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C518 Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus
D2214 Test Method for Estimating the Thermal Conductivity of Leather with the Cenco-Fitch Apparatus (Withdrawn 2008)
F104 Classification System for Nonmetallic Gasket Materials
3. Terminology
3.1 Definitions:
3.1.1 thermal conductivity, k, of a solid material—the time rate of steady heat flow, watts (or Btu/h), through a unit area, m
(or ft ), per unit temperature gradient in the direction perpendicular to an isothermal surface °C/m (or °F/in.). The k-factor is
expressed W/m·K (Btu·in./h·ft ·°F).
3.2 Symbols:
k = thermal conductivity, W/m·K (Btu·in./h·ft ·°F)
2 2
C = thermal conductance, W/m ·K (Btu/h·ft ·°F)
Δx = sample thickness, mm (in.)
2 2
A = sample cross-sectional area, m (ft )
q = heat flow, W (Btu/h)
φ = heat flow transducer output, mV
2 2
N = heat flow transducer calibration constant, W/m ·mV (Btu/h·ft ·mV)
2 2
Nφ = heat flux, W/m (Btu/h·ft )
ΔT = temperature difference, °C (°F) or mV
T = temperature of lower sample surface,°C (°F) or mV
T = temperature of upper sample surface, °C (°F) or mV
T = temperature of HFT surface facing sample,° C (°F) or mV
h
T = temperature of upper heater surface facing sample, °C (°F) or mV
c
T = temperature, °C (°F)
This practice is under the jurisdiction of ASTM Committee F03 on Gaskets and is the direct responsibility of Subcommittee F03.10 on Composite Gaskets.
Current edition approved May 1, 2009July 1, 2014. Published May 2009November 2014. Originally approved in 1964. Last previous edition approved in 20022009 as
F433 – 02.F433 – 02 (2009). DOI: 10.1520/F0433-02R09.10.1520/F0433-02R14E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F433 − 02 (2014)
FIG. 1 Heat Flow Meter Assembly With Water-Cooled Heat Sink
δ = total temperature drop across interfaces between sample and adjacent surfaces, °C (°F) or mV
2 2
ρ = coefficient of thermal resistance at interfaces, m ·K/W (h·ft ·°F/Btu)
α = correction constant
subscripts = unknown sample
subscriptr = known calibration sample
4. Summary of Practice
4.1 The sample and the heat flow transducer (HFT) are sandwiched between two controlled heater plates. The lower heater is
set at a higher temperature than the upper plate to produce a flow of heat through the sample. The differential of these two
temperatures, Δ T, sensed by thermocouples, is amplified along with the electrical output, φ, of the HFT and is directly proportional
2 2
to the heat flow through the sample, expressed as W/m (Btu/h·ft ). See Appendix for further information. This recommended
practice can be used for measuring heat transfer at a hot side temperature up to 200°C (392°F). See Figs. 1-5.
5. Significance and Use
5.1 This practice is designed to compare related materials under controlled conditions and their ability to maintain a minimum
amount of thermal conductance. Test results should be correlated with field results in order to predict heat transfer properties in
particular applications.
5.2 This practice may be used as a routine test when agreed upon by the user and the producer.
6. Apparatus
6.1 Heat Flow Transducer (HFT), with controlled heater plates, thermocouples, and an analog computer module.
7. Test Specimen
7.1 The sample size shall be a 50.8-mm (2-in.) diameter disk 60.25 mm (60.010 in.) from 2.29 to 12.7 mm (0.090 to 0.500
in.) thick.
8. Conditioning
8.1 Condition the cut specimens in accordance with their classification, as required in Classification F104.
9. Procedure
9.1 Test temperatures are suggested from 100 to 175°C (212 to 347°F) or whatever is agreed upon between the producer and
user. (The guard heater is usually set at or near the average sample temperature between the lower and upper heater plates.)
The sole source of supply of the apparatus known to the committee at this time is Holometrix, Inc., 25 Wiggins Avenue, Bedford, MA 01730–2323. If you are aware
of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical
committee, which you may attend.
´1
F433 − 02 (2014)
FIG. 2 HFT Electrical Output and Heat Flow Section With Temperature Sensors
9.1.1 Release the compressive load, pull out the tray, and load the sample. Care must be maintained to ensure that the tray
compartment is free of any foreign matter. Clean as required.
