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Line 1: − + − <li>Fabrics should be woven monofilament or non-woven needle punched. Woven slit film and non-woven heat bonded fabrics should not be used as they are prone to clogging.</li>+ − </ul>+ − <p>Primary considerations are:+ − <ol>+ − <li>Suitable apparent opening size (AOS) for non-woven fabrics, or percent open area (POA) for woven fabrics, to maintain water flow even with sediment and microbial film+ − build-up;</li>+ − <li>Maximum forces that will be exerted on the fabric (i.e., what tensile, tear and puncture strength ratings are required?);</li>+ − <li>Load bearing ratio of the underlying native soil (i.e., is geotextile needed to prevent downward migration of aggregate into the native soil?);</li>+ − <li>Texture (i.e., grain size distribution) of the overlying aggregate material; and</li>+ − + − </ol>+ − </p>+ + + + + + + + + + + + + + + + + + + + + + + + + + + + +
no edit summary
<ul><li>Material specifications should conform to Ontario Provincial Standard Specification (OPSS) 1860 for Class II geotextile fabrics.</li>
[[File: Geotextile-GSI.JPG|thumb|The properties of geotextiles vary widely.]]
See [[Clogging]] for notes on their application in LID structures.
Geotextiles can be used to prevent downward migration of smaller particles in to larger aggregates, and slump of heavier particles into finer underlying courses.
The formation of biofilm on geotextiles has also been shown to improve water quality:
*By degrading petroleum hydrocarbons<ref>Newman AP, Coupe SJ, Spicer GE, Lynch D, Robinson K. MAINTENANCE OF OIL-DEGRADING PERMEABLE PAVEMENTS: MICROBES, NUTRIENTS AND LONG-TERM WATER QUALITY PROVISION. https://www.icpi.org/sites/default/files/techpapers/1309.pdf. Accessed July 17, 2017.</ref>
*By reducing organic pollutant and nutrient concentrations <ref>Paul P, Tota-Maharaj K. Laboratory Studies on Granular Filters and Their Relationship to Geotextiles for Stormwater Pollutant Reduction. Water. 2015;7(4):1595-1609. doi:10.3390/w7041595.</ref>
*When installing geotextiles an overlap of 150 - 300 mm should be used.
Material specifications should conform to OPSS 1860 for Class II geotextile fabrics
<ref>ONTARIO PROVINCIAL STANDARD SPECIFICATION METRIC OPSS 1860 MATERIAL SPECIFICATION FOR GEOTEXTILES. 2012. http://www.raqsb.mto.gov.on.ca/techpubs/OPS.nsf/0/2ccb9847eb6c56738525808200628de1/$FILE/OPSS%201860%20Apr12.pdf. Accessed July 17, 2017</ref>.
<li>Permeability of the native soil</li>
*Fabrics should be woven monofilament or non-woven needle punched.
*Woven slit film and non-woven heat bonded fabrics should not be used, as they are prone to clogging.
In choosing a product, consider:
#The maximum forces that will be exerted on the fabric (i.e., what tensile, tear and puncture strength ratings are required?),
#The load bearing ratio of the underlying native soil (i.e. is the geotextile needed to prevent downward migration of aggregate into the native soil?),
#The texture (i.e., grain size distribution) of the overlying and underlying materials, and
#The suitable apparent opening size (AOS) for non-woven fabrics, or percent open area (POA) for woven fabrics, to maintain water flow even with sediment and microbial film build-up.
{|class="wikitable"
|-
|+Recommended criteria for selection of geotextile fabric
|-
!Percent soil/filter media passing 0.075 mm (#200 sieve)
!Non-woven fabric apparent opening size (AOS, mm)
!Woven fabric percent open area (POA, %)
!Permittivity (sec<sup>-1</sup>)
|-
|>85||≤ 0.3||-||0.1
|-
|50 - 85||≤ 0.3||≥ 4||0.1
|-
|15 - 50||≤ 0.6||≥ 4||0.2
|-
|5 - 15||≤ 0.6||≥ 4||0.5
|-
|≤ 5||≤ 0.6||≥ 10||0.5
|}
===Performance research===
http://www.mdpi.com/2073-4441/7/4/1595/htm
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[[category:materials]]