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    ASTM G200 - 20

    Standard Test Method for Measurement of Oxidation-Reduction Potential (ORP) of Soil

    Active Standard ASTM G200 | Developed by Subcommittee: G01.10

    Book of Standards Volume: 03.02


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    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.

    1. Scope

    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.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D1498 Test Method for Oxidation-Reduction Potential of Water

    E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

    G3 Practice for Conventions Applicable to Electrochemical Measurements in Corrosion Testing

    G51 Test Method for Measuring pH of Soil for Use in Corrosion Testing

    G57 Test Method for Measurement of Soil Resistivity Using the Wenner Four-Electrode Method

    G187 Test Method for Measurement of Soil Resistivity Using the Two-Electrode Soil Box Method

    G193 Terminology and Acronyms Relating to Corrosion


    ICS Code

    ICS Number Code 13.080.30 (Biological properties of soil)

    UNSPSC Code

    UNSPSC Code 11111501(Soil)


    Referencing This Standard
    Link Here
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    DOI: 10.1520/G0200-20

    Citation Format

    ASTM G200-20, Standard Test Method for Measurement of Oxidation-Reduction Potential (ORP) of Soil, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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