RT Requirement as per UW-11 2

[sollapalooza]

Hello,

I would like to ask regarding RT requirement as per UW-1. I've read ASME PTB-4 and as per its logic diagram, I need to determine its service and thickness to establish its RT level (full, spot, etc.) and subsequently its joint efficiency (E).

UW-11(a) and (3): Is the service lethal? If no, refer to UW-11(a)(2) to check its thickness and other specific material requirement.

My question is, before you determine its RT level and E value using thickness, you need to calculate its thickness first. And in order to do that, you need to know E value. Isn't like a chicken-and-egg situation?

If I do my preliminary calculation using E = 1, and along the way it is determined that my RT level is Spot, and E = 0.85, do I need to revisit my calculation AND go through the logic diagram again?

Thank you in advance.

 

[GD2]

OP,
There is no chicken and egg situation.
UW-11 defines where to use full, spot or no radiography. There is also Table UCS-57 which gives guidance to radiography required.

Once you have assigned RT1, RT2 etc for each joint, determine E. Then calculate the wall thickness.


GDD
Canada

 

[SnTMan]

In practice, one Assumes a level of RT based on company practices and nature of the work. Full, Spot, None.

One then runs the calculation of interest and observes if the resulting thickness is acceptable and meets Code rules as to whether the assumed degree of RT complies.

The iterative nature of many of these calculations is why compute programs were employed.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[sollapalooza]

Thank you very much for your replies SnTMan and GD2, really appreciate it.