Rekonstruksi Mekanisme Kegagalan GTM-CNG Tipe 1 ISO 11439 Berdasarkan Bukti Visual dan Data KNKT: Studi Kasus Kecelakaan Sukabumi 2023

Gas Transportation Module (GTM) based on Compressed Natural Gas (CNG) is a high-pressure transportation system requiring high reliability and safety. The Type 1 CNG GTM accident in Sukabumi in 2023 involved cylinders designed to comply with ISO 11439:2013. This study analyzes the failure mechanism using photographic evidence and KNKT investigation data. Fault Tree Analysis (FTA) and Root Cause Analysis (RCA) are used to evaluate three hypotheses: valve-first, frame-first, and corrosion-first. Results show that KNKT data strongly indicate internal pitting corrosion and external general/uniform attack due to acidic water vapor (pH 4–5) with high water content (74–335 lb/mmscf) as the initiating failure. Corrosion potentially reduces cylinder wall integrity, but no quantitative wall-thickness reduction or visual rupture was found. KNKT stated the cylinder leaked before fracture. Valve and frame damage are significant findings in the failure chain, but the sequence of events cannot be definitively determined. This study emphasizes a system-level integrity approach and the need for destructive testing.