I am carrying out API 579 brittle fracture assessment for CS knockout drum (KOD):
MAWP = 14.5 barg
MDMT = -16 degC
New low oper. temp = -27 deg C @ 10 barg.
Thus, CET = -27 degC.
As per assessment calculated MAT = -30 degC < CET [OK]
Basis for MAT reduction is PWHT done post-fab; additionally the coincident ratio Poper / MAWP = 0.7 which yields about 17 degC reduction.
Does MDMT on the nameplate need to be changed?
MAWP = 14.5 barg
MDMT = -16 degC
New low oper. temp = -27 deg C @ 10 barg.
Thus, CET = -27 degC.
As per assessment calculated MAT = -30 degC < CET [OK]
Basis for MAT reduction is PWHT done post-fab; additionally the coincident ratio Poper / MAWP = 0.7 which yields about 17 degC reduction.
Does MDMT on the nameplate need to be changed?