The ASTM D3385-18 standard mandates the .

: Two concentric rings—usually a 12-inch (300 mm) inner ring and a 24-inch (600 mm) outer ring —driven into the soil to a specific depth.

ASTM D3385-18 specifies the standard test method for measuring the infiltration rate of soils in the field using a double-ring infiltrometer

Data interpretation and reporting