Sizing of (powerplant) boiler feedwater pumps acc. to ASME 1

[TWitzke]

Hi everybody,
Sorry, but I'm new in this forum.
My question (and I hope someone is able to answer it) is:
According to applicable European rules for powerplant (boiler) equipment, such like PED or German TRD BFW pumps have to be oversized (acc. to TRD at least 125% of req. flow against MAWP and 100% against 1.1 x MAWP, acc. to PED it could be less in certain cases).
Does a comparable rule exist in ASME rules? And where can I find it? Or am I free to chose oversizing (if any) like I want?
Many thanks for answers!!
TW

 

[davefitz]

see asme sect I paragraph PG 61.1 . It requires the boiler feedpump to be capable of feeding water to the sdum if the pressure at the drum is 3% greater than the safety valve lifting pressure. It does not specifically state that the flow be equal to or greater than design flow, but most people interpret that the flow at 103% MAWP be GTE MCR flow.

 

[TWitzke]

Dear davefitz,
many thanks for that very helpful answer. That is exactly, what I guessed - there is no ruel concerning the flow.
Many thanks again
TWitzke