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Nonwoven needle-punched GT

News, Q&A: GMA Techline | October 1, 2015 | By:

We specify that the geotextile under riprap must be nonwoven, needle-punched, Class 1. NCHRP Report 568 (page C-25, Section 7.1) requires that nonwoven geotextile filter under riprap must have a mass density greater than 12osy (ounces per square yard).

We have the following questions:

  1. What is the cost difference between nonwoven needle-punched, Class 1
    12osy vs. nonwoven needle-punched, Class 1 8osy?
  2. Is nonwoven needle-punched, Class 1, 12osy considered “special order”?
  3. Is nonwoven needle-punched, Class 1, 12osy available in the state of Nevada (local suppliers)?
  4. Does nonwoven, needle-punched, Class 1, 12osy require longer delivery time after ordering if it is considered “special order” that might cause construction delay?

Basil | India


Hi Basil,

Thanks for your questions in which the following apply:

  1. Cost is approximately proportional to the weight. Thus, a 12osy will cost about 50% more than an 8osy geotextile.
  2. Needle-punched nonwovens in the range of 4 to 16osy are standard products.
  3. I certainly hope so since it is a standard product. The only comment that I add is if the project is extremely large a given supplier might have to order more from a manufacturer.
  4. Delivery times should be short since this is not a specialty fabric. Again, if the order is huge there might be a time delay.

Good luck with your project.

Bob Koerner | GMA Techline

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