ASTM C653-97(2012)
(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
SIGNIFICANCE AND USE
This guide provides a method to determine the thermal performance of low-density blanket-type insulation. It may be used for the purposes of quality assurance, certification, or research.
The thermal resistance of low-density insulation depends significantly on the density, the thickness, and thermal conductivity. Typical low-density, mineral-fiber insulation for buildings may vary in density from one specimen to the next.
Thermal tests are time-consuming in comparison with density and thickness measurements. Low-density insulation material is produced in large quantities. A typical lot would be a truckload or the amount necessary to insulate a house.
The relatively low unit cost of this product and the relatively high cost of thermal resistance testing makes it cost-effective to test only a small percentage of the product area. It is recommended that there be a determination of the density that is representative of a lot by the measurement of the average density of a statistically representative sampling.
A fewer number of thermal measurements are then made to determine the apparent thermal conductivity at the previously determined representative density. The essential significance of this guide is that a large lot of variable material is best characterized by: (a) determining the representative density, and by (b) determining the thermal property at this representative density with a small number of thermal measurements.
Building insulation products are commonly manufactured in thicknesses ranging from 19 to 330 mm (0.75 to 13 in.) inclusive. Experimental work has verified that there is a dependence of λapp on thickness for some low density materials.
The upper limit of test thickness for specimens evaluated using Test Methods C177, C518, and C1114 is established based upon the apparatus design, overall dimensions, expected thermal resistivity level and desired target accuracy. The testing organization is responsible for applying these restrictions whe...
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 C177, C518, or C1114.
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 2012)
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 C1045Practice for Calculating Thermal Transmission Prop-
erties Under Steady-State Conditions
1.1 Thisguidedescribesthecalculationandinterpolationof
C1114Test Method for Steady-State Thermal Transmission
a thermal resistance value for low-density blanket-type insula-
Properties by Means of the Thin-Heater Apparatus
tion material at a particular density and thickness having been
selected as representative of the product. It requires measured
3. Terminology
values of this average density and thickness, as well as
apparentthermalconductivityvaluesdeterminedbyeitherTest
3.1 Definitions—For definitions used in this guide, refer to
Method C177, C518,or C1114.
Terminology C168.
1.2 This guide applies to a density range for mineral-fiber
3.2 Definitions of Terms Specific to This Standard:
3 3
material of roughly 6.4 to 48 kg/m (0.4 to 3.0 lb/ft ). It is
3.2.1 apparent thermal conductivity, λ—the ratio of the
primarily intended to apply to low-density, mineral-fiber mass
specimen thickness to thermal resistance of the specimen. It is
insulation batts and blankets, exclusive of any membrane
calculated as follows:
facings.Apparent thermal conductivity data for these products
λ 5 L/R W/m·k or Btu·in./ft ·h·F (1)
~ ! ~ !
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
λ 5 a1bD1c/D (2)
safety concerns, if any, associated with its use. It is the
where a, b, c = parameters characteristic of a product,
responsibility of the user of this standard to establish appro-
and related to the conductivity of the gas, the conductivity
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. of the solid and the conductivity due to radiation.(1)
3.3 Symbols:
2. Referenced Documents
2 2
R = thermal resistance, (m K/W) or (h·ft F/Btu)
2.1 ASTM Standards:
λ = apparent thermal conductivity, (W/m·K) or (Btu·in/
C167Test Methods forThickness and Density of Blanket or
h·ft F)
Batt Thermal Insulations
2 2
Q/A = heat flow per unit area, (W/m ) or (Btu/h·ft )
C168Terminology Relating to Thermal Insulation
3 3
D = bulk density of a specimen, (kg/m ) or (lb/ft )
C177Test Method for Steady-State Heat Flux Measure-
L = measured specimen thickness, (m) or (in.)
ments and Thermal Transmission Properties by Means of
T = apparatus plate temperature, (K) or (F)
the Guarded-Hot-Plate Apparatus
L` = specimen thickness if the sample from which the
C518Test Method for Steady-State Thermal Transmission
specimen is selected does not recover to label
Properties by Means of the Heat Flow Meter Apparatus
thickness, (m) or (in.)
s = estimate of the standard deviation for a set of data
points
This guide is under the jurisdiction of ASTM Committee C16 on Thermal
∆ = apparatus systematic error
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
Ψ = overall uncertainty in a measured R-value
Measurement.
Current edition approved March 1, 2012. Published August 2012. Originally
3.3.1 Subscripts:
approvedin1970.Lastpreviouseditionapprovedin2007asC653–97(2007).DOI:
10.1520/C0653-97R12.
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 (2012)
density, D . Density is determined by using Test Method
= signifies average of a lot
av
av
C167; take care to avoid the use of damaged material.
