Section VIII Div.1 MAWP 1

[anolan23]

It has been told by my Authorized Inspector that if you blow a hole into a 16.5 flange (for the purposes of attaching a nozzle) that it is no longer considered 16.5. At this point, flat head calculations of UG-34 and UG-39 must be used.

How do I calculate the MAWP for this part since it is no longer 16.5? I cannot find a formula like shown in UG-27 or UG-32 for example. THANKS

 

[SnTMan]

Blind flange?

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

 

[henderrj]

Interpretation record #14-1803, for the 2013 Edition may help.

 

[jte]

anolan23-

You didn't flip enough pages. Keep reading until you get to UG-34, and pay particular attention to Figure UG-34(j). Then for opening reinforcement, be sure to skip UG-37 and proceed directly to UG-39.

But before you go to all that effort, be sure to look at B16.5 Table 6 and make sure that your (centered) opening in the blind does not exceed that which is permitted. If you don't exceed the permitted opening size, then it is still compliant with B16.5.

 

[SnTMan]

Assuming you have to perform them, you would calculate the MAWP by incrementing the pressure in the reinforcement calculations until you find the highest pressure at which the given reinforcement is adequate. Note that the UG-34 thickness t and the UG-37 thickness trn will increase with each iteration, while actual thicknesses are held constant.

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