ASTM D6109-19Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastic Lumber and Related Products
ASTM D 6109 determines the flexural properties for any solid or hollow manufactured plastic lumber product of square, rectangular, round, or other geometric cross section that shows viscoelastic behavior. It is used for evaluating the properties of plastic lumber as a product and not a material property test method.
Test Method A is designed for products in the flat or "plank" position. Test Method B is designed for products in the edgewise or "joist" position. Load is applied to the specimen at the specified cross-head rate and load-deflection data is measured at the common centre of the spans. Stress-strain curves are plotted to determine the flexural yield strength and modulus of elasticity.
Before conducting ASTM D6109, it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.