ASTM D2240 Durometer Hardness

ASTM D2240 Durometer Hardness testing measures the indentation hardness of elastomeric and polymeric materials used in medical devices. This test helps determine a material’s resistance to deformation under pressure, which is critical for assessing durability, flexibility, and performance in clinical applications. Durometer readings are taken using standardized scales (e.g., Shore A, D) depending on the material type. In medical device development, this test supports material selection, quality control, and regulatory compliance. It is especially relevant for components like seals, tubing, and soft-touch surfaces where tactile and mechanical properties affect usability and safety. The results guide engineers in optimizing device design for both patient comfort and functional reliability.

Why This Testing is Performed

Durometer hardness testing is performed to evaluate the mechanical integrity and surface resilience of materials used in medical devices. It ensures that elastomers and polymers meet performance requirements for flexibility, compressibility, and wear resistance. This is vital for components that undergo repeated stress or contact with biological tissues, such as catheters, gaskets, and wearable device interfaces.

Have you tried our Test Navigator Tool? Try it now

Steps in Conducting This Test

1. Sample Conditioning: Materials are conditioned per ASTM D618 to ensure consistent temperature and humidity.
2. Durometer Selection: Choose the appropriate scale (e.g., Shore A for soft materials, Shore D for harder ones).
3. Measurement: Apply the durometer to the sample surface and record the indentation hardness.
4. Repeatability: Multiple readings are taken across different points to ensure accuracy.
5. Reporting: Results are averaged and documented with reference to the durometer type and test conditions.

Standards, Guidance, and Regulations

• ASTM D2240: Primary standard for durometer hardness testing of rubber and elastomeric materials.
• ASTM D618: Conditioning plastics for testing.
• ISO 48-4: International standard for rubber hardness testing.
• FDA Guidance: While the FDA does not prescribe ASTM D2240 directly, it requires that materials used in medical devices be characterized using validated, industry-recognized methods. Durometer hardness testing is commonly accepted for assessing mechanical properties of elastomers and polymers in regulatory submissions. The FDA expects manufacturers to report hardness values as part of biocompatibility and performance evaluations, especially for components affecting patient contact, flexibility, or durability.
• ISO/IEC 17025: Laboratory competence for mechanical testing.