Secutex® H geotextile: hydraulic filter for waterways

Secutex^® H - nonwoven filter geotextile for hydraulic engineering (BAW certified)
Variants: H 501 (539 g/m²) | H 751 (772 g/m²)| HB 501 sand mat (~5,500 g/m², underwater)
BAW - Federal Waterways Engineering and Research Institute (RPG 2021, MAG 2021), Federal Ministry of Transport and Digital Infrastructure (TLG 2018), CE (DIN 18200), EN ISO 9001, EPD
Service life 100 years (pH 4-9, T ≤ 25°C)

Secutex^® H is a nonwoven filter geotextile for hydraulic engineering. It is installed between riprap and fine-grained embankment soil as a filter and separation layer. The thick, porous needle-punched polypropylene structure retains soil particles, prevents contact erosion and allows water to pass freely. The filter layer provides its function under wave action and current loads. In addition to the filter efficiency of the product a sufficient robustness with regard to abrasion loads coming from the riprap cover layer and the resistance to dynamic perforation loads for the max. stone class considered by the BAW in waterways is given.

Banks, canal beds and coastal structures face continuous hydraulic loading. Fine-grained subsoils erode progressively under riprap, under current flow or wave loads, where there is no filter layer. Classical mineral filter layers require precise gradation, bulk haulage and multi-layer placement. Secutex^® H replaces multi-layer stone filters with a single nonwoven layer. Secutex^® HB extends this to direct underwater placement without dewatering.

Secutex^® H eliminates mineral filter layers that require excavation, bulk haulage and multi-layer placement. Due to its low thickness, Secutex^® H can be installed without excavation, reducing construction time and transport costs compared to mineral grain filter layers.

Secutex^® H 501 achieves a characteristic opening size O₉₀ of 0.08 mm (EN ISO 12956), water permeability VI_H50 of 4.5 x 10⁻² m/s (EN ISO 11058) and static puncture resistance CBR of 6 kN (EN ISO 12236). Secutex^® H 751 provides higher mass (772 g/m²) and greater CBR (10.6 kN) for more demanding hydraulic loading. Both variants meet all requirements of TLG Edition 2018 of the Federal Institute for Waterway Engineering (BAW), Karlsruhe. Predicted service life: 100 years in natural soils (pH 4-9, T ≤ 25°C, per test method B.4.2.2).

Secutex^® H geotextile functions:

Filtration
Secutex^® H retains fine soil particles while allowing water to pass freely under hydraulic pressure gradients.
Separation
Secutex^® H prevents intermixing of adjacent granular layers with different grain sizes under hydraulic loading.

Secutex^® H geotextile advantages: BAW certified, abrasion resistant, the determined resistance to dynamic loads and fast to install

Abrasion resistance
Secutex^® H is tested for abrasion resistance under RPG 2021, demonstrating its suitability for applications exposed to moving stone by maintaining the filter efficiency. Progressive erosion is prevented throughout service life.
Adapts to bed deformations
The nonwoven adapts to uneven surfaces, settlements and deformations without losing filter continuity.
Fast installation
Wide rolls reduce seam count as well as installation time. No excavation is needed. Secutex^® HB sand mat installs directly underwater.
100 year service life
Predicted service life of 100 years in natural soils (pH 4-9, soil temperature ≤ 25°C), verified for permanent hydraulic engineering applications.
BAW certified
Secutex^® H 501 and H 751 filter geotextiles and Secutex^® HB and HB 751 sand mats carry valid BAW basic test reports for German inland waterway projects. Accepted directly in public tender specifications.

Application areas

Inland waterway and canal revetment
Filter and separation layer between fine-grained subsoil and riprap or stone armour in riverbank and canal revetments
Replacement of multi-layer mineral grain filter courses with a single nonwoven layer
BAW TLG 2018-compliant filtration matched to the subsoil grading (soil types A/B with Secutex^® H 501; A/B/C with Secutex^® H 751, Secutex^® HB 501 and Secutex^® HB 751)
Direct underwater placement in flowing water with the self-sinking Secutex^® HB sand mat; no dewatering or divers
Secutex^® H is the BAW-certified filter geotextile for inland waterway and canal revetments, replacing classical multi-layer soil filters with a single nonwoven layer. For placement below the waterline, the self-sinking Secutex^® HB sand mat stays positionally stable under current.
The sand mat can replace fascine mattresses and mineral filter layers and provides sufficient robustness for stone plancement and flow velocities of up to 0.5 m/s.
To the application:
Hydraulic engineering
Coastal, harbour and scour protection
Filter layer between seabed sediment and ripraps or armour stones at breakwaters and groynes
Erosion or scour protection at harbour quay walls and marine structures
Prevention of fine-sediment migration through armour stone under wave and current action
Underwater placement of the Secutex^® HB sand mat in harbour and breakwater foundations
Under wave and current loading, Secutex^® H provides long-term filter stability with high resistance to abrasion. During installation it is resistant against dynamic perforation loads and can be covered directly with riprap or heavy rock armour. Secutex^® H is installed against breakwaters, predominantly to prevent sand from filtering through the rock fill.
For installation below the waterline, the Secutex^® HB sand mat is placed directly from a work vessel, using a long-arm excavator. Fender piles can be driven through the mat.
To the application:
Hydraulic engineering

