Saddles in ASME SEC I

[xgiorg]

Hello,

Does it exist a saddle calculation method in ASME I?
I'm working in a steam drum, first I worked in asme VIII div 1 ,but now the client wants the calculation in ASME I.
Thanks.

 

[TomBarsh]

Section I does not specifically provide a design method for saddles, nor does Section VIII except in the 2007 and later Division 2. The "Zick" analysis is used as the basis for the the 2007 Division 2, and I believe for the BS PD-5500. You can likely use the Zick analysis for your steam drum.

 

[xgiorg]

Thanks for your comment, I will apply zick analysis, maybe in 2010 we would have a PG- for saddle calculation.

 

[LSThill]

TomBarsh (Structural)

"Zick" analysis will Saddle Pro. be aded to Codeware Softewar Compress Pressure Vessel and heat Exchanger Software?

Leonard

 

[gr2vessels]

Leo,
The PV Elite does full design of saddles for pressure vessels and heat exchangers. Ring Cortex in Melbourne...
Cheers,
gr2vessels

 

[GenB]

Do not forget the Sect I minimum requirements!

 

[LSThill]

gr2vessels (Mechanical)

PV Elite but not PRG SADDLE PRO!

 

[chicopee]

Isn't Zick's analysis for unfired pressure vessel? On the other hand steam drum are designed according to Power Boiler Section 1 and not section VIII.

 

[GenB]

Do not forget the Sect I minimum requirements!

 

[saplanti]

In the conventional boiler the drums are to be hang by rod hangers connected to the suspension structure due to the economics thant shown by major boiler design companiesnot by the saddles. Therefore ASME Sec I does not include the saddle supports.

When HRSGs started using drums the designers put the drums on the structures, and saddle supports became more economical.

ASME Sec I still does not include the saddle supports, however this does not stop the designers using the saddle supports by complying with the juristiction of ASME Sec I in the Zick analysis. There are also some known weaknesses of the Zick analysis. These are given in the reference(PD6497) of PD5500.
Additionally this was discussed in these forums several times. In case large horizontal seismic or etc... loads you need to be carefull in the application of Zick analysis, or you may be forced to use full circle stiffeners at/next to saddles or take the loads structurally by adding guides to the system, and you are the decision maker what to do in accordance with your needs.

Hope it helps.

Ibrahim Demir

 

[saplanti]

I forgot to mention the steam drums supported by mud drums through the boiler evaporator tubes. However these drums are part of the entire boiler furnace and the furnace is supported by saddles attached to the mud drum and lower wall headers. Again the economy is the driving factor how to support the drums or the furnace entirely.

Regards,

Ibrahim Demir