(a) These methods cover nonreferee procedures for the determination of residual chlorine in industrial waste water. A referee method and two nonreferee methods for the determination of residual chlorine in industrial water other than that containing waste are given in the Methods of Test for Residual Chlorine in Industrial Water (ASTM Designation: D 1253). Provision is made in these methods for the determination of total chlorine and free available chlorine. Provision is also made for the determination of the total chlorine in the presence of most of the interfering constituents found in industrial waste water, either through choice of the method employed or by a modification of the same. Two methods are given, as follows: Sections Non-Referee Method A (Starch-Iodide Titration Method) 6 to 11 Non-Referee Method B (Amperometric Titration Method) 12 to 20 (b) Both methods are applicable to the determination of total chlorine in industrial waste water. Only non-referee method B is applicable to the determination of free available chlorine in industrial waste water. (c) The type of residual chlorine to be determined depends on the objective of chlorination. When a free chlorine residual is not required, a determination of the total chlorine normally suffices regardless of the composition of the chlorine residual. (d) Modifications of these methods are provided to eliminate one or more interferences present either initially in the industrial waste water or present subsequent to chlorination. The methods are most dependable when used with industrial waste water of known composition.