EN 14399 is a comprehensive standard that sets out the requirements for high-strength structural bolting assemblies for preloading. This standard covers bolting assemblies with ISO metric coarse pitch thread sizes from M12 to M36 and fine pitch thread sizes from M8 to M36. The document specifies the mechanical properties of bolts, nuts, and washers, as well as the testing and quality control procedures to be followed. It also provides guidance on the selection of suitable bolting assemblies for different structural applications, ensuring safety and reliability in construction projects. Overall, EN 14399 plays a crucial role in ensuring the performance and integrity of structural bolting assemblies, contributing to the overall safety and quality of construction projects.