Significance and Use
5.1 The resistivity of the surrounding soil environment is a factor in the corrosion of underground structures. High resistivity soils are generally not as corrosive as low resistivity soils. The resistivity of the soil is one of many factors that influence the service life of a buried structure. Soil resistivity may affect the material selection and the location of a structure.5
5.2 Soil resistivity is of particular importance and interest in the corrosion process because it is basic in the analysis of corrosion problems and the design of corrective measures.
5.3 The test method is focused to provide an accurate, expeditious measurement of soil resistivity to assist in the determination of a soil’s corrosive nature. Test Method G57 emphasizes an in situ measurement commonly utilized in the design of a buried structures’ corrosion control (cathodic protection systems’ ground bed design, and so forth), but also includes information and procedures on a four-pin soil box method. The two-electrode soil box method is an accurate and more expeditious method than the four-pin soil box and often complements the four-pin, in situ soil resistivity method.
5.4 The saturated soil resistivity determined by this test method does not necessarily indicate the minimum soil resistivity.
Scope
1.1 This test method covers the equipment and procedures for the measurement of soil resistivity, for soil samples removed from the ground, for use in the assessment and control of corrosion of buried structures.
1.2 Procedures allow for this test method to be used in the field or in the laboratory.
1.3 The test method procedures are for the resistivity measurement of soil samples in the saturated condition and in the as-received condition.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. Soil resistivity values are reported in ohm-centimeter.
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 to 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.
