ASTM D790 is 2 determine the flexural properties of unreinforced and reinforced plastics, o high modulus composites and electrical insulating materials utilizing a three - point loading system to apply a load to a simple supported beam (specimen). The method is generally applicable to both it rigid and semi - it rigid materials, but flexural strength always be determined for those materials that do not break or yield in the outer surface of the test specimen within the 5.0% strain limit.
Before conducting ASTM D790, it is important to read the - specification. The Standards can be obtained from the appropriate standard authorities.