UCS-66(c)(4) vs UCS-66.3 governing thickness question

[ETI1]

Hello:
I'm looking for some clarification as to rating a LWN with SA-105 to -20F.
Per UCS-66(c)(4) it appears that if the nozzle (LWN) is produced per B16.5 and the meets the ID requirements then the nozzle is exempt from impact testing. However, in my case I have a 20" CL600 LWN (nozzle wall of 2.000") inserted into a vessel with a wall thickness of 1.625" Per UCS-66.3, the vessel wall is the governing thickness which would lead me to believe that LWN would require impact testing as well. (material change to 350-LF2). I also found Interpretation VIII-1-89-17 and Interpretation VIII-1-01-37 which seem to contradict each other.

Is it correct to assume that in UCS-66(a) that if the nozzle complies with UG-44(j) that it is also exempt from impact testing to -20F?

Any help would be greatly appreciated.

Thank you,

 

[jai2705]

Hi,

If I interpreted UCS-66(a) correctly, when a component is exempted from impact testing as per UCS-66(c)(4),wonder if further evaluation as per fig.UCS-66 is really required.

If i read the scenario in conjunction with the interpretation, LWN flanges are excempted from impact testing and shell required impact testing based on it's governing thickness and corresponding temperature as per the fig.UCS-66 .

Interpretation VIII-1-01-37 referring to UCS-66(b) & Fig UCS-66.1 for the reduction of MDMT with out impact testing.