ASTM C653-97(2007)
(Guide)Standard Guide for Determination of the Thermal Resistance of Low-Density Blanket-Type Mineral Fiber Insulation
Standard Guide for Determination of the Thermal Resistance of Low-Density Blanket-Type Mineral Fiber Insulation
SCOPE
1.1 This guide describes the calculation and interpolation of a thermal resistance value for low-density blanket-type insulation material at a particular density and thickness having been selected as representative of the product. It requires measured values of this average density and thickness, as well as apparent thermal conductivity values determined by either Test Method C 177, C 518, or C 1114.
1.2 This guide applies to a density range for mineral-fiber material of roughly 6.4 to 48 kg/m3 (0.4 to 3.0 lb/ft3). It is primarily intended to apply to low-density, mineral-fiber mass insulation batts and blankets, exclusive of any membrane facings. Apparent thermal conductivity data for these products are commonly reported at a mean temperature of 23.9°C (75°F) and a hot-to-cold plate temperature difference of 27.8°C (50°F) or 22.2°C (40°F).
1.3 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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Designation:C653–97 (Reapproved 2007)
Standard Guide for
Determination of the Thermal Resistance of Low-Density
Blanket-Type Mineral Fiber Insulation
This standard is issued under the fixed designation C653; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope erties Under Steady-State Conditions
C1114 Test Method for Steady-State Thermal Transmission
1.1 Thisguidedescribesthecalculationandinterpolationof
Properties by Means of the Thin-Heater Apparatus
a thermal resistance value for low-density blanket-type insula-
tion material at a particular density and thickness having been
3. Terminology
selected as representative of the product. It requires measured
3.1 Definitions—For definitions used in this guide, refer to
values of this average density and thickness, as well as
Terminology C168.
apparentthermalconductivityvaluesdeterminedbyeitherTest
3.2 Definitions of Terms Specific to This Standard:
Method C177, C518,or C1114.
3.2.1 apparent thermal conductivity, l—the ratio of the
1.2 This guide applies to a density range for mineral-fiber
3 3
specimen thickness to thermal resistance of the specimen. It is
material of roughly 6.4 to 48 kg/m (0.4 to 3.0 lb/ft ). It is
calculated as follows:
primarily intended to apply to low-density, mineral-fiber mass
insulation batts and blankets, exclusive of any membrane
l5 L/R ~W/m·k!or ~Btu·in./ft ·h·F! (1)
facings.Apparent thermal conductivity data for these products
arecommonlyreportedatameantemperatureof23.9°C(75°F)
3.2.1.1 Discussion—For this type of material an expression
andahot-to-coldplatetemperaturedifferenceof27.8°C(50°F)
for the apparent thermal conductivity as a function of density
or 22.2°C (40°F).
is:
1.3 This standard does not purport to address all of the
l5 a 1 bD 1 c/D (2)
safety concerns, if any, associated with its use. It is the
where a, b, c =parameters characteristic of a product, and related to
responsibility of the user of this standard to establish appro-
the conductivity of the gas, the conductivity of the solid and the
priate safety and health practices and determine the applica-
conductivity due to radiation.(1)
bility of regulatory limitations prior to use.
3.3 Symbols:
2. Referenced Documents
2.1 ASTM Standards:
2 2
R = thermal resistance, (m K/W) or (h·ft F/Btu)
C167 TestMethodsforThicknessandDensityofBlanketor
l = apparent thermal conductivity, (W/m·K) or (Btu·in/
Batt Thermal Insulations
h·ft F)
C168 Terminology Relating to Thermal Insulation
2 2
Q/A = heat flow per unit area, (W/m ) or (Btu/h·ft )
C177 Test Method for Steady-State Heat Flux Measure-
3 3
D = bulk density of a specimen, (kg/m ) or (lb/ft )
ments and Thermal Transmission Properties by Means of
L = measured specimen thickness, (m) or (in.)
the Guarded-Hot-Plate Apparatus
T = apparatus plate temperature, (K) or (F)
C518 Test Method for Steady-State Thermal Transmission
L8 = specimen thickness if the sample from which the
Properties by Means of the Heat Flow Meter Apparatus
specimen is selected does not recover to label
C1045 PracticeforCalculatingThermalTransmissionProp-
thickness, (m) or (in.)
s = estimate of the standard deviation for a set of data
points
D = apparatus systematic error
This guide is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal C = overall uncertainty in a measured R-value
Measurement.
3.3.1 Subscripts:
Current edition approved March 1, 2007. Published April 2007. Originally
approvedin1970.Lastpreviouseditionapprovedin2002asC653–97(2002).DOI:
10.1520/C0653-97R07.
