AS 1252:2016 Structural Bolt Assemblies: What Changed, K0 vs K2 and EN 14399

Key things to remember

The essentials from this document in plain words. Check the full document before you rely on a figure.

• ✓AS 1252:2016 is in two parts: Part 1 covers dimensions, manufacture, testing, certification and purchasing; Part 2 covers verification testing of K0 assemblies before they reach the market. It is largely based on EN 14399:2005 and is referenced in AS 4100 and AS 5131.
• ✓AS 1252:1983 (dimensional, 1996 mechanical) structural bolt assemblies are replaced by AS 1252:2016 class 8.8 Type HR with K0 classification. Assembly testing is now compulsory for K0 assemblies.
• ✓K0 paperwork: an Initial Type Testing certificate, a Factory Production Control inspection certificate, and a Verification Testing Report in the Supplier Declaration of Conformance (SDoC). Verification testing must be done by an independent ILAC accredited laboratory.
• ✓EN 14399 class 8.8 HR assemblies with K2 classification meet AS 1252:2016 as an alternative assembly type and can be used directly in Australia. They carry a CE certificate, FPC certificate and Declaration of Performance.
• ✓The k-class is about friction control in the threads. K0 has no k-factor requirement; K1 and K2 are calibrated (K2: mean k-factor 0.10 to 0.23, variation Vk no more than 0.06), so only K1 and K2 assemblies can be tightened by torque.
• ✓HR bolt assemblies are designed to fail by the bolt snapping in a ductile way at the threaded part of the shank, matching the design model in AS 4100.
• ✓Hobson's ranges, hot dip galvanised class 8.8 HR: K0 KBHK0GCM in M12 to M36 (for example M20 x 40 to 800mm, M24 x 50 to 750mm); K2 KBHK2GCM in M12 to M36 except M27 and M33 (for example M20 x 45 to 350mm).

Who it helps: Steel fabricators, erectors, engineers and buyers specifying or checking structural bolt assemblies and their paperwork.