User Guide to Thresholds and Classification - Environmental ...

168User Guide for Thresholds and ClassificationsIf any data show that an ingredient(s) may be corrosive or irritant at a concentration of < 1% (corrosive) or< 3% (irritant), the mixture should be classified accordingly.Table 11.2: Skin corrosive or irritant classifications for mixtures using additivitySum of concentrations ofingredients classified as categoryClassification of a mixture as category8.2A, 8.2B,or 8.2C6.3A 6.3B8.2A, 8.2B, or 8.2C (alone or sum) ≥ 5% ≥ 1% but < 5%6.3A (alone or sum) ≥ 10% ≥ 1% but < 10%6.3B (alone or sum) ≥ 10%(8.2A, 8.2B, and 8.2C × 10) + 6.3A ≥ 10% ≥ 1% but < 10%(8.2A, 8.2B, and 8.2C × 10) + 6.3A + 6.3B ≥ 10%NotesDetermine whether a classification should be assigned by starting at the top left column of the table and workingdown.The percentage of each component(s) that triggers a particular classification (multiplied by a factor of 10 whereindicated) is compared against the concentration cut-offs required to trigger a classification in the mixture.When the sum of all ingredients classified as category 8.2A, 8.2B, or 8.2C is:each 5%, then the mixture is classified in the same subclass (for example, if the sum of 8.2A 5% thenclassify as 8.2A);if the sum of 8.2A is < 5% but the sum of 8.2A + 8.2B is 5%, then classify the mixture as 8.2B; andif the sum of 8.2A + 8.2B is < 5% but the sum of 8.2A + 8.2B + 8.2C is 5%, then classify the mixture as8.2C.Table 11.3: Classification of substances where additivity does not applyIngredient Concentration Mixture classified as categoryAcid with pH ≤ 2 ≥ 1% 8.2A, 8.2B, or 8.2CBase with pH ≥ 11.5 ≥ 1% 8.2A, 8.2B, or 8.2COther corrosive (8.2A, 8.2B, or 8.2C)ingredients for which additivity does not applyOther irritant (6.3A) ingredients for whichadditivity does not apply≥ 1% 8.2A, 8.2B, or 8.2C≥ 3% 6.3AIt may be possible to calculate the molar balance of an acid and base in a neutralisation reaction. This wouldallow the determination of residual acid or base (after neutralisation) and whether the residual acid or baseshould trigger a classification in the mixture.January 2012 EPA0109