Introduction

When geosynthetics are to be used in structurally or environmentally critical applications, conformance with material specifications is important.  Material defects can lead to material failure in the field and undermine the public’s confidence in nontraditional materials like geosynthetics.  Independent manufacturing quality assurance (MQA) protects the contractor, designer, and owner from having inadequate materials installed on the project.

Traditional Approach to Independent MQA

Traditionally, upon delivery of the geosynthetics to the job site, quality assurance begins with on-site sampling in accordance with the governing CQA plan. After the appropriate samples have been cut and labeled, they are packaged and sent to an independent 3^rd party laboratory for testing, accompanied by a document outlining the requested tests and, if possible, a copy of the governing project specifications.  Typically, the 3^rd party lab receives samples via overnight courier, providing shipment tracking.  

It is not uncommon for independent testing to reveal that the materials received on-site do not meet one or more of the requirements of the specification.  Discrepancies occur because the materials are too variable as a result of inadequate manufacturing quality control, or it may be that there are differences in how the tests were performed by the manufacturer and the 3^rd party lab.

When a product does not meet specifications, the various parties must determine the cause of non-compliant test results.  Following is a typical sequence of actions taken by a 3^rd party lab in response to an unsatisfactory test result:

1.	Retest.
2.	If retest passes, furnish all results to the QA firm with explanation
	If retest also fails, examine equipment calibration
3.	If calibration is satisfactory, examine manufacturer’s QC data and call the manufacturer to discuss.  If calibration is not satisfactory, recalibrate and retest.
4.	Call the QA firm with preliminary test data and a suggested course of action based on insight gained from talking with the manufacturer.

  The QA firm will decide the next step in the approval/rejection process.  Possible options include:

·       Acceptance of  material

·       Require 3^rd party lab / manufacturer lab round-robin

·       Require another independent lab / 3^rd party lab / manufacturer lab round-robin

·       Rejection of part or all of the material

For many different reasons, few involving intentional deceit or incompetence, independent test results can identify that unsatisfactory materials may have been shipped to the job site.  The cost of rejecting these materials both in terms of dollars for shipping and restocking and of wasted construction time can be substantial and unacceptable. 

Enhancing Traditional QA via In-Plant Sampling

QA programs that rely on on-site sampling will experience delays.  One way to avoid delays is to have 3^rd party inspection, sampling and testing done before the material is shipped to the site.  This requires the samples to be taken at the manufacturing plant by an independent 3^rd party and shipped from there to the 3^rd party lab for testing.  In-plant sampling allows the owner, or his representative, to make approval decisions without the pressures of maintaining the construction schedule.

Most in-plant 3^rd party activities are done on a project-specific basis using part-time on-call employees.  Close coordination between the 3^rd party representative and the manufacturer assures that the material in question is available and accessible upon arrival at the plant.

In-plant sampling eliminates the possibility of having to reject materials that have already been delivered.  When the materials are urgently needed on-site, portions of the order can be released for shipment as soon as the test results are approved.

Recent Issues in Independent 3^rd Party QA

A frequently asked question about 3^rd party QA is: Is it truly independent quality assurance if the manufacturer selects, cuts, and ships his own samples for 3^rd party testing?  Arguably, unless 3^rd party sampling is performed, there is no way to independently verify that the samples represent the materials being shipped. Therefore, is it reasonable to pay for QA testing when there is no documentation that the testing was done on the appropriate materials? 

Clearly, independent quality assurance should include independent 3^rd party sampling, as well as testing.

Independent sampling can be problematic if it is only needed infrequently or at a remote location.  Currently the best option seems to be sampling at the construction site if a third party representative cannot make it to the manufacturing facility.

Finally, there has been much effort over the last couple decades to create systems and procedures at both manufacturing plants and testing labs that assure quality. In the world of geosynthetic testing, when certain requirements are met to the satisfaction of an industry “watch-dog” such as the Geosynthetics Accreditation Institute (GAI), labs are accredited on a test-by-test basis.  QA programs often require this GAI accreditation of the 3^rd party lab involved on a project.

Choosing a 3^rd Party Lab?

3^rd party labs must do more than just perform tests.  3^rd party labs must frequently and diligently interact with manufacturers’ labs, and they must consistently participate in organizations that govern standards.  Through these activities, the 3^rd party labs can learn how to avoid testing discrepancies that lead to inappropriate material rejections and can help develop better testing standards and material specifications.  Some 3^rd party labs take on educational responsibilities and perform specification reviews.  Ultimately the 3^rd party lab strives to be able to identify only truly inadequate materials before they become a part of critical structures and facilities by incorporating the following elements:

·       an experienced QA staff

·       a history of performing specific QA tests regularly and frequently

·       GAI accreditation for the specific QA tests

·       recognition from industry for self-improvement.

WANT TO PUT THESE PRINCIPLES INTO PRACTICE?

Here’s suggested text you might want to insert into your next geomembrane specification. 

Similar language can be used in other geosynthetic specifications.

MQA/CQA Geosynthetic Laboratory

The Owner or CQA Engineer shall employ a GAI accredited independent Geosynthetics Laboratory to perform QA testing on the geomembrane and seams as well as interface friction and transmissivity tests, if required. The Lab must have an internal Quality Control plan in effect that monitors conformance with ASTM and other applicable testing standards. The Lab must maintain chain of custody records for samples and be capable of reporting data to the CQA Engineer within the allotted time period. The Lab must be willing to allow observation by the owner, CQA Engineer, permitting agency, Installer, or Design Engineer during testing and record keeping for the project, if this is desired. 

Manufacturer Quality Assurance

Sampling - The CQA Personnel are responsible as part of MQA for verifying that the geomembrane materials satisfy the specified properties. This shall be done by sampling the geomembrane material at the specified frequency in accordance with either Paragraph 1 (preferred) or 2.