This document specifies the geometries and proposed finishing procedures of the inner surface of hollow test piece of metallic materials, filled with a high-pressure gaseous medium. The document specifies a tensile testing procedure to evaluate the effect of high-pressure gaseous medium compared to a high pressure inert gas or air. The document can be used for the screening of metallic materials by evaluating mechanical property changes due to the effects of various test gases, including hydrogen. NOTE Temperature range and pressure range depend on the materials to be tested and test gas to be used.