API 653 Documentation 3 — Questions and Answers
Question 1: What information must an API 653 inspection report include regarding the tank's service history?
- Only the current stored product
- Product type, any service changes, and dates of service changes since the last inspection (Correct answer)
- The cost of the stored product at time of inspection
- The number of employees who operated the tank
Correct answer: Product type, any service changes, and dates of service changes since the last inspection
Service history, including product type and any changes, is critical because different products cause different corrosion mechanisms and rates that affect fitness-for-service assessment.
Question 2: Under API 653, who is ultimately responsible for signing and certifying the inspection report?
- The plant manager
- Any qualified welding inspector
- A certified API 653 Inspector (Correct answer)
- The regulatory agency representative
Correct answer: A certified API 653 Inspector
API 653 requires that inspection reports be reviewed and certified by an API 653 Inspector, who bears responsibility for the accuracy and completeness of the findings.
Question 3: When documenting external corrosion found on a tank shell, what details should the inspection record include?
- Only the deepest pit measurement
- Location, extent, depth of corrosion, and remaining thickness at affected areas (Correct answer)
- The cost estimate to repair the corrosion
- The weather conditions when corrosion was found
Correct answer: Location, extent, depth of corrosion, and remaining thickness at affected areas
Complete corrosion documentation enables accurate fitness-for-service calculations and supports determination of the next inspection interval based on corrosion rate trending.
Question 4: What does API 653 require when a tank is returned to service after an internal inspection?
- A pressure test to 150% of operating pressure
- Documentation that all deficiencies found have been addressed or accepted for continued service with an appropriate action plan (Correct answer)
- Immediate re-coating of all internal surfaces
- Regulatory agency sign-off before any product is introduced
Correct answer: Documentation that all deficiencies found have been addressed or accepted for continued service with an appropriate action plan
Before returning a tank to service after inspection, API 653 requires documented evidence that identified deficiencies have been repaired or formally accepted for continued service under a defined monitoring plan.
Question 5: In API 653, what is the role of the maximum fill height in tank documentation?
- It determines the required pump capacity
- It sets a physical operational limit that must be recorded and enforced to avoid overstress of the tank shell (Correct answer)
- It is used to calculate tax liability for stored products
- It determines the color coding required for the tank roof
Correct answer: It sets a physical operational limit that must be recorded and enforced to avoid overstress of the tank shell
The maximum fill height is a critical operational limit derived from structural calculations and must be documented so operating personnel do not overstress the tank shell or foundation.
Question 6: Which document would an API 653 inspector consult to determine the welding procedures used in original tank construction?
- The tank owner's safety data sheet (SDS)
- The welding procedure specifications (WPS) and procedure qualification records (PQR) from original construction (Correct answer)
- The local building department permit
- The OSHA 300 log for the facility
Correct answer: The welding procedure specifications (WPS) and procedure qualification records (PQR) from original construction
WPS and PQR documents establish the qualified welding parameters used in construction and are referenced to ensure repairs use compatible procedures and materials.
Question 7: According to API 653, what must be documented when the inspection interval for a tank is extended beyond the standard schedule?
- A written waiver from the tank manufacturer
- The technical justification, including corrosion rate data and remaining life calculations, reviewed by a qualified inspector (Correct answer)
- Only verbal confirmation from the owner/operator
- A new API 653 certification for the inspector
Correct answer: The technical justification, including corrosion rate data and remaining life calculations, reviewed by a qualified inspector
Extending inspection intervals requires documented technical justification demonstrating that the tank can safely operate to the extended date, signed off by a qualified API 653 inspector.
API 653 Documentation 3
What information must an API 653 inspection report include regarding the tank's service history?