This specification covers requirements and test methods for geotextile fabrics and associated components used in temporary silt fence applications. It is applicable to the use of a geotextile as a vertical permeable interceptor designed to remove suspended soil from overland, nonconcentrated water flow. The function of a temporary silt fence is to trap and allow settlement of soil particles from sediment laden water. The purpose is to greatly limit the transport of eroded soil from the construction site by water runoff. Fibers used in the manufacture of geotextiles for silt fence, and the threads used in joining geotextiles by sewing, shall consist of long-chain synthetic polymers composed of at least 95 % by weight of polyolefins or polyester. They shall be formed into a stable network such that the filaments or yarns retain their dimensional stability relative to each other, including selvages. Geotextiles and related materials used for temporary silt fence shall conform with required grab strength, permittivity, apparent opening size, and ultraviolet stability. The prescribed support posts are described in the specification.
Область применения1.1 This specification covers requirements and test methods for geotextile fabrics and associated components used in temporary silt fence applications. Table 1 is a material purchasing specification based on AASHTO M288. Table 2 is a specification to be used in areas of high water flow.
1.2 Both specifications are applicable to the use of a geotextile as a vertical permeable interceptor designed to remove suspended soil from overland, nonconcentrated water flow. The function of a temporary silt fence is to trap and allow settlement of soil particles from sediment laden water. The purpose is to greatly limit the transport of eroded soil from construction sites and other areas affected by water runoff.
Note 1: It should be noted that proper installation and maintenance are critical for the effective functioning of silt fence.
1.3 The tests used to characterize the silt fence are intended to ensure good workmanship and quality and are not necessarily adequate for design purposes in view of the wide variety of possible sediments and performance objectives.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents, therefore each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
Note 2: Although the Table 1 specification should be acceptable in most erosion control applications, it should be noted that an alternative silt fence specification for a higher water flow rate, listed in Table 2, may be required by the engineers in areas that are susceptible to higher water runoff; using Table 2 specification will minimize safety hazards such as hydroplaning in these areas.
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