This document describes the objectives and procedures for the metrological monitoring of wind turbine structures (structural health monitoring - SHM). It provides guidelines and instructions for the general design of SHM systems for monitoring wind turbine structures, and gives an overview of the objectives that can be pursued with SHM and their benefits, in accordance with the principles outlined in part 1 In contrast to methods from the field of machine monitoring (described in part 2), which typically deal with the monitoring of rotating machine components, SHM is primarily used to monitor objects with load-bearing properties (structures). The document provides instructions for dealing with the variety of methods and technologies appropriate to Wind Turbine structures, both on- and off-shore. It describes the framework conditions for the efficient use of SHM and refers to possible economic and/or technical application limits. Basic strategies for action are presented and criteria for their optimal implementation are named, in relation to the objectives of SHM. The necessary requirements for technical implementation in SHM systems are listed and weighted, depending on the SHM objective. The document refers to the tasks of integrating monitoring measures into the ongoing construction or operating process of the load-bearing structures and provides information for their consideration in project and process management. The guideline is aimed at owners and operators of structures, designers, certifiers and inspectors of structures, service providers for metrological solutions as well as manufacturers of SHM technologies and authorities (keyword certification). The use of an SHM system makes sense in technical installations and constructions in which either the technical functionality can be improved or an economic benefit can arise. Examples of advantages are : - Operational safety - Approval (in individual cases) - Asset management, condition-based maintenance (CBM), - Design verification - Extension of service life - Risk-based inspection regimes (where permissible) This document includes the foundation, tower and nacelle structures of the wind turbine. The effect of the blade motion and aerodynamics on the tower is included, but structural assessment of the blades themselves is excluded. Blade condition monitoring is expected to form a future part of this standard.