API 653 Study Guide 2026
Everything you need to pass the API 653 exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 API 653 Exam Format at a Glance
📚 API 653 Topics to Study (71)
✍️ Sample API 653 Questions & Answers
1. When planning thickness measurements for a tank bottom, API 653 recommends which scanning pattern to detect bottom corrosion accurately?
API 653 requires a systematic grid or scanning pattern across the entire tank bottom to ensure representative coverage and detection of localized corrosion.
2. According to API 653, which welding process is most commonly specified for repair welding on aboveground storage tanks?
SMAW is the most commonly specified process for tank repair welding due to its versatility and wide applicability per API 653 requirements.
3. Per API 653, what is the minimum overlap required when installing a lap-welded patch plate on a tank shell?
API 653 requires a minimum overlap of 2 inches (51 mm) for lap-welded patch plates on tank shells to ensure adequate fillet weld length and structural integrity.
4. What does API 653 require the inspector to document when evaluating a tank roof for fitness for service?
Roof documentation must include thickness measurements, weld integrity, accessory condition, and all defects observed so that a complete fitness-for-service determination can be made.
5. In API 653, what is the purpose of determining the 'corrosion allowance' during inspection planning?
The corrosion allowance represents the difference between current measured thickness and minimum required thickness, indicating how much additional corrosion is permissible.
6. Which factor should API 653 professionals consider first when choosing an assessment method?
The most important consideration is whether the assessment method is appropriate and validated for the specific population being assessed.