Filter and separation layer between fine-grained subsoil and riprap or stone armour in riverbank and canal revetments
Replacement of multi-layer mineral grain filter courses with a single nonwoven layer
BAW TLG 2018-compliant filtration matched to the subsoil grading (soil types A/B with Secutex^® H 501; A/B/C with Secutex^® H 751, Secutex^® HB 501 and Secutex^® HB 751)
Direct underwater placement in flowing water with the self-sinking Secutex^® HB sand mat; no dewatering or divers

Secutex^® H is the BAW-certified filter geotextile for inland waterway and canal revetments, replacing classical multi-layer soil filters with a single nonwoven layer. For placement below the waterline, the self-sinking Secutex^® HB sand mat stays positionally stable under current.

The sand mat can replace fascine mattresses and mineral filter layers and provides sufficient robustness for stone plancement and flow velocities of up to 0.5 m/s.

Two excavators working along a riverbank, placing a geotextile filter nonwoven for a protection measure.

To the application:

Hydraulic engineering

Filter layer between seabed sediment and ripraps or armour stones at breakwaters and groynes
Erosion or scour protection at harbour quay walls and marine structures
Prevention of fine-sediment migration through armour stone under wave and current action
Underwater placement of the Secutex^® HB sand mat in harbour and breakwater foundations

Under wave and current loading, Secutex^® H provides long-term filter stability with high resistance to abrasion. During installation it is resistant against dynamic perforation loads and can be covered directly with riprap or heavy rock armour. Secutex^® H is installed against breakwaters, predominantly to prevent sand from filtering through the rock fill.

For installation below the waterline, the Secutex^® HB sand mat is placed directly from a work vessel, using a long-arm excavator. Fender piles can be driven through the mat.

Aerial view of coastal construction with dredging vessels, a rock breakwater, and machinery reshaping a shoreline near an industrial port.

To the application:

Hydraulic engineering

Technical properties

Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Product build-up
Product type	—	Single-layer, mechanically bonded filter nonwoven	Single-layer, mechanically bonded filter nonwoven	Multi-layer, mechanically bonded filter nonwoven with quartz sand layer	Multi-layer, mechanically bonded nonwoven with quartz sand filling
Raw material	—	Polypropylene (PP)	Polypropylene (PP)	Polypropylene (PP)	Polypropylene (PP)
Colour	—	White	White	White	White
Complete product
Mass per unit area (DIN EN ISO 9864)	g/m²	539	772	5,500	5,750
Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Thickness, nominal / minimum (DIN EN ISO 9863-1)	mm	5.0 / ≥ 4.5	6.7 / ≥ 6.0	11.0	11.5
Max. tensile strength, md / cmd (DIN EN ISO 10319)	kN/m	≥ 20 / ≥ 25	≥ 45 / ≥ 50	≥ 25.0 / ≥ 45.0	≥ 35.0 / ≥ 60.0
Elongation at max. tensile strength, md / cmd (DIN EN ISO 10319)	%	60 / 40	60 / 45	50 / 40	70 / 40
Static puncture resistance, CBR (DIN EN ISO 12236)	kN	6	10.6	4	6
Dynamic perforation resistance (DIN EN ISO 13433)	mm	8.0	4.0	—	—
Characteristic opening size O₉₀ (DIN EN ISO 12956)	mm	0.08	0.07	0.07	0.07
Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Water permeability normal to the plane, VI_(H50) index (DIN EN ISO 11058)	m/s	4.5 x 10⁻²	2.5 x 10⁻²	1.7 x 10⁻²	1.2 x 10⁻²
Flow rate (H50) (DIN EN ISO 11058)	l/(s·m²)	45	25	17	12
Layer build-up of the sand mats
Cover nonwoven – raw material, colour, mass per unit area	—	—	—	PP, white, 300 g/m²	PP, white, 300 g/m²
Sand layer – mass per unit area	—	—	—	Quartz sand, 4,700 g/m²	Quartz sand, 4,700 g/m²
Carrier nonwoven – raw material, colour	—	—	—	PP, white	PP, white
Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Carrier nonwoven – mass per unit area	g/m²	—	—	500	750
Carrier nonwoven – thickness, nominal / minimum	mm	—	—	—	6.7 / ≥ 6.0
Carrier nonwoven – max. tensile strength, md / cmd	kN/m	—	—	—	≥ 35.0 / ≥ 55.0
Carrier nonwoven – characteristic opening size O₉₀	mm	—	—	0.08	0.07
Carrier nonwoven – water permeability VI(H50) / flow rate	—	—	—	—	2.8 x 10⁻² m/s / 28 l/(s·m²)
Requirements acc. to RPG and TLG 2018 of the BAW
Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Hydraulic filtration efficiency against soil type	—	A and B	A, B and C	A, B and C	A, B and C
Resistance to dynamic perforation by ripraps, drop energy	Nm	1,800 – fulfilled	1,800 – fulfilled	1,800 – fulfilled	1,800 – fulfilled
Resistance to abrasion loads	—	Fulfilled	Fulfilled	Fulfilled	Fulfilled
Valid RPG test certificate of the BAW to be submitted with the tender	—	For the nonwoven	For the nonwoven	For the sand mat	For the nonwoven
Delivery form, installation and certification
Roll dimensions	m	Width 6.0	Width 6.0	Width x length 4.80 x 30	Width x length 4.80 x 30
Property	Unit	Secutex^® H 501	Secutex^® H 751	Secutex^® HB 501	Secutex^® HB 751
Covering after installation	—	Within one month	Within one month	On the day of installation; immediate covering may be required	On the day of installation; immediate covering may be required
Installation	—	Overlap or sew panels at the joints; secure against wind suction and flow attack	Overlap or sew panels at the joints; secure against wind suction and flow attack	Overlap panels at the joints	Overlap panels at the joints
Monitoring and certification	—	DIN 18200, EN ISO 9001, CE marking, product group EPD	DIN 18200, EN ISO 9001, CE marking, product group EPD	DIN 18200, EN ISO 9001:2015, CE marking, product group EPD	DIN 18200, EN ISO 9001:2015, CE marking, product group EPD
Durability acc. to Annex B, test procedure B.4.2.2, natural soils pH 4–9, ≤ 25 °C	years	≥ 100	≥ 100	≥ 100	≥ 100

