3886SILT FENCE

3886.1SCOPE

Provide silt fence to retain sediment.

3886.2

Provide Machine Sliced (MS) silt fence consisting of a woven geotextile fabric installed by machine and supported by steel posts.

Provide Hand Installed (HI) silt fence consisting of a woven geotextile fabric installed by hand and supported by steel posts.

Provide Super Duty (SD) silt fence consisting of concrete or water filled jersey barriers with fabric wrapped around the front face of the barrier. The Contractor may provide woven or nonwoven geotextile fabric or poly/polyreinforced sheeting.

Provide Pre-Assembled (PA) silt fence consisting of a woven geotextile fabric supported by wood posts preattached to the fabric.

Provide Turbidity Barrier (TB) silt fence consisting of a low permeable fabric barrier, installed in water and supported by steel cable and steel posts.

3886.2REQUIREMENTS

Provide geotextiles for MS and HI silt fences from the Approved/Qualified Products List.

AFabric

Provide fabric meeting the following requirements and characteristics:

(1)Uniform in texture,

(2)Uniform in appearance,

(3)Contains no defects, flaws, or tears affecting the physical properties,

(4)Contains UV inhibitors and stabilizers providing a minimum service life of at least 2years during outdoor exposure, and

(5)Meets the requirements specified in Table38861:

Table38861
Silt Fence Requirements
Silt Fence Type / Width, in [mm] / Grab Tensile (machine direction), lb [kg]* / Apparent Opening Size║ / Puncture Strength† / UV Stability, 500h, % ‡ / MAX
Permittivity # / Flow Rates, gpm/sq. ft [L/min/sq. m]
MS, HI woven geotextile § / 36 [915] / 130 [59] / No. 30 sieve [0.60mm] / — / 70 / 1.0s−1 / 100 [4,073]
PA woven geotextile / 36 [915] / 100 [45] / No. 30 sieve [0..60mm] / — / 70 / 0.1s−1 / 5 [170]
SD woven or nonwoven geotextile ** / 36 [915] / 100 [45] / No. 30 sieve [0.60mm] / — / 70 / — / —
TB polyester or polyvinyl Fabric / 60
[1524] / 200 [91] / — / 90lb [41kg] / 70 / impervious / —
Values in table are Minimum Average Roll Values (MARV)
*ASTMD4632
║ASTMD4751 Maximum average roll value.
†ASTMD4833
‡ASTMD4355
#ASTMD4491
§Provide MS, HI woven geotextile with monofilament in both directions. Do not make substitutions.
**The Contractor may use poly/polyreinforced sheeting with a thickness of at least 6mil [0.152mm] or an equivalent.

3886.2

For TB fabric width is finished width with a 4 inch overlap heat sealed hem pocket at the top.

BFasteners

Provide fasteners with a tensile strength of at least 50lb [22kg]. Use plastic zip ties to fasten geotextile to posts on MS, HI and TB applications. Use wire ties or plastic zip ties to fasten geotextile to anchor points on SD applications.

CSupports

Provide steel posts for MS, HI, and TB silt fence types per 3403, “HotRolled Steel Fence Posts,” and the following:

Table38862
Steel Silt Fence Post Requirements
Characteristic / Requirement
Type / Tpost
Weight / 0.95 lb/ft [1.4kg/m]
Length / ≥ 5.0ft [1.5m]
Embedment / ≥ 24in [610mm]
Post spacing / 6.0ft [1.8m]

Provide wood posts for PA silt fence type meeting the following requirements:

Table38863
Wooden Silt Fence Post Requirements
Characteristic / Requirement
Type / Hardwood
Size / ≥ 2in × 2in [50mm × 50mm]
Length / ≥ 4.0ft [1.25m]
Embedment / ≥ 18in [460mm]
Post Spacing / < 5.0ft [1.5m]

DPortable Precast Concrete Jersey Barriers

For SD, use portable precast concrete barriers per 2533, “Portable Precast Concrete Barrier,” for main support and strength. If placing the barrier adjacent to traffic, provide a barrier with a shape meeting the requirements of the standard plates design designation shown on the plans. The Contractor may use barriers meeting obsolete standard plate designs in nontraffic areas.

EPortable Water Filled Jersey Barriers

For SD, provide main support strength of at least 1,200lb [544kg] when filled with water. Provide a plastic, waterfilled barrier. If placing the barrier adjacent to traffic, provide a barrier with a shape meeting the requirements of the standard plates design designation shown on the plans.

FSteel Cable

Provide a top line for TB made of a 5/16in [8mm] galvanized steel cable with a breaking strength of at least 9,800lb [40.0kN]. Incorporate into the 4 inch hem pocket at top of fabric.

3886.3SAMPLING AND TESTING

Provide the following to the Engineer with each shipment of geotextile:

(1)A manufacturer’s Certificate of Compliance, and

(2)Document stating the manufacturer’s minimum average roll values (MARV) and maximum average roll values for the geotextile.

The Department defines MARV as two standard deviations below the mean value of the rolls tested.

3886.2

3973.3