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STEEL CONSTRUCTION FASTENERS
7
1.1
What is an HV set EN 14399-4?
The marking HV is derived from the German term “Hochfest Vorgespannt”, which refers to a high-strength, preloaded bolt.
Currently, HV refers to hexagon bolt and nut assemblies according to standard EN 14399-4. These bolt assemblies are used
in bolt connections of preloaded, load-bearing steel structures.
HV bolt assemblies also include washers pursuant to EN 14399-6. All system components (bolts, nuts, washers) must be
procured from the same manufacturer.
Preloaded bolt connections are used for ensuring slip resistance, for structures located in seismic regions or structures that are
otherwise subjected to dynamic loads. Preloading is also utilised for improving fatigue resistance and long-term durability.
These types of connections can also be executed with an HR bolt assembly according to EN 14399-3. In Finland, however,
the use of HV sets has been established as the standard for design and execution. These two assemblies should not be con-
fused with one another. They are two distinct systems with different characteristics and component dimensions.
HV bolt assembly standards were revised back in 2007. Some old bolt lists or drawings may still include the following old
designations from the DIN standard:
Product
Old standard
Current standard
HV bolt
DIN 6914
EN 14399-4
HV nut
DIN 6915
EN 14399-4
HV washer
DIN 6916
EN 14399-6