Myth 1: "It only applies to mechanical testing." False. ASTM D618-21 explicitly covers electrical, optical, and even thermal testing.
Myth 2: "Room temperature is fine." No. "Laboratory ambient" varies daily. D618-21 requires a controlled chamber, not a room air conditioner.
Myth 3: "Older revisions are good enough." Accreditation bodies (A2LA, UKAS, NABL) now reference D618-21. If your quality manual says "D618-13," you are non-conforming.
Plastics are hygroscopic (they absorb moisture from the air) and thermally sensitive. The physical properties of polymers—such as tensile strength, impact resistance, and electrical conductivity—can fluctuate significantly based on:
ASTM D618-21 ensures that every lab starts the race from the same starting line by normalizing the environmental history of the material. astm d618-21 pdf
In countries like Canada (SCC), the UK (BSI), or Germany (DIN), you can purchase ASTM D618-21 through your local national standards body, often in local currency.
Avoid: Scribd, Academia.edu, or random PDF hosting sites. These files are often older revisions (e.g., D618-05), scanned poorly, missing figures, or illegally shared.
Q1: Can I get ASTM D618-21 for free? A: Not legally unless your employer subscribes to ASTM Compass or you have academic access.
Q2: What is the difference between D618-21 and D618-13? A: The 2021 revision tightens humidity tolerances, clarifies test time limits, and updates referenced standards. Myth 1: "It only applies to mechanical testing
Q3: How long does conditioning take? A: For Cycle A (standard), a minimum of 40 hours, but moisture equilibrium may take longer (e.g., 4 days for thick nylon bars).
Q4: Do I need to condition all plastics? A: Yes, except for tests where the standard test method (e.g., ASTM D638 for tensile) specifies a different condition.
Q5: Where is the official PDF download link? A: Go to www.astm.org and search for "D618-21." Click "Add to Cart."
Q6: Can I use a dehumidifier instead of a chamber? A: No. D618-21 requires closed, controlled chambers with active humidity control. ASTM D618-21 ensures that every lab starts the
Q7: What humidity sensor is required? A: A calibrated hygrometer with accuracy of ±2% RH or better.
Q8: Does D618-21 cover polymers in liquid form? A: No. This standard applies only to solid molded, extruded, or cast specimens.
Q9: How do I cite ASTM D618-21 in a test report? A: Use: "Conditioned per ASTM D618-21, Cycle A (23°C ± 2°C / 50% RH ± 5%) for 72 hours."
Q10: What if my chamber fails humidity tolerance? A: Your test results are invalid per Section 4 of the standard. Recondition and retest after recalibration.