ASTM C421-08(2020)

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.
Designation: C421 − 08 (Reapproved 2020)
Standard Test Method for
Tumbling Friability of Preformed Block-Type and Preformed
Pipe-Covering-Type Thermal Insulation
This standard is issued under the fixed designation C421; 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.
1. Scope 4. Significance and Use
1.1 This test method covers determination of the mass loss
4.1 Several test methods for measuring mass loss by abra-
of preformed block-type and preformed pipe-covering-type
sion and impact of preformed block-type and preformed
thermal insulation as a result of a combination of abrasion and
pipe-covering-type thermal insulation have been used previ-
impact produced by a laboratory tumbling mechanism.
ously. It is believed that no single test method completely
covers all factors involving such forces for different kinds of
1.2 The values stated in inch-pound units are to be regarded
materials, but this test method is intended to provide a
as standard. The values given in parentheses are mathematical
procedure that gives reproducible results. It is used for com-
conversions to SI units that are provided for information only
paring the mass loss by tumbling before and after a specific
and are not considered standard.
treatment of the insulation, as agreed upon by the purchaser
1.3 This standard does not purport to address all of the
and the manufacturer.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 Box—A cubical box of oak wood, having inside dimen-
1 3 3
1.4 This international standard was developed in accor-
sions of 7 ⁄2 by 7 ⁄4 by 7 ⁄4 in. (190 by 197 by 197 mm),
3 3
dance with internationally recognized principles on standard-
mounted rigidly at the center of one 7 ⁄4 by 7 ⁄4 in. (197 by 197
ization established in the Decision on Principles for the
mm) end, so that the axis normal to a face of the box is that of
Development of International Standards, Guides and Recom-
a rotatable horizontal shaft. One side of the box shall be hinged
mendations issued by the World Trade Organization Technical
as a door and shall be gasketed to be dust-tight. The box shaft
Barriers to Trade (TBT) Committee.
shall be motor driven at a constant speed of 60 6 2 r/min.
3 1
2. Referenced Documents
5.2 Cubes—Twenty-four room-dry, solid oak, ⁄4 6 ⁄32-in.
(19 6 0.8-mm) cubes shall be placed in the box with the test
2.1 ASTM Standards:
specimens. The specific gravity of the oak cubes shall be
C168 Terminology Relating to Thermal Insulation
approximately 0.65; white oak meets this requirement.
C302 Test Method for Density and Dimensions of Pre-
formed Pipe-Covering-Type Thermal Insulation
NOTE 1—Number each group of wood cubes 1 through 24. At the end
C303 Test Method for Dimensions and Density of Pre-
of every 600-revolution test, remove one “used” cube (follow the number
formed Block and Board–Type Thermal Insulation sequence and remove the oldest cube) and replace with a correspondingly
numbered “new” cube. In this manner, cube wear is eliminated as an
3. Terminology
uncontrolled variable in the test method. When the corners of the wood
cubes have been worn so that the radius of curvature is greater than ⁄16 in.
3.1 Definitions—Definitions pertaining to thermal insulat-
(1.6 mm) or the cubes have become altered so as not to be comparable
ing materials are defined in Terminology C168.
with new cubes, they shall be discarded and new ones used. A conven-
tional machinist’s radius gage is used for checking the edge wear.
This test method is under the jurisdiction ofASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.32 on Mechanical
6. Test Specimens
Properties.
Current edition approved March 1, 2020. Published March 2020. Originally
6.1 Cut the insulation with a fine-tooth saw (similar to a
approved in 1958. Last previous edition approved in 2014 as C421 – 08 (2014).
16-tooth band saw) into 1 6 ⁄16-in. (25.4 6 1.6-mm) cubes.
DOI: 10.1520/C0421-08R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.2 Test twelve cubes at a time cut from one piece of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
insulation. When flat insulation has special surfaces due to
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. treatment or molding, cut each cube to include such special
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C421 − 08 (2020)
TABLE 1 Precision
surfaces as one face, except that the edges and corne
...