ASTM C1303-00
(Test Method)Standard Test Method for Estimating the Long-Term Change in the Thermal Resistance of Unfaced Rigid Closed Cell Plastic Foams by Slicing and Scaling Under Controlled Laboratory Conditions
Standard Test Method for Estimating the Long-Term Change in the Thermal Resistance of Unfaced Rigid Closed Cell Plastic Foams by Slicing and Scaling Under Controlled Laboratory Conditions
SCOPE
1.1 This test method covers a procedure for estimating the long-term change in thermal resistance of unfaced rigid closed cell plastic foams by reducing the material thickness to accelerate aging under controlled laboratory conditions (1-3).
1.2 This test method is limited to unfaced, homogeneous materials (see 3.2.4). It may be applied to a wide range of rigid closed cell plastic foam types, including but not limited to, polystyrenes, polyurethanes, polyisocyanurates, and phenolics produced in board form, foamed-in-place, or spray-applied applications. No specific procedures are detailed in this test method to address the effects of permeable or impermeable facings or skins, manufactured thickness, orientation, manufacturing process, density, quality, the influence of structures or containments, or the end-use environmental conditions on internal cell gas composition. The user of this test method shall consider if these parameters limit the use of this test method for a specific application.
1.3 This test method utilizes standard test procedures for measuring the thermal resistance of insulation materials. Periodic measurements are performed on specimens to observe the effects of aging. Specimens of reduced thickness are used to shorten the time required for these observations. The results of these measurements are coupled with a scaling factor to estimate the thermal resistance of the material under evaluation for other thicknesses as a function of time.
1.4 This test method specifies methods of specimen preparation, procedures for determining the specimen effective diffusion thickness (see 3.2.3), and precautions for determining the thermal resistance of thin specimens.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.6 This test method should be used to measure and describe the relative change in thermal resistance of rigid closed cell plastic foams under controlled laboratory conditions. It should not be used to describe or appraise the performance of these materials or products under actual use conditions. With continuing development, results from this test method may be used as an element in an assessment which takes into account all of the factors that are pertinent to an estimation of the thermal performance of these materials. Critical elements of this assessment are presently not available. See 1.2.
1.7 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.
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Standards Content (Sample)
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Designation:C1303–00
Standard Test Method for
Estimating the Long-Term Change in the Thermal
Resistance of Unfaced Rigid Closed-Cell Plastic Foams by
Slicing and Scaling Under Controlled Laboratory
,
1 2
Conditions
This standard is issued under the fixed designation C 1303; 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.
1. Scope 1.5 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
1.1 This test method covers a procedure for estimating the
only.
long-termchangeinthermalresistanceofunfacedrigidclosed-
1.6 Thistestmethodshouldbeusedtomeasureanddescribe
cell plastic foams by reducing the material thickness to
the relative change in thermal resistance of rigid closed-cell
accelerate aging under controlled laboratory conditions (1-3).
plastic foams under controlled laboratory conditions. It should
1.2 This test method is limited to unfaced, homogeneous
not be used to describe or appraise the performance of these
materials (see 3.2.4). It may be applied to a wide range of rigid
materials or products under actual use conditions. With con-
closed cell plastic foam types, including but not limited to,
tinuingdevelopment,resultsfromthistestmethodmaybeused
polystyrenes, polyurethanes, polyisocyanurates, and phenolics
as an element in an assessment which takes into account all of
produced in board form, foamed-in-place, or spray-applied
the factors that are pertinent to an estimation of the thermal
applications. No specific procedures are detailed in this test
performance of these materials. Critical elements of this
method to address the effects of permeable or impermeable
assessment are presently not available. See 1.2.
facings or skins, manufactured thickness, orientation, manu-
1.7 This standard does not purport to address all of the
facturingprocess,density,quality,theinfluenceofstructuresor
safety concerns, if any, associated with its use. It is the
containments, or the end-use environmental conditions on
responsibility of the user of this standard to establish appro-
internal cell gas composition.The user of this test method shall
priate safety and health practices and determine the applica-
consideriftheseparameterslimittheuseofthistestmethodfor
bility of regulatory limitations prior to use.
a specific application.
1.3 This test method utilizes standard test procedures for
2. Referenced Documents
measuring thermal resistance. Periodic measurements are per-
2.1 ASTM Standards:
formed on specimens to observe the effects of aging. Speci-
C 168 Terminology Relating to Thermal Insulating Materi-
mensofreducedthicknessareusedtoshortenthetimerequired
als
for these observations. The results of these measurements are
C 177 Test Method for Steady-State Heat Flux Measure-
coupled with a scaling factor to estimate the thermal resistance
ments and Thermal Transmission Properties by Means of
of the material under evaluation for other thicknesses as a
the Guarded-Hot-Plate Apparatus
function of time.
