Overlapping standardized test methods
GSI News
By Bob & George Koerner
It is generally recognized that generic test methods for all geosynthetic products are essential to manufacturing, design, permitting, specifying, and acceptance organizations to provide for a successful project at reasonable cost. Even further, it is desirable that such test methods are generated and accepted on a worldwide basis.
Conflicting test methods, even if subtle in details (such as specimen dimensions, testing equipment details, laboratory environments, incubation details, etc.) are often expensive, time consuming, and, sometimes, controversial to accommodate. Furthermore, they tend to bring about confusion in many circumstances.
That said, if an individual owner or geoenvironmental agency desires specific test methods, it is their right to do so. However, it does have the effect of limiting local, national, and international commerce and trade.
To provide the greatest platform for the industry in its entirety many feel that geosynthetic test methods should come from international organizations such as ASTM or ISO.
The purpose of this column is not to prefer one over the other but to encourage these two organizations to harmonize their test methods to one another or to avoid duplication altogether. In this regard the duplication of some test methods (many with quite different procedures or even subtle changes) are the following:
| Geosynthetic type | Description of method | ASTM designation | ISO designation |
| Geotextiles | grab tensile strength | D5034 | 13934-2 |
| Geotextiles | wide width tension | D4595 | 10319 |
| Geotextiles | seam strength | D4884 | 10321 |
| Geotextiles | CBR puncture strength | D6241 | 12236 |
| Geotextiles | permittivity | D4491 | 11058 |
| Geotextiles | opening size | D4751 | 12956 |
| Geotextiles | transmissivity | D4716 | 12958 |
| Geomembranes | thickness | D5199 | 2286-3 |
| Geomembranes | density | D792 | 1183-1 |
| Geomembranes | tensile strength | D6993 | 527-3 |
| Geomembranes | tear strength | D1004 | 34-1 |
| Geomembranes | puncture strength | D4833 | 12236 |
For the above limited number of test methods it is still manageable to have correlations between the different test designations, but note that there are 245 actual tests available to be accredited by GSI’s Laboratory Accreditation Program. If the trend of duplicative test methods continues to perpetuate through many or all of these tests, it will become a major burden for all involved with little or no value added for the industry.
That said, there are ongoing activities to normalize the situation and bring consensus among the two organizations. We certainly applaud these activities and congratulate the people involved for taking the time and expense to facilitate such agreements for the sake of us all.
