Technical Notes


Thrace-LINQ TECH NOTE #14
Sampling and Sampling Frequency of Nonwoven Geotextiles

Sampling

All master samples are cut by production to the full width of the master roll, 18 inches wide. Production associates mark the following information on each sample: Machine #, left side, roll #, and net weight of the master roll. Right and left are determined by looking in the direction of the fabric flow. These master samples are cut into test specimens as described in the test methods and specimen cutting procedure (in general, five samples taken from across the width of the fabric). The master samples are held by the lab until it is determined that they are no longer needed.

Samples are put in a designated area for each line. The lab technician routinely (approximately every 2 hours) gathers these samples from each line and carries them to the lab for testing. All start up rolls, are carried by production to the lab for immediate testing.

Sampling Frequency

Thrace-LINQ tests a minimum of every 20th roll for products greater than 6 ounces/yd2. We test a minimum of every 30th roll for products less than or equal to 6 ounces/yd2. Product history, current production properties, and recent test results are only a few items that may cause the sampling frequency to change.

Testing Frequency

The following tests with the corresponding ASTM method are conducted in the Nonwoven facility at the above sampling frequency. (Note: Anytime a product fails to meet a specification, 100% of that product is tested until two sequential samples meet all specifications.)

  • Weight (oz/yd2) - ASTM D-5261
  • Thickness (mils) - ASTM D-5199
  • Tensile (lbs) - ASTM D-4632*
  • Elongation (%) - ASTM D-4632*
  • Trapezoidal Tear (lbs) - ASTM D-4533*
  • Mullen Burst (psi) - ASTM D-3786
  • Puncture (lbs) - ASTM D-4833

* Indicates both machine and cross-machine directions will be tested

The following tests with the corresponding ASTM method are conducted in the Nonwoven facility at the sampling frequency of every 100 rolls.

  • EOS (AOS) (US sieve size) - ASTM D-4751
  • Water Permittivity (sec-1) - ASTM D-4491
  • Flow Rate (gal/min/ft2) - ASTM D-4491