ASTM C303-21

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Designation: C303 − 10 (Reapproved 2016) C303 − 21
Standard Test Method for
Dimensions and Density of Preformed Block and
Board–Type Thermal Insulation
This standard is issued under the fixed designation C303; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Editorially corrected 5.2 and 6.2 in November 2016.
1. Scope
1.1 This test method covers determination of the dimensions and density of block and board insulation as defined in Terminology
C168.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
C167 Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations
C168 Terminology Relating to Thermal Insulation
C390 Practice for Sampling and Acceptance of Thermal Insulation Lots
C870 Practice for Conditioning of Thermal Insulating Materials
3. Terminology
3.1 General—Terminology C168 shall be considered as applicable to the terms used in this test method.
4. Summary of Test Method
4.1 The material shall be tested in the “dry” condition or in the “as manufactured and received” condition (see Note 1) but the
This test method is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.32 on Mechanical
Properties.
Current edition approved Oct. 15, 2016March 1, 2021. Published November 2016March 2021. Originally published as approved in 1952. Last previous edition approved
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in 20102016 as C303 – 10.C303 – 10 (2016) . DOI: 10.1520/C0303-10R16E01.10.1520/C0303-21.
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C303 − 21
procedure must be consistent with that as given in the material specification. If the material is to be tested in the “dry” condition
it shall be dried to constant mass. If the material specification does not give conditioning instructions, a conditioning environment
of 73°F 6 4°F (23°C 6 2°C) and 50 6 5 % relative humidity per Practice C870 shall be used. From the measured mass and
measured dimensions, the density of the product is calculated.
NOTE 1—Some materials may contain volatiles such as moisture when manufactured or shipped, or both.
5. Significance and Use
5.1 Dimensional measurements of the product thermal insulation are essential in determining compliance of a product with
specification limits. Dimensional measurements of various test specimens are also required by the specific test method.
5.2 Density measurements of the product insulation are useful in determining compliance of a product with specification limits,
and in providing a relative gage of product weights. For any one kind of insulation, some important physical and mechanical
properties, such as thermal conductivity, heat capacity, strength, etc., bear a specific relationship with its density. In order to design
for equipment supports, check the material for the “as received density” where the moisture content of the product as received and
then installed has the potential to be consequential.
6. Apparatus
6.1 Steel measure, (ruler or tape), graduated in millimetres or better, suitable for measuring dimensions to 6 1.0 % (see Note 2).
6.2 Instrument, such as caliper, dial gage, or micrometer graduated in millimetres or better, with a minimum plate diameter of 6
mm, and a maximum plate of 1.0 by 1.0 in. (25 by 25 mm). This instrument shall be suitable for measuring the dimensions to
61.0 %. This instrument shall not cause deformation of the product when measuring it. Ensure that the pressure exerted by this
measuring plate does not exceed 0.040 psi or 5psf (0.245 kPa).
6.3 Pin probe depth gage per Test Methods C167.
6.4 Scales, accurate to within 0.0lb (5g) or within 1 % of the specimen mass (whichever is less). If the material specification calls
for a greater accuracy, this shall take precedence. If the samples are
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