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www.sname.org/sname/mt July 2012 As mentioned earlier, a number of assumptions are made when perform -ing an evacuation analysis based on IMO guidelines such as those accounted for by the safety factor. is results in an idealized evacuation simulation. In order to give more realism to the evac -uation analysis, the effects of the hazard needs to be included in the simulation. By doing so, in addition to the estimation of the total time needed to assemble all the people onboard, the potential loss of life resulting from the hazards also can be estimated. The two main hazards onboard ships are re and ooding. Simulations of these two hazards are performed with appropri -ate engineering tools. Resulting data are then linked to the evacuation simulation to account for their eect on the mustering process as follows. Linking ooding and motion data For static conditions, heel and/or trim angles can be specied as an input to the model. For dynamic flooding simulation, the data about flooded compartment (location and amount of water) and the motions as time series are read by the evacuation model. Linking re data Fire simulation software produces re haz -ards data at discrete points in space. But to be eciently used in the evacuation simu -lation tool, they need to be organized in a regular grid structure. The fire state at each grid point is a weighted combination of re data located within a certain radius from the grid point in question. Appropriate re hazards data used to assess eect of re on a passenger at an arbitrary position can be located by using the position of the person in question and the spacing interval of the grid. Eect of ooding and motions Two major aspects are considered in a flooded ship scenario: the water ingress, and the ship motions (roll) and position (heel/ trim). If agents are located in ooded spaces, they will be aected by the water height, which might either slow them down if it is below a certain threshold (usually 2 m), or they will be considered as casualty if the water height is above the threshold. The ship position and motions affect the agents in their movements by reducing their walking speed and making them reli -ant on handrails. Few studies have been undertaken on the effect of inclination on the speed of people, but none have been particu -larly comprehensive, and all have used young and physically t subjects in a rel -atively small environment. e results of some of these studies using motion plat -for ms imply that ship listing up to 15-20 degrees has little inuence on the pedes -trian walking speeds. At the other extreme, it may be assumed that walking stops when the heel angles reach 30-35°. Considering these key facts, the speed reduction rela -tionship as depicted in Figure 1 is used in the evacuation simulation software. Here, no reduction occurs up to 20 degrees, and thereafter a linear reduction with angle occurs until 35 degrees where walking is assumed to be impossible. e use of handrails takes place at high heel angles or at accelerations in excess of 0.5 m per second squared. is changes the use of the available space, as the people can 0þÿ 5þÿ 10þÿ 15 þÿ 20 þÿ 25þÿ 30þÿ 35 þÿ 40 Heel angle (degrees) Percent of nominal speed 100 9080706050403020100FIGURE 1: SPEED REDUCTION FUNCTION e search objective is used to model crew traveling around the environment making passenger agents aware of the evacuation.