APi653 Chapter 5/6 Flashcards
When does tank failure due to brittle fracture ? (4)
- shortly after erection during hydrostatic testing
- first filling in cold weather
- after a change in lower temperature service
- after repair/alteration
How to reduce the risk of BF? (2)
- demonstrated ability to withstand the combined effects of max liquid level and
- lowest operating temperature.
When is assessment should be made for BF?
- if service temp is reduced
2. change product to one with greater SG
What are some consideration if the tank is not per latest API 650 and will be change to a more severe service? (6)
- had to have prior hydro demonstrates fitness for continued service
- Tank thickness 0.5” or below?
- Operates at above 60F?
- membrane stress below 7KSI?
- Tank steel exempt from impact testing?
- Tank full at lowest one day temp ?
Lastly if all consideration is not met, what can be done?
Rerate tank based on prior operating history, (restrict fill height, min metal temp or both)
What can be done to establish inspection frequencies?
On stream, NDE methods
Frequency of routine inservice inspections?
not exceed ONE month
frequency of external inspection and by whom?
LESS (5 years or RCA/4N) , AI
frequency of UT (when CR is known and not ) and by whom?
- Not known = not to exceed 5 years
2. Known = LESS (RCA/2N )
When can a UT be subsittued?
During an internal inspection
What can supplement on tream UT?
Electromagnetic methods
fiberglass-reinforce lining added how many years?
5 years
internal thin film coating how many years added?
2 years
RPB adds how many years
10 years
Cathodic protection adds how many years
5 years
