View Full Version : Tolerance for wall thickness

09-17-2008, 12:15 PM

I want to ask...............How to calculate the wall thickness for pipe including the tolerance mil (table 11) as per as API 5L 44Th Edition ( October 2008).


10-06-2008, 09:26 PM
When I calculate the wall thickness, I take the smallest POSSIBLE thickness. If the published thickness was 0.25" and mill tolerance was 12.5%, I would use (1-.125)*.25"=0.21875" as the smallest thickness.

If I was calculating the thickness of the pipe based on 31.1, 31.3, 31.8, etc. , I would make sure I chose a pipe (don't forget to subtract mill tolerances, thread allowances, if needed and corrosion allowances) whose thickness was greater than the calculated thickess above.

am I confusing?

05-16-2009, 04:41 AM
Dear All members,

I would like to know what is the permissible limit of offset when joining between 2 welded pipe(longitudinal seam). ASME VIII clearly stated but B31.3 silent on it. Any other reference, code or recommended practice that i can refer to it. If any could you share with me. Thank in advance for you cooperation



Abdel Halim Galala
08-13-2009, 07:57 AM
Please see the following CR4 Thread with a solved example per ASME code indicating how to calculate the min. pipe wall thickness, taking into consideration the tolerance:

The pipe wall thickness tolerance as per API 5L is in accordance with Table 9, see the following CR4 Thread :