The first part of the test determines the as-received soil resistivity. A sample of soil is placed in a soil box and the resistivity is determined in ohm-cm. Then, distilled water is added to the sample and the resistivity is measured until the minimum values are determined. This gives the range of resistivity that can be expected over the course of the year. Based on those tests, select a sample with the lowest resistivity plus a sample in the middle of the range of resistivity for chemical analysis.
Total acidity measures the reservoir of acid content in the soil.
Whatever the pipe product selected, elements in the pipe burial environment may affect its long-term performance. Proper characterization of that environment and designing into installation the appropriate responses will produce the long life that is expected.