Overview of the EN 14399 Standard Series
The EN 14399 standard series regulates the production and application of high-strength structural bolting assemblies intended for preloading in steel structures. EV Group China presents an expert breakdown of the technical requirements for HR, HV, and HRC system components.
EN 14399-1: General Requirements
The standard establishes basic requirements for assemblies (bolt-nut-washer). EV Group China’s products comply with these standards to ensure the reliability of steel structures.
- Products smaller than M12 are not intended for preloading.
- Bolting assemblies must not be welded.
- The standard does not apply to components for railway tracks.
EN 14399-2: Suitability for Preloading
Defines test methods that guarantee the assembly will maintain the design preload force when installed according to EN 1090-2, ensuring the necessary degree of ductility.
EN 14399-3: HR System (High Resistance)
Technical requirements for bolts and nuts with large widths across flats. Diameter range: M12–M36. Property classes: 8.8/8, 8.8/10, 10.9/10.
| Parameter | Description |
|---|---|
| Nut type | Standard height (type 1) according to EN ISO 4032 |
| Thread length | In accordance with ISO 888 |
| Application | Steel structures under high loads |
EN 14399-4: HV System (High Voltage)
Regulates HV assemblies with thread sizes M12–M36 and class 10.9/10. Ductility is achieved through deformation of the threaded part. Nuts have a height of 0.8d.
EN 14399-5 and EN 14399-6: Washers
These standards describe requirements for hardened flat washers (part 5) and chamfered washers (part 6) for assembling high-strength bolting units.
EN 14399-7 and EN 14399-8: Countersunk and Hexagon Modifications
Specialized standards for countersunk head bolts (HR) and standard hexagon bolts (HV) with increased shaft diameters.
EN 14399-9: Direct Tension Indicators
Regulates the use of Direct Tension Indicators (DTI), which allow for visual inspection of the achieved design preload in HR and HV systems.
EN 14399-10: HRC System (High Resistance Calibrated)
Describes bolting assemblies with calibrated preload. The system includes bolts with hexagon or domed heads, ensuring controlled plastic elongation of the shank.