Woven Silt Fence Fabrics

This application claims priority to and the benefit of U.S. Provisional Application No. 63/662,301 filed Jun. 20, 2024 and U.S. Provisional Application No. 63/750,130 filed Jan. 27, 2025. The entire disclosures of the above provisional applications are incorporated herein by reference.

The present disclosure relates to woven silt fence fabrics.

This section provides background information related to the present disclosure which is not necessarily prior art.

Silt fence systems, which include silt fence fabric, vertical supporting members (such as wooden stakes or metal posts), and fasteners (like staples, wire ties, or zip ties), have been utilized for many years to temporarily control erosion and sediment. The fabric component is often referred to as silt fence, perimeter control fabric, or sediment and erosion control fabric, among other names.

Typically, the silt fence fabric is installed vertically in the field, perpendicular to the ground, and is attached to and supported by wooden or metal posts placed at varying intervals (e.g., 4 feet, 6 feet, or 10 feet apart). Silt fences may be installed within a trench approximately 6 inches deep, supported by posts, as depicted in.

Traditionally, the primary purpose of the silt fence fabric in the system is to allow water to flow through the fabric while filtering out sediment. The wooden stakes and metal posts are used to maintain the vertical position of the silt fence fabric, bearing most of the load from the sediment and water in the system.

Today, silt fence systems are considered the last line of defense against off-site discharge of stormwater and are recognized as critical best management practices in construction. But as recognized herein, the overall structural stability of this technology still needs to be better understood and developed.

Example embodiments will now be described more fully with reference to the accompanying drawings.

Disclosed herein are exemplary embodiments of high-strength high-modulus monofilament woven silt fence fabrics. Exemplary embodiments including using 100% monofilament woven silt fence fabrics in silt fence applications. In exemplary embodiments, the woven silt fence fabrics are woven entirely from very high modulus monofilament yarns and configured to have high-strength and high-modulus, e.g., characterized by tensile strength at 2% and 5% strain per ASTM D-4595 along with ultimate strength per ASTM D-4595 exceeding that of conventional slit tape geotextiles or conventional monofilament/slit fibrillated geotextiles at low strain levels, etc. Advantageously, the high-strength high-modulus 100% monofilament woven silt fence fabrics disclosed herein may be used in silt fence applications to improve durability, filtration, and cost-efficiency.

In exemplary embodiments, the high-strength high-modulus monofilament woven silt fence fabric is configured to have a wide width tensile strength (per ASTM D-4595) greater than 700 pounds/foot (lbs/ft) at 2% strain in the machine direction (MD) and cross-machine direction (CMD) and greater than 1400 lbs/ft at 5% strain in the machine direction (MD) and cross-machine direction (CMD). In such exemplary embodiments, the high-strength high-modulus monofilament woven silt fence fabric may be configured to have a wide width tensile strength (per ASTM D-4595) of at least about 1000 lbs/ft at 2% strain in the machine direction (MD) and cross-machine direction (CMD) and at least about 2000 lbs/ft at 5% strain in the machine direction (MD) and cross-machine direction (CMD).

Exemplary embodiments disclosed herein address the need for superior strength, improved filtration, and erosion control in civil engineering and construction projects, leveraging monofilament woven materials' high tensile strength and low strain characteristics in both the machine direction (MD) and cross-machine direction (CMD) in applications where additional reinforcement with wire, netting, or chain link fence is not desired. Additionally, the monofilament woven silt fence fabrics disclosed herein can be made as anisotropic or isotropic by using weaving technologies to bundle the fill yarns together. Further, multiple marker yarns may be included, which allow for identification to grade lines, install lines, monitor lines, aid in high visibility, etc.

As mentioned in the background, silt fence systems serve as a final barrier against off-site stormwater discharge and are widely recognized as essential best management practices in construction. However, as discussed below, a better understanding and further development of the structural stability of silt fence technology is necessary.

In the 1980s, Amoco Fabrics and Fibers Company introduced an early version of silt fence fabric, marketed under the trade name AMOCO™ PROPEX™ Silt Stop. This fabric was made using slit tape yarn in the warp direction and open-end spun (OES) fill yarns. While the OES yarn provided excellent filtration, it had lower strength and modulus due to its lack of stiffness. Additionally, the OES yarn's manufacturing process was not cost-effective.

