High-strength Structural Bolting

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High-strength Structural Bolting

We are a manufacturer of pre-loaded fasteners to BS EN 14399. Our high-strength structural bolting assemblies are manufactured and tested in full compliance with BS EN 14399, the harmonized European standard for preloaded connections in steel structures. Designed for critical applications where safety, durability, and reliability are paramount, these assemblies ensure consistent preload performance and secure friction-type joints. Each assembly—comprising bolts, nuts, and hardened washers—is CE Marked, guaranteeing conformity with EU Construction Products Regulation and providing full traceability through batch certification. Available in System HR and System HV configurations, with diameters ranging from M12 to M36 and strength grades 8.8 and 10.9, our products are independently tested under BS EN 14399-2 by accredited bodies. We are regularly independently assessed by DEDAL, to make sure, that our company is fully compliant with BS EN 14399 requirements.

BS EN 14399 High-strength structural bolting assemblies for preloading- (CE Marked)

We provide Hex bolts in various types.

Standard Series: EN 14399-1 to EN 14399-10
Certification: CE Marked
System Types: HR High Resistance & HV Hochfest Vorgespann

BS EN 14399-3 Hexagon bolting assemblies for preloading (System HR)

System HR refers to hexagon head bolt and nut assemblies designed specifically for preloaded structural connections in steelwork. These assemblies are intended for friction-type joints, where the clamping force of the preloaded bolts ensures slip-resistant, durable, and safe connections.

Key Features
Components:
  • • Hexagon nut (BS EN 14399-3)
  • • Hardened washer (BS EN 14399-5, placed under the nut)
  • • Chamfered hard washer (BS EN 14399-6 usually used under bolt head).
Strength Grades: 8.8 and 10.9
Diameter Range: M12 to M36
Thread: Metric coarse, tolerance class 6g/6H
Surface Finish: Phosphate and oiled, hot-dip galvanized, Geomet® (zinc-flake coating), Dacromet
k-Class: K0, K1, K2
Marking:

Bolts: HR8.8 or HR10.9

Nuts: HR8 or HR10
Washers: H

BS EN 14399-4 Hexagon bolting assemblies for preloading (System HV)

System HV refers to a specific type of high-strength structural bolting assembly used for preloaded connections in steel construction. The term "HV" originates from the German phrase “Hochfest Vorgespannt”, meaning high-strength preloaded

Components:
  • • Hexagon head bolt (BS EN 14399-4)
  • • Hexagon nut (BS EN 14399-4)
  • • • Hardened washer (BS EN 14399-5, placed under the nut)
  • • Chamfered hard washer (BS EN 14399-6 usually used under bolt head).
Strength Grades: 10.9
Diameter Range: M12 to M36
Thread: Metric coarse, tolerance class 6g/6H
Surface Finish: Phosphate and oiled, hot-dip galvanized, Geomet® (zinc-flake coating), Dacromet
k-Class: K0, K1, K2
Marking:

Bolts: HV10.9

Nuts: HV10

Washers: H

BS EN 14399-9 Direct Tension Indicators (DTI)

Direct tensions indicator washers (DTI) to BS EN 14399-9 are supplied with bolting assemblies designed for k-Class K0. DTI washers are used during tightening of the assemblies, to ensure, that correct force for pre-loaded fasteners is achieved. DTI washers reduce necessary to use Torque figures and risk of over-tightening of the assemblies.

Assemblies designed for k-Class K1, combined method of installation, or k-Class K2, for tightening with a torque wrench can be installed with DTI washers under k-Class K0.

  • Bridges and heavy civil engineering structures
  • High-rise buildings and steel frameworks
  • Industrial plants, power stations, and infrastructure projects
  • Any structural steelwork requiring slip-resistant, preloaded bolted joints