AATCC Red 40 Stain Scale
The stain resistance of pile floor coverings to acid food colors is determined by using AATCC Test Method 175, Stain Resistance: Pile Floor Coverings. The residual color left on the pile floor covering is evaluated using the AATCC Red 40 Stain Scale. The depth of the stain is visually compared to the ten step stain scale and given a rating.