C 236 Test Method for Steady-State Thermal Performance
1.4 This test method specifies methods of specimen prepa-
of Building Assemblies by Means of a Guarded Hot Box
ration, procedures for determining the specimen effective
C 518 Test Method for Steady-State Heat Flux Measure-
diffusion thickness (see 3.2.3), and precautions for determining
ments and Thermal Transmission Properties by Means of
the thermal resistance of thin specimens.
the Heat Flow Meter Apparatus
C 578 SpecificationforRigid,CellularPolystyreneThermal
Insulation
This test method is under the jurisdiction of ASTM Committee C-16 on
Thermal Insulation and is the direct responsibility of Subcommittee C16.30 on C 591 Specification for Unfaced Preformed Rigid Cellular
Thermal Measurement.
Polyisocyanurate Thermal Insulation
Current edition approved March 10, 2000. Published May 2000.
C 976 Test Method for Thermal Performance of Building
Originally published as C 1303-95. Last previous edition C 1303-95.
Assemblies by Means of a Calibrated Hot Box
ISO/TC163/SC2/WG7 is also developing a standard to address the aging of
unfacedrigidclosed-cellplasticfoams.Thisdocumentisentitled,“Determinationof
C 1029 Specification for Spray-Applied Rigid Cellular
the Long-Term Thermal Resistance of Closed-Cell Cellular Plastic Thermal
Insulation.”
The boldface numbers in parentheses refer to the list of references at the end of
this standard. Annual Book of ASTM Standards, Vol 04.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
C1303–00
Polyurethane Thermal Insulation sample. See 7.1.1 and 7.1.2. As more data becomes available,
C 1045 Practice for Calculating Thermal Transmission this description will be refined.
Properties from Steady-State Heat Flux Measurements
3.2.5 normalized thermal resistance—thermal resistance di-
C 1114 TestMethodforSteady-StateThermalTransmission
vided by the intial thermal resistance.
Properties by Means of the Thin-Heater Apparatus
3.2.6 primary stage—that portion of the aging process
C 1126 Specification for Faced or Unfaced Rigid Cellular
where changes in thermophysical properties are primarily
Phenolic Thermal Insulation
influenced by the diffusion of air components into the rigid
C 1289 Specification for Faced Rigid Cellular Polyisocya-
closed-cell plastic foam.
nurate Thermal Insulation Board
3.2.7 scaled time—time divided by the square of the speci-
D 2856 Test Method for Open-Cell Content of Rigid Cel-
men thickness.
lular Plastics by the Air Pycnometer
3.2.8 scaling factor, n—the square of the material thickness
E 122 Practice for Choice of Sample Size to Estimate a
Measure of Quality for a Lot or Process dividedbythesquareofthetestspecimenthickness(see5.2.4).
This ratio represents the acceleration rate that is being applied
3. Terminology
to the aging process of a rigid closed-cell plastic foam because
ofthicknessdifferences.SeeRef(1)foradetailedderivationof
3.1 Definitions—For definitions of terms and symbols used
scaling factor.
in this test method, refer to Terminology C 168C 168.
3.2 Definitions of Terms Specific to This Standard: 3.2.9 secondary stage, n—that portion of the aging process
3.2.1 aging, v—the change in thermophysical properties of
where changes in thermophysical properties are primarily
rigid closed– cell plastic foam with time primarily due to
influenced by the diffusion of blowing agent(s) from the rigid
changes in the composition of the gas contained within the
closed–cell plastic foam.
closed cells.
3.2.10 service life, n—theanticipatedperiodoftimethatthe
3.2.2 effective diffusion coeffıcient, n—a material property
material is expected to maintain claimed thermophysical prop-
that relates the rate of gas transport to the gas partial pressure
erties. The service life may be dependent on the specific
gradients across the material of a given thickness at a given
end-use application.
temperature. The term “effective” is used to describe mass
3.2.11 thickness of damaged surface layer (TDSL), n—the
transport by several mechanisms.
average thickness of surface cells, on one surface, that are
3.2.3 effective diffusion thickness, n—the geometric thick-
either destroyed (ruptured or opened) during the preparation of
ness minus two times the thickness of damaged surface layer
test specimens or were originally open due to the manufactur-
(TDSL). See thickness of damaged surface layer (TDSL).
ing process.
3.2.4 homogeneous material, n—a material with a variation
3.2.12 time-averaged thermal resistance, n—the thermal
of less than 10 % in the slope of the primary stage thermal
*
resistance of a material of given thickness averaged over a
resistivity versus t results, for specimens within a specific
specified time period.
3.2.13 transition point , n—the estimated age of a rigid
closed-cell plastic foam when the aging process switches from
Annual Book of ASTM Standards, Vol 08.02.
Annual Book of ASTM Standards, Vol 14.02. the primary to secondary stage (see Fig. 1).
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
C1303–00
agent(s) is a gas whose apparent thermal conductivity and effective
diffusioncoefficientarebothlowerthanthoseoftheaircomponents.Ifthe
blowing agent diffuses faster than the air components, definitions of the
stages of aging would require modification and any discussions regarding
diffusionrateswouldneedtobechanged.However,thetestproceduresare
applicable in either case.
4.2 The change in thermal resistance due to the phenomena
describedin4.1usuallyoccursoveranextendedperiodoftime
at room temperature. Information regarding changes in the
thermal resistance of these materials as a function of time is
required so that decisions regarding formulations, production,
and comparisons with other materials can be made. Ideally,
aging curves and estimated time-averaged thermal resistance
data for the expected service life should be available after as
short a period as possible.
