This document specifies a flexural test method for determining the through-thickness (out-of-plane) tensile properties of laminated carbon fibre-reinforced plastic (CFRP) composites, including strength, fracture strain, and modulus. This document is applicable to unidirectional CFRP (UD-CFRP) laminates. In addition, the calculation of effective volume is also described due to size effects of the through-thickness tensile strength.