ASTM (American Society for Testing and Materials) standards are widely used in manufacturing, especially in the testing of composite materials, for several key reasons:

1. Uniformity: With such a set of standards, engineers, researchers, manufacturers and buyers can discuss and understand material properties on a global scale. Not only does it ensure fairness in business transactions, but it also provides a benchmark for research and development, optimisation and reproduction.

2. Reliability: ASTM standards are developed and maintained by industry experts to ensure the reliability and validity of testing processes and results. The use of these standards ensures that all parties involved, whether manufacturers, engineers or consumers, have a clear and equal understanding of the nature of the material.

3. High quality: ASTM standards are very rigorous, and each test is carefully designed to ensure that the specific properties of a material are accurately measured. This also ensures consistent product quality and comparable material properties.

4. Recognition: ASTM standards are widely accepted and recognised around the world, including regulatory requirements for material properties or specifications that often reference ASTM standards.

Simply put, testing composites using ASTM standards ensures the performance, quality and reliability of the material, and ensures that this information is shared and understood with others in the industry in a timely and efficient manner.