The ASTM D5459-95 (2020) standard test method is used to evaluate the longitudinal resilience recovery, long-term deformation, and stress retention of stretched parcel membranes. The resilience recovery test measures the film's ability to return to its original shape after elongation, while long-term deformation and stress retention are related to the tightness and sealing performance of Encasement. The method includes different expansion levels to analyze the effect of small and large expansions. Users should establish appropriate safety and health measures and follow relevant regulations before testing. This standard provides a scientific basis for the evaluation of Encasement material performance.