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ASTM C421-08(R2020) pdf free download

ASTM C421-08(R2020) pdf free download.Standard Test Method for Tumbling Friability of Preformed Block-Type and Preformed Pipe-Covering-Type Thermal Insulation
1. Scope
1.1 This test method covers determination of the mass loss of preformed block-type and preformed pipe-covering-type thermal insulation as a result of a combination of abrasion and impact produced by a laboratory tumbling mechanism. 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 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.
4. Significance and Use
4.1 Several test methods for measuring mass loss by abra- sion and impact of preformed block-type and preformed pipe-covering-type thermal insulation have been used previ- ously. It is believed that no single test method completely covers all factors involving such forces for different kinds of materials, but this test method is intended to provide a procedure that gives reproducible results. It is used for com- paring the mass loss by tumbling before and after a specific treatment of the insulation, as agreed upon by the purchaser and the manufacturer.
5. Apparatus
5.1 Box—A cubical box of oak wood, having inside dimen- sions of 7 1 ⁄ 2 by 7 3 ⁄ 4 by 7 3 ⁄ 4 in. (190 by 197 by 197 mm), mounted rigidly at the center ofone 7 3 ⁄ 4 by 7 3 ⁄ 4 in. (197 by 197 mm) end, so that the axis normal to a face of the box is that of a rotatable horizontal shaft. One side ofthe box shall be hinged 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. 5.2 Cubes—Twenty-four room-dry, solid oak, 3 ⁄ 4 6 1 ⁄ 32 -in. (19 6 0.8-mm) cubes shall be placed in the box with the test specimens. The specific gravity of the oak cubes shall be approximately 0.65; white oak meets this requirement. N OTE 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 sequence and remove the oldest cube) and replace with a correspondingly numbered “new” cube. In this manner, cube wear is eliminated as an uncontrolled variable in the test method. When the corners of the wood cubes have been worn so that the radius ofcurvature is greater than 1 ⁄ 16 in. (1.6 mm) or the cubes have become altered so as not to be comparable 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.
6. Test Specimens
6.1 Cut the insulation with a fine-tooth saw (similar to a 16-tooth band saw) into 1 6 1 ⁄ 16 -in. (25.4 6 1.6-mm) cubes. 6.2 Test twelve cubes at a time cut from one piece of insulation. When flat insulation has special surfaces due to treatment or molding, cut each cube to include such special surfaces as one face, except that the edges and corners of the insulation shall not be used. 6.3 Dry and condition specimens prior to test, following applicable specifications for the material. If the material is adversely affected by oven temperatures, then condition speci- mens for not less than 40 h at 73.46 1.8°F (23 6 1°C), and 50 6 5 % relative humidity before testing. In the absence of definitive drying specifications, dry specimens in an oven at 215 to 250°F (102 to 121°C) to constant mass, and hold in a desiccator to cool to room temperature before testing. Where circumstances or requirements preclude compliance with these conditioning procedures, exceptions agreed upon by the pur- chaser and the manufacturer are acceptable, but they shall be specifically listed in the test report.

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