Permeability Apparatus Falling Constant Head is used for testing the permeability of granular soils (sands and gravels).The specimen is formed in a permeability cell and water is passed through it from a constant level tank Take-off points located along the sides of the permeability cell are connected to three manometer tubes mounted on a panel complete with a meter scale. Water passing through the specimen is collected and measured, either for a specific quantity or over a period of time. The reduction of head is noted from the variation of water level in the manometer tubes.

Permeability Apparatus - In soil machines Permeability is one of the important Engineering properties, as it governs rate of settlement of saturated compressible soil layer and rate of flow of equifer. Permeability is that property of soil which permits flow of water through its interconnecting voids.