9.1.2 Push the tray back into the chamber with a ball and plunger locking the tray into position.
9.1.3 Close the test section door and switch the air control to “stack clamped.” The sample holder is now raised automatically
until the sample is clamped in place between the upper and lower heaters. The compressive load can be adjusted by controlling
the air pressure at the rear of the unit. A pressure of 0.345 MPa (50 psi) is the recommended maximum and should be specified
by both the producer and user to ensure repeatable results.
9.1.4 Allow from 1 to 2 h for the reading to stabilize. Read the sample thermal conductance and temperature directly from
digital meters on the front panel. The instrument has stabilized when the temperature indicated changes by no more than 65 % ⁄h
and the conductance indicated changes no more than 62 % ⁄h.
10. Report
10.1 The report shall include the following:
10.1.1 Sample conditioning procedure,
10.1.2 Ambient temperature,
10.1.3 Sample hot side temperature, T ,
h
10.1.4 Sample cold side temperature, T ,
c
10.1.5 Sample temperature drop, T − T ,
h c
10.1.6 Average sample temperature, (T + T )/2,
h c
10.1.7 Sample thickness, Δx,
10.1.8 Thermal conductivity, k, and
10.1.9 Compressive load.
11. Precision and Bias
11.1 The precision of the practice is expected to be within 65 %.
´1
F433 − 02 (2014)
FIG. 3 Location of Thermocouples to Produce a Temperature Gradient Through the Test Sample
FIG. 4 The Hot and Cold Sample Surface Temperature Differential Amplified with the HFT Output, Divided Electronically, and Displayed
Digitally
FIG. 5 Clarification of Fig. 4 Showing the Calibration to Obtain the Correction Constant Correct Value Before Testing an Unknown
Sample
12. Keywords
12.1 comparative thermal conductance; heat flow; thermal conductance
APPENDIXES
(Nonmandatory Information)
X1. GENERAL INFORMATION
X1.1 If a test specimen in the form of a disk is held between two flat surfaces, each controlled at a different temperature, a flow
of heat passes through the sample from the hot to the cold surface. The thermal conductivity is determined by the following
equation:
q Δx
k 5 W/m·K or Btu·in./h·ft ·°F (X1.1)
@ # @ #
A ΔT
´1
F433 − 02 (2014)
where:
q = heat flow through the sample, watt (Btu/h),
2 2
A = cross-sectional area of the sample, m (ft ),
Δx = sample thickness, mm (in.), and
ΔT = temperature difference across the sample, °C (°F).
X1.2 The heat flow per unit area is measured with a heat flow transducer, a sensitive device producing an electrical output that
is directly proportional to the heat flux, q/A.If the output of the heat flow transducer (HFT) is called φ than thek -factor can be
calculated from:
Δx
k 5 Nφ (X1.2)
ΔT
X1.3 In this equation φ, ΔT, and Δx can be measured by simple means, while the calibration constant, N, can be determined by
testing a sample of known thermal conductivity.
X2. CALCULATIONS
X2.1 After thermal equilibrium has been established, the various sensors may be read and recorded. Data reduction is dependent
upon the positions of the thermocouples for measuring the sample ΔT, as follows:
X2.1.1 If thermocouples are installed in the sample surface then:
ΔT 5 T 2 T mV (X2.1)
~ !
1 2
NOTE X2.1—The sample thickness must be adjusted to account for the thermocouples being slightly below the surface, see Fig. 2.
X2.1.2 A calibration run must first be made using a calibration standard of known thermal conductivity, k . This procedure is
r
identical to the procedure for the unknown sample as follows:
X2.1.2.1 k-factor, unknown sample:
Δx
s
k 5 Nφ (X2.2)
s s
ΔT
s
X2.1.2.2 k-factor, known sample:
Δx
r
k 5 Nφ (X2.3)
r r
ΔT
r
X2.1.2.3 Combining the unknown and known samples:
φ Δx ΔT
s s r
k 5 k (X2.4)
s r
φ Δx ΔT
r r s
X2.1.3 If thermocouples are located permanently in the surface adjacent to the sample, then, in accordance with Fig. 3, the ΔT
obtained by subtracting T and T is not equal to the ΔT across the sample itself due to contact resistance. (A correction factor can
h c
be obtained from the calibration test data.)
X2.1.4 The calibration sample must have a set of thermocouples installed in grooves in the upper and lower surfaces. During
calibration the following results are obtained:
Δx
r
k 5
...

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