Pass
Vessels that have a remaining life over 10 years or protected against external
corrosion shall:
be observed at least every 5 years
Period between internal or on-stream inspection not to exceed
the lesser of 1/2 remaining corrosion life or 10 years
LT corrosion rate
(tINITIAL - tACTUAL)/ years between
ST corrosion rate
(tPREVIOUS - tACTUAL)/ years between
Hydro, to minimize risk of brittle fracture temp should be maintained
at least 30F above MDMT for vessel thicker than 2", 10F above MDMT for 2" or less
Max carbon content for vessels
0.35%
Remaining life
(tLAST - tMIN)/ CR
Inspection interval rules
Internal: a. Normally lesser of 10 years or 1/2 life.
b. 2 years if life is from 2-4yrs
c. Full life is life is less than 2 years
External: 5 years or inspection interval.
Next inspection date
Last inspection date + Interval
Corrosion rate
(tPREVIOUS - tLAST) / time period
Inspector/examiner?