How Can I Ensure My Products Meet ASTM Standards?

ASTM standards, developed by the American Society for Testing and Materials, are defined as documents outlining ASTM procedures and regulations. Ensuring products meeting ASTM standards shows compliance with regulatory requirements and increases customer confidence. This blog post covers testing for ASTM certification, situations faced by organizations to ensure their products meet the required standards, and checklists to verify compliance.

Testing For ASTM Certification

ASTM test methods are performed to determine the fundamental properties of materials. An ASTM test method includes information on the description of the test procedure, directions for preparing the specimens and for performing the test, information on the required testing machine, applicable accessories and devices, and the required calculations to achieve satisfactory precision and bias. As explained by the Committee, ASTM test methods are frequently intended for use in the buying and selling of materials according to specifications.

Products Meeting ASTM Standards

The three types of situations below covers how an organization may be asked to ensure the products meet ASTM standards:

1. Industry requires certification
   • Certain industries require certification in order for materials to be used in the making of products and/or for products to be used in the assembly processes. For example, military applications require standardization per MIL-STD as specified by the U.S. Department of Defense. Military standards detail the processes and materials to be used to make the product and ASTM test methods are often used and referenced when materials require testing. 
2. Customer requires certification
   • If you’re working in an organization where the manufactured product is shipped to another organization, your customer may ask for product certification prior to shipment. The material or product should be tested and results analyzed for the appropriate certification.
3. Customer requires a specific test
   • Similar to above, when materials/products are sent to a customer, but in this instance the customer decides on the testing application prior to shipment. Manufacturer should show the customer that the requested testing procedure was properly followed and present the results and pass/fail criteria as agreed upon. 

How to verify your tests are in accordance with ASTM standards?

For all the three types of situations explained above, proper and accurate testing is required. Some industries have auditors to verify tests are being run correctly while others require the organization’s quality team to stay on top of all steps and processes. In the recent publication, Form and Style for ASTM Standards, the Committee states: “ASTM test methods are frequently intended for use in the buying and selling of materials according to specifications and therefore should provide such precision that when the test is properly performed by a competent operator the results will be found satisfactory for judging the compliance of the material with the specification.”

To ensure tests are properly performed, organizations should review the ASTM test method in detail. We have compiled three checklists below as an example on how to approach this type of verification.

Checklist I: The ASTM Test Method

• Ensure the ASTM specification you have is up to date and valid
  • Check the date
  • Check for revision or reapproval
• Check the test specimen dimensions
  • Ensure sample preparation is properly conducted prior to loading the specimen in the equipment
  • Use a specimen cutting die if needed
• Check the required test rate
  • • Set up the testing machine so tests are run at the specified test rate. If more than one rate is requested, add test segments to the test profile
  

  MTESTQuattro Stress-strain curve for a polypropylene 2.35mm W x 0.98mm T x 50mm L sample at three strain rates

• Check graphing requirements 
  • If a Stress-Strain graph is required, which properties and/or points should it show?
  • If using automated material testing software, set up multi-graph report, graph axes, units, and other properties as needed.
• Check the tolerance of the specification
  • Check the precision of reported results

Checklist II: The Equipment

• Ensure the testing system calibration is up to date and certification is valid
  • You may see ASTM E4 referenced in many ASTM test methods. This is a type of certified calibration that describes the procedures for the force verification of tension or compression, or both, static or quasi-static testing machines. ASTM certified calibrations can be performed by an accredited calibration company. 
• Closed-loop vs. Open-loop feedback requirement
  • Most ASTM test methods require the closed-loop control mechanism. See this post on the difference between open-loop and closed-loop controls within the context of material testing.
• Ensure test fixtures meet the specification
  • Some test methods will include information on the fixture and some will provide drawings for the appropriate fixturing.
  • Check out our Test Fixtures Based on Standards page here

• If an extensometer is used, check class of extensometer
  • In addition to calibration per ASTM E83, extensometers are classified based on accuracy 
• Verify results calculations
  • How are the results calculated? Does the material testing software automatically generate results? Does the operator manually calculate them?

ASTM E8 Metal Tensile Testing – MTESTQuattro Test Report

Checklist III: Calibration

• Ensure calibration of the system is up to date, this can vary upon industry
  • Most calibration intervals are good for 12 months but some may require measurement accuracy once a month
  • Note: Equipment must also be checked for calibration after a move
• Check system components that need to be calibrated
  • Load – ASTM E4
  • Speed – ASTM E2658
  • Displacement – ASTM E2309
  • Extensometer – ASTM E83
  • Torque- ASTM E2624
• Check the required type of calibration
  • May vary based on organization’s quality requirementsISO/IEC 17025:2017 Accredited CalibrationThis accreditation verifies the competency of the calibrator and the traceability of equipment back to the National Institute of Standards and Technologies (NIST). If the end user is basing a critical decision on measurement results or publishing data, an ISO/IEC 17025:2017 calibration is recommended.

Why is proper calibration required to meet ASTM standards?

 In order to ensure that a materials testing system is providing accurate and precise measurements, ASTM standards recommend or require certified calibration. Often times, the product’s test results must fall within a range of values in order to the product to “pass”. Performing these validation tests with a system whose calibration certifications have expired may yield inaccurate test results, which may ultimately lead to a company distributing non-conforming products. In order to reduce the potential of manufacturing errors within a company, maintaining an up-to-date calibration schedule is vital.