WHAT SHALL BE VESSEL EXTERNAL PRESSURE VALUE MENTION ON NAME PLATE AS PER ASME VIII DIV.1 1

[staticmh]

Hi Folks!

I need quick clarification regarding the vessel external pressure value which shall be mentioned on vessel ASME name plate in compliance of ASME VIII Div. 1 UG-119

I have two cases:

1. one vessel which external pressure is based on (bouncy forces + FV) value i.e. 0.1294 Mpa

2. Second vessel which external pressure is only "FV" but PV elite calculating the MAEWP higher than the "FV" and its concluded as 0.352 Mpa

So please advice me what shall be the maximum allowable pressure (external) marked on ASME Name plate. whether MAEWP 0.352 value shall be or only upto maximum "FV" shall be maintained on Name plate.

I discussed with some colleague, he is emphasizing to only maintain the "FV" value on name plate regardless of calculated MAEWP value which always seems high. Please share also an reference of this case from COde.

 

[SnTMan]

staticmh, question: Can either of these vessels, during operation, be subjected to external pressure exceeding FV? This answer should help to clarify your nameplate stamping.

See also Fig U-118, Note 5.

Regards,

Mike

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

 

[staticmh]

SnTMan,

Yes as per the client data sheet, the vessel shall be in concrete pit and during operating external pressure may go higher than the FV, if in case the pit is flooded with rain water and hydrostatic pressure shall be acting on the outside surface of the vessel.

Thus, the external pressure value shall be FV (0.103 Mpa) + Hydrostatic pressure (0.02595 Mpa).. = 0.1294 Mpa Approx.

Now this is the case and please advice. what shall be the value stamp on ASME name plate. Either 0.1294 Mpa or MAEWP i.e. 0.991 Mpa or FV.

 

[SnTMan]

staticmh, by my reading the Code would allow stamping for the calculated MAEWP. However, as a matter of trust (or lack thereof) in the software I would only stamp it for the design value (0.1294 in this case) unless I verified the software calculations. Assuming such calculations were obtained from software in the first place, of course.

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

 

[marty007]

Agree with SnTMan

Just a small clerical comment - the term MAEWP was dropped in the ASME VIII-1 code in the 2013 code edition.

Proper terminology is now to refer to it as MAWP Internal or MAWP External.

The acronym MAEWP should no longer be stamped on a nameplate, instead you should be stamping: MAWP: -0.1294 MPA @ ??? °C

Cheers!
Marty

 

[staticmh]

@marty007

@ SntMan

Correct! the MAEWP terminology waved off by the code now and only addressing the term in Fig UG-118 as MAWP (INT) & MAWP (EXT).

However, in this case i have never ever seen any pressure vessel stamped higher than the "FV" at name plate. regardless of what software is already calculating the MAWP (Ext) higher pressure value.

Even though we understand that compress & PV elite calculate the MAWP (Ext) value higher than the "FV".

However, if code allow to stamp the vessel MAWP (Ext) higher than the "FV" then could you quote me any reference from SEC VIII Div. 1 ? I'll be appreciable for your kind words. Thank you.

 

[r6155]

Wind load (external pressure) must also be added to FV.

Regards

 

[SnTMan]

staticmh, Fig U-118, Note 5 is the only reference I have found.

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