ASTM C687 - 18

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Designation: C687 −18
Standard Practice for
Determination of Thermal Resistance of Loose-Fill Building
Insulation
1
This standard is issued under the ﬁxed designation C687; 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
1.1 This practice presents a laboratory guide to determine
the thermal resistance of loose-ﬁll building insulations at mean
temperatures between −20 and 55°C (−4 to 131°F).
1.2 This practice applies to a wide variety of loose-ﬁll
thermal insulation products including but not limited to ﬁbrous
glass, rock/slag wool, or cellulosic ﬁber materials; granular
types including vermiculite and perlite; pelletized products;
and any other insulation material installed pneumatically or
poured in place. It does not apply to products that change their
character after installation either by chemical reaction or the
application of binders or adhesives, nor does it consider the
effects of structures, containments, facings, or air ﬁlms.
1.3 Since this practice is designed for reproducible product
comparison, it measures the thermal resistance of an insulation
material which has been preconditioned to a relatively dry
state. Consideration of changes of thermal performance of a
hygroscopic insulation by sorption of water is beyond the
scope of this practice.
1.4 The sample preparation techniques outlined in this
practice do not cover the characterization of loose-ﬁll materials
intended for enclosed applications. For those applications, a
separate sample preparation technique that simulates the in-
stalled condition will be required. However, even for those
applications, some other aspects of this practice are applicable.
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 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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
C167 Test Methods for Thickness and Density of Blanket or
Batt Thermal Insulations
C168 Terminology Relating to Thermal Insulation
C177 Test Method for Steady-State Heat Flux Measure-
ments and Thermal Transmission Properties by Means of
the Guarded-Hot-Plate Apparatus
C518 Test Method for Steady-State Thermal Transmission
Properties by Means of the Heat Flow Meter Apparatus
C653 Guide for Determination of the Thermal Resistance of
Low-Density Blanket-Type Mineral Fiber Insulation
C739 Speciﬁcation for Cellulosic Fiber Loose-Fill Thermal
Insulation
C1045 Practice for Calculating Thermal Transmission Prop-
erties Under Steady-State Conditions
C1114 Test Method for Steady-State Thermal Transmission
Properties by Means of the Thin-Heater Apparatus
C1363 Test Method for Thermal Performance of Building
Materials and Envelope Assemblies by Means of a Hot
Box Apparatus
C1373 Practice for Determination of Thermal Resistance of
Attic Insulation Systems Under Simulated Winter Condi-
tions
3. Terminology
3.1 Unless otherwise stated, the terms and deﬁnitions found
in Terminology C168 are applicable herein.
4. Signiﬁcance and Use
4.1 The thermal resistance, R, of an insulation is used to
describe its thermal performance.
1
This practice is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
Measurement.
Current edition approved Sept. 1, 2018. Published October 2018. Originally
approved in 1971. Last previous edition approved in 2017 as C687 – 17. DOI:
10.1520/C0687-18.
2
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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.
1
 

4.2 The thermal resistance of an insulation is related to the

density and thickness of the insulation. It is desirable to obtain

test data on thermal resistances at thicknesses and densities

related to the end uses of the product.

4.3 In normal use, the thickness of these products range

from less than 100 mm (4 in.) to greater than 500 mm (20 in.).

Installed densities depend upon the product type, the installed

thickness, the installation equipment used, the installation

techniques, and the geometry of the insulated space.

4.4 Loose-ﬁll insulations provide coverage information us-

ing densities selected by manufacturers to represent the product

settled densities. Generally, it is necessary to know the product

thermal performance at a representative density. Some cover-

age charts utilize multiple densities to show that greater

thickness installations usually result in higher installed densi-

ties. The use of multiple densities can be detected from the

coverage chart by calculating the density for several different

thermal resistance levels. (The density for a given thermal

resistance can be calculated from the coverage chart by

dividing the minimum mass per unit area by the minimum

thickness.) If the calculated densities are signiﬁcantly different

at different thermal resistances, the multiple density strategy

has been used.

