and reconstruction Questions and Answers
correct
What type of tanks does the standard apply? API 653 1.1.1 - answerSteel storage tanks
built to API 650 and its predecessor API 12C
In case of a parent conflict between the requirements of API 650 and API 653 which
standard Govern? API 653 1.1.2 - answerAPI 653
What is meant by the term alteration? What are some examples of alterations? API 653
3.1 - answerAnything that changes the physical dimensions
Man way 12" nozzles
What is the break over point? API 653 3.6 - answerThe area on the tank bottom where
settlement begins
What is meant by the term repair? What are some examples of repairs? API 653 3.15 -
answerAny work necessary to restore and maintain a tank to a condition suitable for
safe operation
What conditions would Necessitate the repair or replacement of a roof plate? API 653
4.2.1.2 - answerCorrosion to a thickness of .09 in any 100 sq in area. Holes
What possibility must be given particular attention when inspecting pipe columns
supporting fixed roofs? API 653 4.2.2 - answerSevere internal corrosion
When a tank is to undergo a change in service what are five factors that should be
considered when evaluating the roof and roof to shell junction? API 653 4.2.4 -
answerA) internal pressure
B) external pressure
C) elevated temp
D) Low temp
E) normal and emergency venting
When determining controlling thickness in shell courses widely scattered pits may be
ignored provided that two conditions are met. What are these two conditions? API 653
4.3.2.2 - answerA) hope it being less than 1/2 the original shell thickness
B) The sum of dimensions does not exceed 2 inches in a 8 inch length
What are some typical forms of shell distortion? API 653 4.3.5.1 - answerOut of round,
buckled sides, flat spots, peeking and banding at weld joints
, Do temperature cracks in concrete seriously affect the strength of the concrete
foundation? What can temperature cracks in concrete eventually result in? API 653
4.5.1.2 - answerNo
Potential access points for moisture
What are 12 historical causes of tank bottom leakage listed in this document? API 653
4.4.2 - answerA) internal pitting
B) corrosion of weld joints
C) cracking weld joints
D) stress on bottom plates from settlement and roof supports
E) underside corrosion
F) in adequate drainage
G) lack of annular ring
H) uneven settlement
I) movement in roof supports
J) Rock or gravel foundation pads
K) non-homogenous fill under tank
J) inadequate supported sumps
What problems are indicated by distortion of anchor bolts and excessive cracking of the
concrete in which they are in embedded? API 653 4.5.3 - answerSerious foundation
settlement
Overpressure uplift condition
Below what shell thickness is the potential for failure due to brittle fracture minimal?
What can be done to gain assurance against brittle fracture? API 653 5.3.4, 5.3.5 -
answer.5
Increase the metal temp by heating the tank contents
What are 12 factors that should be considered when determining inspection intervals for
storage tanks? API 653 6.2.1 - answerA) nature of stored product
B) results of visual maintenance checks
C) corrosion rates
D) condition of previous inspections
E) corrosion prevention systems
F) methods and materials of construction and repair
G) Location of tank
H) risk of water or air pollution
I) leak detection system
J) change in operating modes fill and emptying
K) jurisdictional requirements
I) change in service
How often should routine in-service inspections be conducted? API 653 6.3.1.2 -
answerDepends on condition of site not to exceed one month