This part of IEC 61400 specifies requirements to ensure the engineering integrity of wind turbine blades as well as an appropriate level of operational safety throughout the design lifetime. It includes requirements for: " aerodynamic and structural design " material selection, evaluation and testing " manufacture (including associated quality management) " transportation, installation, operation and maintenance of the blades The purpose of this standard is to provide a technical reference for designers, manufacturers, purchasers, operators, third party organizations and material suppliers, as well as to define requirements for certification. With respect to certification, this standard provides the detailed basis for fulfilling the current requirements of IEC 61400-22 and, when available, the IECRE system, as well as other IEC standards relevant to wind turbine blades. When used for certification, the applicability of each portion of this document should be determined based on the extent of certification, and associated certification modules per IEC 61400-22 and/or the IECRE system. The rotor blade is defined as all components integrated in the blade design, excluding removable bolts in the blade root connection and support structures for installation. This standard is intended to be applied to rotor blades for all wind turbines. For rotor blades used on small wind turbines according to IEC 61400-2, the requirements in that document may be applied instead. At the time this standard was written, most blades were produced for horizontal axis wind turbines. The blades were mostly made of fiber reinforced plastics. However, most principles given in this standard would be applicable to any rotor blade configuration, size and material. This standard should be used together with the appropriate IEC and ISO standards mentioned in Section 2.