Hi Mariog,
thank you for replying. For my case, its a replacement job for tube bundle with pressure of 11.2Mpa tube side. shell side is 0.7 Mpa. It seems that its hard to argue that i have no bolt acting my tubesheet. My tubesheet required thickness is 106.5MM and my actual tubesheet is 155.7mm,actual tubesheet flanged extension is 128.6mm. Since my flanged extension is larger than my required tubesheet thickness, does this allow me to to skip UHX-9.5(a). Thank you and a pleasant day to you.


Lemonlime