= refers to hot surface
H
= refers to cold surface
C
5.2 In order to account for the variation in λ-value due to
= refers to test specimen
T
product density variability, measure a minimum of three “λ
= refers to nominal property for the product, as shown on
N
versus D” data points on three different samples. This repre-
the product label
sentsninedatapointsforthe“λversus D”curve.Again,this“λ
= refers to a set of data points
i
versus D” curve is developed to determine the λ-value at a
= refers to a particular specimen
s
particular representative density characteristic of a lot of
material.
4. Significance and Use
5.3 The size of a lot of material to be characterized, the
4.1 This guide provides a method to determine the thermal
amount of material measured for the representative values of
performance of low-density blanket-type insulation. It may be
density and thickness, and the frequency of tests all depend on
used for the purposes of quality assurance, certification, or
theuser’sneeds,whichcouldberelatedtoqualityassuranceby
research.
a manufacturer, certification, or research.
4.2 The thermal resistance of low-density insulation de-
pends significantly on the density, the thickness, and thermal 6. Procedure
conductivity. Typical low-density, mineral-fiber insulation for
6.1 This procedure uses nine {λ; D} data points all
i i
buildings may vary in density from one specimen to the next.
measured at the same hot and cold plate temperatures, to
establish an interpolation equation for the determination of the
4.3 Thermal tests are time-consuming in comparison with
λ-value at the average density, D . That is, the subscript i
density and thickness measurements. Low-density insulation
av
th
refers to the i test point. The D is the average density of the
material is produced in large quantities.Atypical lot would be
i
a truckload or the amount necessary to insulate a house. specimen within the apparatus meter-area. The thermal resis-
tance at L and D is as follows:
av av
4.4 The relatively low unit cost of this product and the
R 5 L /λ (3)
relatively high cost of thermal resistance testing makes it av av av
cost-effective to test only a small percentage of the product
6.2 Before the set of “apparent thermal conductivity versus
area. It is recommended that there be a determination of the
test density (λ versus D)” data points can be measured on an
i i
densitythatisrepresentativeofalotbythemeasurementofthe
apparatus, it is necessary to choose the test densities and
average density of a statistically representative sampling.
thicknesses. Three procedures for this choice are described in
Annex A1.
4.5 Afewernumberofthermalmeasurementsarethenmade
6.2.1 Procedure A—Asingletestspecimeniscompressedto
to determine the apparent thermal conductivity at the previ-
obtain different densities (A1.2). This procedure offers the
ously determined representative density. The essential signifi-
advantage of less test time to obtain three test points.
canceofthisguideisthatalargelotofvariablematerialisbest
6.2.2 Procedure B—A different specimen is used for each
characterized by: (a) determining the representative density,
test point (A1.3). This method has the advantage of a better
and by (b) determining the thermal property at this represen-
statistical sampling with regard to material variability.
tative density with a small number of thermal measurements.
6.2.3 ProcedureC—TestatD therebyeliminatingtheneed
av
4.6 Building insulation products are commonly manufac-
for an interpolation (A1.4).
turedinthicknessesrangingfrom19to330mm(0.75to13in.)
6.3 Obtain a test value for λ at each of the three densities.
inclusive. Experimental work has verified that there is a
These three sets of test values result in three equations of the
dependence of λ on thickness for some low density materi-
app
form of Eq 2 in 3.2.1. These are solved simultaneously to
als.
determine the values of a , b , and c corresponding to
s s s
4.7 The upper limit of test thickness for specimens evalu-
specimen s (see A2.1.2).
atedusingTestMethodsC177,C518,and C1114isestablished
NOTE 1—Small errors in the measured values of λ will result in large
based upon the apparatus design, overall dimensions, expected
variations in the values of a, b, and c. Even so, the uncertainty of the
thermal resistivity level and desired target accuracy. The
interpolated value of λ will be comparable to the measured error in λ.
testing organization is responsible for applying these restric-
6.4 Whenever possible, calculate running averages for the
tions when evaluating a product to ensure that the results meet
specific product lot based on a number N equal to 20 or more
applicable product labels and any existing regulatory require-
sets of product curve parameters (a;b;c ). Remember from
s s s
ments.(2)
6.3 that each of these sets requires three test points (see
4.8 Extrapolation of the apparent thermal conductivity or
A2.1.3).
the thermal resistance beyond the ranges of thickness or
6.4.1 A larger number N results in more consistent values
density of products tested is not valid.
for a, b,and c;asmaller Nrepresentsamorecurrentdatabase.
