BS 5930:2015 makes it clear: in-situ permeability is not an optional extra. It is the foundation of any solid groundwater control plan. In Wolverhampton, where the geology shifts dramatically from Triassic sandstone across the city centre to glacial till and alluvial deposits in the Smestow Valley, laboratory tests alone often paint a misleading picture. Fracture flow in the Kidderminster Formation can be orders of magnitude higher than matrix porosity values suggest. Our team runs field permeability tests using both the Lefranc constant-head method and the Lugeon packer test, depending on the strata and project depth. The data feeds directly into dewatering design, cut-off wall specification, and deep excavation stability assessments, ensuring the numbers reflect what actually happens underground in the West Midlands.
A single Lugeon value means nothing without the flow-pressure curve. The shape of that curve reveals dilation, washout, or true laminar flow.
Method and coverage
Regional considerations
Wolverhampton sits on Sherwood Sandstone, a principal aquifer with highly variable secondary permeability. What we observe repeatedly is that unweathered sandstone cores can test below 1x10^-7 m/s, yet a Lugeon test just two metres deeper in a fractured zone yields values above 1 Lugeon unit. If the site investigation misses these contrasts, the contractor faces groundwater inflows during excavation that the dewatering system was never sized for. In the Chapel Ash area, where the sandstone lies shallow beneath made ground, we have recorded hydraulic conductivities varying by two orders of magnitude within a single borehole. This is not unusual for the region. It means that a desk study alone, or a single test at the base of a borehole, creates significant residual risk. A properly sequenced programme of Lefranc and Lugeon tests, interpreted by an engineer who knows the local hydrogeology, turns that risk into a manageable design parameter.
Standards that apply
BS 5930:2015 - Code of practice for ground investigations, BS EN ISO 22282-2:2012 - Geotechnical investigation and testing - Geohydraulic testing - Part 2: Water permeability tests in a borehole using open systems, BS EN ISO 22282-3:2012 - Geohydraulic testing - Part 3: Water pressure tests in rock
Complementary services
Lugeon Packer Testing in Rock
Multi-stage pressure tests in sandstone and mudstone using single or double pneumatic packers. Five-step pressure sequence to characterise fracture flow behaviour, with real-time flow monitoring and Q-pressure curve analysis.
Lefranc Testing in Soils
Constant-head and falling-head permeability tests in overburden and weathered zones. Suitable for glacial till, alluvium, and fill materials encountered across the Wolverhampton area.
Dewatering Parameter Reports
Synthesis of field permeability data into design-ready hydraulic conductivity profiles. Includes assessment of anisotropy, radius of influence, and inflow estimates for temporary and permanent works.
Typical parameters
Top questions
What does a field permeability test cost in Wolverhampton?
Testing programmes in Wolverhampton typically range from £540 to £720 per test stage, depending on depth, access constraints, and whether Lefranc or Lugeon configuration is required. A full day of multi-stage Lugeon testing with pneumatic packers, including engineer attendance and factual reporting, is at the upper end. We provide fixed-price proposals after reviewing the borehole logs and project specification.
When should I specify a Lugeon test instead of a Lefranc test?
The Lugeon test is designed for rock masses, particularly where fracture flow governs permeability. In Wolverhampton, we specify it for any investigation encountering the Sherwood Sandstone or Kidderminster Formation. The Lefranc test is more appropriate for soils and heavily weathered rock, such as the glacial till and alluvial deposits found in the Smestow Valley. If the borehole straddles both, we run both methods at different depths.
How long does a typical permeability testing programme take?
A single Lugeon stage with five pressure steps takes roughly 45 to 60 minutes once the packer is set. A multi-stage test across three or four zones in a 30-metre borehole typically occupies half a day. Lefranc tests in soil are quicker per stage, but the overall programme duration depends on the number of boreholes and the drilling schedule. We coordinate directly with the drilling contractor to minimise downtime.