1.1 本试验方法包括通过直接安培滴定法测定水中的余氯。 1.2 在第节规定的约束范围内 6. ，该试验方法不受常见干扰的影响，适用于大多数水域。然而，一些水可能会产生碘需求，这通常是因为有机物质，使得通过本试验方法测量的碘更少。因此，即使测试方法工作正常，也可能在用户不知情的情况下获得错误的低氯读数。 1.3 在河口、内陆干流、淡水湖、公海和淡水冷却塔排污水中获得了该测试方法的精度数据。 由于水中氯溶液的不稳定性，无法确定偏差数据。用户有责任确保未经测试的水的测试方法的有效性。 1.4 在验证本标准的试验中，发现直接和反向碘化淀粉滴定和安培反向滴定（以前是本标准的一部分）不可行，并于1986年停止。历史信息如所示 附录X1 . 注1: 由于精度和准确性较差，省略了正交试验方法。 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 氯用于破坏或钝化水和废水中的各种有害化学物质和微生物。 5.2 水中未经控制的过量氯，无论是游离的还是结合的，都会对水的后续使用产生不利影响。

1.1 This test method covers the determination of residual chlorine in water by direct amperometric titration. 1.2 Within the constraints specified in Section 6 , this test method is not subject to commonly encountered interferences and is applicable to most waters. Some waters, however, can exert an iodine demand, usually because of organic material, making less iodine available for measurement by this test method. Thus, it is possible to obtain falsely low chlorine readings, even though the test method is working properly, without the user's knowledge. 1.3 Precision data for this test method were obtained on estuary, inland main stem river, fresh lake, open ocean, and fresh cooling tower blowdown water. Bias data could not be determined because of the instability of solutions of chlorine in water. It is the user's responsibility to ensure the validity of the test method for untested types of water. 1.4 In the testing by which this standard was validated, the direct and back starch-iodide titrations and the amperometric back titration, formerly part of this standard, were found to be unworkable and were discontinued in 1986. Historical information is presented in Appendix X1 . Note 1: Orthotolidine test methods have been omitted because of poor precision and accuracy. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Chlorine is used to destroy or deactivate a variety of unwanted chemicals and microorganisms in water and wastewater. 5.2 An uncontrolled excess of chlorine in water, whether free available or combined, can adversely affect the subsequent use of the water.