Q: Can we correlate laboratory versus outdoor weathering of geomembranes? I would appreciate your thoughts on this matter because we are getting technical challenges on this issue from regulators.
A: Yes, we do this all the time. The results are location dependent based on ambient temperature and solar radiation. We have several papers on the subject ( https://geosynthetic-institute.org/whitepapers.htm ) that predict the service life of exposed geosynthetics. The Geosynthetic Institute (GSI) published a report in 2019 offering predictions of the lifetime of exposed geosynthetics using laboratory weathering devices. The report shows that the service life of exposed geosynthetic products can be predicted by measuring the oxidative induction time (OIT) depletion, strength and elongation half-life after exposure to elevated temperature and ultraviolet (UV) radiation. A QUV-fluorescent weathering device using the ASTM D7238 Standard Test Method for Effect of Exposure of Unreinforced Polyolefin Geomembrane Using Fluorescent UV Condensation Apparatus protocol was used for the laboratory portion of the test. We tested at three temperatures and then did Arrhenius modeling to compute the half-life of the materials.