ASTM C 1378

This test method details the standard procedures for the determination of the resistance to staining of ceramic tile surfaces. A unsanded contrasting tile grout, black carbon lamp, waterproof black ink, washable ink, potassium permanganate solution, and methylene blue solutions are the staining agents required for this test method. Also, the following materials and apparatuses are needed: plain end glass test tubes; glass pipets; an oven; lintless, absorbent clothes or paper towels; distilled or deionized water; a light source; cleaning agents; hot water; weak commercial cleaning agent not containing abrasive; strong commercial cleaning agent containing abrasive; and suitable solvents such as hydrochloric acid and potassium hydroxide solution. The resistance to staining is determined by maintaining test solutions in contact with ceramic tile surfaces for a specified period of time. After exposure, the surface is cleaned in a defined manner, and the test specimens are inspected visually for change.