ISO 15705:2002规定了使用密封管法测定化学需氧量（ST-COD）的方法。该测试是经验性的，适用于任何含水样品，包括所有污水和废水。 该方法适用于ST-COD值高达1000 mg/l且氯化物浓度不超过1000 mg/l的未稀释样品。ST-COD值较高的样品需要预稀释。对于COD较低的样品，测量精度将降低，检测限将降低。 该方法氧化几乎所有类型的有机化合物和大多数无机还原剂。根据一家实验室的报告，在600 nm处进行光度检测时，其检测限（空白或极低标准品的批内标准偏差的4.65倍）为6 mg/l，而在滴定检测时，其检测限为15 mg/l，该实验室使用范围高达1000 mg/l的商用试剂盒对光度和滴定技术进行了比较。 本方法的滴定部分适用于消化阶段后呈现非典型颜色或浊度的样品。

ISO 15705:2002 specifies a method for the determination of the chemical oxygen demand (ST-COD) using the sealed tube method. The test is empirical and is applicable to any aqueous sample, which includes all sewage and waste waters. The method is applicable to undiluted samples having ST-COD values up to 1 000 mg/l and a chloride concentration not exceeding 1 000 mg/l. Samples with higher ST-COD values require predilution. For samples with a low COD, the precision of the measurement will be reduced and the detection limit will be poorer. The method oxidizes almost all types of organic compounds and most inorganic reducing agents. It has a detection limit (4,65 times the within-batch standard deviation of a blank or very low standard) of 6 mg/l for photometric detection at 600 nm, and 15 mg/l for titrimetric detection as reported by one laboratory comparing the photometric and titrimetric techniques using a commercial test kit with a range up to 1 000 mg/l. The titrimetric part of this method is applicable to samples exhibiting an atypical colour or turbidity after the digestion stage.