Can high-strength structural bolting assemblies for preloading (HSFG) be de-assembled once they have been assembled?

Due to safety reasons and according to BS 4604-1 (Withdrawn):

“If after final tightening a bolt or nut is slackened off for any reason, the bolt, nut and washer shall be discarded and not re-used.

Under the latest BS EN 14399 standard:

If the assembly has been tightened to the minimum force of 70%, the assembly cannot be re-used.

Andrews Fasteners recommend, once assembly has been preloaded, in any form and needs to be de-assembled, to discard it and replace it with fresh assembly (and relevant components like DTI washers) due to wearing off applied lubrication which may invalidate torque figures supplied for installation (k-Class K1 or K2) or cause difficulty to compress DTI washers at the right level (k-Class K0).

↫ Go back