Field Permeability Testing (Lefranc & Lugeon) in Celbridge

A Lefranc test measures hydraulic conductivity in soil by injecting or extracting water from an isolated section of a borehole and recording the pressure or flow response. A Lugeon test is the rock mechanics equivalent: it injects water under pressure into a sealed section of a rock borehole and measures the water take in litres per minute per metre of test section at each pressure stage. The Lugeon value (1 Lu ≈ 1 l/min/m at 10 bar) characterises fracture permeability. In Celbridge we use Lefranc in the till and Lugeon once we hit the limestone.

The cost ranges from €580 to €1050 depending on the number of test intervals, the depth, and whether the borehole is already drilled. A single Lefranc test in a pre-existing borehole falls at the lower end. A full five-stage Lugeon test with packer setup, pressure control, and real-time data acquisition in a deep rock borehole reaches the upper end. We provide a fixed-price quote after reviewing the borehole log and the target depth.

Kildare County Council's planning department requires a groundwater control plan for any excavation deeper than three metres. That plan must be based on a site-specific hydraulic conductivity value measured in the field, not estimated from grain size charts. The shallow water table near the Rye River and the risk of encountering solution features in the limestone make field permeability data essential for designing a safe and compliant dewatering system.

A single five-stage Lugeon test in a 3-metre isolated section typically takes 45 to 60 minutes, including packer inflation, pressure stabilisation at each stage, and data recording. We run the test immediately after drilling the rock section so the fracture walls are clean. The pressure-flow data is reduced on-site and we can give you the Lugeon values and the interpreted flow regime before the rig demobilises.