Feature 2 | LIFESAVING & SHIP SAFETY
simulation is tracked and their movement is determined by a set of heuristics or rules For the FIREPROOF project a novel
Figure. 6
mathematical fire modelling, fault and event trees and Bayesian networks have been deployed to develop a probabilistic model. Tese include the reliability and effectiveness of the fire safety systems, incorporated in the methodology using generic fault trees. Te Heat Release Rate (HRR) curve is one
of the most important elements in fire safety engineering analysis. It defines the main stages of the fire, which are the incipient, the growth, the fully developed and decay stages. Uncertainty in values, such as fuel load, within the space is addressed probabilistically. This results in a probabilistic description of the HRR curve for the space. Figure 3 shows a fire load distribution for a passenger cabin, and the resulting range of HRR curves generated is shown in Figure 4. In addition to the range of numerical values, the two main possibilities of early extinction (highlighted) versus fully developed fires can be seen.
Consequence assessment Te aim of the FIREPROOF method is to encapsulate the fire risk in the design, which includes scenarios of low consequence – minor fires which do not spread – and a
much smaller number of potentially serious scenarios. Te scenarios of highest risk are examined in greater detail using predictive simulation tools in order to gain deeper insight into their potential consequences. Tis allows the evaluation of the final term in the risk formulation in Figure 1. There are two analysis components
necessary to evaluate the fire risk to passengers on board a passenger ship. Te first is the fire model that predicts the spread of fire products and heat within a ship environment. FIREPROOF adopted the SMARTFIRE CFD fire model tool. Te second component, maritimeEXODUS, is an evacuation model that can use the previously generated fire and smoke environment to predict the effect on an evacuating population in both terms of time to evacuate the ship and casualties caused. The maritimeEXODUS software takes
into consideration people-people, people-fire and people-structure interactions, as shown in Figure 5. Te EXODUS soſtware has been written in C++ using Object Orientated techniques and rule-base concepts to control the simulation. Each individual in the
hybrid extension to the SMARTFIRE model has been developed whereby a simpler empirical zone model has been interfaced with the CFD model to reduce the necessary runtime for such a model, while maintaining the applicability of the modelling methods used. Te relationship between these models is shown in Figure 6. CFD modelling is used for complex geometries and areas beyond the reliable application of zone models and the zone models are applied in areas where the empiricism can be consistently applied.
The ship product model In the FIREPROOF software framework the Ship Product Model (SPM) acts as a database which can be queried by interface tools to extract data for use in simulation and analysis tools (primarily SmartFIRE and maritimeExodus for the FIREPROOF demonstration, but also including the analytical risk metrics). Te aims of the SPM soſtware framework are to demonstrate:
1. The properties and capabilities required of a ship product data model to act as part of the FIREPROOF framework;
2. The storage of a ship model in a
Product Data Management (PDM) system, containing the additional information needed to perform fire safety analysis;
3. Te successful extraction of this ship and simulation input data and transfer into analysis tools.
Tese aims required the project team to
examine the information types required for the modelling and analysis, determine ways to store this in a demonstrator SPM implementation, develop interface tools and enhance the capabilities of simulation soſtware to accept the SPM outputs. Tis development has used a mix of existing software (Paramarine, SMARTFIRE and maritimeEXODUS) and new interface tools. For the FIREPROOF demonstration, the
Paramarine software was chosen for the implementation of the SPM. Paramarine is
Figure. 7 42 The Naval Architect October 2012
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