A Technical Guidance Manual:
Terminology and Index Testing Procedures for Rolled Erosion Control Products

3. STANDARD TERMINOLOGY FOR ROLLED EROSION CONTROL PRODUCTS

3.1 Rolled erosion control product (RECP); A temporary degradable or long-term non-degradable material manufactured or fabricated into rolls designed to reduce soil erosion and assist in the growth, establishment and protection of vegetation.

3.2 Temporary degradable; An RECP composed of biologically, photochemically or otherwise degradable materials that temporarily reduces soil erosion and enhances the establishment of vegetation.

3.3 Long term non-degradable; An RECP composed of non-degradable materials that furnishes erosion protection and extends the erosion control limits of vegetation for the design life of a project.

3.4 Erosion control net (ECN); A planar woven natural fiber or extruded geosynthetic mesh used as a component in the manufacture of RECPs, or separately as a temporary degradable RECP to anchor loose fiber mulches.

3.5 Open weave textile (OWT); A temporary degradable RECP composed of processed natural or polymer yarns woven into a matrix, used to provide erosion control and facilitate vegetation establishment.

3.6 Erosion control blanket (ECB); A temporary degradable RECP composed of processed natural or polymer fibers mechanically, structurally or chemically bound together to form a continuous matrix.

3.7 Turf reinforcement mat (TRM); A long term non-degradable RECP composed of UV stabilized, non-degradable, synthetic fibers, nettings and/or filaments processed into three dimensional reinforcement matrices designed for permanent and critical hydraulic applications where design discharges exert velocities and shear stresses that exceed the limits of mature, natural vegetation. TRMs provide sufficient thickness, strength and void space to permit soil filling and/or retention and the development of vegetation within the matrix.

3.8 Atmosphere for testing rolled erosion control products; Air maintained at a relative humidity of 65±5% and temperature of 21±2 degrees C (70 ±4 degrees F).

3.9 Tensile strength; The resistance to deformation developed for a specific material and subsequent modulus and elongation when subjected to tension by an external force.

3.10 Specimen; A specific portion of a material or laboratory sample upon which a test is performed or which a measurement is taken for that purpose.

3.11 Stiffness; A resistance to bending.

3.12 Specific gravity; The ratio of the density of the substance in question to the density of a reference substance at specified conditions of temperature and pressure.

3.13 Performance test; A test that simulates as closely as practicable selected conditions experienced in the field and which can be used in design.

3.14 Yarn; A generic term for continuous strands of textile fibers or filaments used to form a textile fabric.

3.15 Machine direction; The direction in the plane of the fabric parallel to the direction of manufacture.

3.16 Transverse direction; The direction in the plane of the fabric perpendicular to the direction of manufacture. Often referred to as the "cross-machine direction".

3.17 Warp; (1) The yarn running the length of the fabric in the machine direction. (2) The sheet of yarns wound together or a beam for the purpose of weaving or knitting. (3) Often referred to as the "machine direction".

3.18 Weft; (1) The yarn running the length of the fabric perpendicular to the machine direction when manufacturing woven or knitted fabrics. (2) Often referred to as the "cross-machine direction".

3.19 Porosity; The ratio of the volume of air or void contained within the boundaries of a material to the total volume expressed as a percentage.

3.20 Polyolefin; A family of polymeric materials that includes polypropylene and polyethylene.

3.21 Natural; A class name of various genera fibers, of animal, mineral or vegetable origin.

3.22 Absorption; The process by which a liquid is drawn into and tends to fill permeable pores in a porous solid body, also, the increase in mass of a porous solid body resulting from penetration of a liquid into its permeable pores.

3.23 Geosynthetic; A product manufactured from polymeric material used with soil, rock, earth, or other geotechnical engineering material as an integral part of a man-made project, structure, or system.

3.24 Geotextile; A permeable geosynthetic material comprised solely of textiles.

3.25 Index test; A test procedure that may contain a known bias but which may be used to establish an order for a set of specimens with respect to the property of interest.

3.26 Lot; A unit of production, or a group of other units or packages, taken for sampling or statistical examination, having one or more common properties and being readily separable from other similar units.

3.27 Sample; A portion of material, which is taken for testing or for recorded purposes and used in the laboratory as a source of individual specimens.