In the late 1980s and early 1990s, Amoco and other industry players introduced silt fence products featuring slit tape yarns in both the warp and fill directions. Notable examples included Amoco's PROPEX™ 2125 and PROPEX™ 2130. These fabrics offered varying levels of strength, sediment retention, and hydraulic properties while remaining cost-effective. However, industry experts noted that these fabrics still faced challenges with strength in practical applications. Moreover, flaws in the weaving process could cause yarns to fold, negatively impacting sediment retention and water flow.

Manufacturers have continuously explored alternative yarn types to address these limitations. As discussed, using monofilament yarns in fabric constructions provides superior sediment retention and water flow for various geotextile and agricultural applications. Monofilament fabrics are generally less prone to weaving issues than slit tape fabrics, resulting in improved filtration and water flow. Additionally, design calculations for sediment control and water flow are more reliable with monofilament-based geotextiles.

Consequently, monofilament fabrics have become the preferred choice for filtration applications, despite their higher cost and more complex manufacturing process. The significantly improved and more consistent water flow rates in practical use justify this preference.

As silt fence fabrics have evolved to enhance filtration efficiency, their use has become more widespread. Although various perimeter control methods and products are available, silt fence systems continue to be the preferred choice. However, the overall structural stability of these systems, especially in high-flow areas, has not been fully understood until now.

Silt fences are commonly used in environmentally sensitive areas during construction, serving both as protective barriers and visual markers. However, despite their utility, silt fences often struggle to maintain their vertical position, requiring additional measures to reduce risks either alongside or integrated into the silt fence system.

The use of slit tape warp and fill fabrics, along with monofilament/slit tape combination fabrics, has highlighted the need for advancement in silt fence materials. As demand for these fabrics grows, it has become evident that they must function as part of a comprehensive silt fence system. These fabrics should not only serve as effective filters but also possess the strength needed to ensure the integrity of the system under challenging field conditions, even at very low strain rates.

In construction areas with severe hydraulic conditions, silt fence fabric is often reinforced with materials like wire, plastic mesh, or chain link fencing. This reinforcement enhances the system's strength, helping maintain the fabric's upright position for optimal filtration, even when subjected to varying hydraulic forces and sediment loads, or during prolonged installation periods.

There are clear opportunities to improve silt fence systems, now often called the “super silt fence system” or other similar names, by adding a fourth component. The current limitations of the fabric used in these systems can be addressed by adding redundancy to perimeter control. For example, this could involve installing two rows of silt fence or adding a backing to the fabric. Additionally, the inventors have identified that increasing the strength of the silt fence fabric itself, without sacrificing its filtration capabilities, could provide several benefits, such as:

As disclosed herein, key design principles for silt fence fabrics include strength (specifically tensile, tear, and puncture properties), sediment retention (measured by Apparent Opening Size or AOS), and hydraulic properties (such as water flow and permittivity). While the overall filtration capabilities of silt fence fabrics are well established, there is a growing need for fabrics that provide structural reinforcement to the overall system. This requires a fabric that exhibits high modulus strength at very low strains. Preferably, the silt fence fabric is strong and rigid enough to eliminate the need for wire or netting reinforcements.

One example of a standard fabric is the WINFABR 2020HDX silt fence fabric, which is made entirely from 100% monofilament warp and fill yarns. This fabric boasts high modulus properties, including a wide-width tensile strength (according to ASTM D-4595) of 600 pounds per foot (lbs/ft) at 2% strain and 1200 lbs/ft at 5% strain in both the machine direction (MD) and cross-machine direction (CMD). It also has an ultimate tensile strength (per ASTM D-4595) of 3800 lbs/ft in the machine direction (MD) and 2300 lbs/ft in the cross-machine direction (CMD). Due to its high modulus properties, the WINFAB® 2020HDX silt fence fabric is an excellent replacement for other conventional fabrics like the WINFABR 2098CS, which combines WINFAB® 2098 silt fence fabric with a 12-pound polypropylene net.

Another example of a traditional fabric is the SMARTfencewoven geotextile sediment fence. This fabric is a blended alternative, featuring a combination of monofilament warp yarn and fibrillated slit tape fill yarn.

The table below shows a progression of properties over time. Tensile strengths have improved when comparing 100% woven slit tape geotextiles to monofilaments. Monofilament fabrics also exhibit significantly better water flow properties (higher flow rates) compared to slit tape or hybrid monofilament combination fabrics. Sediment retention properties are, in some cases, exceptionally high. However, if sediment retention is too high (such as a 70 AOS versus a 30 AOS) the fabric may clog, which impairs its ability to allow water to pass through. This is generally undesirable in most cases. It is also worth noting the strength difference between WINFABR 2020HDX fabric and the SMARTfencefabric is significant, with the cross-machine direction (CMD) strength of the SMARTfencefabric being 85% greater than that of WINFAB® 2020HDX fabric.

