Duplex Long weld neck flanges as per PD5500 Enquiry Case87

[fizzy]

Hi All,

I'm designing a pressure vessel to PD5500 with a MDMT of -45C which requires a 24"NB RFLWN manway with a 60mm thk nozzle neck. Enquiry Case 5500/87 of the code states a max thickness of 50mm for temp range of -50C to 0C. I'm assuming this statement is for the vessel shell/head as my vessel thickness is less than 50mm thk. Pls can someone throw more light on this or direct me to a text where i could get more educated on this as i've come accross it a couple of times.

Thanks in advance.

 

[gr2vessels]

The clause h) of the case 5500/87 said to use the Annex U for thickness greater than 50 mm and temperatures lower than -30 deg C. Read/use the clause U2 of PD5500.
Also, it appears that the case 87 has been withdrawn, perhaps it was far too restrictive and thus irrelevant to other duplex steels.
Cheers,
gr2vessels

 

[fizzy]

Thanks gr2vessel for your reply, i guess you're referring to clause j) of case 5500/87 for additional testing requirements as per Annex U. I'll however confirm enquiry case 87 has been withdrawn from the code as my client also made reference to it on the mech datasheet.

fizzy.