Geotextile-Filter Fabric

None.

artist,

As PWSlack's one word answer suggests, the differences are mostly semantic...

Geotextiles by definition are used to hold (engineered) soil in place by allowing drainage of interstitial water through the soil bed, while preventing fine grained soil/sediment from washing into the drainage system below.

Whereas, the term filter fabric can apply to woven, spun, or extruded filter media utilized in many industries, including wastewater treatment, water supply, chemical processing, food processing, pharmaceutical processing, etc...

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Just my $0.02...

You might try Mirafi, they maintain a glossary of geosynthetics terms. The difference is not semantics. Filter fabrics are a subcategory of geotextiles that are designed for the purpose of functioning as a filter. There are other types of geotextiles. More commonly geotechnical engineers refer to geotextiles, instead of specifically identifying as filter fabric, to identify geosynthetic fabrics used to impart strength to a foundation material in a roadway that overlays a weaker subgrade. Some materials, such as mirafi 500x are used to bear loads over a small area of weak subgrade, and impart streangth to the overlying materials. These materials are designed to provide tension and a friction interaction with soils. They usually do not have a EOS or AOS rating for filtration. Purely filter fabric materials tend to be quite weak and should not be used for these purposes, but do have EOS or AOS ratings for filtration.

From the mirafi's website i found the folowing definitions:

Geotextile: Any permeable textile used with foundation, soil, rock, earth, or any other geotechnical engineering-related material as an integral part of a human-made project, structure, or system.

Filtration/drainage: Fabric to soil system that allows for free liquid flow (but no soil loss) across or through the plane of the fabric over an indefinitely long period of time.