Underwater cross-section showing loosely placed riprap above a fine sandy and silty subsoil, separated by a white Naue Secutex® H geotextile for hydraulic engineering. — Exemplary illustration. Naue Secutex^® H geotextile provides filtration and separation beneath riprap in hydraulic engineering, allowing water to pass while preventing the fine subsoil from mixing with the protection layer.

Why BAW approval and O90 matter for certified hydraulic engineering

Secutex^® H acts as a geotechnical filter between fine-grained soil and a riprap or armour stone layer. It retains soil particles under hydraulic flow while letting pore water pass and keeps the two granular layers from intermixing under wave action and current - continuously and under cyclic loading.

Engineering detail

The performance of a needle-punched nonwoven filter depends on both soil retention and hydraulic capacity. The characteristic opening size O₉₀, determined in accordance with EN ISO 12956, is an important indicator of soil retention - but it is not, by itself, proof of suitability for every soil. Under RPG 2021, O₉₀ is determined from the grain-size distribution of the soil passing through the geotextile; it is not defined as the opening below which 90% of the product’s pores lie. The value must be assessed in relation to the relevant soil grading and hydraulic conditions.

Hydraulic performance must likewise be considered in relation to the geotextile’s water permeability normal to its plane and its thickness. Together, these describe flow through the product’s interconnected pore structure; thickness is also explicitly included in the RPG calculation of permeability. Crucially, the RPG does not assess hydraulic filtration stability from the clean geotextile alone: it measures the water permeability of specimens previously used in the mechanical filtration test, at a hydraulic head of 50 cm, and calculates the soil-conditioned filter’s permeability using the measured V_H50 and geotextile thickness.

The RPG assesses mechanical filtration stability separately. For sandy to slightly silty soils with d₂₀ ≥ 0.06 mm, it uses the flow-through method; for finer soils with d₂₀ < 0.06 mm, it uses the turbulent-flow method with granular material type BT C. Both methods evaluate soil passing through the filter over successive test phases, including whether the passing rate stabilises. Product suitability should therefore be based on the relevant soil-specific test results and intended loading conditions - not on O₉₀ or clean-product permeability alone. Dynamic perforation and abrasion resistance are separate properties assessed by their respective tests.

What it means for your project

All products meet the highest robustness requirements defined in the BAW RPG 2021 with regard to abrasion resistance and dynamic puncture resistance at a drop energy of 1,800 Nm. Secutex^® H 751, Secutex^® HB 501 and Secutex^® HB 751 are additionally filter-stable in direct contact with soil types A, B and C, covering the full range of BAW application conditions. Secutex^® H 501 is suitable for soil types A and B only due to its lower thickness; where soil type C is present, Secutex^® H 751 must be used.