Traditional silt fences typically utilize geotextiles constructed from slit tape materials or a combination of slit tape and monofilament. While these materials deliver basic functionality, they have limitations in terms of tensile strength, durability, and filtration efficiency, especially in high-stress or harsh environmental conditions. These shortcomings can result in decreased performance as described herein, the need for frequent replacements, and increased maintenance costs.

Building on the observations above, the inventors developed and/or disclose high-strength, high-modulus monofilament woven silt fence fabrics specifically for silt fence applications. In exemplary embodiments, a 100% monofilament woven fabric is used as the fabric component in a silt fence system, providing significant improvements over traditional slit tape geotextiles or blended alternatives.

To assess the performance of these high-strength, high-modulus monofilament woven silt fence fabric modulus values at 2% and 5% strain can be measured. Typically, the modulus values for the fabrics disclosed here are twice as high at both 2% and 5% strain in the machine direction (MD) and cross-machine direction (CMD) when compared to the WINFAB® 2020HDX fabric.

In exemplary embodiments, the high-strength, high-modulus monofilament woven silt fence fabrics are configured to have a wide-width tensile strength (per ASTM D-4595) greater than 700 pounds per foot (lbs/ft) at 2% strain in both the machine direction (MD) and cross-machine direction (CMD), and greater than 1400 lbs/ft at 5% strain in both MD and CMD directions. In these embodiments, the fabric may have a wide-width tensile strength (per ASTM D-4595) of at least about 1000 lbs/ft at 2% strain and at least about 2000 lbs/ft at 5% strain in both the machine and cross-machine directions.

In exemplary embodiments, the high-strength, high-modulus characteristics of the monofilament woven silt fence fabrics disclosed herein are achieved by utilizing high-modulus monofilament yarns. These yarns are then woven into the fabric in a way that optimizes sediment retention and water flow properties. Notably, exemplary embodiments include 100% monofilament, high-modulus woven silt fence fabrics, which are suitable as filter fabrics in silt fence systems and exhibit one or more (preferably all, but not necessarily any or all) of the following properties or characteristics:

The high-strength, high-modulus properties of the monofilament woven silt fence fabrics disclosed herein make them ideal for erosion and sediment control in construction sites, highways, agricultural land management, and other civil engineering applications where silt fences are used and extreme hydraulic or sediment loading conditions are present. The high-strength, high-modulus properties of the monofilament woven silt fence fabrics disclosed herein sets a new standard for silt fence applications, offering unmatched strength, reliability, and environmental compatibility.

The monofilament yarns used in the high-strength, high-modulus woven silt fence fabrics disclosed herein may comprise a wide range of materials, such as polypropylene, polyester, polyethylene terephthalate (PET), nylon, rayon, polyethylene, fiberglass, terpolymer, acrylic, aramid fibers, natural fibers, biodegradable fibers, other polymers, other raw materials, etc. Additionally, the high-strength, high-modulus woven silt fence fabrics disclosed herein may be configured to have a wide range of end counts, e.g., depending on the particular installation, etc. Accordingly, the high-strength, high-modulus woven silt fence fabrics disclosed herein are not limited to any one particular material(s) or end count.

With reference to the figures,illustrates a cross section of a woven silt fence fabric according to an exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament yarn in the machine direction. The monofilament warp yarn has a 975 denier and a flat (e.g., rectangular, etc.) cross-sectional shape. Also in this example, the woven silt fence fabric includes monofilament yarn and fibrillated tape yarn in the transverse or cross machine direction. The monofilament and fibrillated tape fill yarns may be inserted generally parallel to each other in an alternating arrangement in the transverse or machine direction during the weaving process. The monofilament fill yarn in the transverse or machine direction has a 1000 denier and round cross-sectional shape. The fibrillated tape fill yarn in the transverse or machine direction has a 4000 denier and a general rectangular cross-sectional shape that will conform to the woven construction of the fabric into which the fibrillated tape fill yarn is inserted. The yarn types, cross-sectional shapes, and deniers shown inare provided for purpose of illustration only as other exemplary embodiments may include different yarn types, cross-sectional shapes, and deniers in the machine direction and/or in the cross machine/transverse direction.

