Assessing post-fire material degradation: A ship structural analysis case study

Abstract A bulk carrier ship caught fire while loading fertilizer at the dock, originating from generator of auxiliary engine No. 2 portside. It took approximately 12 hours to successfully extinguish the fire. As the consequence of this accident, the ship suffered significant damage to its structure, machinery, and electrical systems in various areas, including the engine room, superstructure and deck house. A comprehensive assessment was conducted to evaluate the structural integrity of the ship, particularly concerning the post-fire material strength degradation, as well as the impacts of using seawater to extinguish the fire. Destructive tests were carried out on eight material samples taken from parts of the structure heavily affected by fire-induced deformation and from areas that were visually affected by the fire accident. The test results show that there is a decrease in strength of the materials, particularly in areas experiencing slow cooling due to the annealing phenomenon. Areas of the structure exposed to water spray during the firefighting process did not exhibit material embrittlement, as no martensite phase was detected in the microstructure. Additionally, the hardness value remained significantly lower than that associated with the martensite phase.