Pipe tolerance in calculating MAWP

[Spoonful]

Hi All,

Do you include pipe tolerance when calculation for internal pressure? If use SA106B pipe, there is 12.5% tolerance on the wall thickness, I think the schedule wall thickness need to be reduced by 12.5% to truly reflect the worse case shell thickness.

If use formula given in UG-27
P=SET/(R+0.6t) where t is schedule thickness times 0.785

Agreed?


So shall we also apply tolerance on the Pipe OD? so for worse case scenario, max OD, with min wall.
BTW, what is the max allowable manufacture under thickness for for A516 70 plate ?

But I found, when using PV Elite, it did not consider any tolerance.

 

[fegenbush]

I know that Compress by Codeware does account for the under tolerance for pipe wall thickness as required by UG-16(d) for calculating the MAWP of the nozzle. It is not required to account for the under tolerance when calculating the reinforcement area.

The over tolerance for pipe is provided in ASTM A530 Table 2. The values presented there are quite small in comparison to the -12.5% allowed in Table 1 of the aforementioned standard. Additionally, it is not required to check for this condition per ASME Section VIII Division 1.

Per ASTM A20 Table A1.1 Note 1, the under tolerance for plates is 0.01 in.

 

[SnTMan]

Spoonful, see UG-16(c).

Regards,

Mike