Selection of Section I paragraphs from different parts

[pietkoning]

When using ASME B&PV Section I, some topics are not in Part General, but in one of the specific parts like PFT (firetube boilers) or PWT (watertube boilers). For example:

(*) external pressure is covered by Part PFT (PFT-50 covers some rules for cylinders (tubes) under external pressure). When I'm designing a watertube boiler, how are the external pressure calculations covered? It seems strange to me that I need to decide myself to apply a paragraph that is not in part PG or PWT while designing a watertube boiler.

(*) attachment of tubesheets is covered by PFT-11. When I have a tubesheet in a watertube boiler, how should I analyze the tubesheet attachment. There is no reference in Part PG or PWT to PFT-11.

Am I missing something. I'm experienced in the analysis of pressure vessels conform Section VIII. With this experience, it is hard to understand what should be in your Section I analysis as explained by the above examples.

Thanks for comments and response.

 

[metengr]

Section I has general design rules to be followed first, in addition to specific rules applicable to welding or brazing (fabrication) and the type of boiler - PWT, firetube boiler - PFT. You follow the general rules in addition to the applicable specific rules.

 

[GenB]

you can mix the parts as long as they are applicable. your designing WT vs FT are 2 different boiler designs. tell me where do you have external pressures on the WT boiler? I do not see any; vs FT which all tubes and furnaces are external P.
TS's: the TS on WT and TS on FT are completely different; and yes there are rules for TS's of WT in the WT and PG sections. good luck. GenBlr

 

[pietkoning]

@GenB

I'm now in the phase of studying the design calculations for boilers in general, without having a specific design.

Coming from generic Pressure Vessel design, it takes some time to get acquainted with boiler specifics. However, thinking it over somewhat more, I now see that it is not possible to have external pressure on components of a WT.

 

[Fizza453]

In 2013 Edition, external pressure rules are moved from Part PFT to Part PG, that is more logical. Now you can see PG-28.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN