Technical training
Basic Technical Training Standard / V9 2024-06-24
7. Bolt tensioning values Training provider: you should modify the table below to match bolts being used in your training. GWO recommends using tension values at 50% of bolt yield strength for safety purposes.
Stainless and bolt tightened into aluminium
Bolt Type
Hot Dip Galvanized
Property Class
8.8
10.9
All Property Classes
Min. Tension Force
Size ↓
kN
kN
kN
M8
15
30
5
M10
30
55
10
M12
55
95
25
M16
95
145
40
M20
145
180
65
M24
180
210
80
M30
210
335
95
M33
335
490
-
M36
490
585
-
M42
585
640
-
M48
640
725
-
8. Marking for Bolts
Marking is a visual indication that a bolt has been tightened to specification. Therefore, bolts may NEVER be marked prior to tightening, marking must follow the below process:
IMPORTANT!
Always tight and mark before going to next bolt/stud
Description of 1-stage marking
Training provider: please fill in the marking procedure to be used in training.
Training provider: insert photo of 2-stage marking
Global Wind Organisation / www.globalwindsafety.org
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