Fire Risk Assessment for Piping System of LCT CNG Carrier

Utilization of Natural Gas as a source of electrical energy is supported by the increasing of world electricity demand, especially Indonesia. Indonesia's geographical conditions, as archipelago country, provide challenges in the distribution of natural gas throughout the region. The distribution of gas from the gas source to the plant site requires an effective, efficient, and safe CNG Carrier. Some Landing Craft Tank (LCT) in Indonesia that is currently not functioned properly bring the idea to be utilized as one of the right choices as a CNG carrier. For conversion of LCT to CNG carrier must keep priority on safety aspect such as in the storage piping system. The piping system is highly vulnerable to explosion hazards caused by gas leaked. The released gas causes the piping system to have potential risks that need to be minimized. The fire risk assessment method is conducted under the BKI Reference Notes of Risk Assessment Applications for the Marine and Offshore Oil and Gas Industries, where the hazard identification is performed by using HAZOP (Hazard Operability). The HAZOP is performed by dividing the systems into several sub-systems. Released gas frequency is analysed using Fault Tree Analysis (FTA). As well as the accident analysis frequency of occurrence which will be scripted stage that gas released as the last order due to the malfunction order. Gas released near ignition source may lead to Flash Fire, Gas Dispersion and Gas Explosion. Using Event Tree Analysis (ETA) the frequency of occurrence will be calculated according to the impacts. Consequence analysis is then performed using the fire spread software. To represent the risk, F-N curve is used to determine the acceptance criteria classified into three conditions such as tolerable, in-tolerable and As Low as Reasonably Practicable (ALARP). The results obtained from this research are divided into two conditions is immediate ignition and nonimmediate ignition. in immediate ignition conditions, the risks are flash fire and gas explosion but in tolerable levels of risk. In Non-immediate ignition conditions, the risk is Flash Fire and Gas Dispersion in tolerable level of risk and non-immediate ignition conditions, gas explosion in ALARP level. The ALARP condition to be still at a safe level but some things of concern must be taken to cope or reduce the severity of the impact of the gas explosion. In ensuring the safety of the installation high pressure pipe CNG mounted it is necessary to note the safety provisions for the type of ship carrying gas above the deck including the hazardous area (cargo containment arrangement). Maritime Safety International Conference (MASTIC 2018) Published by CSP © 2019 the Authors 54