Specified root reinforcement
Applied to joint
Supplementary symbol applied to fillet weld
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Description
A supplementary symbol specifying that a minimum amount of weld reinforcement (excess metal) must be present on the root side of a groove weld. The minimum height of the root reinforcement is dimensioned.
In plain English
On the root side of a groove weld, you want a certain minimum amount of metal sticking through -- the root reinforcement or root bead. This symbol (a filled semicircle) says 'the root must protrude by at least this much'. It is the opposite of flush-finishing the root. Common on pipe welds where you want to see a consistent root bead as proof of full penetration, and on pressure vessels where the root reinforcement adds strength.
Symbol position
Filled semicircle on the root side of the weld symbol.
Size notation
Minimum reinforcement height dimensioned next to the symbol.
Common uses
- Pressure vessel and piping root welds
- Pipe butt welds where root bead profile is critical
- Joints where root reinforcement provides additional strength
- Code-required minimum root reinforcement specifications
