Petrochemical Case Study. The client was planning to apply for 21 months Certificate of Fitness (CoF) extension for unfired pressure vessels in their plant. DOSH performed a fitness inspection in May 2021, and the next CoF expiry date would be June 2022. This is according to the regular 15 month CoF interval.

According to Factories and Machinery (Notification, Certificate of Fitness and Inspection) Regulations, Part III – Inspection, Regulation 14. Regular Inspection:

After an initial inspection every factory and every machinery shall be inspected at regular intervals by an inspector so long as such factory remains in operation or such machinery remains in use.

Therefore, in order to avoid shutdown, the client needed to extend the Certificate of Fitness (CoF) of the unfired pressure vessel from 15 months to 36 months.

IPETRO Services SDN BHD team was appointed to perform a risk based inspection (RBI) study based on API 581. They did so with Antea asset integrity management (AIM) software.

The Cof extension application required support from DOSH State and approval.

If granted, the CoF extension would enable the client to avoid shutdown, thereby resulting in substantial cost savings and avoiding productivity interruptions to operations.


IPETRO performed the RBI study using Antea AIM software, and prepared all required documentation:

  1. RBI Assessment Study Report
  2. Asset Register
  3. Inspection Summary
  4. Corrosion Study
  5. Production Impact
  6. Internal Thinning Corrosion Rate & Remaining Life Tabulation
  7. RBI Analysis Result
  8. Inspection Plan
  9. DOSH Cof Extension Checklist

The study evaluates risks for pressure vessels that are subjected to different damage mechanisms that may lead to loss of containment with safety and economic consequences. Some equipment was split into various components to allow for different damage mechanisms.


Based on the RBI analysis, 20% of equipment were ranked in the “Medium” Risk category while the other 80% of equipment were ranked in the “Low” Risk category.

Photo 2: RBI assessment using Antea AIM Software

As a result, Antea’s RBI supported the client in successfully obtaining the 21-month CoF extension. This has helped them minimize shutdown frequency and the production loss cost.

Photo 3: CoF Extension Approval Letter by DOSH Putrajaya

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