ASTM C485 - 09

    Standard Test Method for Measuring Warpage of Ceramic Tile

    Active Standard ASTM C485 | Developed by Subcommittee: C21.06

    Book of Standards Volume: 15.02


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    Significance and Use

    This test method provides a means for determining whether or not a lot of ceramic tile meets the warpage requirements that may appear in specifications to assure satisfactory tile installations. In accordance with this test method, warpage is calculated as a percentage of the length of the edge or diagonal being tested. It is realized that the percentage values based on the overall edge length, or on the overall diagonal length of a tile will be slightly lower than those based on the distance between reference points. However, the ratio of the overall lengths to the distance between reference points will be practically constant for any particular size of tile and, therefore, the percentage values will be comparable and equally indicative of warpage.


    FIG. 1 Apparatus for Square Tile, Set Up for Measurement of 4 ¼- by 4¼-in. (108- by 108-mm) Tile


    FIG. 2 Apparatus as Shown in Fig. 1, Showing Arrangement of Stem Extender

    1. Scope

    1.1 This test method covers procedures for measuring diagonal and edge warpages of the following categories of ceramic tile:

    1.1.1 Square Tile, 2 by 2 in. (51 by 51 mm) or larger, that are nominally flat, of uniform overall thickness, and have a smooth face of one of the types: unglazed, bright glazed, matte glazed, or finely crystalline glazed.

    1.1.2 Oblong Tile, no facial dimension smaller than 2 in. (51 mm), that are flat, of uniform overall thickness, and have a smooth face of one of the types: unglazed, bright glazed, matte glazed, or finely crystalline glazed.

    1.1.3 Square and Oblong Tile, no facial dimension smaller than 2 in. (51 mm), that are flat, but have an irregular face such as embossed, sloped, bumpy, wavy, coarsely crystalline, or wire-cut textured.

    1.1.4 Nonrectilinear Tile, larger than 4 in.2 (26 cm2), that are flat and of uniform body thickness with smooth or irregular face, such as hexagonal, diamond, Spanish type, and so forth.

    1.1.5 Trim Tile meeting one of the descriptions in 1.1.1-1.1.4 except that only a part of the tile surface is flat. (Surface trim tile should be treated as flat tile whenever possible.)

    1.1.6 Square or Oblong Tile with facial area less than 4 in.2 (26 cm2) and at least two straight sides equal to or greater than 1.0 in. (25 mm) long. (Modular 1- by 1-in. tile are not in the scope of this test method.)

    1.2 This test method is not applicable to tile having embossed surfaces that are not flat, or that have a combination of variable body thickness and an irregular face.

    1.3 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.

    1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    C242 Terminology of Ceramic Whitewares and Related Products


    ICS Code

    ICS Number Code 91.100.25 (Terracotta building products)

    UNSPSC Code

    UNSPSC Code


    DOI: 10.1520/C0485-09

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