Page 74 - Pipeline Rules of Thumb Handbook
P. 74
Construction 61
Figure 5. Radiographs of porosity.
the root spacing. Within limits, this can be fairly effective. For A skillful line-up crew can be helpful in juggling the root
example: spacing to bring about the most favorable results, but this has
limitations. And it is at best a poor substitute for a uniform
and consistent joint preparation.
Condition Change in Root Spacing
Land too small. Decrease root spacing. Internal chamfer
Land too large. Increase root spacing.
High-low condition. Decrease root spacing. It is important to remove any burr or overhang on the
Bevel too small. Increase root spacing. inside edge of the pipe after the root face has been machined
Figure 6. Recommended joint preparation and
typical procedures—operate within these toler-
ances to help ensure good quality welds.
