The general arrangements inside passenger ships are getting more complicated to fulfil the passengers' expectations in comfort, luxury and variety of services. Hence, with the new designs, safety is becoming a target hard to achieve and especially regarding fire safety where the new materials and complexity in arrangement can pose great hazards. Prescriptive rules in this sense are becoming outdated as it has proven hard to keep regulations development at the same pace with novel designs. This is also shown in the introduction of the alternative design and arrangements regulations to provide a new methodology for novel design safety. This fast advance in ship design and regulations necessitate the use of performance based means to address fire protection among other safety aspects onboard. Simulation tools form the core of performance based techniques where the level of safety performance of a design can be measured. This paper will illustrate the use of computerized programs in assessing fire safety onboard passenger ships.