Geotextile Fabrics

Mirafi® F - Two-Layer Filtration Geotextile

Two-layer continuous filament nonwoven: one layer engineered as the filter, the second as protection for the filter. The construction delivers 25–40 constrictions through the filter layer, giving extremely low clogging risk and high soil retention security. F60, F70 and F80 at 400, 600 and 800 g/m².

Two-Layer Filter + Protection Construction

25–40 Filter Layer Constrictions

O90 90–80 µm · Low Clogging Risk

Marine & River Chemical Resistance

UV Strength Retained >80 % (EN 12224)

Overview

Mirafi® F is a two-layer continuous filament nonwoven in 100 % UV-stabilised polypropylene. One layer is designed as the filter; the second protects that filter from damage. The construction produces an optimum number of constrictions through the filter layer - between 25 and 40 - which is what delivers extremely low clogging risk together with high soil retention security.

That distinction matters because clogging, not rupture, is how a filtration geotextile usually fails. A single-layer nonwoven has to compromise between an opening size fine enough to retain soil and a structure open enough to keep passing water, and it has no protection against the installation damage that changes its filter behaviour. The two-layer construction separates those duties, so the filter layer can be optimised for retention while the protective layer takes the mechanical abuse.

Three grades are available. F60 at 400 g/m² and 3.70 mm, F70 at 600 g/m² and 4.70 mm, and F80 at 800 g/m² and 6.50 mm. Tensile strength runs from 30 kN/m to 40 kN/m, CBR puncture resistance from 4.60 kN to 7 kN, and characteristic opening size tightens from 90 µm to 80 µm. All three retain more than 80 % of strength under UV testing to EN 12224, and all are resistant to the chemical agents and microorganisms usually occurring in seas and rivers. F60 and F70 are ASQUAL certified for filtration, separation, drainage and protection; F80 for filtration, separation and drainage.

The chemical and biological resistance data points to where Mirafi F earns its place: marine and riverine filtration, revetments, scour protection, outfall structures and permanent drainage systems where the filter has to keep working for decades without maintenance access.

Material100 % UV-stabilised polypropylene (continuous filament)
StructureTwo-layer mechanically bonded nonwoven · F60–F80, 400–800 g/m²
ColourGrey
StandardASQUAL certified · CE marked · ISO 9001 / 14001 / 45001
Roll Width6 m
Roll Length100 m (F60) · 60 m (F70) · 40 m (F80)

Typical Properties

Property	Test Method	MIRAFI® S	MIRAFI® F	MIRAFI® P	MIRAFI® AR
Mass per Unit Area	EN ISO 9864	90–385 g/m²	400–800 g/m²	200–1,200 g/m²	-
Tensile Strength MD	EN ISO 10319	5–30 kN/m	30–40 kN/m	16–80 kN/m	-
CBR Puncture Resistance	EN ISO 12236	0.7–4.5 kN	4.6–7.0 kN	2.4–11.3 kN
Opening Size O90 (CMD)	EN ISO 12956	85–135 µm	80–90 µm	70–110 µm	55 µm
Permeability	EN ISO 11058	55–180 mm/s	30–60 mm/s	10–90 mm/s	10 mm/s
Abrasion Resistance	ASTM D3884	-	-	-	Tested
Mechanical Sustainability	Vibrogir (SNCF)	-	-	-	Up to 20 yrs @ 100,000 t/day
Liner Protection Efficiency	EN 13719	-	-	0.6–1.7% @ 300 kPa	-
ASQUAL Certification	-	✓ S21–S82	✓ F60–F80	✓ P20–P120	-
Roll Width	-	2–6 m	6 m	6 m (5.2–5.4 m heavy grades)	3.5–4 m

Note: The above specifications represent the product family properties. Please refer to the product datasheet for individual SKU values.

Typical Applications

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Road and pavement separation

Separation of fine-grained subgrade from coarse aggregate in road and pavement construction, preventing intermixing so the load-distributing and drainage properties of the sub-base are retained. Reduces aggregate requirement and prevents the pumping that shortens pavement life. MIRAFI S, grade selected from subgrade strength, traffic loading and aggregate particle size.

Subsoil and trench drainage

Filter wrapping to French drains, fin drains, blanket drains and trench systems. The filter must pass water freely while retaining fines, with O90 between 0.08 and 0.12 mm and permeability of at least 50 l/m²s proven effective in practice. MIRAFI S for standard duty; MIRAFI F where clogging risk is high or the drain cannot be maintained.

Geomembrane liner protection

Cushioning geomembrane liners against puncture from the subgrade below and the drainage or ballast layer above. MIRAFI P is certified to EN 13719 for protection efficiency, the figure a liner designer specifies against, with deformation at 300 kPa from 1.7 % to 0.6 % across the range.

