API 510 Repair, Alteration & Rerating Procedures 3

Question 1

Under API 510, when can PWHT be waived for a repair weld on a vessel that originally required PWHT?

Accepted Answer

When approved by the API 510 inspector and supported by engineering analysis or code alternatives

Answer

PWHT may be waived when alternative measures are approved by the inspector and justified by engineering analysis or applicable code provisions.

Question 2

A vessel alteration changes the design pressure from 150 psi to 200 psi. According to API 510, the rerating:

Accepted Answer

Requires an engineering review to verify the vessel is suitable for the higher pressure

Answer

Any rerating to higher pressure requires engineering calculations verifying that all components can safely handle the new MAWP.

Question 3

What is the purpose of a hydrostatic test following a major repair or alteration under API 510?

Accepted Answer

To verify the repair integrity and absence of leaks under pressure

Answer

Post-repair hydrostatic testing verifies the structural integrity of the repaired area and ensures there are no leaks.

Question 4

When is a pneumatic test permitted instead of a hydrostatic test after a repair, per API 510?

Accepted Answer

When the vessel design or support structure cannot support the water weight, and precautions are taken for the hazard

Answer

Pneumatic tests may substitute for hydrostatic tests when filling with water is impractical, but additional safety precautions are required due to the stored energy hazard.

Question 5

Under NBIC and API 510, a 'repair' is distinguished from an 'alteration' because a repair:

Accepted Answer

Restores a vessel to its original design condition without changing its pressure-temperature rating or configuration

Answer

A repair restores a vessel to its original design condition, while an alteration changes a design parameter such as MAWP, temperature, or configuration.

(API 510) API 510 Inspector Certification Practice Test

(API 510) API 510 Inspector Certification Practice Test

API 510 Repair, Alteration & Rerating Procedures 3