ASTM D6639-18 PDF Download

ASTM D6639-18 is a standard guide that provides an overview of the frequency domain electromagnetic (FDEM) method for subsurface site characterizations. This guide summarizes the equipment, field procedures, and interpretation methods used in assessing subsurface conditions using FDEM measurements. The FDEM method is versatile and can be applied to various applications such as geologic, geotechnical, hydrologic, environmental, agricultural, archaeological, forensic site characterizations, and mineral exploration.

The FDEM method involves measuring the secondary magnetic field induced in the earth by a time-varying primary magnetic field. The measurements are typically conducted using instruments that measure two components of the secondary magnetic field: the in-phase component and the quadrature component. The in-phase response is more sensitive to metallic items, while the quadrature response is more sensitive to geologic variations in the subsurface. Both components can be influenced by both metallic and geologic features, and the measurements are dependent on the electrical properties of the subsurface and the orientation of geological features or man-made objects.

The standard guide also lists limitations and precautions when using the FDEM method. It emphasizes that this guide provides an overview and does not delve into the electromagnetic theory, field procedures, or data interpretation in detail. It recommends referring to other references for more comprehensive information. The guide also highlights the importance of safety precautions and complying with relevant regulations when using the FDEM method at sites with hazardous materials, operations, or equipment.