COMMENTARY ON SURVEY RESULTS
Table 2 provides the summary of the survey information retrieved from Table 1. In Question #1, it is seen that 22 states do not require specific conformance testing in their state regulations. That said, all states must comply with the minimum technology guidance (MTG) set forth by the U.S. Environmental Protection Agency, but these are quite generalized and only refer to field seam testing. There are some states, however, that address the product conformance issue specifically and go beyond MTG for various types of geosynthetics, mainly geomembranes, but again in a very generalized manner.
Thus, the major finding of this survey, on the specific issue of conformance testing, is that no specificity of what tests, what frequency, what values, etc., is being required in existing state regulations. We assume that the states are relying on design and CQA organizations to set site-specific and product-specific conformance requirements in this regard. This is corroborated by the response to Question #2.
In Question #2, it is seen that in addition to federal MTG, most states rely on information from manufacturers, design consultants, published literature, or other available historical data.
Questions #3 and #4 focus on destructive testing intervals for field fabricated geomembrane seams. Of the thirteen states that address the topic, all of them use the Federal EPA interval of one sample for every 500 feet (150m) of seam. Other variations on this issue are given in Question #5 which seems to indicate that some state regulators are accepting alternative recommendations.
Question #6 addresses the possible use of nondestructive (NDT) methods for geomembranes. This is interesting in that there appears to be some flexibility insofar as several modern approaches to the topic. In particular, eleven states allow for electrical leak integrity surveys.
This, of course, leads to Question #7 which is the second major reason (after assessing the conformance testing issue) for conducting this survey, i.e., whether or not a reduction in destructive seam testing can occur when using a NDT method such as the electrical leak integrity survey. Only three states said “yes”, six said “maybe/possibly” and fifteen said “no”. The other states were silent on the issue.