To implement these procedures, you need the official, current standard document.
The official and most reliable way to obtain the standard is through ASTM International. You can purchase the PDF, redline versions, or hard copies directly from their website. It is also available through technical document resellers like IHS Markit or Techstreet. Important Note on "Free PDF" Searches
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Disclaimer: This blog post is for informational purposes only. Always refer to the official ASTM D618-21 document published by ASTM International for precise testing protocols. astm d618-21 pdf
Beginning October 1, 2025, ASTM implemented stronger DRM for standards sold on the ANSI Webstore. The measures include:
Polymers have low thermal conductivity. It takes time for the core of a thick plastic specimen to match the temperature of the testing room.
Heating to a specific temperature (e.g., 50°C or 105°C) for a set duration, then cooling in a desiccator. To implement these procedures, you need the official,
The definitive framework for stabilizing polymeric samples prior to physical, mechanical, or electrical evaluation is defined by , titled Standard Practice for Conditioning Plastics for Testing . Because the physical and electrical properties of plastics are highly sensitive to environmental factors like temperature and relative humidity, this standard ensures that test results remain accurate and reproducible across different global laboratories.
Conditioning Duration / Temperature / Relative HumidityConditioning Duration / Temperature / Relative Humidity Example 1:
Unlike metals or ceramics, polymers are highly sensitive to their immediate environment due to their molecular structure. Two main factors dictate this sensitivity: It is also available through technical document resellers
Without the strict guidelines laid out in ASTM D618-21, a manufacturer in a tropical climate and a QA laboratory in an arid region could test the exact same batch of plastic resin and generate vastly different data sheets. Standard Laboratory Atmosphere: The Baseline
Users of the standard should be aware of its relationship with its international counterpart. ASTM D618-21 explicitly notes a technical difference in Note 1: "This standard and ISO 291 address the same subject matter, but differ in technical content. , or both". ASTM D618-21, in contrast, offers a broader set of procedures, providing more flexibility for a wider range of plastic types and testing scenarios.
To write accurate Standard Operating Procedures (SOPs) for internal testing labs.
To ensure that test results are reproducible and comparable across different labs and geographic locations, the industry relies on .
Your test report must state: "Specimens were conditioned per ASTM D618-21, Procedure A (40 hours at 23°C/50% RH)."