API 653 Pressure Testing 4

Question 1

Under API 653, what is the maximum allowable test pressure for a pneumatic pressure test on a tank shell expressed relative to the design pressure?

Accepted Answer

1.1 times design pressure

Answer

API 653 limits pneumatic shell tests to 1.1 times the design pressure to reduce the stored energy risk associated with compressed gas.

Question 2

An inspector observes that the roof-to-shell junction is weeping during a hydrostatic fill. According to API 653, what is the correct course of action?

Accepted Answer

Stop filling, de-water, repair the junction weld, and retest

Answer

Any active leak discovered during a hydrostatic test requires stopping the test, removing the water to a safe level, repairing the defect, and performing a retest.

Question 3

For an API 653 inspection, what type of nozzle attachment weld repair on a shell course would trigger a requirement for a shell hydrostatic test or radiography?

Accepted Answer

Any full penetration groove weld repair on a shell nozzle

Answer

Full penetration groove weld repairs on shell nozzles are pressure-retaining welds that require post-repair hydrostatic testing or radiographic examination per API 653.

Question 4

According to API 653, which of the following is an acceptable leak test method for a reconstructed tank annular weld where water flooding of the foundation is a concern?

Accepted Answer

Vacuum box testing of the inside bottom edge weld

Answer

Vacuum box testing of the inside bottom edge (annular-to-shell) weld is an API 653 accepted alternative when water flooding of the ring foundation must be avoided.

Question 5

When calculating the maximum allowable fill height for an API 653 hydrostatic test, which factor primarily limits how high the tank may be filled?

Accepted Answer

The allowable stress in the lowest shell course

Answer

Hydrostatic hoop stress is highest at the lowest shell course, and the allowable stress in that course determines the maximum safe fill height.

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

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

API 653 Pressure Testing 4