illustrates a cross section of a woven silt fence fabric according to another exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament yarn in the machine direction and monofilament yarn in the transverse or cross machine direction. The monofilament warp yarn in the machine direction has a 1200 denier and a flat (e.g., rectangular, etc.) cross-sectional shape. The monofilament fill yarn in the transverse or machine direction has a 1200 denier and round cross-sectional shape. The yarn types, cross-sectional shapes, and deniers shown inare provided for purpose of illustration only as other exemplary embodiments may include different yarn types, cross-sectional shapes, and deniers in the machine direction and/or in the cross machine/transverse direction.

illustrates a cross section of a woven silt fence fabric according to a further exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament yarn in the machine direction. The monofilament warp yarn in the machine direction has a 1600 denier and an oval cross-sectional shape. Also in this example, the woven silt fence fabric includes monofilament yarn and fibrillated tape yarn in the transverse or cross machine direction. The monofilament and fibrillated tape fill yarns may be inserted generally parallel to each other in an alternating arrangement in the transverse or machine direction during the weaving process. The monofilament fill yarn in the transverse or machine direction has a 1700 denier and round cross-sectional shape. The fibrillated tape fill yarn in the transverse or machine direction has a 2700 denier and a general rectangular cross-sectional shape that will conform to the woven construction of the fabric into which the fibrillated tape fill yarn is inserted. The yarn types, cross-sectional shapes, and deniers shown inare provided for purpose of illustration only as other exemplary embodiments may include different yarn types, cross-sectional shapes, and deniers in the machine direction and/or in the cross machine/transverse.

includes test data for a woven silt fence fabric according to an exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament warp yarn having a 1200 denier, an oval cross-sectional shape, and count of 27. Also in this example, the woven silt fence fabric includes monofilament fill yarn having an 1800 denier, a round oval cross-sectional shape, and count of 27. As shown in, this example woven silt fence fabric had a wide width tensile strength (per ASTM D-4595) of 769 lbs/ft at 2% strain in the machine direction (MD), a wide width tensile strength (per ASTM D-4595) of 1534 lbs/ft at 2% strain in the cross-machine direction (CMD), a wide width tensile strength (per ASTM D-4595) of 1611 lbs/ft at 5% strain in the machine direction (MD), and a wide width tensile strength (per ASTM D-4595) of 3485 lbs/ft at 5% strain in the cross-machine direction (CMD). This example woven silt fence fabric also had an apparent opening size (per ASTM D-4751) of 30 U.S standard sieve, a water flow rate (per ASTM D-4491) of 105 gallons per minute (gpm), and a permittivity (per ASTM D-4491) of 1.40 sec.

includes test data for a woven silt fence fabric according to an exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament warp yarn having a 1200 denier, an oval cross-sectional shape, and count of 27. Also in this example, the woven silt fence fabric includes monofilament fill yarn having a 700 denier, a round oval cross-sectional shape, and count of 40. As shown in, this example woven silt fence fabric had a wide width tensile strength (per ASTM D-4595) of 789 lbs/ft at 2% strain in the machine direction (MD), a wide width tensile strength (per ASTM D-4595) of 898 lbs/ft at 2% strain in the cross-machine direction (CMD), a wide width tensile strength (per ASTM D-4595) of 1669 lbs/ft at 5% strain in the machine direction (MD), and a wide width tensile strength (per ASTM D-4595) of 1764 lbs/ft at 5% strain in the cross-machine direction (CMD). This example woven silt fence fabric also had an apparent opening size (per ASTM D-4751) of 40 U.S standard sieve, a water flow rate (per ASTM D-4491) of 65.3 gallons per minute (gpm), and a permittivity (per ASTM D-4491) of 0.87 sec.

includes test data for a woven silt fence fabric according to an exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament warp yarn having a 1600 denier, an oval cross-sectional shape, and count of 27. Also in this example, the woven silt fence fabric includes monofilament fill yarn having a 1700 denier, a round oval cross-sectional shape, and count of 18 and fibrillated fill yarn having a 2700 denier and count of 9. As shown in, this example woven silt fence fabric had a wide width tensile strength (per ASTM D-4595) of 860 lbs/ft at 2% strain in the machine direction (MD), a wide width tensile strength (per ASTM D-4595) of 1528 lbs/ft at 2% strain in the cross-machine direction (CMD), a wide width tensile strength (per ASTM D-4595) of 1765 lbs/ft at 5% strain in the machine direction (MD), and a wide width tensile strength (per ASTM D-4595) of 3067 lbs/ft at 5% strain in the cross-machine direction (CMD). This example woven silt fence fabric also had an apparent opening size (per ASTM D-4751) of 35 U.S standard sieve, a water flow rate (per ASTM D-4491) of 88.2 gallons per minute (gpm), and a permittivity (per ASTM D-4491) of 1.18 sec.

