CQA test frequency for geomembranes and geocomposites

From the GMA Techline

Subject: CQA test frequency for geomembranes and geocomposites I have comments from a state agency concerning CQA test frequencies and field tests conducted on geocomposites. The questions I have are:

• What are the typical frequencies used for CQA testing of geomembranes and geocomposites?
• What CQA tests are performed in the field ongeocomposites?

(Jerry, Chicago)

Reply: The CQA plan on tests and their frequencies is the right and duty of the CQA organization, since they are signing off on the completed project. This is why we have not put out a guidance document on the subject. Perhaps we should do at least a white paper in this regard. That said, here are our suggestions:

(a) For single measurements by field personnel on every roll: geomembrane thickness via D5199 for smooth sheet or D5994 for textured core thickness; geocomposite thickness via D5199 and perhaps mass per unit area via D5261.

(b) For statistical process control, the frequency is the cube root of the number of rolls (now we are talking about sending samples back to a lab): geomembrane thickness, tensile and C.B content, geocomposite thickness, mass per unit area, and peel strength.

Bob Koerner | GMA Techline