Wait, let me check. The ASTM standards have a specific nomenclature. Each standard has a designation, like D618-21, where D is the section, 618 is the standard number, and 21 is the year of publication. So maybe the user is referring to ASTM D618-21. The hyphen is important because in the format Designation: D618-21, the hyphen separates the standard number from the year. The user might have omitted the hyphen and written it as D61821. That makes sense. So the correct designation would be ASTM D618-21.
The test method involves extracting the plastic material with a solvent, followed by analysis of the extract to determine the amount of extractable content. astm d61821 pdf
Specimens are conditioned at 23°C and 50% relative humidity . Duration: 40 hours for specimens ≤is less than or equal to 7 mm thick; 88 hours for specimens > 7 mm. Wait, let me check
: 96 hours at 35°C and 90% humidity (for high moisture impact). So maybe the user is referring to ASTM D618-21
Exposed to 90% relative humidity at 35 °C (95 °F) for a duration of 96 hours.