The document specifies the procedure for the determination of the mechanical performances of prefabricated reinforced components of autoclaved aerated concrete or lightweight aggregate with open structure under transversal load. These include: the midspan deflection for different load levels, the cracking load, the ultimate load by progressive loading until collapse, the position and the shape of fracture. The component (e.g. floor slab, roof slab, or wall slab, lintel) is simply supported at both ends in horizontal position and laoded by two vertical line loads in the outer quarter points of the span until collapse in order to determine the deflaction and cracking behaviour and the loadbearing capacity.