1.1 本试验方法涵盖现场或从地面移除的土壤样品的氧化还原电位（ORP）测量程序和相关测试设备。 1.2 第节中的程序 9 适用于现场和实验室测量。 1.3 准确测量氧化还原电位有助于分析土壤腐蚀性及其对埋地金属结构腐蚀速率的影响。 1.4 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.5 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。 1.6 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 土壤ORP，以及其他土壤特性，如pH（见试验方法 G51 )和电阻率（见测试方法 G57 和 G187页 )，用于预测埋地金属结构（例如管道和涵洞）的腐蚀趋势。土壤的ORP是影响结构使用寿命的众多因素之一。其测量用于设计新的埋地结构和评估现有的埋地结构。 5.2 土壤ORP是一个时间- 敏感测量。为了准确指示土壤腐蚀性，应在现场进行测量，或在从地面移除土壤样本后尽快进行测量。 5.3 本试验方法的使用者负责确定报告的ORP测量值的重要性。通常不应单独使用ORP来表征特定土壤的腐蚀性。在评估氧相关反应时，ORP测量是合适的。 5.4 ORP测量有时可能非常可变且不可再现。这在一定程度上与给定土壤的一般异质性有关。它还与提取后将增加的氧气引入样品有关。土壤ORP的解释应考虑其一般范围，而不是绝对测量。 5.5 ORP测量可用于确定特定土壤是否有支持微生物影响腐蚀（MIC）攻击的倾向。这些测量还可用于指示土壤条件是需氧还是厌氧。 附录X1 为ORP数据的一般解释提供参考指南。

1.1 This test method covers a procedure and related test equipment for measuring oxidation-reduction potential (ORP) of soil samples in-situ or removed from the ground. 1.2 The procedure in Section 9 is appropriate for field and laboratory measurements. 1.3 Accurate measurement of oxidation-reduction potential aids in the analysis of soil corrosivity and its impact on buried metallic structure corrosion rates. 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 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. 1.6 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 Soil ORP, in conjunction with other soil characteristics such as pH (see Test Method G51 ), and electrical resistivity (see Test Methods G57 and G187 ), is used to predict corrosion tendencies of buried metallic structures (for example, pipelines and culverts). The ORP of the soil is one of many factors that influence structure service life. Its measurement is used in the design of new buried structures and in the evaluation of existing buried structures. 5.2 Soil ORP is a time-sensitive measurement. For an accurate indication of soil corrosivity, the measurement should be made in-situ in the field or as soon as practicable after removal of the soil sample from the ground. 5.3 The user of this test method is responsible for determining the significance of reported ORP measurements. ORP alone should typically not be used in characterizing the corrosivity of a particular soil. ORP measurements are appropriate when evaluating oxygen related reactions. 5.4 ORP measurements can sometimes be quite variable and non-reproducible. This is related, in part, to the general heterogeneity of a given soil. It is also related to the introduction of increased oxygen into the sample after extraction. The interpretation of soil ORP should be considered in terms of its general range rather than as an absolute measurement. 5.5 ORP measurements can be used to determine if a particular soil has the propensity to support microbiologically influenced corrosion (MIC) attack. These measurements can also be used to provide an indication of whether soil conditions will be aerobic or anaerobic. Appendix X1 provides reference guidelines for general interpretation of ORP data.