Tailings and heap leach facilities

Protection layers to TSF and heap leach pad liner systems, where liner integrity under placement and operational loading determines containment performance. MIRAFI P in heavy grades from P60 to P120, supported by MIRAFI S for underdrainage filtration.

Landfill capping and lining

Protection and separation layers in landfill basal lining and capping systems, including protection of the geomembrane from the leachate drainage stone above. MIRAFI P for protection, MIRAFI S for separation of cover soils.

Compatible Systems

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MIRAFI® S - Separation & Filtration

Mechanically bonded continuous-filament UV-stabilised PP nonwoven with a 50-year track record in separation and filtration of trafficked areas on weak soils. Nine grades from S21 to S82 (90–385 g/m²) cover garden paths and light access roads through to heavy vehicle platforms and road or rail formation, all ASQUAL certified. Permeability 55–180 mm/s, O90 85–135 µm.

MIRAFI® F - Anti-Clogging Filtration

Two-layer continuous-filament PP nonwoven - one layer engineered as the filter, the other as integral protection against filter damage. The construction delivers 25–40 constrictions through the filter layer, giving extremely low clogging risk and high soil retention security. Three grades: F60, F70 and F80 (400–800 g/m²), O90 80–90 µm. Resistant to chemical agents and microorganisms occurring in seas and rivers

MIRAFI® P - Geomembrane Liner Protection

Needle-punched continuous-filament PP nonwoven developed specifically for geomembrane protection efficiency. Nine grades from P20 to P120 (200–1,200 g/m²), certified to EN 13719 with deformation at 300 kPa from 1.7 % down to 0.6 %. CBR puncture 2.4–11.3 kN. Specified for tailings storage facilities, heap leach pads, landfill cells, reservoirs and dams.

MIRAFI® AR20 - Abrasion Resistance

Continuous-filament PP nonwoven with abrasion-resistant additive and UV stabiliser, developed with European railway authorities for the mechanical stresses at the ballast interface. Validated by vibrogir testing with SNCF: 200 hours of loading, equivalent to 20 years at 100,000 load tons per day, with no loss of puncture resistance and no major decrease in permeability or flow rate.

Installation Guidance

Standard Method Statement

Subgrade Preparation - Prepare a smooth, stable subgrade free from sharp objects, large stones, roots and debris that could damage the geotextile during installation.

Geotextile Placement - Unroll directly onto the prepared surface without wrinkles or folds, ensuring full contact with the underlying ground and correct panel orientation.

Overlaps & Seaming - Provide overlaps in accordance with project specifications and ground conditions. Increase overlap widths or use sewn seams where very weak subgrades are encountered.

Aggregate Placement - Place cover material carefully to prevent displacement or damage to the geotextile. Do not allow construction traffic directly on exposed geotextile unless specified by the engineer.

Quality Assurance & Testing

Field QA/QC Checklist

Delivery & Storage: Rolls identified, stored and handled to ASTM D4873: wrapped, off the ground and protected from UV until installation.
Material Conformance: Roll labels and certificates checked against the specified class (e.g. AASHTO M288) and properties: mass, tensile strength (ISO 10319 / ASTM D4632), CBR puncture (ISO 12236) and opening size.
Subgrade Preparation: Surface cleared of sharp objects and graded so the geotextile lies flat without folds or bridging.
Placement & Overlaps: Overlaps or sewn seams to the specified minimum; geotextile anchored against wind and placed in the direction of fill placement.
Cover & Damage Check: Covered within the UV exposure limit stated by the manufacturer; tears or holes patched with an overlapping piece before covering.

Manufacturing Standards

ASTM D4873 identification, storage and handling
ASTM D4759 conformance to manufacturer specification
ISO 10319 / ASTM D4632 tensile strength
ISO 12236 CBR puncture resistance
AASHTO M288 (where specified)
ASQUAL certified · CE marked · ISO 9001 / 14001 / 45001

Documents

CATEGORY GUIDEPDF DOCUMENT

Product Selection Guide

Compare performance properties across the entire category hierarchy before specifying.

View guides

INSTALLATIONPDF DOCUMENT

Installation & Method Statement

Standard deployment procedures, installation specifications, and field application method statements.

QUALITY CHECKLISTREQUEST ON DEMAND

QA/QC Site Checklist

Field quality control procedures, inspection checklists, and testing standards to verify installation integrity.

TECHNICAL SPECREQUEST ON DEMAND

Technical Data Sheet (TDS)

Guaranteed minimum average roll values (MARV) and material testing properties.

ACCESSORIES GUIDEREQUEST ON DEMAND

Chemical Resistance / Accessories Guide

Chemical compatibility matrix and list of auxiliary materials needed for installation.

Projects Using Mirafi® F - Two-Layer Filtration Geotextile

Case studies and reference projects for Mirafi® F - Two-Layer Filtration Geotextile will be published shortly. Contact our technical team for reference projects across Africa.