4.5 When applicable speciﬁcations or codes do not specify

the nominal thermal resistance level to be used for comparison

purposes, a recommended practice is to use the R

(met-

ric) = 3.3 m

K/W (R

=19[hft

F/Btu]) label density and

thickness for that measurement.

4.6 If the density for test purposes is not available from the

coverage chart, a test density shall be established by use of

applicable speciﬁcations and codes or, if none apply, agreement

between the requesting body and the testing organization.

4.7 Generally, thin sections of these materials are not

uniform. Thus, the test thickness must be greater than or equal

to the product’s representative thickness if the results are to be

consistent and typical of use.

NOTE 1—The representative thickness is speciﬁc for each product and

is determined by running a series of tests in which the density is held

constant but the thickness is increased. The representative thickness is

deﬁned here as that thickness above which there is no more than a 2 %

change in the resistivity of the product. The representative thickness is a

function of product blown density. In general, as the density decreases, the

representative thickness increases. Fortunately, most products are de-

signed to be blown over a small range of densities. This limited range

yields a range of representative thicknesses between 100 to 200 mm (4 to

8 in.) for most products. To simplify the process for this Practice, the

representative thickness for the C687 tests shall be determined at the

midpoint of the blown density range. Once this is accomplished, all

thermal testing on this product is conducted at a thickness that is greater

or equal to the representative thickness.

4.7.1 For this practice, the minimum test thickness shall be

100 mm (4 in.) or the representative thickness, whichever is

larger. If the test is to represent an installation at a lesser

thickness, the installed thickness shall be used.

4.8 Because of the high cost of construction and operation

of large test equipment, it is impractical to test at the higher

thicknesses at which products are used. For purposes of this

practice, it is acceptable to estimate the thermal resistance at

any thickness from the thermal resistivity obtained from tests

on the product at the minimum test thickness (see 4.7.1) and at

the density expected for the proposed thickness.

4.9 In principle, any of the standard methods for the

determination of thermal resistance are suitable for loose-ﬁll

products. These include Test Methods C177,C518,C1114, and

C1363. Of these test methods, the heat ﬂow meter apparatus,

Test Method C518, is preferred.

4.10 The thermal resistance of low-density insulations de-

pend upon the direction of heat ﬂow. Unless otherwise

speciﬁed, tests shall be performed for the maximum heat ﬂow

condition, that is, a horizontal specimen with heat ﬂow-up.

4.11 Specimens shall be prepared in a manner consistent

with the intended installation procedure. Products for pneu-

matic installation shall be pneumatically applied (blown), and

products for pour-in-place installation shall be poured into

specimen frames.

4.12 Looseﬁll insulation installed in attic applications will

have heat ﬂow up during the winter. At winter design condi-

tions in many areas, the winter design temperature difference

will cause convective heat transfer to occur within some

loose-ﬁll insulations. The procedure outlined in Practice C687

is not applicable to that measurement unless a Test Method

C1363 test apparatus is used to reproduce the correct boundary

conditions. To determine how seasonal differences can affect

product performance, use Practice C1373. Practice C1373

measures the expected winter thermal performance of loose-ﬁll

insulation under simulated winter design temperature condi-

tions and provides specimen requirements necessary for that

determination.

5. Apparatus

5.1 Thermal test apparatus used for this practice shall meet

these requirements.

5.1.1 Conformance to Standards—The apparatus shall con-

form to all requirements of the ASTM thermal test method

used.

5.1.2 Size and Error—The apparatus shall be capable of

testing specimens up to at least 150-mm (6-in.) thickness with

an estimated error not greater than 1 % attributed to thickness/

guard dimensions. (Parametric studies using a mathematical

model of the proposed apparatus will give insight to this

evaluation. For example see Table 1 in the 1976 revision of

Test Method C518.

