Flammability? Zip ties? MARV? Ponds? GT specs?
Questions and answers from the GMA Techline.
I have reviewed GRI White Paper #10, GRI Test Method GT12(a), ASTM D4354, and ASTM D4759 and have a question. I have reviewed some recent CQA test results of a nonwoven cushion geotextile roll sample and while the average of the 10 test results for that roll is higher than the manufacturer’s certified MARV value, a few of the 10 test results are less than the manufacturer’s certified MARV value. The MARV value is the required minimum value in the project specifications for the MQC testing and for the CQA testing.
The way I understand GRI’s guidance and
the ASTM test methods, the sampled roll meets the project specifications because
the average of the 10 test results is greater than the manufacturer’s certified MARV. Is that correct?
Nathan | South Carolina
If you look on our website under specifications you will find one for geotextile cushions. For the various required test values they all follow the MARV concept. Further, you have read the GRI White Paper #10 correctly in that some values will be less than the mean value and they represent the two standard deviations less than the mean. In my opinion, you have interpreted MARV correctly.
Bob Koerner | GMA Techline