Here are the Top 10 most repeated API 570 exam questions—these show up again and again in different forms in the American Petroleum Institute API 570 (Piping Inspector) exam.
🔥 TOP 10 MOST REPEATED API 570 QUESTIONS
🔴 1. What is corrosion rate (CR)?
👉 Formula:
CR = (Initial thickness − Current thickness) / Time
✔ Core calculation used everywhere
🔴 2. What is remaining life (RL)?
👉 Formula:
RL = (Current thickness − Minimum thickness) / CR
✔ MOST tested calculation in exam
🔴 3. What determines inspection interval?
👉 Answer:
✔ Based on remaining life
✔ Typically ≤ ½ RL (within code limits)
🔴 4. Which thickness value should be used?
- Average thickness
B. Maximum thickness
C. Minimum measured thickness
D. Nominal thickness
👉 Answer: C
🔴 5. If corrosion rate increases, what happens?
👉 Answer:
✔ Remaining life decreases
✔ Inspection interval decreases
🔴 6. If current thickness equals minimum thickness, what is required?
👉 Answer:
✔ Immediate action (repair/replace)
✔ No further calculation needed
🔴 7. Which corrosion rate should be used?
- Lowest
B. Average
C. Highest (conservative)
D. Random
👉 Answer: C
🔴 8. What should be done if inspection data is inconsistent?
👉 Answer:
✔ Recheck / verify data
✔ Do not assume
🔴 9. What happens after a repair?
👉 Answer:
✔ Re-evaluate piping
✔ Verify compliance
✔ Update inspection plan
🔴 10. Maximum inspection interval is controlled by?
👉 Answer:
✔ API 570 code limits
🧠 ULTRA-FAST MEMORY (30 SECONDS)
✔ CR = thickness loss / time
✔ RL = (current − minimum) / CR
✔ Interval ≈ ½ RL
✔ Use minimum thickness
✔ Use highest corrosion rate
✔ Follow code limits
🎯 WHY THESE 10 MATTER
These questions cover:
✔ 80% of calculation logic
✔ Most repeated exam patterns
✔ Core decision-making rules
🚀 FINAL EXAM EDGE
If stuck:
👉 Choose the answer that:
✔ Uses worst-case values
✔ Is conservative
✔ Follows code
