Project Highlight:  ABOVE GROUND STORAGE TANK INSPECTION - PETROLIMEX

• Client:PETROLIMEX

• Location: BINH DINH

• Execution Time: 2024 -2025

External In-Service Inspection in Accordance with API 653 (Substitute for Internal Inspection)

In cases where internal entry and out-of-service inspection are not feasible, an external in-service inspection program is implemented in strict accordance with API 653 requirements. The purpose is to evaluate the structural integrity and corrosion status of atmospheric aboveground storage tanks through the following methods:

• Acoustic Emission Testing (AET):
  Non-intrusive screening technique used to detect active corrosion and structural defects at the tank bottom under operational stress, in compliance with API 653 recommendations.

• External Visual Examination:
  Conducted based on Appendix C1 of API 653 – External Inspection Checklist (without internal entry) to identify surface anomalies such as cracks, localized corrosion, leakage, or deformation.

• Assessment of Weld Seam Deformations (Vertical and Horizontal):
  Geometric measurements are performed to identify buckling or distortion in circumferential and longitudinal welds on the tank shell.

• Ultrasonic Thickness Measurement (UTM):
  Thickness gauging of the tank shell, roof plates, and nozzles using calibrated ultrasonic instruments, aimed at quantifying material loss and validating compliance with minimum allowable thickness.

• Settlement Survey (SST):
  Precision leveling is conducted to detect differential settlement of the tank foundation, which may compromise structural stability.

• Plumbness Survey (PNT):
  Assessment of the tank's vertical axis to determine deviation from true verticality, which may indicate foundation or shell deformation.

• Roundness Survey (RNT):
  Evaluation of tank shell circularity along multiple elevations to detect ovality or mechanical distortion.

• Data Evaluation and Reporting:
  All inspection data is critically analyzed in reference to API 653 acceptance criteria. A comprehensive technical report is issued, including fitness-for-service evaluation, classification of findings, and recommended maintenance or monitoring actions.