Longevity Testing

There are two main synthetic components to the ClosureTurf® System. They are the Engineered Synthetic Turf and the 50-mil Super Gripnet Geomembrane. Longevity predictions for each component under long term exposure have been evaluated.

The synthetic turf yarns are the only synthetic component of the system that is directly exposed to the elements, specifically ultraviolet light (UV). Weathering tests of these yarns have been performed in accordance with ASTM G147 and G7 at Atlas Material Testing Laboratories in New River, AZ. Samples were exposed to direct UV facing south at a 45 degree angle. An example of the weathering apparatus is shown in the photograph.

Weathering Apparatus at Atlas Material Testing Laboratories

Weathering Apparatus at Atlas Material Testing Laboratories

The samples were exposed for a given period and then the retained tensile strength was measured. Four (4) samples have been tested for the exposure periods of 1.3, 5, 7, and 10 years. Retained tensile strength was plotted against exposure duration as shown in the graph. A logarithmic line was fit to the four (4) points and extrapolated out to 1,000,000 hours. At 50 years (438,000 hours), the retained tensile strength of the synthetic turf yarn is projected to be approximately 70%. At 70% retained tensile strength, it will continue to function as designed and provide retention of the infill, protection of the geotextile backing layers, and protection of the underlying geomembrane.

Retained Tensile Strength of Synthetic Turf Fibers vs. Weathering Exposure Duration

Retained Tensile Strength of Synthetic Turf Fibers vs.
Weathering Exposure Duration

The Geosynthetic Institute (GSI) has performed extensive testing evaluations of the longevity of HDPE geomembranes. This research is presented in Geosynthetic Institute, White Paper #6 – “Geomembrane Lifetime Prediction”, February 8, 2011. For an in-situ annual average temperature of 30 degrees Celsius, GSI estimates a lifetime prediction of 265 years for an HDPE geomembrane.

Therefore based on these evaluations, the ClosureTurf® System will have a 50+ year functional longevity when properly maintained.