Proof Test UG-101

[steris]

We had a number of proof tests done on our vessels back in 1999. After reviewing the proof tests, the chamber & jacket MAWP were determined by formula UG-101(m)(2). According to the code as of 1999, this formula was

P = B/5 * Su*E/Su_avg
where:
B = bursting pressure
Su = minimum material tensile strength
E = joint efficiency
Su_avg = material tensile strength from test cert

According to the 2007 code, this formula is now P = B/4 * Su*E/Su_avg. This new formula allows an increase of MAWP by 25%! Are we allowed to redo the calcs on the proof test without redoing the proof test? If we update the calculations to reflect the current code, is there anything in particular that we should be aware of?

Thanks in advance for your help!

 

[eliebl]

If my memory serves you can recalculate. One item to note is that you need to ensure that the entire design meets the updated code. There were other items changed as a result of the reduction in design factor.

Regards,
EJL