)

NOTE 2—Thermal test apparatus in use for this practice have overall

plate dimensions of 457 to 1220 mm (18 to 48 in.) square with metering

areas 152 to 457 mm (6 to 18 in.) square. Other sizes are acceptable if

proper consideration of the size-thickness restrictions as outlined in the

test method are observed in their design. (See Practice C1045 for

additional discussion.)

5.1.3 Temperature—As a minimum, the apparatus shall be

capable of testing at a mean temperature of 23.9°C (75°F) with

a temperature difference of 20 to 28°C (36 to 50°F). The

See Table 1, “Maximum Spacing Between Warm and Cold Plates of Heat

Flowmeter Apparatus,” of Test Method C518 – 76 published in 1985 Annual Book

of ASTM Standards, Vol 04.06.

C687 − 18

equipment shall be calibrated at the same temperatures as the

test conditions. Some existing test apparatus have been de-

signed to provide measurements over a range of mean tem-

peratures from −20 to 55°C (−4 to 131°F) and for a wider range

of temperature differences.

5.1.4 Humidity—The absolute humidity within the test ap-

paratus shall be maintained low enough to prevent condensa-

tion within the specimen or on the cold plate(s). A maximum

9°C (48°F) dew point is consistent with the recommended

material conditioning levels.

5.1.5 Orientation and Direction of Heat Flow—The thermal

test apparatus shall be capable of testing horizontal specimens

with heat ﬂow-up. This orientation represents the most adverse

heat ﬂow condition for testing between two solid boundaries.

5.1.6 Thermal Test Specimen Frame—The test frame shall

be sized to match the test apparatus and shall be made of

materials having low thermal conductivity (<0.12 W/m K) and

minimum thickness. A thin, thermally insigniﬁcant, screen or

membrane is stretched across the bottom to support the

material. Frames have ﬁxed rigid sides or fold-down,

collapsible, or compressible sides (see Fig. 1 and Fig. 2).

5.2 Specimen Preparation Equipment:

5.2.1 Blowing Machine—A blowing apparatus is required

when pneumatically applied specimens are to be tested.

Choose the combination of hopper, blower, and hose size and

length that is representative of common use for the application

of the material to be tested. The following machine speciﬁca-

tions have been developed for use with mineral wool and

cellulosic materials.

5.2.1.1 Mineral Fiber Insulations:

(1) Blowing Machine—A commercial blowing machine

with a design capacity for delivering the subject material at a

rate between 4 and 15 kg (9 to 33 lb)/min.

(2) Blowing Hose—The machine shall utilize 46 m (150 ft)

of typical 75 to 100 mm (3 to 4 in.) diameter ﬂexible, internally

corrugated blowing hose. At least 30 m (100 ft) of the hose

shall be elevated between 3 and 6 m (10 and 20 ft) above the

outlet of the blowing machine to simulate a typical installation

conﬁguration. The hose shall have no more than eight 90°

bends and all bends shall be greater than 1.2-m (4-ft) radius.

Before each sample preparation session, examine the hose for

material remaining from previous blows. Dislodge any remain-

ing material by mechanically agitating the hose when the

machine is running. Repeat as necessary to maintain a clean

hose for each specimen.

NOTE 3—In case of dispute, for mineral ﬁber insulations a 75 mm (3 in.)

hose shall be used to prepare the specimens.

5.2.1.2 Cellulosic Insulations:

NOTE 1—Dimensions to match thermal test apparatus.

FIG. 1 Rigid Test Frame

C687 − 18

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摘要：

ASTM C687 - 18 是一项由美国材料与试验协会发布的标准测试方法，专门用于测定板状或卷状隔热材料在稳态条件下的热流量和热阻性能。该标准详细规范了使用热流计装置对隔热材料进行热性能测试的步骤、仪器要求、样品制备及数据计算方法，适用于建筑、工业设备及管道中常用隔热材料的质量评估与性能对比。通过遵循ASTM C687测试规程，工程师和质量控制人员能够获得可靠的热导率数据，从而优化保温层设计、降低能耗并确保符合建筑节能规范。

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