Information on the most widely used ASTM standards within the materials testing industry
Model: UT4071A; ISO 12958, ASTM D4716
The Geotextile Horizontal Permeability Tester (also called In-Plane Water Flow Tester or Horizontal Permeability Apparatus for Geosynthetics) is a specialized laboratory instrument engineered by UnitedTest to measure the in-plane water flow capacity, horizontal permeability coefficient (kₕ), and transmissivity (θ) of geotextiles and geotextile-related products under constant head flow and controlled normal pressure.
This equipment is indispensable for geosynthetic quality control labs, highway & railway engineering, landfill drainage design, water conservancy projects, and geotechnical research institutions.
ISO 12958-1 Index test for determination of in-plane water flow capacity
General Introduction
Geotextile Horizontal Permeability Tester — GB/T 17633 & ISO 12958 Compliant | UnitedTest
The Geotextile Horizontal Permeability Tester (also called In-Plane Water Flow Tester or Horizontal Permeability Apparatus for Geosynthetics) is a specialized laboratory instrument engineered by UnitedTest to measure the in-plane water flow capacity, horizontal permeability coefficient (kₕ), and transmissivity (θ) of geotextiles and geotextile-related products under constant head flow and controlled normal pressure.
This equipment is indispensable for geosynthetic quality control labs, highway & railway engineering, landfill drainage design, water conservancy projects, and geotechnical research institutions.

This model is the cost-effective basic model launched by UnitedTest for conventional testing scenarios. It retains all standard test functions required by GB/T 17633 and ISO 12958, and adopts manual operation mode, which is suitable for users with conventional test volume and limited budget.
Main features
Structural Design: Acrylic + aluminum profile frame — corrosion-resistant and visually clear for observation
Loading System: Pneumatic normal pressure loading, safe and reliable
Head Control: Manual adjustment via lifting screw; water head height read from scale with ±1 mm accuracy
Water System: Built-in water tank (≈120 L) for environmental adaptability
Manual adjustment of test water head and normal compressive pressure, with intuitive mechanical scale display
Manual timing and water volume collection through professional measuring tools
Test data is recorded and calculated manually by operators to obtain in-plane flow rate and transmissivity
No intelligent software system, simple equipment structure, low failure rate and convenient maintenance
Ideal For:
Projects where budget is a primary consideration
Laboratories performing standard index tests per GB/T 17633 / ISO 12958-1
ISO 12958-1 Index test for determination of in-plane water flow capacity
ISO 12958-2 Performance test under simulated boundary conditions
GB/T 17633 Geotextiles and geotextile-related products — Determination of water flow capacity in their plane
SL/T 235 Specification for geosynthetic testing (China Water Conservancy)
JTG E50 T1143 Highway engineering geosynthetic test protocol
ASTM D4716 Standard test method for in-plane flow of geotextiles under constant head
Under a specified hydraulic gradient and in contact with defined boundary materials, the tester applies a controlled normal compressive stress (simulating overburden load) to the saturated geotextile specimen. Constant-head water flows in-plane through the specimen. By measuring the volumetric flow rate over a timed interval, the instrument calculates:
In-plane water flow rate q [L/(m·s)]
Horizontal permeability coefficient kh [cm/s]
Transmissivity θ [cm³/s]
Per ISO 12958-1:2020, the apparatus must feature a minimum width of 200 mm, a minimum net hydraulic length of 300 mm, accommodate specimens up to 50 mm thick, maintain normal pressure tolerance within ±5%, and limit leakage to ≤5% of measured flow.
UnitedTest Geotextile Horizontal Permeability Testers are widely deployed for:
Highway & Railway Engineering: Drainage performance validation of geosynthetics in subgrade and retaining structures
Landfill & Environmental Engineering: Leachate drainage layer design
Water Conservancy: Dam filtration and drainage blankets
Coastal & River Protection: Revetment and erosion control systems
Manufacturing QC: Geotextile production line quality verification
Independent Testing Institutes: Third-party certification per GB/T 17633, ISO 12958, ASTM D4716
Specimen Preparation: Cut geotextile specimens of appropriate dimensions; saturate in water containing 0.1% non-ionic surfactant for ≥12 hours to remove air bubbles
Assembly: Place closed-cell foam rubber → specimen → upper foam rubber → pressure plate
Initial Seating Pressure: Apply 2 kPa normal pressure; flush with de-aired water to expel residual air
Stabilization: Adjust normal pressure to 20 kPa and hold for 360 s
Gradient Setting: Set hydraulic gradient to 0.1 (or as specified); allow flow for 120 s
Measurement: Collect outflow in a graduated cylinder over a timed interval
Calculation: Compute in-plane flow rate, permeability coefficient, and transmissivity
Multi-pressure Testing: Repeat at 20 kPa, 100 kPa, 200 kPa (per ISO 12958-1) or project-specified stresses
Geotextile Horizontal Permeability Tester, In-Plane Water Flow Tester, GB/T 17633-2019, ISO 12958, Geosynthetic Horizontal Permeability Apparatus, UnitedTest, Automatic Horizontal Permeability Tester, Geotextile Transmissivity Test, Constant Head In-Plane Flow, ASTM D4716 Equipment
Main Technical Specification
| Equipment Structure | Includes a sample installation device, water supply device, constant water level device, loading device, and water level measurement device. |
| Sample Size | Width not less than 100mm, length should be more than twice the width. |
| Normal Force Adjustment Range | 0-500kPa |
| Water Level Adjustment Range | 0-300mm |
| Dimensions | 700*500*1700mm |
| Power | 220V, 50HZ, 1 phase |
| Weight | 70Kg |
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