FIG. 1 The Log of the Normalized Thermal Resistance (see
4.3 Specifications C 578, C 591, C 1029, C 1126C 578 and
9.2.2.2) v.s. the Scaled Time for Three Thickness of a Rigid
C 1289 C 591C 1029C 1126C 1289, on rigid closed-cell plas-
Closed-Cell Plastic Foam. Data is from Ref (17).
tic foams, indicate that this decrease in thermal resistance
occurs over an extended period of time at room temperature.
3.3 Symbols:
However, these standards currently require that freshly manu-
factured foams be measured for thermal resistance after con-
ditioning at 23 6 1°C (73 6 2°F) for 180 6 5 days from the
A = surfaceareaofTestMethodD 2856D 2856speci-
time of manufacture, or at 60 6 1°C (1406 2°F) for 90 days.
men, m
These standards do not currently specify long-term or time-
D = diffusion coefficient, m /s
averaged thermal resistance criteria.
R = thermal resistance, (m ·K)/W
*
R = normalized thermal resistance=R/R
4.4 Theproceduredescribedinthistestmethodrequiresthat
t 0
R = initial thermal resistance
0 the material characteristics of the thin specimens approximate
R = estimated time-averaged thermal resistance,
a
those of the material under investigation. In particular, the
(m ·K)/W
specimens of reduced thickness must have the same effective
th 2
R = thermal resistance on t day, (m ·K)/W
t
diffusion coefficient and initial cell gas content as those of the
t = time, days
full thickness material, and that one-dimensional diffusion
t = service life, days
m
dominates, limiting the application of this test method to
TDSL = average thickness of damaged surface layer, m
* 2 unfaced homogeneous materials as defined in 3.2.4.
t = scaled time, sec/mm
4.4.1 When the thin specimen does not effectively represent
V = bulk geometric specimen volume of Test Method
b
D 2856D 2856 specimen, m the average behavior of the material, the results obtained by
V = closed–cell volume of the specimen of Test this test method may have a limited value.
c
Method D 2856D 2856 specimen, m
4.5 This test method addresses three separate elements
DX = geometric thickness of thermal resistance speci-
geo
relating to the aging of rigid closed–cell plastic foams.
men, m
4.5.1 Specimen Preparation—Techniques for the prepara-
DX = effective diffusion thickness of thermal resistance
eff
tion of thin flat specimens and the measurement of specimen
specimen, m
thickness are discussed, along with their limitations.
DX = specimen thickness,m
4.5.2 Measurement of the Thermal Resistance—In prin-
q = heat flux, W/m
ciple, any of the referenced test methods for the determination
q = heat flux due to the cell gas mixture,W/m
g
q = heat flux due to thermal radiation,W/m of thermal resistance are suitable. These include Test Methods
r
q = heat flux due to the solid polymer,W/m C 177, C 236, C 518, C 976, and
s
s = standard deviation
C 1114C 177C 236C 518C 976C 1114, used in conjunction
with Practice C 1045C 1045. Of these test methods, the heat
4. Significance and Use
flow meter apparatus, Test Method C 518C 518, is preferred.
4.1 Rigid closed–cell plastic foam insulations are produced
4.5.3 Interpretation of Data—Procedures are detailed for
byfoamingvariouspolymers.Asmanufactured,thecellsofthe
utilizingperiodicshort-termthermalresistancedatatoestimate
foam usually contain their highest percentage of blowing agent
long-term changes in the thermal resistance of the material.
and the lowest percentage of air components. As time passes,
Examples are provided in Annex A1.
the relative concentrations of these gases change due primarily
4.6 The procedure outlined in this test method can be used
todiffusion,resultinginareductionofthethermalresistanceof
to produce a characteristic aging curve (relationship between
the foam due to an increase in the thermal conductivity of the
the thermophysical properties with time). This relationship has
resultant cell gas mixture.
been used by researchers to calculate effective diffusion coef-
NOTE 1—The discussions in Sections 4 and 5 assume that the blowing ficients (2, 3).
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Please contact ASTM International (www.astm.org) for the latest information.
C1303–00
5. Background and Theory
5.1 The Aging Process:
5.1.1 During the service life of a rigid closed-cell plastic
foam, air components diffuse into the cells, and the blowing
agent diffuses out of the cells or partially dissolves into the
polymer matrix. Each process occurs at a rate that depends on
the type of polymer, the foam structure, the temperature, the
gas type, and its pressure (1).
5.1.2 In general, as the inward diffusion of air components
is much faster than the outward diffusion of the captive
blowing agent, the aging process comprises two stages. During
the primary stage, the cell gas composition changes at a
significantratebecauseoftherapiddiffusionofaircomponents
into the cell and the outward diffusion of all diffuse blowing
agents, if present; so too does the thermal resistance of the
FIG. 2 The Normalized Thermal Resistance (see 9.2.2.2)ofTwo
material.
Thicknesses of a Rigid Closed Cell Plastic Foam
...
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