本文报告了N，N-二乙基对苯二胺（DPD）试验程序与游离有效氯试验和丁香醛嗪（FACTS）试验程序的比较结果，FACTS试验程序与安培滴定法的比较结果，以及DPD、FACTS和安培滴定法的有限三天比较结果。调查涉及在16个参与实验室分析192个样品中的游离有效氯。本文描述了研究中使用的方法和程序，并给出了详细的结果。 讨论了以下主要结论:测量游离氯的FACTS和DPD试验程序是等效的，测量游离氯的FACTS和安培试验程序是等效的。包括7个参考文献、表格、图表。

The article reports the results of a comparison of the N,N-diethyl-p-phenylenediamine (DPD) test procedure with the free available chlorine test with syringaldazine (FACTS) procedure, a comparison of the FACTS test procedure with amperometric titration, and a limited three-day comparison of DPD, FACTS, and amperometric titration. The investigation involved analyzing 192 samples for free available chlorine at 16 participating laboratories. Methods and procedures used in the study are described, and detailed results are presented. The following major conclusions are discussed: the FACTS and DPD test procedures for measuring free chlorine are equivalent, and the FACTS and amperometric test procedures for measuring free chlorine are equivalent. Includes 7 references, tables, figures.