External Pressure on a Flat Head

[zakk]

Are there rules in ASME Sec VIII Div 1 that covers the design of flat heads on a vessel under vaccuum?

 

[doct9960]

There are no provisions in ASME Section VIII Div. 1 which addresses flat heads under external pressure. U-2(g) applies.

 

[jte]

Yep, what doct9960 said. Here’s the official word:

Question (1): Do the requirements for unstayed flat heads in UG-34 of Section VIII, Division 1 apply only to internal pressure?

Reply (1): Yes.

Question (2): Are there any requirements in Section VIII, Division 1 which allow the calculation of minimum thickness for unstayed flat heads under external pressure?

Reply (2): There are no specific provisions which address the condition described; see U-2(g).

jt