4.1 GCLs must be properly manufactured in a manner consistent with a minimum level of quality control as determined by in-house testing of the final product. This practice suggests the types of tests, the methods of the testing and the minimum testing frequencies.

MD = machine direction
    CD = cross-machine direction
    Minimum = lowest result for the produced lot from which the supplied rolls were selected
    Maximum = highest result for the produced lot from which the supplied rolls were selected
    n/a = not applicable

(A) The tests on the bentonite are to be performed on the as-received material before fabrication into the GCL product.(B) Cert letter from component manufacturer or QA from GCL manufacturer, or both. Cert letters must arrive and be checked before the components are used for the GCL production.(C) If the moisture content from the bentonite added during production did not change, the mass per unit area and moisture content of the bentonite (evaluated according to 1.3 in Table 1) can be used to determine the values of the finished GCL product.(D) Components from finished GCL product should not be separated and tested, because the production process may alter the properties of the components.(E) MARV-minimum average roll value, only evaluated for a one-year production period with an average value minus 2 standard deviations. If the production period is less than one year, for example, for job-specific products, a MARV value may not be able to be evaluated, then the minimum value shall be reported.(F) Dried bentonite should be defined as 0 % moisture content.(G) Internal shear testing (Test Method D6243/D6243M) may be applicable to quality control of the bonding strength of non-needle-punched reinforced and stitch-bonded GCLs.(H) This test is not applicable for multi-component GCLs (for example, products with geomembrane backing(s), geofilm backing(s), or polymer backing(s)).

4.2 It should be clearly recognized that manufacturers may perform additional tests or at greater frequency than required in this practice, or both. In this case, the manufacturer's quality control plan will then take precedence over this practice. The quoted tests and test methods in Table 1 must appear in the QC plan and the QC report.

4.3 It should also be recognized that purchasers and installers of GCLs may require additional tests or at a great frequency than called for in this practice, or both. The organization(s) producing such project specific specification or quality assurance plan should recognize that such requirements are beyond the current state of the practice. If such a request is made by purchasers or installers, they should clearly communicate the requirements to the manufacturer or supplier during the contract decisions in order that disputes do not arise at a subsequent time.