Evaluation of fire safety onboard passenger ships

Abstract

Fire safety is the whole of the measures and practices related to the prevention of fires, ensuring the safety of life and property in case of fire and carrying out rescue activities after fire. The design of fire safety covers various areas such as fire detection and extinguishing systems, structural passive fire prevention systems, emergency exit routes, fire drills and training. The aim is to create an effective system to prevent the outbreak of fires and to ensure the safety of people in case of fire. Fire safety measures are of critical importance on ships and marine vessels. The International Convention for Safety of Life at Sea (SOLAS), which was established to ensure the safety of life and property at sea, includes maritime safety criteria and standards, including fire safety. In addition to the SOLAS convention, the International Fire Safety Systems (FSS) code is an important part of the SOLAS convention. It contains detailed details about fire safety systems and equipment on board ships. The FSS code consists of 15 chapters, each dealing with different areas of fire safety. Although there is detailed legislation, regulations, codes and standards, it is not possible to ensure 100% fire safety on ships. As a result, fire incidents on ships cause loss of life and property. The Global Integrated Shipping Information System (GISIS) by the International Maritime Organization (IMO) contains data in many different areas, including fire incidents. As the first study within the scope of this thesis, statistical data were analyzed according to ship type and severity of fire incident. In the fire incidents that took place between January 2000 and December 2022, fire incidents with serious and very serious consequences were considered. The 323 serious and very serious fire incidents reported between these dates were categorized according to different ship types such as tanker, passenger ship, cargo, fishing vessel, bulk carrier, container and support vessel. When the number of active vessels of each ship type globally is added to this statistic, the fire occurrence rate per 1,000 vessels is calculated. Here, with an average fire occurrence rate of 6.82, passenger ships are the ship type with the highest fire occurrence rate. This statistic is the main reason why passenger ships are selected as the ship type in this study and evaluated in terms of fire safety. Fire safety, which is an interdisciplinary science, needs to be examined in different fields. Within the scope of this study, which is based on fire safety in ships, fire safety regulations and standards, fire dynamics simulation, fire protection systems used in ships and fire risk management issues have been examined in the literature. As a result of this review, fire dynamics simulation and fire risk modelling applications including passive and active fire protection systems have been applied on selected passenger ship types. Using these fire safety assessment methods aims to establish performance-based fire safety design and execution onboard passenger ships. Fire dynamics simulations monitor temperature and pressure vectors across selected zones. On the other hand, fire risk modelling identifies fire risks and determines the precautions against fire incidents. In this study, 3 different case studies were selected, and the results are shared. In the first case, the 600-passenger capacity SH SUTLUCE passenger ship with IMO number 9564009, which is in the ship fleet of the Şehir Hatları subsidiary company operating in the field of maritime passenger transport of Istanbul Metropolitan Municipality, was evaluated for fire safety by applying fire dynamics simulation modelling, which is a computational fluid dynamics (CFD) method. In this case, simulation models were created for 5 different scenarios of fire in the ship's engine room according to the presence and number of fire extinguishing system and fire-resistant bulkheads / decks. These scenarios are categorized as best, medium and worst scenarios in terms of fire severity. Simulation outputs were analyzed at critical locations based on temperature and pressure. Especially in the engine room, the temperature rises to 500 °C from the first seconds, this level reduces the structural strength of the steel elements used in the ships and causes structural collapse. Fire safety on passenger ships is profoundly influenced not only by fire extinguishing systems but also by the presence of structural fire protection systems such as fire-resistant bulkheads and decks. To reduce the risk of fire hazards, structural fire protection systems such as fire-resistant bulkheads and decks can be used in important compartments such as engine rooms. It is of great importance to ensure that fire-resistant bulkheads and decks are properly installed with suitable materials and to pay particular attention to their stability. During the maintenance and operation of passenger ships, regular inspection of fire-resistant bulkheads and decks by both crew and technical teams is mandatory. Findings from fire dynamics simulations underline the critical role that fire-resistant bulkheads play in preventing the spread of fire on passenger ships. In addition, the effect of fire extinguishing systems and the number of nozzles on the temperature was also analyzed by varying the number of fire extinguishing nozzles as 1, 2 and 4 in the so-called best scenario. It was recommended that the number of nozzles should be optimally selected as 2 after 100 seconds of fire outbreak. In the second case, the fire safety of ROPAX passenger ships, which provide the transportation of electric vehicles, the number and popularity of which have increased rapidly in recent years, by sea, was modelled using computational fluid dynamics and fire safety was evaluated. In this case, the deck with electric vehicles on the 146m long ROPAX ship with a capacity of 800 passengers, 90 vehicles and 60 trucks were selected to be examined. Temperature distributions throughout the control area are important to assess the severity of the fire event. Therefore, to monitor the temperature distribution, the center of the fire sources was aligned, and the temperature distributions were plotted. As a result, it was observed that the temperature increased dramatically to almost 1200 °C. Structural elements, electric vehicles and equipments used on board can organically ignite and lose their function at this temperature level. Due to this temperature level on ferries, areas or compartments where electrical vehicles are transported on ferries need to be designed with structurally fire-resistant materials. In this study, ignition and explosion were ignored due to the reduced complexity of the case study. In the last case study, the fire safety of a Ro-Ro passenger ship was analyzed with Event Tree Analysis (ETA), one of the fire risk assessment methods. The chain of events starting with the fire outbreak, the type of space where the fire started, whether the detection systems are working or not, user reaction, decision making, extinguishing, compartmentalization and evacuation ends. Event tree analyses for a total of 21 different scenarios constitute the first step in determining the fire risk in Ro-Ro passenger ships. The event tree structure created in this study is planned to be used as an input in the planning of fire safety training of the crew. As a result, the design, implementation and operation of a performance-based passenger ship that includes fire dynamics simulations and fire risk assessment methods are important in establishing fire safety. In this study, fire safety assessments have been carried out for different types of passenger ships, namely passenger transport ships, ROPAX carrying electric vehicles and Ro-Ro. Thus, performance-based passenger ship design, implementation and operation are carried out by prioritizing the fire safety point of view with fire dynamics simulation and fire risk assessment methods. These performance-based studies will contribute to the updating of regulations, rules and standards published specifically for fire regulations on ships.