According to president director of Pertamina refinery operator PT Kilang Pertamina Internasional, Djoko Priyono, the investigation has determined that a thunder strike at a leak point on oil tank G was the most probable cause of the fire.
"PT LAPI ITB has concluded that the leakage occurred at the first thunder strike that caused the thunder heat to spread to the tank body and affect weak points of the tank, particularly at the welding point. The tank then leaked as the tank body could not hold the oil fluid pressure inside the tank after the thunder strike," Priyono explained during a hearing meeting with Commission VII of the House of Representatives (DPR RI) in Jakarta on Wednesday.
Pertamina employed four external bodies to investigate the fire at the Balongan oil refinery: the Energy and Mineral Resources Ministry's Directorate General of Oil and Gas, the Agency for the Assessment and Application of Technology (BPPT), Bandung Institute of Technology's (ITB's) engineering consultant PT LAPI ITB, and international audit company Det Norske Veritas (DNV), he informed.
The analysis by the Directorate General of Oil and Gas found that the initial oil leakage was caused by corrosion at welding points, while the DNV investigation found the leakage was caused by undetected corrosion on the tank's inside, which caused the tank to burst after its body could not hold the oil fluid pressure, the director informed.
Meanwhile, the PT LAPI ITB investigation found that the fire was caused by a second thunder strike igniting the air and the hydrocarbon vapor from the leaking tank, thereby completing the combustion triangle and causing the explosion, he added.
"The Oil and Gas Directorate General concluded the combustion triangle was formed by the air, hydrocarbon vapor, and the heat from the electric transformer beside the tank," Priyono said.
State electricity company PT PLN's lightning detection system recorded a total of 241 thunder strikes at the Balongan oil refinery over a period of two hours from 11 p.m. to 1 a.m. on that day, he said.
Data from the Meteorology, Climatology, and Geophysical Agency (BMKG) also recorded clouds and thunder strikes within a radius of 17 km around the refinery during the fire.
"The data we retrieved from the BMKG and the PLN's lightning detection system showed a high level of thunder strikes at the refinery," Priyono said.
At the same meeting, president director of Pertamina, Nicke Widyawati, confirmed the investigation's conclusion and expressed her commitment to improving the refinery's activities.
"We will consider the investigation audit conclusions for improvement measures in our refinery activities," Widyawati said.
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Translator: Sugiharto P, Nabil Ihsan
Editor: Sri Haryati
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