includes test data for a woven silt fence fabric according to an exemplary embodiment of the present disclosure. In this example, the woven silt fence fabric includes monofilament warp yarn having a 1600 denier, an oval cross-sectional shape, and count of 27. Also in this example, the woven silt fence fabric includes monofilament fill yarn having a 1100 denier, a round oval cross-sectional shape, and count of 32. As shown in, this example woven silt fence fabric had a wide width tensile strength (per ASTM D-4595) of 1059 lbs/ft at 2% strain in the machine direction (MD), a wide width tensile strength (per ASTM D-4595) of 1259 lbs/ft at 2% strain in the cross-machine direction (CMD), a wide width tensile strength (per ASTM D-4595) of 2166 lbs/ft at 5% strain in the machine direction (MD), and a wide width tensile strength (per ASTM D-4595) of 2428 lbs/ft at 5% strain in the cross-machine direction (CMD). This example woven silt fence fabric also had an apparent opening size (per ASTM D-4751) of 30 U.S standard sieve, a water flow rate (per ASTM D-4491) of 96.4 gallons per minute (gpm), and a permittivity (per ASTM D-4491) of 1.29 sec.

Exemplary methods include weaving only monofilament yarns to thereby provide a woven silt fence fabric as disclosed herein such that the woven silt fence fabric is woven entirely from the monofilament yarns. Such exemplary methods may include weaving only monofilament yarns comprising using a weave pattern for the woven silt fence fabric that comprises a plain or 1×1 weave, any twill weave (e.g., 2×1, 2×2, 3×1, 3×3, 4×4, etc.), herringbones, satin, baskets, or leno.

In exemplary embodiments, the woven silt fence fabric comprises two or more different monofilament warp yarns having different cross-sectional shapes, and/or two or more different monofilament fill yarns having different cross-sectional shapes.

In exemplary embodiments, the woven silt fence fabric includes a lower grade line and an upper edge defining an installed height between the lower grade line and the upper edge.

In exemplary embodiments, the woven silt fence fabric includes one or more marker yarns having a different color than adjacent yarn(s) to thereby identify one or more of a grade line, install line, monitor line, and/or high visibility line. In such exemplary embodiments, the one or more marker yarns comprise multiple groups of marker yarns having different color(s) than adjacent yarn(s) such the woven silt fence fabric includes two or more a grade line, an install line, a monitor line, and/or a high visibility line. And each group of marker yarns may have a same width as the other groups of marker yarns, or at least one group of marker yarns may have a different width than at least one other group of marker yarns. Additionally, or alternatively, the one or more of the grade line, install line, monitor line, and/or high visibility line identified by the one or more marker yarns may comprise a singular end(s) of the one or more marker yarns, or a wider group of multiple ends of the one or more marker yarns.

In exemplary embodiments, a silt fence system includes a high-strength high-modulus monofilament woven silt fence fabric as disclosed herein. One or more support posts are configured for attachment to the woven silt fence fabric for supporting the woven silt fence fabric. In such exemplary embodiments, the woven silt fence fabric may be configured to have high-strength, high-modulus characteristics that enable the silt fence system to be usable without additional wire, netting, or chain link fence reinforcement for the woven silt fence fabric.

Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. In addition, advantages and improvements that may be achieved with one or more exemplary embodiments of the present disclosure are provided for purpose of illustration only and do not limit the scope of the present disclosure, as exemplary embodiments disclosed herein may provide all or none of the above mentioned advantages and improvements and still fall within the scope of the present disclosure.

Specific dimensions, specific materials, and/or specific shapes disclosed herein are example in nature and do not limit the scope of the present disclosure. The disclosure herein of particular values and particular ranges of values for given parameters are not exclusive of other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is envisioned that any two particular values for a specific parameter stated herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values could also be employed for the given parameter). For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping, or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if parameter X is exemplified herein to have values in the range of 1-10, or 2-9, or 3-8, it is also envisioned that Parameter X may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, when permissive phrases, such as “may comprise”, “may include”, and the like, are used herein, at least one embodiment comprises or includes the feature(s). As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being “on”, “engaged to”, “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to”, “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

The term “about” when applied to values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters. For example, the terms “generally”, “about”, and “substantially” may be used herein to mean within manufacturing tolerances.