ISO 22282-3:2012

Overview - ISO 22282-3:2012 (Water pressure tests in rock)

ISO 22282-3:2012 is the International Standard that specifies requirements for water pressure tests (WPT) performed in boreholes drilled into rock as part of geotechnical investigation and testing (referencing EN 1997-1 and EN 1997-2). The standard focuses on geohydraulic testing to evaluate rock mass hydraulic behaviour governed by discontinuities, including permeability (lugeon), absorption, tightness, groutability and geomechanical responses such as hydrofracturing and hydrojacking.

Key technical topics and requirements

• Test types: single pressure step tests (tightness checks) and multiple pressure step tests (investigate water take and discontinuity behaviour).
• Equipment: pressure-controlled pump, pipes/hoses, single or double inflatable packer assemblies, shut-off valve, pressure measuring devices/ transducers, flow meter and data recording system.
• Packer specifications: effective sleeve length ≥ 10× borehole diameter and ≥ 0.5 m; inflation pressure ≥ 30% above expected maximum test pressure.
• Pump & flow: typical pump output up to 150 l/min; 1.5 MPa often suitable; oscillation-free flow or pressure dampers within ±3%.
• Flow meter: measuring range matched to expected flow; accuracy better than 3%; dual meters may be used to cover wide ranges (examples given for ~10 and ~100 l/min ranges).
• Test procedure: borehole cleaning by flushing prior to testing; record pressure and water flow simultaneously for each pressure step; each step lasts at least 10 minutes. If steady state is not reached, continue until variation