Geotextile Water Permeability Tester

Geotextile Permeability Testers | ISO 11058 & ASTM D4491 Cross-Plane Flow Testing

A geotextile permeability tester determines how easily water flows through the thickness of a fabric. This characteristic is essential for evaluating whether a filter provides adequate drainage or becomes clogged. ISO 11058 specifies the measurement of water permeability perpendicular to the fabric plane under zero pressure, with flow velocity reported at a 50 mm hydraulic head. ASTM D4491 evaluates the same property as permittivity under uncompressed conditions.

Qualitest offers ten geotextile permeability tester configurations, ranging from manual bench-top instruments to fully automated systems featuring de-aired, temperature-controlled water. Manufacturers use these instruments for production lot approval, while hydraulic engineers assess filter compatibility with the soil being retained. The range also includes a pressure-operated model designed to measure barrier membranes.

Applications

Cross-plane permeability testing is essential for filtration and drainage evaluations in civil engineering projects and geosynthetic manufacturing.

Geotextile Manufacturing: Confirms that woven and nonwoven filter fabrics consistently meet the water flow capacity specified in product data sheets across successive production lots.
Landfill and Containment: Evaluates filter geotextile performance above leachate collection layers and beneath drainage systems installed in landfill caps.
Embankment Dams and Levees: Verifies that filter fabrics discharge seepage faster than water enters from the surrounding soil, preventing pressure buildup behind the fabric.
Canal and Reservoir Lining: Assesses fabrics installed beneath lining systems to prevent trapped seepage from lifting or displacing the lining.
Highway and Railway Drainage: Checks the performance of separation and filtration fabrics used in edge drains, drainage blankets, and subgrade applications.
Coastal and Erosion Control: Measures water flow through fabrics placed beneath riprap, gabions, and revetments, where inadequate filtration can result in soil loss.
Barrier Liner Qualification: Determines the permeability coefficient of geomembranes and waterproofing sheets under applied pressure.
Acceptance and Third-Party Laboratories: Supports shipment acceptance inspections of commercial geotextile deliveries before materials are released for installation.

Geotextile Permeability Tester Range

Qualitest offers ten models to accommodate everything from occasional bench-top measurements to high-throughput, fully automated laboratory testing. Nine models force water through the specimen using a hydraulic head, while the tenth uses pump-generated pressure for testing barrier membranes.

Model	Test Principle	Control and Automation	Description
QualiGTX™ GPT MN	Constant head, 250 mm maximum	Manual valve control, timer to 0.01 s	Benchtop unit with a ø50 mm clamp, 1000 mL graduated cylinder, and integrated 0 to 50 °C thermometer. Accepts specimens up to 20 mm thick. At 36 kg it suits laboratories running permeability as an occasional confirmation test.
QualiGTX™ GPT E	Head driven, ASTM D4491 configuration	Touchscreen, automatic timing	Entry-level cabinet configured for permittivity testing, with dissolved oxygen measurement fitted. The most direct route to a standards-referenced result for routine quality control.
QualiGTX™ GPT GS	Head driven, ISO 11058 configuration	Touchscreen, automatic timing	Shares the QualiGTX™ GPT E chassis, configured for velocity index testing with full dissolved oxygen specification. Choose it where reporting follows the ISO route rather than ASTM.
QualiGTX™ GPT V	Head driven, fixed 20 cm² test area	Touchscreen, automatic timing	Floor-standing analyzer for water resources work, with a machined aluminum alloy clamp that seals the specimen perimeter against edge leakage. Built for dam, levee, and canal filter verification.
QualiGTX™ GPT GW	Head driven, ø80 mm test area	Touchscreen, automatic timing	Floor-standing system with heated and cooled water held at a set point, plus a custom-configured source tank. The largest test area in the range at roughly 50 cm², which tightens repeatability on nonwovens that vary in density across a roll.
QualiGTX™ GPT T	Head driven, thermostatic bath	Touchscreen, temperature and DO control	Holds test water between 10 °C and 60 °C with dissolved oxygen control. Suits laboratories that study how flow capacity shifts with temperature rather than correcting for it after the run.
QualiGTX™ GPT M	Head driven, motorized water level	Touchscreen, powered head adjustment	Steps the head through several settings without a manual reset at each point. Multiple head readings show whether flow has left the laminar regime, which decides whether the reported coefficient is valid.
QualiGTX™ GPT A	Head driven, automated head sequence	Touchscreen, automated positioning and timing	Runs the full sequence with minimal operator input, with compressor cooling on the water circuit. Built for laboratories processing specimens in volume, where setup minutes accumulate across a shift.
QualiGTX™ GPT D	Head driven, de-aired water supply	Touchscreen, de-aeration and DO control	Top of the range, combining de-aired water, dissolved oxygen control, and temperature regulation. Removing dissolved air stops bubbles lodging in the pore structure and drifting readings downward through a run.
QualiGTX™ GPT GM 100	Applied pressure, 0 to 1 MPa	10-inch touchscreen, automatic timing	Pressure driven rather than head driven, measuring the permeability coefficient of barrier membranes across three specimens at once. Built for liner qualification, where the flow being measured sits close to zero.

How to Choose the Right Geotextile Permeability Tester

For occasional confirmation testing on a bench: Select the GPT MN, which offers a limited calibration scope and requires a bench area of 500 × 550 mm.
For standards-based testing at an economical entry cost: Choose the QualiGTX™ GPT E for ASTM D4491 permittivity measurements or the GPT GS for the ISO 11058 velocity index.
For dam, levee, and canal filter verification: Choose the GPT V, designed around the fixed 20 cm² test area commonly used in water resources testing.
For improved repeatability when testing non-uniform nonwoven fabrics: Select the GPT GW, featuring a 50 cm² test area that evaluates a larger portion of the fabric structure in each specimen.
For applications requiring controlled test temperatures rather than temperature corrections: Choose the GPT GW or QualiGTX™ GPT T, both of which regulate water temperature from 10 °C to 60 °C.
For confirming laminar flow conditions: Select the GPT M, which features a motorized head and collects measurements at multiple head points during a single test.
For high specimen throughput: Choose the QualiGTX™ GPT A for automated test sequencing, or the GPT D when de-aired water is required to maintain stability during extended testing.
For geomembranes and waterproofing sheets: Select the QualiGTX™ GPT GM 100, the only pressure-driven instrument in the range.

Why Choose Qualitest for Your Geotextile Permeability Tester

Qualitest North America provides testing and measurement equipment for laboratories, quality control departments, and manufacturers, supported by responsive technical assistance and calibration services. Our geotextile permeability tester range is designed to deliver dependable results in accordance with applicable testing standards, allowing customers to source their equipment and technical support through one trusted supplier.

Our specialists help identify the appropriate instrument configuration based on your specimen types, applicable standards, and testing volume. From initial equipment selection and installation to ongoing technical assistance, Qualitest supports your testing requirements at every stage.

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