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Frequently asked questions

Secutex^® H is a single-layered, needle-punched nonwoven filter geotextile manufactured from polypropylene (PP) for application as a filter and separation layer in hydraulic engineering. It is installed between riprap or stone armour and fine-grained subsoil to retain soil particles, prevent contact erosion and allow water to pass freely. Applications include river revetments, canal bed protection, groynes, breakwaters and harbour construction.

Secutex H nonwoven geotextiles have been successfully tested in accordance with the BAW RPG 2021 for use as filter geotextiles in revetments along German federal waterways. They hold a valid BAW basic test report, providing the required technical basis for planning in accordance with BAW MAG 2021 and for deliveries in compliance with TLG 2018, the Technical Delivery Conditions for Geotextiles and Geotextile-Related Products on Navigable Waterways. This confirms their suitability for use in approved hydraulic engineering applications under the applicable BAW requirements.

Standard Secutex^® is designed as separation, filter or protection geotextile for road, railway and landfill applications. Always specify Secutex^® H when the geotextile is in direct contact with flowing or wave-driven water.

Secutex^® H 501 and H 751 hold CE marking per DIN 18200, valid BAW basic test reports from the Federal Institute for Waterway Engineering (BAW), Karlsruhe, confirming compliance with TLG Edition 2018 (Technical Delivery Conditions for Geotextiles in Waterways). An EPD (Environmental Product Declaration) is available.

Use Secutex^® H 501 (539 g/m², CBR 6 kN, O90 0.08 mm) for revetment systems where the subsoil corresponds to soil types A and B. Use Secutex^® H 751 (772 g/m², CBR 10.6 kN, O₉₀ 0.07 mm) when subsoil orresponds to soil type C.

Secutex^® HB 501 is a multi-layered sand mat consisting of a PP cover nonwoven, a quartz sand filling (~4,700 g/m²) and a carrier layer (Secutex^® H 501). The sand weight makes it self-sinking, so that it can be installed directly underwater from a work vessel with a long arm excavator without dewatering. It is used where dry installation is impractical: canal revetments or revetment systems in flowing water, harbour foundations, scour protection at water depths beyond manual reach. Roll dimensions: 4.80 m x 30 m.

O₉₀ is the characteristic opening size, measured per EN ISO 12956. It represents the sieve opening through which 90% of geotextile pores are smaller. Secutex^® H 501 has O₉₀ = 0.08 mm. H 751 has O₉₀ = 0.07 mm. This value is matched against the grain size distribution of the adjacent soil using the RPG filtration criteria of the BAW. A wrong O₉₀ causes either clogging (builds hydraulic pressure) or piping (progressive erosion of the fine subsoil) - both are structural failure modes.

Yes. Secutex^® H is used in coastal protection applications including revetment systems, filter layers below breakwaters, groyne construction and scour protection. The BAW certification covers filter stability and abrasion resistance under hydraulic loading conditions. For offshore or underwater installation, Secutex^® HB sand mats are the preferred solution as they are self-sinking and maintain positional stability on the seabed under current.

Secutex^® H has a predicted service life of 100 years in natural soils with pH 4-9 and soil temperature not exceeding 25 °C, based on test method B.4.2.2. This is stated in the BAW specification documents and applies to both H 501 and H 751.

Secutex^® H 501 achieves a CBR static puncture resistance of 6 kN (EN ISO 12236) and elongation of 60% MD (EN ISO 10319). H 751 provides CBR of 10.6 kN for greater robustness under heavy stone placement. Both variants resist abrasion and dynamic perforation loads per RPG of BAW, tested for riprap fall energy of 1,800 Nm on soil type B. The product must be covered within one month after installation per TLG requirements.

Yes. Secutex^® H replaces classical multi-layer mineral grain filter courses. Due to its very low thickness, installation does not require excavation of additional substrate. This reduces construction time and transport volumes.

Secutex^® H must be unrolled and overlapped at joints. Rolls must be secured against wind uplift and flow forces during placement. The product must be covered within one month after installation per TLG Edition 2018 requirements. Roll width is 6.0 m. Secutex^® HB 501 sand mat (standard roll dimensions: 4.80 m x 30 m) must be covered on the day of installation; project-specific conditions may require immediate coverage.

In hydraulic engineering systems, Secutex^® H is often used alongside GSC Secutex^® Soft Rock (erosion protection system for river and coastal applications). In complex embankment systems, Secugrid^® geogrid reinforcement may be used in the embankment fill above the revetment.

Proposed specification texts for Secutex^® H 501 and H 751 are available. Please see the download section above or contact us via the request form below for any assistance. Technical consultants are available for project-specific filter design and BAW compliance review.