API 650 Construction

[magesh2010]

Hi All

I am just wondering where to measure the radius of each course and how the tolernce applies to tank contruction as per API. (API indicates the measure the radius of bottom course 0.3 mtr from base, but not sure about the other courses)

Please advise

 

[JStephen]

Radius is measured only at that height. Tolerance in the upper shell is based on the radius at the bottom and the out-of-plumb tolerance.

 

[magesh2010]

Thanks JStephen, Is out-of plumb tolerance is worked out for each course? ie say if the bottom course is 2400 heigh, it should be with in +/- 12mm (2400/200) or it is only measured at overall tank height?