API 653 Sec-04 (Suitability for Service) Flashcards
When the results of a tank inspection show that a change has occurred from the original physical condition of that tank, ………… shall be made to determine its suitability for continued use.
an evaluation
Roof plates corroded to an average thickness of ………………………..or roof plates with any holes through the roof plate shall be repaired or replaced.
< 0.09” (2.286mm) in any 100 in2 area
When a frangible roof-to-shell joint is required, evaluate for items impacting compliance with requirements
under API 650
Areas that are pitted shall be evaluated to determine the likelihood of through-pitting occurring prior ……………. If so, the affected areas shall be ………………..
to the next scheduled internal inspection
repaired or replaced
Guidance for the evaluation of existing floating roofs/ external floating roof shall be based on the criteria of ,,,,
API 650, Annex C
Guidance for the evaluation of internal floating roofs shall be based on the criteria of,,,,,,
API 650, Annex H
For internal pressure. The requirements of evaluation and subsequent alterations to the tank roof and roof-to-shell junction shall be considered as per
current applicable standard (e.g. API 650, Annex F)
External pressure as applicable to the
- roof support structure (if any),
- roof-to-shell junction
shall be evaluated for the effects of design partial vacuum. as per The criteria outlined in
API 650, Annex V
All requirements of Operation at Elevated Temperature (>200 F) shall be considered as per
API 650, Annex M
If the operating temperature is changed to a lower temperature than the original design, the requirements of the
current applicable standard for the lower temperature shall be met.
Vents shall be inspected for proper operation and screens shall be verified to ………..
be clear of obstruction.
The evaluation for the suitability of the existing tank shell shall be conducted by a ……….
storage tank engineer and shall include ananalysis
Shell corrosion occurs in many forms and varying degrees of severity and may result in a ………….
generally uniform loss of metal over a large surface area or in localized areas
If the requirements of corroded or damaged areas cannot be satisfied,
- areas shall be repaired,
- allowable liquid level of the tank reduced
- the tank retired
to establish the liquid level limit
The actual thickness, as determined by inspection,minus the corrosionallowance shall be used
Formula to Calculate the critical length, L
L = 3.7 √ Dt2, but not more than 40 in.
For averaged over a length of L, use at least….
five equally spaced measurements over length L.
the value t1 (T avg.) shall be …..
≥ tmin
the value t2 shall be………
≥ 60 % of tmin
corrosion allowance required for service until the time of the next inspection shall be …..
added to tmin and 60 % of tmin.
Widely scattered pits may be ignored provided that……
- remaining shell thickness being not < 1/2 the minimum
acceptable tank shell thickness exclusive of the
corrosion allowance; - sum of their dimensions along any vertical line does
not exceed 2 in. in an 8-in