6.5 In 6.3 a set of parameter values was calculated, and in
5. Sampling
6.4 a running average was calculated. This section describes
5.1 For low-density mineral-fiber insulation, a lot sample how to obtain an interpolation curve (or equivalently a set of
size of 75 to 150 ft is recommended to determine the average interpolation curve parameters) for the next sample, s, when it
C653 − 97 (2012)
has been possible to previously obtain a running average set, 8.5 The material variability is partly taken into account by
¯ ¯
(a¯; b; c¯). The given values are the set {a¯; b; c¯} and the the λversus Dcurve.Whendifferentspecimensaretestedthere
measured values of λ at three densities, D. will be an amount of variation about the average λ versus D
i i
curve in addition to the apparatus precision. This additional
NOTE2—Parameter cisexpectedtoaccountformostofthevariationin
variation is here called the material variability and is desig-
the “λ versus D” curve from specimen to specimen. When the density is
3 3
nated by s .
less than 16 kg/m (1 lb/ft ), c is the dominant parameter causing the
m
varianceof λfromspecimentospecimen.Thenthe previously determined
8.6 The total “repeatability” uncertainty on a λ versus D
values, a¯, and b are used, along with a measurement of λ at a particular
graph will be the sum of the aforementioned uncertainties and
density, to calculate a value of c for a particular specimen, s. In order to
is designated by s .
have a better estimate of the mean, the value of c is thusly determined for
λ
three values of density resulting in the value c¯ . The interpolation to the λ
s 2 2 0.5
s 5 ~s 1s ! (6)
λ a m
value at the average density, D , is calculated as follows, using Eq 3.
av
8.7 In order to know what s is, it is necessary to plot a
λ
¯
λ 5 a¯1bD 1c¯ /D (4)
s av s av
number of λ versus D test points. Twenty or more points are
recommended.Itisthenpossibletodeterminebyagraphicalor
An example of this calculation is in A2.1.4
a mathematical method (see Annex A3) what is the 1s band
¯
6.6 Compute the average value of λ based on as many
av
within which 68% of the points lie or what is the 2s band
values of λ that have been determined. Remember from 6.3
s
within which 95% of the points lie.
and 6.5 that three test points are required to obtain a value for
¯
8.8 When more than one apparatus is used to develop the λ
λ . Common practice is to base an average λ on three values
av av
versus D curve, there will be a difference between the average
of λ .
s
values on the same set of specimens due to a systematic
6.7 Calculate the R-value, R , of the product at the average
av
difference among the apparatus.
density and thickness (see Section 5 and A1.1) as follows:
8.9 The measured data from an apparatus have associated
R 5 L /λ (5)
av T av
with it an estimate of the possible systematic error in λ of that
7. Report apparatus. It is designated by ∆ and is provided as input from
λ
Test Method C177, C518,or C1114.
7.1 The report shall contain the following information:
7.1.1 The values of the average thermal resistance, density 8.10 Forthepurposesofthisguidetheoverallaccuracy, Ψ ,
λ
of the reported λ-value is the sum of the overall repeatability
and thickness, the sample size, and the supporting data.
7.1.2 The test methods used and the information on the (1s for a 68% confidence band) and the apparatus systematic
error.
values and uncertainties of apparent thermal conductivity and
density that is required in Test Method C167, C177, C518,or
Ψ 5 s 1∆ (7)
λ λ λ
C1114.
8.11 The percent “precision and bias” uncertainties in the
7.1.3 The procedure used to obtain the λ versus D curve
reported R-value is calculated as follows, based on Eq 1:
along with the equation for the curve itself.
R 5 L /λ (8)
av T av
8. Precision and Bias
8.11.1 Theestimateoftheresidualstandarddeviationof L
av
8.1 There are a number of ways to combine the systematic
and λ is made by statistical methods (see Annex A3). The
av
and random uncertainties that contribute to an overall uncer-
percent residual standard deviation in the reported R-value is
tainty of a measured quantity. The following procedure is
then:
intended as a guideline.
2 2 0.5
s s s
R L λ
8.2 The term precision is used in this guide in the sense of
5 1 (9)
S D
2 2
R L λ
av T r
repeatability. The estimation of the standard deviation, s, for a
set of measurements with a normal distribution is the plus and 8.11.2 In order to calculate the percent bias uncertainty in
minus range about an average value or curve, within which R , it is necessary to obtain from Test Method C167 the
v
68% of the observations lie. The s is used to quantify the estimate of systematic uncertainty in the measurement of L .
av
precision. This is of the order of the resolution of the measurement
device, and it is designated here by ∆ . For the purpose of this
L
8.3 The term bias as used in this guide represents the total
guide, the overall percent bias in the reported R-value is
uncertainty in a set of measurements, including apparatus
calculated as follows:
systematicerror,apparatusprecision,andthematerialvariabil-
2 2 0.5
Ψ s
...
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