This document specifies the classification, requirements, sampling, test methods, inspection rules, marking, packaging, transportation, storage and safety of by-product sulfuric acid. This document applies to the by-product sulfuric acid produced during the production of trifluoroacetic acid (TFA) from 1,1,1-trichlorotrifluoroethane (CFC-113a). The main technical contents are as follows: 1. Appearance: colorless, light yellow or yellow liquid, no visible mechanical impurities. 2. Total acidity (calculated as H2SO4): I: 55.0±5.0%, II: 45.0±5.0% (when the total acidity is 50.0%, it is calculated as Type I). 3. Chloride (calculated as Cl): ≤15.0%. 4. Other impurities: according to user requirements (the manufacturer shall provide other impurity information and test methods at the user's request).