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 boldface numbers in parentheses refer to a list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C653–97 (2007)
versus D” data points on three different samples. This repre-
= signifies average of a lot
av
sentsninedatapointsforthe“lversusD”curve.Again,this“l
= refers to hot surface
H
versus D” curve is developed to determine the l-value at a
= refers to cold surface
C
= refers to test specimen particular representative density characteristic of a lot of
T
= refers to nominal property for the product, as shown
material.
N
on the product label
5.3 The size of a lot of material to be characterized, the
= refers to a set of data points
amount of material measured for the representative values of
i
= refers to a particular specimen
s
density and thickness, and the frequency of tests all depend on
theuser’sneeds,whichcouldberelatedtoqualityassuranceby
4. Significance and Use
a manufacturer, certification, or research.
4.1 This guide provides a method to determine the thermal
performance of low-density blanket-type insulation. It may be
6. Procedure
used for the purposes of quality assurance, certification, or
6.1 This procedure uses nine {l; D} data points all
i i
research.
measured at the same hot and cold plate temperatures, to
4.2 The thermal resistance of low-density insulation de-
establish an interpolation equation for the determination of the
pends significantly on the density, the thickness, and thermal
l-value at the average density, D . That is, the subscript i
av
conductivity. Typical low-density, mineral-fiber insulation for
th
refers to the i test point. The D is the average density of the
i
buildings may vary in density from one specimen to the next.
specimen within the apparatus meter-area. The thermal resis-
4.3 Thermal tests are time-consuming in comparison with
tance at L and D is as follows:
av av
density and thickness measurements. Low-density insulation
R 5 L /l (3)
av av av
material is produced in large quantities.Atypical lot would be
a truckload or the amount necessary to insulate a house.
6.2 Before the set of “apparent thermal conductivity versus
4.4 The relatively low unit cost of this product and the
test density (l versus D)” data points can be measured on an
relatively high cost of thermal resistance testing makes it
i i
apparatus, it is necessary to choose the test densities and
cost-effective to test only a small percentage of the product
thicknesses. Three procedures for this choice are described in
area. It is recommended that there be a determination of the
Annex A1.
densitythatisrepresentativeofalotbythemeasurementofthe
6.2.1 ProcedureA—Asingletestspecimeniscompressedto
average density of a statistically representative sampling.
obtain different densities (A1.2). This procedure offers the
4.5 Afewernumberofthermalmeasurementsarethenmade
advantage of less test time to obtain three test points.
to determine the apparent thermal conductivity at the previ-
6.2.2 Procedure B—A different specimen is used for each
ously determined representative density. The essential signifi-
test point (A1.3). This method has the advantage of a better
canceofthisguideisthatalargelotofvariablematerialisbest
characterized by: (a) determining the representative density, statistical sampling with regard to material variability.
6.2.3 Procedure C—Test at D thereby eliminating the
and by (b) determining the thermal property at this represen-
av
need for an interpolation (A1.4).
tative density with a small number of thermal measurements.
6.3 Obtain a test value for l at each of the three densities.
4.6 Building insulation products are commonly manufac-
These three sets of test values result in three equations of the
turedinthicknessesrangingfrom19to330mm(0.75to13in.)
form of Eq 2 in 3.2.2. These are solved simultaneously to
inclusive. Experimental work has verified that there is a
determine the values of a , b , and c corresponding to
dependence of l on thickness for some low density materi-
s s s
app
specimen s (see A2.1.2).
als.
4.7 The upper limit of test thickness for specimens evalu-
NOTE 1—Small errors in the measured values of l will result in large
atedusingTestMethodsC177,C518,and C1114isestablished
variations in the values of a, b, and c. Even so, the uncertainty of the
based upon the apparatus design, overall dimensions, expected
interpolated value of l will be comparable to the measured error in l.
thermal resistivity level and desired target accuracy. The
6.4 Whenever possible, calculate running averages for the
testing organization is responsible for applying these restric-
specific product lot based on a number N equal to 20 or more
tions when evaluating a product to ensure that the results meet
sets of product curve parameters (a;b;c ). Remember from
s s s
applicable product labels and any existing regulatory require-
6.3 that each of these sets requires three test points (see
ments.(2)
A2.1.3).
4.8 Extrapolation of the apparent thermal conductivity or
6.4.1 A larger number N results in more consistent values
the thermal resistance beyond the ranges of thickness or
for a, b,and c;asmaller Nrepresentsamorecurrentdatabase.
density of products tested is not valid.
