The ASTM D618-21 standard is intended for use by:
Elias spent the next 48 hours following the "Procedure A" protocol. He placed the new samples in the controlled chamber, letting the plastic breathe and reach equilibrium with the moisture in the air. astm d618-21 pdf
Your test report must state: "Specimens were conditioned per ASTM D618-21, Procedure A (40 hours at 23°C/50% RH)." The ASTM D618-21 standard is intended for use