This document identifies the requirements, the basic performance criteria and evaluation of conformity for precast ribbed elements made of reinforced or prestressed normal weight concrete, used in floors or roofs. The elements consist of a top and/or bottom slab and one or more (usually two) ribs; transverse ribs may also be present.Some examples of precast elements considered in this document are shown in Annex A.Specific requirements for minor floor elements are listed in Annex B.This document covers terminology, performance criteria, tolerances, relevant physical properties, test methods and aspects of transport and erection.This document does not cover