ASTM C421-08

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C421 − 08
StandardTest Method for
Tumbling Friability of Preformed Block-Type and Preformed
1
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 Department of Defense.
1. Scope covers all factors involving such forces for different kinds of
materials, but this test method is intended to provide a
1.1 This test method covers determination of the mass loss
procedure that gives reproducible results. It is used for com-
of preformed block-type and preformed pipe-covering-type
paring the mass loss by tumbling before and after a specific
thermal insulation as a result of a combination of abrasion and
treatment of the insulation, as agreed upon by the purchaser
impact produced by a laboratory tumbling mechanism.
and the manufacturer.
1.2 The values stated in inch-pound units are to be regarded
as the standard. The values in parentheses are provided for
5. Apparatus
information only.
5.1 Box—A cubical box of oak wood, having inside dimen-
1.3 This standard does not purport to address all of the
1 3 3
sions of 7 ⁄2 by 7 ⁄4 by 7 ⁄4 in. (190 by 197 by 197 mm),
safety concerns, if any, associated with its use. It is the
3 3
mounted rigidly at the center of one 7 ⁄4 by 7 ⁄4 in. (197 by 197
responsibility of the user of this standard to establish appro-
mm) end, so that the axis normal to a face of the box is that of
priate safety and health practices and determine the applica-
a rotatable horizontal shaft. One side of the box shall be hinged
bility of regulatory limitations prior to use.
as a door and shall be gasketed to be dust-tight. The box shaft
shall be motor driven at a constant speed of 60 6 2 r/min.
2. Referenced Documents
3 1
2 5.2 Cubes—Twenty-four room-dry, solid oak, ⁄4 6 ⁄32-in.
2.1 ASTM Standards:
(19 6 0.8-mm) cubes shall be placed in the box with the test
C168 Terminology Relating to Thermal Insulation
specimens. The specific gravity of the oak cubes shall be
C302 Test Method for Density and Dimensions of Pre-
approximately 0.65; white oak meets this requirement.
formed Pipe-Covering-Type Thermal Insulation
C303 Test Method for Dimensions and Density of Pre-
NOTE 1—Number each group of wood cubes 1 through 24. At the end
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
3.1 Definitions—Definitions pertaining to thermal insulat- 1
cubes have been worn so that the radius of curvature is greater than ⁄16 in.
(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.
4. Significance and Use
4.1 Several test methods for measuring mass loss by abra-
6. Test Specimens
sion and impact of preformed block-type and preformed
6.1 Cut the insulation with a fine-tooth saw (similar to a
pipe-covering-type thermal insulation have been used previ-
1
16-tooth band saw) into 1 6 ⁄16-in. (25.4 6 1.6-mm) cubes.
ously. It is believed that no single test method completely
6.2 Test twelve cubes at a time cut from one piece of
insulation. When flat insulation has special surfaces due to
1
This test method is under the jurisdiction ofASTM Committee C16 on Thermal
treatment or molding, cut each cube to include such special
Insulation and is the direct responsibility of Subcommittee C16.32 on Mechanical
Properties.
surfaces as one face, except that the edges and corners of the
Current edition approved April 15, 2008. Published May 2008. Originally
insulation shall not be used.
approved in 1958. Last previous edition approved in 2005 as C421 – 05. DOI:
10.1520/C0421-08.
6.3 Dry and condition specimens prior to test, following
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
applicable specifications for the material. If the material is
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
adversely affected by oven temperatures, then condition speci-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. mens for not less than 40 h at 73.46 1.8°F (23 6 1°C), and 50
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