Probabilistic Gas Dispersion Analysis Due to Natural Gas Pipeline Leakage Using ALOHA: A Case Study of Transmission Pipeline from Custody Metering to Tire Plant

Fitra Suharianto (Safety and Risk Engineering Department in Politeknik Perkapalan Negeri Surabaya, Surabaya 60111, Indonesia.)
Burniadi Moballa (Safety and Risk Engineering Department in Politeknik Perkapalan Negeri Surabaya, Surabaya 60111, Indonesia)
Anda Iviana Juniani (Safety and Risk Engineering Department in Politeknik Perkapalan Negeri Surabaya, Surabaya 60111, Indonesia)

International Journal of Marine Engineering Innovation and Research
Vol. 11 No. 2 (2026)

Gas leakage in pipeline systems represents a critical hazard in the oil and gas industry, posing significant risks to human safety and the environment. This study aims to perform a probabilistic analysis of natural gas dispersion resulting from pipeline leakage using ALOHA (Areal Locations of Hazardous Atmospheres) integrated with statistical wind data analysis. Meteorological data over 25 years (2000–2024; 219,167 observation hours) were analyzed using Weibull distribution and wind rose methods to characterize the dominant wind regime. The results indicate that low wind speeds (0.5–2.5 m/s) dominate site conditions (77.1%), limiting gas dilution and increasing accumulation near the source. The dominant dispersion direction is identified in the southwest-to-south sector (213.75°–236.25°). Under these conditions, the red zone (≥30,000 ppm, 60% LEL) extends approximately 89.6 m, while in worst-case scenarios it reaches up to 198 m. Vapor Cloud Explosion (VCE) overpressure remains below 1.0 psi. Probabilistic integration of all scenarios produces a consequence probability map identifying high-risk zones along the right-of-way (ROW). These findings support improved risk assessment and provide a basis for targeted mitigation strategies in pipeline safety management.