ASTM F433-02(2020)
(Practice)Standard Practice for Evaluating Thermal Conductivity of Gasket Materials
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F433 − 02 (Reapproved 2020)
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.
1. Scope 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,
1.1 This practice covers a means of measuring the amount
2 2
m (or ft ), per unit temperature gradient in the direction
of heat transfer quantitatively through a material or system.
perpendicular to an isothermal surface °C/m (or °F/in.). The
1.2 This practice is similar to the Heat Flow Meter System 2
k-factor is expressed W/m·K (Btu·in./h·ft ·°F).
of Test Method C518, but modified to accommodate small test
3.2 Symbols:
samples of higher thermal conductance.
1.3 The values stated in SI units are to be regarded as the k = thermal conductivity, W/m·K (Btu·in./h·ft ·°F)
2 2
standard. The values given in parentheses are for information C = thermal conductance, W/m ·K (Btu/h·ft ·°F)
∆x = sample thickness, mm (in.)
only.
2 2
A = sample cross-sectional area, m (ft )
1.4 This standard does not purport to address all of the
q = heat flow, W (Btu/h)
safety concerns, if any, associated with its use. It is the
φ = heat flow transducer output, mV
responsibility of the user of this standard to establish appro-
N = heat flow transducer calibration constant,
2 2
priate safety, health, and environmental practices and deter-
W/m ·mV (Btu/h·ft ·mV)
2 2
mine the applicability of regulatory limitations prior to use.
Nφ = heat flux, W/m (Btu/h·ft )
1.5 This international standard was developed in accor-
∆T = temperature difference, °C (°F) or mV
dance with internationally recognized principles on standard-
T = temperatureoflowersamplesurface,°C(°F)or
ization established in the Decision on Principles for the
mV
Development of International Standards, Guides and Recom-
T = temperature of upper sample surface, °C (°F)
mendations issued by the World Trade Organization Technical
or mV
Barriers to Trade (TBT) Committee. T = temperature of HFT surface facing sample,° C
h
(°F) or mV
2. Referenced Documents
T = temperature of upper heater surface facing
c
2.1 ASTM Standards: sample, °C (°F) or mV
T = temperature, °C (°F)
C518Test Method for Steady-State Thermal Transmission
δ = total temperature drop across interfaces be-
Properties by Means of the Heat Flow Meter Apparatus
tweensampleandadjacentsurfaces,°C(°F)or
D2214Test Method for Estimating the Thermal Conductiv-
mV
ityofLeatherwiththeCenco-FitchApparatus(Withdrawn
ρ = coefficient of thermal resistance at interfaces,
2008)
2 2
m ·K/W (h·ft ·°F/Btu)
F104Classification System for Nonmetallic Gasket Materi-
α = correction constant
als
subscript s = unknown sample
3. Terminology subscript r = known calibration sample
3.1 Definitions:
4. Summary of Practice
1 4.1 The sample and the heat flow transducer (HFT) are
ThispracticeisunderthejurisdictionofASTMCommitteeF03onGasketsand
is the direct responsibility of Subcommittee F03.10 on Composite Gaskets.
sandwiched between two controlled heater plates. The lower
Current edition approved Jan. 1, 2020. Published January 2020. Originally
heater is set at a higher temperature than the upper plate to
ε1
approved in 1964. Last previous edition approved in 2014 as F433–02 (2014) .
produce a flow of heat through the sample. The differential of
DOI: 10.1520/F0433-02R20.
these two temperatures, ∆ T, sensed by thermocouples, is
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
amplified along with the electrical output, φ, of the HFTand is
Standards volume information, refer to the standard’s Document Summary page on
directly proportional to the heat flow through the sample,
the ASTM website.
2 2
3 expressed as W/m (Btu/h·ft ). See Appendix for further
The last approved version of this historical standard is referenced on
www.astm.org. information. This recommended practice can be used for
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F433 − 02 (2020)
FIG. 1 Heat Flow Meter Assembly With Water-Cooled Heat Sink
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
FIG. 2 HFT Electrical Output and Heat Flow Section With Tem-
properties in particular applications. perature Sensors
5.2 This practice may be used as a routine test when agreed
9.1.1 Release the compressive load, pull out the tray, and
upon by the user and the producer.
load the sample. Care must be maintained to ensure that the
6. Apparatus tray compartment is free of any foreign matter. Clean as
required.
6.1 Heat Flow Transducer (HFT), with controlled heater
9.1.2 Push the tray back into the chamber with a ball and
plates, thermocouples, and an analog computer module.
plunger locking the tray into position.
7. Test Specimen 9.1.3 Closethetestsectiondoorandswitchtheaircontrolto
“stack clamped.” The sample holder is now raised automati-
7.1 The sample size shall be a 50.8-mm (2-in.) diameter
cally until the sample is clamped in place between the upper
disk 60.25 mm (60.010 in.) from 2.29 to 12.7 mm (0.090 to
and lower heaters. The compressive load can be adjusted by
0.500 in.) thick.
controllingtheairpressureattherearoftheunit.Apressureof
0.345 MPa (50 psi) is the recommended maximum and should
8. Conditioning
bespecifiedbyboththeproducerandusertoensurerepeatable
8.1 Condition the cut specimens in accordance with their
results.
classification, as required in Classification F104.
9.1.4 Allow from 1 to 2 h for the reading to stabilize. Read
the sample thermal conductance and temperature directly from
9. Procedure
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
user. (The guard heater is usually set at or near the average
62%⁄h.
sample temperature between the lower and upper heater
plates.)
10. Report
10.1 The report shall include the following:
The sole source of supply of the apparatus known to the committee at this time
10.1.1 Sample conditioning procedure,
is Holometrix, Inc., 25 Wiggins Avenue, Bedford, MA 01730–2323. If you are
10.1.2 Ambient temperature,
aware of alternative suppliers, please provide this information toASTM Headquar-
10.1.3 Sample hot side temperature, T ,
ters. Your comments will receive careful consideration at a meeting of the h
responsible technical committee, which you may attend. 10.1.4 Sample cold side temperature, T ,
c
F433 − 02 (2020)
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
10.1.5 Sample temperature drop, T −T , 12. Keywords
h c
10.1.6 Average sample temperature, (T + T )/2,
h c
12.1 comparative thermal conductance; heat flow; thermal
10.1.7 Sample thickness, ∆x,
conductance
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%.
F433 − 02 (2020)
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 pre
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