ISO 11275:2004 specifies a laboratory method for the simultaneous determination in soils of the unsaturated hydraulic conductivity and of the soil water-retention characteristic. It is applicable only to measurement of the drying or desorption curve. Application of the method is restricted to soil samples which are, as far as possible, homogeneous. The method is not applicable to soils which shrink in the range of matric head 0 cm to -800 cm.
The range of the determination of the conductivity depends on the soil type. It lies between matric heads of approximately -50 cm and -700 cm.
The range of the determination of the water-retention characteristic lies between matric heads of approximately 0 cm and -800 cm.