6.5 In 6.3 a set of parameter values was calculated, and in
6.4 a running average was calculated. This section describes
5. Sampling
how to obtain an interpolation curve (or equivalently a set of
5.1 For low-density mineral-fiber insulation, a lot sample
interpolation curve parameters) for the next sample, s, when it
size of 75 to 150 ft is recommended to determine the average
has been possible to previously obtain a running average set, (
density, D . Density is determined by using Test Method
av
¯ ¯
a¯; b; c¯). The given values are the set { a¯; b; c¯} and the
C167; take care to avoid the use of damaged material.
measured values of l at three densities, D.
i i
5.2 In order to account for the variation in l-value due to
product density variability, measure a minimum of three “l NOTE 2—Parameter cisexpectedtoaccountformostofthevariationin
C653–97 (2007)
the “l versus D” curve from specimen to specimen. When the density is
curve in addition to the apparatus precision. This additional
3 3
less than 16 kg/m (1 lb/ft ), c is the dominant parameter causing the
variation is here called the material variability and is desig-
varianceof lfromspecimentospecimen.Thenthe previously determined
nated by s .
m
values, a¯, and b are used, along with a measurement of l at a particular
8.6 The total “repeatability” uncertainty on a l versus D
density, to calculate a value of c for a particular specimen, s. In order to
graph will be the sum of the aforementioned uncertainties and
have a better estimate of the mean, the value of c is thusly determined for
is designated by s .
three values of density resulting in the value c¯ .The interpolation to the l
l
s
value at the average density, D , is calculated as follows, using Eq 3.
2 2 0.5
av
s 5 ~s 1 s ! (6)
l a m
¯
l 5 a¯ 1 bD 1 c¯ /D (4)
s av s av
8.7 In order to know what s is, it is necessary to plot a
l
An example of this calculation is in A2.1.4
number of l versus D test points. Twenty or more points are
6.6 Compute the average value of l¯ based on as many
av
recommended.Itisthenpossibletodeterminebyagraphicalor
values of l that have been determined. Remember from 6.3
s
a mathematical method (see Annex A3) what is the 1s band
and 6.5 that three test points are required to obtain a value for
within which 68% of the points lie or what is the 2s band
l .Commonpracticeistobaseanaverage l¯ onthreevalues
av av
within which 95% of the points lie.
of l .
s
8.8 When more than one apparatus is used to develop the l
6.7 Calculate the R-value, R , of the product at the average
av
versus D curve, there will be a difference between the average
density and thickness (see Section 5 and A1.1) as follows:
values on the same set of specimens due to a systematic
R 5 L /l (5)
av T av
difference among the apparatus.
8.9 The measured data from an apparatus have associated
with it an estimate of the possible systematic error in l of that
7. Report
apparatus. It is designated by D and is provided as input from
l
7.1 The report shall contain the following information:
Test Method C177, C518,or C1114.
7.1.1 The values of the average thermal resistance, density
8.10 Forthepurposesofthisguidetheoverallaccuracy, C ,
l
and thickness, the sample size, and the supporting data.
of the reported l-value is the sum of the overall repeatability
7.1.2 The test methods used and the information on the
(1s for a 68% confidence band) and the apparatus systematic
values and uncertainties of apparent thermal conductivity and
error.
density that is required in Test Method C167, C177, C518,or
C 5s 1D (7)
l l l
C1114.
7.1.3 The procedure used to obtain the l versus D curve
8.11 The percent “precision and bias” uncertainties in the
along with the equation for the curve itself.
reported R-value is calculated as follows, based on Eq 1:
R 5 L /l (8)
8. Precision and Bias av T av
8.1 There are a number of ways to combine the systematic
8.11.1 Theestimateoftheresidualstandarddeviationof L
and random uncertainties that contribute to an overall uncer- av
and l is made by statistical methods (see Annex A3). The
av
tainty of a measured quantity. The following procedure is
percent residual standard deviation in the reported R-value is
intended as a guideline.
then:
8.2 The term precision is used in this guide in the sense of
2 2 0.5
repeatability. The estimation of the standard deviation, s, for a
s s s
R L l
5 1 (9)
S 2 2D
set of measurements with a normal distribution is the plus and
R
av L l
T r
minus range about an average value or curve, within which
8.11.2 In order to calculate the percent bias uncertainty in
68% of the observations lie. The s is used to quantify the
R , it is necessary to obtain from Test Method C167 the
v
precision.
estimate of systematic uncertainty in the measurement of L .
av
8.3 The term bias as used in this guide represents the total
This is of the order of the resolution of the measurement
uncertainty in a set of measurements, including apparatus
device, and it is designated here by D . For the purpose of this
L
systematicerror,apparatusprecision,andthematerialvariabil-
guide, the overall percent bias in the reported R-value is
ity.
calculated as follows:
8.4 The apparatus precision is the variation that occurs
2 2 0.5
C ~s 1D ! ~s 1D !
when repeated observations are made on a single specimen or
R L L l l
5 1 (10)
S 2 2 D
R
identical specimens. It is quant
...
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