API 653 Fitness-for-Service & Repair 5

Question 1

According to API 653, when is a full hydrostatic test NOT required after a repair?

Accepted Answer

When only the roof structure (not shell) is repaired and no new penetrations are added

Answer

API 653 permits waiving the hydrostatic test for roof-only structural repairs that do not involve new penetrations, provided other specified inspections are completed.

Question 2

A tank shell course shows widespread pitting with the deepest pit measuring 40% metal loss. The average metal loss over a 2-inch diameter area is 25%. Per API 653 simplified FFS criteria, this area is:

Accepted Answer

Evaluated using both maximum pit depth and average area criteria to determine acceptability

Answer

API 653 FFS assessment uses both the maximum pit depth criterion and the average thickness criterion over the assessment area, and both must be satisfied.

Question 3

Which of the following tank conditions is specifically addressed by API 653's external floating roof fitness-for-service criteria?

Accepted Answer

Pontoon corrosion that compromises buoyancy

Answer

API 653 includes criteria for evaluating pontoon corrosion on external floating roofs because buoyancy loss leads to sinking and potential product loss.

Question 4

When API 653 refers to 'temporary repairs,' which statement is most accurate?

Accepted Answer

Temporary repairs such as clamps or plugs may be used but require a plan for permanent repair within a defined timeframe

Answer

API 653 allows temporary repairs as a short-term measure provided there is an engineering basis for their use and a plan for permanent repair is established.

Question 5

For the purpose of API 653 fitness-for-service calculations, what value of specific gravity (SG) is used when the stored product SG is unknown?

Accepted Answer

SG = 1.0 (water)

Answer

When the stored product specific gravity is unknown, API 653 uses SG = 1.0 (water) as a conservative default for minimum thickness calculations.

(API 653) API 653 Aboveground Storage Tank Inspector Certification Practice Test

(API 653) API 653 Aboveground Storage Tank Inspector Certification Practice Test

API 653 Fitness-for-Service & Repair 5