Changes in physical dimensions of tile due to exposure to water and water vapor are determined by this method. Such dimensional changes may influence the integrity and stability of an installation. Tile specimens are tested for elongation of size due to rehydration by autoclaving.
Three (3) test pieces of size 1" × 4", cut from the center of whole tiles, are required for one test. The test pieces are measured with a micrometer and subjected to steam under pressure in an autoclave for five hours. After autoclaving, the test pieces are dried to a constant mass and measured again with a micrometer to determine expansion due to moisture exposure.
In this test method, water absorption of tile specimens is calculated based on a five hour boiling water method. This test is used to determine the degree of maturation of the ceramic tile body or for evaluating structural properties that may be required during installation.